1fa9e4066Sahrens /* 2fa9e4066Sahrens * CDDL HEADER START 3fa9e4066Sahrens * 4fa9e4066Sahrens * The contents of this file are subject to the terms of the 5033f9833Sek * Common Development and Distribution License (the "License"). 6033f9833Sek * You may not use this file except in compliance with the License. 7fa9e4066Sahrens * 8fa9e4066Sahrens * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9fa9e4066Sahrens * or http://www.opensolaris.org/os/licensing. 10fa9e4066Sahrens * See the License for the specific language governing permissions 11fa9e4066Sahrens * and limitations under the License. 12fa9e4066Sahrens * 13fa9e4066Sahrens * When distributing Covered Code, include this CDDL HEADER in each 14fa9e4066Sahrens * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15fa9e4066Sahrens * If applicable, add the following below this CDDL HEADER, with the 16fa9e4066Sahrens * fields enclosed by brackets "[]" replaced with your own identifying 17fa9e4066Sahrens * information: Portions Copyright [yyyy] [name of copyright owner] 18fa9e4066Sahrens * 19fa9e4066Sahrens * CDDL HEADER END 20fa9e4066Sahrens */ 21fa9e4066Sahrens /* 223f9d6ad7SLin Ling * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23e9103aaeSGarrett D'Amore * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 2494dd93aeSGeorge Wilson * Copyright (c) 2012 by Delphix. All rights reserved. 25fa9e4066Sahrens */ 26fa9e4066Sahrens 27fa9e4066Sahrens /* 2844cb6abcSbmc * DVA-based Adjustable Replacement Cache 29fa9e4066Sahrens * 30ea8dc4b6Seschrock * While much of the theory of operation used here is 31ea8dc4b6Seschrock * based on the self-tuning, low overhead replacement cache 32fa9e4066Sahrens * presented by Megiddo and Modha at FAST 2003, there are some 33fa9e4066Sahrens * significant differences: 34fa9e4066Sahrens * 35fa9e4066Sahrens * 1. The Megiddo and Modha model assumes any page is evictable. 36fa9e4066Sahrens * Pages in its cache cannot be "locked" into memory. This makes 37fa9e4066Sahrens * the eviction algorithm simple: evict the last page in the list. 38fa9e4066Sahrens * This also make the performance characteristics easy to reason 39fa9e4066Sahrens * about. Our cache is not so simple. At any given moment, some 40fa9e4066Sahrens * subset of the blocks in the cache are un-evictable because we 41fa9e4066Sahrens * have handed out a reference to them. Blocks are only evictable 42fa9e4066Sahrens * when there are no external references active. This makes 43fa9e4066Sahrens * eviction far more problematic: we choose to evict the evictable 44fa9e4066Sahrens * blocks that are the "lowest" in the list. 45fa9e4066Sahrens * 46fa9e4066Sahrens * There are times when it is not possible to evict the requested 47fa9e4066Sahrens * space. In these circumstances we are unable to adjust the cache 48fa9e4066Sahrens * size. To prevent the cache growing unbounded at these times we 49fa94a07fSbrendan * implement a "cache throttle" that slows the flow of new data 50fa94a07fSbrendan * into the cache until we can make space available. 51fa9e4066Sahrens * 52fa9e4066Sahrens * 2. The Megiddo and Modha model assumes a fixed cache size. 53fa9e4066Sahrens * Pages are evicted when the cache is full and there is a cache 54fa9e4066Sahrens * miss. Our model has a variable sized cache. It grows with 55fa94a07fSbrendan * high use, but also tries to react to memory pressure from the 56fa9e4066Sahrens * operating system: decreasing its size when system memory is 57fa9e4066Sahrens * tight. 58fa9e4066Sahrens * 59fa9e4066Sahrens * 3. The Megiddo and Modha model assumes a fixed page size. All 60fa9e4066Sahrens * elements of the cache are therefor exactly the same size. So 61fa9e4066Sahrens * when adjusting the cache size following a cache miss, its simply 62fa9e4066Sahrens * a matter of choosing a single page to evict. In our model, we 63fa9e4066Sahrens * have variable sized cache blocks (rangeing from 512 bytes to 64fa9e4066Sahrens * 128K bytes). We therefor choose a set of blocks to evict to make 65fa9e4066Sahrens * space for a cache miss that approximates as closely as possible 66fa9e4066Sahrens * the space used by the new block. 67fa9e4066Sahrens * 68fa9e4066Sahrens * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" 69fa9e4066Sahrens * by N. Megiddo & D. Modha, FAST 2003 70fa9e4066Sahrens */ 71fa9e4066Sahrens 72fa9e4066Sahrens /* 73fa9e4066Sahrens * The locking model: 74fa9e4066Sahrens * 75fa9e4066Sahrens * A new reference to a cache buffer can be obtained in two 76fa9e4066Sahrens * ways: 1) via a hash table lookup using the DVA as a key, 77fa94a07fSbrendan * or 2) via one of the ARC lists. The arc_read() interface 78fa9e4066Sahrens * uses method 1, while the internal arc algorithms for 79fa9e4066Sahrens * adjusting the cache use method 2. We therefor provide two 80fa9e4066Sahrens * types of locks: 1) the hash table lock array, and 2) the 81fa9e4066Sahrens * arc list locks. 82fa9e4066Sahrens * 83*fc98fea5SBart Coddens * Buffers do not have their own mutexes, rather they rely on the 84*fc98fea5SBart Coddens * hash table mutexes for the bulk of their protection (i.e. most 85*fc98fea5SBart Coddens * fields in the arc_buf_hdr_t are protected by these mutexes). 86fa9e4066Sahrens * 87fa9e4066Sahrens * buf_hash_find() returns the appropriate mutex (held) when it 88fa9e4066Sahrens * locates the requested buffer in the hash table. It returns 89fa9e4066Sahrens * NULL for the mutex if the buffer was not in the table. 90fa9e4066Sahrens * 91fa9e4066Sahrens * buf_hash_remove() expects the appropriate hash mutex to be 92fa9e4066Sahrens * already held before it is invoked. 93fa9e4066Sahrens * 94fa9e4066Sahrens * Each arc state also has a mutex which is used to protect the 95fa9e4066Sahrens * buffer list associated with the state. When attempting to 96fa9e4066Sahrens * obtain a hash table lock while holding an arc list lock you 97fa9e4066Sahrens * must use: mutex_tryenter() to avoid deadlock. Also note that 9844eda4d7Smaybee * the active state mutex must be held before the ghost state mutex. 99fa9e4066Sahrens * 100ea8dc4b6Seschrock * Arc buffers may have an associated eviction callback function. 101ea8dc4b6Seschrock * This function will be invoked prior to removing the buffer (e.g. 102ea8dc4b6Seschrock * in arc_do_user_evicts()). Note however that the data associated 103ea8dc4b6Seschrock * with the buffer may be evicted prior to the callback. The callback 104ea8dc4b6Seschrock * must be made with *no locks held* (to prevent deadlock). Additionally, 105ea8dc4b6Seschrock * the users of callbacks must ensure that their private data is 106ea8dc4b6Seschrock * protected from simultaneous callbacks from arc_buf_evict() 107ea8dc4b6Seschrock * and arc_do_user_evicts(). 108ea8dc4b6Seschrock * 109fa9e4066Sahrens * Note that the majority of the performance stats are manipulated 110fa9e4066Sahrens * with atomic operations. 111fa94a07fSbrendan * 112fa94a07fSbrendan * The L2ARC uses the l2arc_buflist_mtx global mutex for the following: 113fa94a07fSbrendan * 114fa94a07fSbrendan * - L2ARC buflist creation 115fa94a07fSbrendan * - L2ARC buflist eviction 116fa94a07fSbrendan * - L2ARC write completion, which walks L2ARC buflists 117fa94a07fSbrendan * - ARC header destruction, as it removes from L2ARC buflists 118fa94a07fSbrendan * - ARC header release, as it removes from L2ARC buflists 119fa9e4066Sahrens */ 120fa9e4066Sahrens 121fa9e4066Sahrens #include <sys/spa.h> 122fa9e4066Sahrens #include <sys/zio.h> 123fa9e4066Sahrens #include <sys/zfs_context.h> 124fa9e4066Sahrens #include <sys/arc.h> 125fa9e4066Sahrens #include <sys/refcount.h> 126c5904d13Seschrock #include <sys/vdev.h> 127573ca77eSGeorge Wilson #include <sys/vdev_impl.h> 128fa9e4066Sahrens #ifdef _KERNEL 129fa9e4066Sahrens #include <sys/vmsystm.h> 130fa9e4066Sahrens #include <vm/anon.h> 131fa9e4066Sahrens #include <sys/fs/swapnode.h> 132033f9833Sek #include <sys/dnlc.h> 133fa9e4066Sahrens #endif 134fa9e4066Sahrens #include <sys/callb.h> 13544cb6abcSbmc #include <sys/kstat.h> 136b24ab676SJeff Bonwick #include <zfs_fletcher.h> 137fa9e4066Sahrens 138fa9e4066Sahrens static kmutex_t arc_reclaim_thr_lock; 139fa9e4066Sahrens static kcondvar_t arc_reclaim_thr_cv; /* used to signal reclaim thr */ 140fa9e4066Sahrens static uint8_t arc_thread_exit; 141fa9e4066Sahrens 1421ab7f2deSmaybee extern int zfs_write_limit_shift; 1431ab7f2deSmaybee extern uint64_t zfs_write_limit_max; 14405715f94SMark Maybee extern kmutex_t zfs_write_limit_lock; 1451ab7f2deSmaybee 146033f9833Sek #define ARC_REDUCE_DNLC_PERCENT 3 147033f9833Sek uint_t arc_reduce_dnlc_percent = ARC_REDUCE_DNLC_PERCENT; 148033f9833Sek 149fa9e4066Sahrens typedef enum arc_reclaim_strategy { 150fa9e4066Sahrens ARC_RECLAIM_AGGR, /* Aggressive reclaim strategy */ 151fa9e4066Sahrens ARC_RECLAIM_CONS /* Conservative reclaim strategy */ 152fa9e4066Sahrens } arc_reclaim_strategy_t; 153fa9e4066Sahrens 154fa9e4066Sahrens /* number of seconds before growing cache again */ 155fa9e4066Sahrens static int arc_grow_retry = 60; 156fa9e4066Sahrens 1575a98e54bSBrendan Gregg - Sun Microsystems /* shift of arc_c for calculating both min and max arc_p */ 1585a98e54bSBrendan Gregg - Sun Microsystems static int arc_p_min_shift = 4; 1595a98e54bSBrendan Gregg - Sun Microsystems 1605a98e54bSBrendan Gregg - Sun Microsystems /* log2(fraction of arc to reclaim) */ 1615a98e54bSBrendan Gregg - Sun Microsystems static int arc_shrink_shift = 5; 1625a98e54bSBrendan Gregg - Sun Microsystems 16313506d1eSmaybee /* 164b19a79ecSperrin * minimum lifespan of a prefetch block in clock ticks 165b19a79ecSperrin * (initialized in arc_init()) 16613506d1eSmaybee */ 167b19a79ecSperrin static int arc_min_prefetch_lifespan; 16813506d1eSmaybee 169fa9e4066Sahrens static int arc_dead; 170fa9e4066Sahrens 1713a737e0dSbrendan /* 1723a737e0dSbrendan * The arc has filled available memory and has now warmed up. 1733a737e0dSbrendan */ 1743a737e0dSbrendan static boolean_t arc_warm; 1753a737e0dSbrendan 176a2eea2e1Sahrens /* 177a2eea2e1Sahrens * These tunables are for performance analysis. 178a2eea2e1Sahrens */ 179a2eea2e1Sahrens uint64_t zfs_arc_max; 180a2eea2e1Sahrens uint64_t zfs_arc_min; 1811116048bSek uint64_t zfs_arc_meta_limit = 0; 1825a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_grow_retry = 0; 1835a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_shrink_shift = 0; 1845a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_p_min_shift = 0; 185a2eea2e1Sahrens 186fa9e4066Sahrens /* 187fa94a07fSbrendan * Note that buffers can be in one of 6 states: 188fa9e4066Sahrens * ARC_anon - anonymous (discussed below) 189ea8dc4b6Seschrock * ARC_mru - recently used, currently cached 190ea8dc4b6Seschrock * ARC_mru_ghost - recentely used, no longer in cache 191ea8dc4b6Seschrock * ARC_mfu - frequently used, currently cached 192ea8dc4b6Seschrock * ARC_mfu_ghost - frequently used, no longer in cache 193fa94a07fSbrendan * ARC_l2c_only - exists in L2ARC but not other states 1940e8c6158Smaybee * When there are no active references to the buffer, they are 1950e8c6158Smaybee * are linked onto a list in one of these arc states. These are 1960e8c6158Smaybee * the only buffers that can be evicted or deleted. Within each 1970e8c6158Smaybee * state there are multiple lists, one for meta-data and one for 1980e8c6158Smaybee * non-meta-data. Meta-data (indirect blocks, blocks of dnodes, 1990e8c6158Smaybee * etc.) is tracked separately so that it can be managed more 200fa94a07fSbrendan * explicitly: favored over data, limited explicitly. 201fa9e4066Sahrens * 202fa9e4066Sahrens * Anonymous buffers are buffers that are not associated with 203fa9e4066Sahrens * a DVA. These are buffers that hold dirty block copies 204fa9e4066Sahrens * before they are written to stable storage. By definition, 205ea8dc4b6Seschrock * they are "ref'd" and are considered part of arc_mru 206fa9e4066Sahrens * that cannot be freed. Generally, they will aquire a DVA 207ea8dc4b6Seschrock * as they are written and migrate onto the arc_mru list. 208fa94a07fSbrendan * 209fa94a07fSbrendan * The ARC_l2c_only state is for buffers that are in the second 210fa94a07fSbrendan * level ARC but no longer in any of the ARC_m* lists. The second 211fa94a07fSbrendan * level ARC itself may also contain buffers that are in any of 212fa94a07fSbrendan * the ARC_m* states - meaning that a buffer can exist in two 213fa94a07fSbrendan * places. The reason for the ARC_l2c_only state is to keep the 214fa94a07fSbrendan * buffer header in the hash table, so that reads that hit the 215fa94a07fSbrendan * second level ARC benefit from these fast lookups. 216fa9e4066Sahrens */ 217fa9e4066Sahrens 218fa9e4066Sahrens typedef struct arc_state { 2190e8c6158Smaybee list_t arcs_list[ARC_BUFC_NUMTYPES]; /* list of evictable buffers */ 2200e8c6158Smaybee uint64_t arcs_lsize[ARC_BUFC_NUMTYPES]; /* amount of evictable data */ 2210e8c6158Smaybee uint64_t arcs_size; /* total amount of data in this state */ 22244cb6abcSbmc kmutex_t arcs_mtx; 223fa9e4066Sahrens } arc_state_t; 224fa9e4066Sahrens 225fa94a07fSbrendan /* The 6 states: */ 226fa9e4066Sahrens static arc_state_t ARC_anon; 227ea8dc4b6Seschrock static arc_state_t ARC_mru; 228ea8dc4b6Seschrock static arc_state_t ARC_mru_ghost; 229ea8dc4b6Seschrock static arc_state_t ARC_mfu; 230ea8dc4b6Seschrock static arc_state_t ARC_mfu_ghost; 231fa94a07fSbrendan static arc_state_t ARC_l2c_only; 232fa9e4066Sahrens 23344cb6abcSbmc typedef struct arc_stats { 23444cb6abcSbmc kstat_named_t arcstat_hits; 23544cb6abcSbmc kstat_named_t arcstat_misses; 23644cb6abcSbmc kstat_named_t arcstat_demand_data_hits; 23744cb6abcSbmc kstat_named_t arcstat_demand_data_misses; 23844cb6abcSbmc kstat_named_t arcstat_demand_metadata_hits; 23944cb6abcSbmc kstat_named_t arcstat_demand_metadata_misses; 24044cb6abcSbmc kstat_named_t arcstat_prefetch_data_hits; 24144cb6abcSbmc kstat_named_t arcstat_prefetch_data_misses; 24244cb6abcSbmc kstat_named_t arcstat_prefetch_metadata_hits; 24344cb6abcSbmc kstat_named_t arcstat_prefetch_metadata_misses; 24444cb6abcSbmc kstat_named_t arcstat_mru_hits; 24544cb6abcSbmc kstat_named_t arcstat_mru_ghost_hits; 24644cb6abcSbmc kstat_named_t arcstat_mfu_hits; 24744cb6abcSbmc kstat_named_t arcstat_mfu_ghost_hits; 24844cb6abcSbmc kstat_named_t arcstat_deleted; 24944cb6abcSbmc kstat_named_t arcstat_recycle_miss; 25044cb6abcSbmc kstat_named_t arcstat_mutex_miss; 25144cb6abcSbmc kstat_named_t arcstat_evict_skip; 2525ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_cached; 2535ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_eligible; 2545ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_ineligible; 25544cb6abcSbmc kstat_named_t arcstat_hash_elements; 25644cb6abcSbmc kstat_named_t arcstat_hash_elements_max; 25744cb6abcSbmc kstat_named_t arcstat_hash_collisions; 25844cb6abcSbmc kstat_named_t arcstat_hash_chains; 25944cb6abcSbmc kstat_named_t arcstat_hash_chain_max; 26044cb6abcSbmc kstat_named_t arcstat_p; 26144cb6abcSbmc kstat_named_t arcstat_c; 26244cb6abcSbmc kstat_named_t arcstat_c_min; 26344cb6abcSbmc kstat_named_t arcstat_c_max; 26444cb6abcSbmc kstat_named_t arcstat_size; 265fa94a07fSbrendan kstat_named_t arcstat_hdr_size; 2665a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_data_size; 2675a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_other_size; 268fa94a07fSbrendan kstat_named_t arcstat_l2_hits; 269fa94a07fSbrendan kstat_named_t arcstat_l2_misses; 270fa94a07fSbrendan kstat_named_t arcstat_l2_feeds; 271fa94a07fSbrendan kstat_named_t arcstat_l2_rw_clash; 2725a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_l2_read_bytes; 2735a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_l2_write_bytes; 274fa94a07fSbrendan kstat_named_t arcstat_l2_writes_sent; 275fa94a07fSbrendan kstat_named_t arcstat_l2_writes_done; 276fa94a07fSbrendan kstat_named_t arcstat_l2_writes_error; 277fa94a07fSbrendan kstat_named_t arcstat_l2_writes_hdr_miss; 278fa94a07fSbrendan kstat_named_t arcstat_l2_evict_lock_retry; 279fa94a07fSbrendan kstat_named_t arcstat_l2_evict_reading; 280fa94a07fSbrendan kstat_named_t arcstat_l2_free_on_write; 281fa94a07fSbrendan kstat_named_t arcstat_l2_abort_lowmem; 282fa94a07fSbrendan kstat_named_t arcstat_l2_cksum_bad; 283fa94a07fSbrendan kstat_named_t arcstat_l2_io_error; 284fa94a07fSbrendan kstat_named_t arcstat_l2_size; 285fa94a07fSbrendan kstat_named_t arcstat_l2_hdr_size; 2861ab7f2deSmaybee kstat_named_t arcstat_memory_throttle_count; 28744cb6abcSbmc } arc_stats_t; 28844cb6abcSbmc 28944cb6abcSbmc static arc_stats_t arc_stats = { 29044cb6abcSbmc { "hits", KSTAT_DATA_UINT64 }, 29144cb6abcSbmc { "misses", KSTAT_DATA_UINT64 }, 29244cb6abcSbmc { "demand_data_hits", KSTAT_DATA_UINT64 }, 29344cb6abcSbmc { "demand_data_misses", KSTAT_DATA_UINT64 }, 29444cb6abcSbmc { "demand_metadata_hits", KSTAT_DATA_UINT64 }, 29544cb6abcSbmc { "demand_metadata_misses", KSTAT_DATA_UINT64 }, 29644cb6abcSbmc { "prefetch_data_hits", KSTAT_DATA_UINT64 }, 29744cb6abcSbmc { "prefetch_data_misses", KSTAT_DATA_UINT64 }, 29844cb6abcSbmc { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, 29944cb6abcSbmc { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, 30044cb6abcSbmc { "mru_hits", KSTAT_DATA_UINT64 }, 30144cb6abcSbmc { "mru_ghost_hits", KSTAT_DATA_UINT64 }, 30244cb6abcSbmc { "mfu_hits", KSTAT_DATA_UINT64 }, 30344cb6abcSbmc { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, 30444cb6abcSbmc { "deleted", KSTAT_DATA_UINT64 }, 30544cb6abcSbmc { "recycle_miss", KSTAT_DATA_UINT64 }, 30644cb6abcSbmc { "mutex_miss", KSTAT_DATA_UINT64 }, 30744cb6abcSbmc { "evict_skip", KSTAT_DATA_UINT64 }, 3085ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_cached", KSTAT_DATA_UINT64 }, 3095ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_eligible", KSTAT_DATA_UINT64 }, 3105ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, 31144cb6abcSbmc { "hash_elements", KSTAT_DATA_UINT64 }, 31244cb6abcSbmc { "hash_elements_max", KSTAT_DATA_UINT64 }, 31344cb6abcSbmc { "hash_collisions", KSTAT_DATA_UINT64 }, 31444cb6abcSbmc { "hash_chains", KSTAT_DATA_UINT64 }, 31544cb6abcSbmc { "hash_chain_max", KSTAT_DATA_UINT64 }, 31644cb6abcSbmc { "p", KSTAT_DATA_UINT64 }, 31744cb6abcSbmc { "c", KSTAT_DATA_UINT64 }, 31844cb6abcSbmc { "c_min", KSTAT_DATA_UINT64 }, 31944cb6abcSbmc { "c_max", KSTAT_DATA_UINT64 }, 320fa94a07fSbrendan { "size", KSTAT_DATA_UINT64 }, 321fa94a07fSbrendan { "hdr_size", KSTAT_DATA_UINT64 }, 3225a98e54bSBrendan Gregg - Sun Microsystems { "data_size", KSTAT_DATA_UINT64 }, 3235a98e54bSBrendan Gregg - Sun Microsystems { "other_size", KSTAT_DATA_UINT64 }, 324fa94a07fSbrendan { "l2_hits", KSTAT_DATA_UINT64 }, 325fa94a07fSbrendan { "l2_misses", KSTAT_DATA_UINT64 }, 326fa94a07fSbrendan { "l2_feeds", KSTAT_DATA_UINT64 }, 327fa94a07fSbrendan { "l2_rw_clash", KSTAT_DATA_UINT64 }, 3285a98e54bSBrendan Gregg - Sun Microsystems { "l2_read_bytes", KSTAT_DATA_UINT64 }, 3295a98e54bSBrendan Gregg - Sun Microsystems { "l2_write_bytes", KSTAT_DATA_UINT64 }, 330fa94a07fSbrendan { "l2_writes_sent", KSTAT_DATA_UINT64 }, 331fa94a07fSbrendan { "l2_writes_done", KSTAT_DATA_UINT64 }, 332fa94a07fSbrendan { "l2_writes_error", KSTAT_DATA_UINT64 }, 333fa94a07fSbrendan { "l2_writes_hdr_miss", KSTAT_DATA_UINT64 }, 334fa94a07fSbrendan { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, 335fa94a07fSbrendan { "l2_evict_reading", KSTAT_DATA_UINT64 }, 336fa94a07fSbrendan { "l2_free_on_write", KSTAT_DATA_UINT64 }, 337fa94a07fSbrendan { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, 338fa94a07fSbrendan { "l2_cksum_bad", KSTAT_DATA_UINT64 }, 339fa94a07fSbrendan { "l2_io_error", KSTAT_DATA_UINT64 }, 340fa94a07fSbrendan { "l2_size", KSTAT_DATA_UINT64 }, 3411ab7f2deSmaybee { "l2_hdr_size", KSTAT_DATA_UINT64 }, 3421ab7f2deSmaybee { "memory_throttle_count", KSTAT_DATA_UINT64 } 34344cb6abcSbmc }; 34444cb6abcSbmc 34544cb6abcSbmc #define ARCSTAT(stat) (arc_stats.stat.value.ui64) 34644cb6abcSbmc 34744cb6abcSbmc #define ARCSTAT_INCR(stat, val) \ 34844cb6abcSbmc atomic_add_64(&arc_stats.stat.value.ui64, (val)); 34944cb6abcSbmc 350b24ab676SJeff Bonwick #define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1) 35144cb6abcSbmc #define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1) 35244cb6abcSbmc 35344cb6abcSbmc #define ARCSTAT_MAX(stat, val) { \ 35444cb6abcSbmc uint64_t m; \ 35544cb6abcSbmc while ((val) > (m = arc_stats.stat.value.ui64) && \ 35644cb6abcSbmc (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ 35744cb6abcSbmc continue; \ 35844cb6abcSbmc } 35944cb6abcSbmc 36044cb6abcSbmc #define ARCSTAT_MAXSTAT(stat) \ 36144cb6abcSbmc ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64) 36244cb6abcSbmc 36344cb6abcSbmc /* 36444cb6abcSbmc * We define a macro to allow ARC hits/misses to be easily broken down by 36544cb6abcSbmc * two separate conditions, giving a total of four different subtypes for 36644cb6abcSbmc * each of hits and misses (so eight statistics total). 36744cb6abcSbmc */ 36844cb6abcSbmc #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ 36944cb6abcSbmc if (cond1) { \ 37044cb6abcSbmc if (cond2) { \ 37144cb6abcSbmc ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ 37244cb6abcSbmc } else { \ 37344cb6abcSbmc ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ 37444cb6abcSbmc } \ 37544cb6abcSbmc } else { \ 37644cb6abcSbmc if (cond2) { \ 37744cb6abcSbmc ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ 37844cb6abcSbmc } else { \ 37944cb6abcSbmc ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ 38044cb6abcSbmc } \ 38144cb6abcSbmc } 38244cb6abcSbmc 38344cb6abcSbmc kstat_t *arc_ksp; 384b24ab676SJeff Bonwick static arc_state_t *arc_anon; 38544cb6abcSbmc static arc_state_t *arc_mru; 38644cb6abcSbmc static arc_state_t *arc_mru_ghost; 38744cb6abcSbmc static arc_state_t *arc_mfu; 38844cb6abcSbmc static arc_state_t *arc_mfu_ghost; 389fa94a07fSbrendan static arc_state_t *arc_l2c_only; 39044cb6abcSbmc 39144cb6abcSbmc /* 39244cb6abcSbmc * There are several ARC variables that are critical to export as kstats -- 39344cb6abcSbmc * but we don't want to have to grovel around in the kstat whenever we wish to 39444cb6abcSbmc * manipulate them. For these variables, we therefore define them to be in 39544cb6abcSbmc * terms of the statistic variable. This assures that we are not introducing 39644cb6abcSbmc * the possibility of inconsistency by having shadow copies of the variables, 39744cb6abcSbmc * while still allowing the code to be readable. 39844cb6abcSbmc */ 39944cb6abcSbmc #define arc_size ARCSTAT(arcstat_size) /* actual total arc size */ 40044cb6abcSbmc #define arc_p ARCSTAT(arcstat_p) /* target size of MRU */ 40144cb6abcSbmc #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ 40244cb6abcSbmc #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ 40344cb6abcSbmc #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ 40444cb6abcSbmc 40544cb6abcSbmc static int arc_no_grow; /* Don't try to grow cache size */ 40644cb6abcSbmc static uint64_t arc_tempreserve; 4072fdbea25SAleksandr Guzovskiy static uint64_t arc_loaned_bytes; 4080e8c6158Smaybee static uint64_t arc_meta_used; 4090e8c6158Smaybee static uint64_t arc_meta_limit; 4100e8c6158Smaybee static uint64_t arc_meta_max = 0; 411fa9e4066Sahrens 412fa94a07fSbrendan typedef struct l2arc_buf_hdr l2arc_buf_hdr_t; 413fa94a07fSbrendan 414fa9e4066Sahrens typedef struct arc_callback arc_callback_t; 415fa9e4066Sahrens 416fa9e4066Sahrens struct arc_callback { 417fa9e4066Sahrens void *acb_private; 418c717a561Smaybee arc_done_func_t *acb_done; 419fa9e4066Sahrens arc_buf_t *acb_buf; 420fa9e4066Sahrens zio_t *acb_zio_dummy; 421fa9e4066Sahrens arc_callback_t *acb_next; 422fa9e4066Sahrens }; 423fa9e4066Sahrens 424c717a561Smaybee typedef struct arc_write_callback arc_write_callback_t; 425c717a561Smaybee 426c717a561Smaybee struct arc_write_callback { 427c717a561Smaybee void *awcb_private; 428c717a561Smaybee arc_done_func_t *awcb_ready; 429c717a561Smaybee arc_done_func_t *awcb_done; 430c717a561Smaybee arc_buf_t *awcb_buf; 431c717a561Smaybee }; 432c717a561Smaybee 433fa9e4066Sahrens struct arc_buf_hdr { 434fa9e4066Sahrens /* protected by hash lock */ 435fa9e4066Sahrens dva_t b_dva; 436fa9e4066Sahrens uint64_t b_birth; 437fa9e4066Sahrens uint64_t b_cksum0; 438fa9e4066Sahrens 4396b4acc8bSahrens kmutex_t b_freeze_lock; 4406b4acc8bSahrens zio_cksum_t *b_freeze_cksum; 4413f9d6ad7SLin Ling void *b_thawed; 4426b4acc8bSahrens 443fa9e4066Sahrens arc_buf_hdr_t *b_hash_next; 444fa9e4066Sahrens arc_buf_t *b_buf; 445fa9e4066Sahrens uint32_t b_flags; 446ea8dc4b6Seschrock uint32_t b_datacnt; 447fa9e4066Sahrens 448fa9e4066Sahrens arc_callback_t *b_acb; 449ad23a2dbSjohansen kcondvar_t b_cv; 450ad23a2dbSjohansen 451ad23a2dbSjohansen /* immutable */ 452ad23a2dbSjohansen arc_buf_contents_t b_type; 453ad23a2dbSjohansen uint64_t b_size; 454ac05c741SMark Maybee uint64_t b_spa; 455fa9e4066Sahrens 456fa9e4066Sahrens /* protected by arc state mutex */ 457fa9e4066Sahrens arc_state_t *b_state; 458fa9e4066Sahrens list_node_t b_arc_node; 459fa9e4066Sahrens 460fa9e4066Sahrens /* updated atomically */ 461fa9e4066Sahrens clock_t b_arc_access; 462fa9e4066Sahrens 463fa9e4066Sahrens /* self protecting */ 464fa9e4066Sahrens refcount_t b_refcnt; 465fa94a07fSbrendan 466fa94a07fSbrendan l2arc_buf_hdr_t *b_l2hdr; 467fa94a07fSbrendan list_node_t b_l2node; 468fa9e4066Sahrens }; 469fa9e4066Sahrens 470ea8dc4b6Seschrock static arc_buf_t *arc_eviction_list; 471ea8dc4b6Seschrock static kmutex_t arc_eviction_mtx; 47240d7d650Smaybee static arc_buf_hdr_t arc_eviction_hdr; 47344eda4d7Smaybee static void arc_get_data_buf(arc_buf_t *buf); 47444eda4d7Smaybee static void arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock); 4750e8c6158Smaybee static int arc_evict_needed(arc_buf_contents_t type); 476ac05c741SMark Maybee static void arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes); 477ea8dc4b6Seschrock 4785ea40c06SBrendan Gregg - Sun Microsystems static boolean_t l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab); 4795ea40c06SBrendan Gregg - Sun Microsystems 480ea8dc4b6Seschrock #define GHOST_STATE(state) \ 481fa94a07fSbrendan ((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \ 482fa94a07fSbrendan (state) == arc_l2c_only) 483ea8dc4b6Seschrock 484fa9e4066Sahrens /* 485fa9e4066Sahrens * Private ARC flags. These flags are private ARC only flags that will show up 486fa9e4066Sahrens * in b_flags in the arc_hdr_buf_t. Some flags are publicly declared, and can 487fa9e4066Sahrens * be passed in as arc_flags in things like arc_read. However, these flags 488fa9e4066Sahrens * should never be passed and should only be set by ARC code. When adding new 489fa9e4066Sahrens * public flags, make sure not to smash the private ones. 490fa9e4066Sahrens */ 491fa9e4066Sahrens 492ea8dc4b6Seschrock #define ARC_IN_HASH_TABLE (1 << 9) /* this buffer is hashed */ 493fa9e4066Sahrens #define ARC_IO_IN_PROGRESS (1 << 10) /* I/O in progress for buf */ 494fa9e4066Sahrens #define ARC_IO_ERROR (1 << 11) /* I/O failed for buf */ 495fa9e4066Sahrens #define ARC_FREED_IN_READ (1 << 12) /* buf freed while in read */ 496ea8dc4b6Seschrock #define ARC_BUF_AVAILABLE (1 << 13) /* block not in active use */ 49713506d1eSmaybee #define ARC_INDIRECT (1 << 14) /* this is an indirect block */ 498fa94a07fSbrendan #define ARC_FREE_IN_PROGRESS (1 << 15) /* hdr about to be freed */ 4993baa08fcSek #define ARC_L2_WRITING (1 << 16) /* L2ARC write in progress */ 5003baa08fcSek #define ARC_L2_EVICTED (1 << 17) /* evicted during I/O */ 5013baa08fcSek #define ARC_L2_WRITE_HEAD (1 << 18) /* head of write list */ 502fa9e4066Sahrens 503ea8dc4b6Seschrock #define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_IN_HASH_TABLE) 504fa9e4066Sahrens #define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS) 505fa9e4066Sahrens #define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_IO_ERROR) 5065a98e54bSBrendan Gregg - Sun Microsystems #define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_PREFETCH) 507fa9e4066Sahrens #define HDR_FREED_IN_READ(hdr) ((hdr)->b_flags & ARC_FREED_IN_READ) 508ea8dc4b6Seschrock #define HDR_BUF_AVAILABLE(hdr) ((hdr)->b_flags & ARC_BUF_AVAILABLE) 509fa94a07fSbrendan #define HDR_FREE_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FREE_IN_PROGRESS) 5103baa08fcSek #define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_L2CACHE) 5113a737e0dSbrendan #define HDR_L2_READING(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS && \ 5123a737e0dSbrendan (hdr)->b_l2hdr != NULL) 513fa94a07fSbrendan #define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_L2_WRITING) 514fa94a07fSbrendan #define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_L2_EVICTED) 515fa94a07fSbrendan #define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_L2_WRITE_HEAD) 516fa9e4066Sahrens 517e6c728e1Sbrendan /* 518e6c728e1Sbrendan * Other sizes 519e6c728e1Sbrendan */ 520e6c728e1Sbrendan 521e6c728e1Sbrendan #define HDR_SIZE ((int64_t)sizeof (arc_buf_hdr_t)) 522e6c728e1Sbrendan #define L2HDR_SIZE ((int64_t)sizeof (l2arc_buf_hdr_t)) 523e6c728e1Sbrendan 524fa9e4066Sahrens /* 525fa9e4066Sahrens * Hash table routines 526fa9e4066Sahrens */ 527fa9e4066Sahrens 528fa9e4066Sahrens #define HT_LOCK_PAD 64 529fa9e4066Sahrens 530fa9e4066Sahrens struct ht_lock { 531fa9e4066Sahrens kmutex_t ht_lock; 532fa9e4066Sahrens #ifdef _KERNEL 533fa9e4066Sahrens unsigned char pad[(HT_LOCK_PAD - sizeof (kmutex_t))]; 534fa9e4066Sahrens #endif 535fa9e4066Sahrens }; 536fa9e4066Sahrens 537fa9e4066Sahrens #define BUF_LOCKS 256 538fa9e4066Sahrens typedef struct buf_hash_table { 539fa9e4066Sahrens uint64_t ht_mask; 540fa9e4066Sahrens arc_buf_hdr_t **ht_table; 541fa9e4066Sahrens struct ht_lock ht_locks[BUF_LOCKS]; 542fa9e4066Sahrens } buf_hash_table_t; 543fa9e4066Sahrens 544fa9e4066Sahrens static buf_hash_table_t buf_hash_table; 545fa9e4066Sahrens 546fa9e4066Sahrens #define BUF_HASH_INDEX(spa, dva, birth) \ 547fa9e4066Sahrens (buf_hash(spa, dva, birth) & buf_hash_table.ht_mask) 548fa9e4066Sahrens #define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)]) 549fa9e4066Sahrens #define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock)) 5503f9d6ad7SLin Ling #define HDR_LOCK(hdr) \ 5513f9d6ad7SLin Ling (BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth))) 552fa9e4066Sahrens 553fa9e4066Sahrens uint64_t zfs_crc64_table[256]; 554fa9e4066Sahrens 555fa94a07fSbrendan /* 556fa94a07fSbrendan * Level 2 ARC 557fa94a07fSbrendan */ 558fa94a07fSbrendan 559fa94a07fSbrendan #define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */ 5605a98e54bSBrendan Gregg - Sun Microsystems #define L2ARC_HEADROOM 2 /* num of writes */ 5615a98e54bSBrendan Gregg - Sun Microsystems #define L2ARC_FEED_SECS 1 /* caching interval secs */ 5625a98e54bSBrendan Gregg - Sun Microsystems #define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */ 563fa94a07fSbrendan 564fa94a07fSbrendan #define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent) 565fa94a07fSbrendan #define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done) 566fa94a07fSbrendan 567fa94a07fSbrendan /* 568fa94a07fSbrendan * L2ARC Performance Tunables 569fa94a07fSbrendan */ 570fa94a07fSbrendan uint64_t l2arc_write_max = L2ARC_WRITE_SIZE; /* default max write size */ 5713a737e0dSbrendan uint64_t l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra write during warmup */ 572fa94a07fSbrendan uint64_t l2arc_headroom = L2ARC_HEADROOM; /* number of dev writes */ 573fa94a07fSbrendan uint64_t l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */ 5745a98e54bSBrendan Gregg - Sun Microsystems uint64_t l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval milliseconds */ 575fa94a07fSbrendan boolean_t l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ 5765a98e54bSBrendan Gregg - Sun Microsystems boolean_t l2arc_feed_again = B_TRUE; /* turbo warmup */ 5775a98e54bSBrendan Gregg - Sun Microsystems boolean_t l2arc_norw = B_TRUE; /* no reads during writes */ 578fa94a07fSbrendan 579fa94a07fSbrendan /* 580fa94a07fSbrendan * L2ARC Internals 581fa94a07fSbrendan */ 582fa94a07fSbrendan typedef struct l2arc_dev { 583fa94a07fSbrendan vdev_t *l2ad_vdev; /* vdev */ 584fa94a07fSbrendan spa_t *l2ad_spa; /* spa */ 585fa94a07fSbrendan uint64_t l2ad_hand; /* next write location */ 586fa94a07fSbrendan uint64_t l2ad_write; /* desired write size, bytes */ 5873a737e0dSbrendan uint64_t l2ad_boost; /* warmup write boost, bytes */ 588fa94a07fSbrendan uint64_t l2ad_start; /* first addr on device */ 589fa94a07fSbrendan uint64_t l2ad_end; /* last addr on device */ 590fa94a07fSbrendan uint64_t l2ad_evict; /* last addr eviction reached */ 591fa94a07fSbrendan boolean_t l2ad_first; /* first sweep through */ 5925a98e54bSBrendan Gregg - Sun Microsystems boolean_t l2ad_writing; /* currently writing */ 593fa94a07fSbrendan list_t *l2ad_buflist; /* buffer list */ 594fa94a07fSbrendan list_node_t l2ad_node; /* device list node */ 595fa94a07fSbrendan } l2arc_dev_t; 596fa94a07fSbrendan 597fa94a07fSbrendan static list_t L2ARC_dev_list; /* device list */ 598fa94a07fSbrendan static list_t *l2arc_dev_list; /* device list pointer */ 599fa94a07fSbrendan static kmutex_t l2arc_dev_mtx; /* device list mutex */ 600fa94a07fSbrendan static l2arc_dev_t *l2arc_dev_last; /* last device used */ 601fa94a07fSbrendan static kmutex_t l2arc_buflist_mtx; /* mutex for all buflists */ 602fa94a07fSbrendan static list_t L2ARC_free_on_write; /* free after write buf list */ 603fa94a07fSbrendan static list_t *l2arc_free_on_write; /* free after write list ptr */ 604fa94a07fSbrendan static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */ 605fa94a07fSbrendan static uint64_t l2arc_ndev; /* number of devices */ 606fa94a07fSbrendan 607fa94a07fSbrendan typedef struct l2arc_read_callback { 608fa94a07fSbrendan arc_buf_t *l2rcb_buf; /* read buffer */ 609fa94a07fSbrendan spa_t *l2rcb_spa; /* spa */ 610fa94a07fSbrendan blkptr_t l2rcb_bp; /* original blkptr */ 611fa94a07fSbrendan zbookmark_t l2rcb_zb; /* original bookmark */ 612fa94a07fSbrendan int l2rcb_flags; /* original flags */ 613fa94a07fSbrendan } l2arc_read_callback_t; 614fa94a07fSbrendan 615fa94a07fSbrendan typedef struct l2arc_write_callback { 616fa94a07fSbrendan l2arc_dev_t *l2wcb_dev; /* device info */ 617fa94a07fSbrendan arc_buf_hdr_t *l2wcb_head; /* head of write buflist */ 618fa94a07fSbrendan } l2arc_write_callback_t; 619fa94a07fSbrendan 620fa94a07fSbrendan struct l2arc_buf_hdr { 621fa94a07fSbrendan /* protected by arc_buf_hdr mutex */ 622fa94a07fSbrendan l2arc_dev_t *b_dev; /* L2ARC device */ 623f9d8334fSGeorge Wilson uint64_t b_daddr; /* disk address, offset byte */ 624fa94a07fSbrendan }; 625fa94a07fSbrendan 626fa94a07fSbrendan typedef struct l2arc_data_free { 627fa94a07fSbrendan /* protected by l2arc_free_on_write_mtx */ 628fa94a07fSbrendan void *l2df_data; 629fa94a07fSbrendan size_t l2df_size; 630fa94a07fSbrendan void (*l2df_func)(void *, size_t); 631fa94a07fSbrendan list_node_t l2df_list_node; 632fa94a07fSbrendan } l2arc_data_free_t; 633fa94a07fSbrendan 634fa94a07fSbrendan static kmutex_t l2arc_feed_thr_lock; 635fa94a07fSbrendan static kcondvar_t l2arc_feed_thr_cv; 636fa94a07fSbrendan static uint8_t l2arc_thread_exit; 637fa94a07fSbrendan 638fa94a07fSbrendan static void l2arc_read_done(zio_t *zio); 639fa94a07fSbrendan static void l2arc_hdr_stat_add(void); 640fa94a07fSbrendan static void l2arc_hdr_stat_remove(void); 641fa94a07fSbrendan 642fa9e4066Sahrens static uint64_t 643ac05c741SMark Maybee buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth) 644fa9e4066Sahrens { 645fa9e4066Sahrens uint8_t *vdva = (uint8_t *)dva; 646fa9e4066Sahrens uint64_t crc = -1ULL; 647fa9e4066Sahrens int i; 648fa9e4066Sahrens 649fa9e4066Sahrens ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 650fa9e4066Sahrens 651fa9e4066Sahrens for (i = 0; i < sizeof (dva_t); i++) 652fa9e4066Sahrens crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ vdva[i]) & 0xFF]; 653fa9e4066Sahrens 654ac05c741SMark Maybee crc ^= (spa>>8) ^ birth; 655fa9e4066Sahrens 656fa9e4066Sahrens return (crc); 657fa9e4066Sahrens } 658fa9e4066Sahrens 659fa9e4066Sahrens #define BUF_EMPTY(buf) \ 660fa9e4066Sahrens ((buf)->b_dva.dva_word[0] == 0 && \ 661fa9e4066Sahrens (buf)->b_dva.dva_word[1] == 0 && \ 662fa9e4066Sahrens (buf)->b_birth == 0) 663fa9e4066Sahrens 664fa9e4066Sahrens #define BUF_EQUAL(spa, dva, birth, buf) \ 665fa9e4066Sahrens ((buf)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \ 666fa9e4066Sahrens ((buf)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \ 667fa9e4066Sahrens ((buf)->b_birth == birth) && ((buf)->b_spa == spa) 668fa9e4066Sahrens 6693f9d6ad7SLin Ling static void 6703f9d6ad7SLin Ling buf_discard_identity(arc_buf_hdr_t *hdr) 6713f9d6ad7SLin Ling { 6723f9d6ad7SLin Ling hdr->b_dva.dva_word[0] = 0; 6733f9d6ad7SLin Ling hdr->b_dva.dva_word[1] = 0; 6743f9d6ad7SLin Ling hdr->b_birth = 0; 6753f9d6ad7SLin Ling hdr->b_cksum0 = 0; 6763f9d6ad7SLin Ling } 6773f9d6ad7SLin Ling 678fa9e4066Sahrens static arc_buf_hdr_t * 679ac05c741SMark Maybee buf_hash_find(uint64_t spa, const dva_t *dva, uint64_t birth, kmutex_t **lockp) 680fa9e4066Sahrens { 681fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); 682fa9e4066Sahrens kmutex_t *hash_lock = BUF_HASH_LOCK(idx); 683fa9e4066Sahrens arc_buf_hdr_t *buf; 684fa9e4066Sahrens 685fa9e4066Sahrens mutex_enter(hash_lock); 686fa9e4066Sahrens for (buf = buf_hash_table.ht_table[idx]; buf != NULL; 687fa9e4066Sahrens buf = buf->b_hash_next) { 688fa9e4066Sahrens if (BUF_EQUAL(spa, dva, birth, buf)) { 689fa9e4066Sahrens *lockp = hash_lock; 690fa9e4066Sahrens return (buf); 691fa9e4066Sahrens } 692fa9e4066Sahrens } 693fa9e4066Sahrens mutex_exit(hash_lock); 694fa9e4066Sahrens *lockp = NULL; 695fa9e4066Sahrens return (NULL); 696fa9e4066Sahrens } 697fa9e4066Sahrens 698fa9e4066Sahrens /* 699fa9e4066Sahrens * Insert an entry into the hash table. If there is already an element 700fa9e4066Sahrens * equal to elem in the hash table, then the already existing element 701fa9e4066Sahrens * will be returned and the new element will not be inserted. 702fa9e4066Sahrens * Otherwise returns NULL. 703fa9e4066Sahrens */ 704fa9e4066Sahrens static arc_buf_hdr_t * 705fa9e4066Sahrens buf_hash_insert(arc_buf_hdr_t *buf, kmutex_t **lockp) 706fa9e4066Sahrens { 707fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); 708fa9e4066Sahrens kmutex_t *hash_lock = BUF_HASH_LOCK(idx); 709fa9e4066Sahrens arc_buf_hdr_t *fbuf; 71044cb6abcSbmc uint32_t i; 711fa9e4066Sahrens 712ea8dc4b6Seschrock ASSERT(!HDR_IN_HASH_TABLE(buf)); 713fa9e4066Sahrens *lockp = hash_lock; 714fa9e4066Sahrens mutex_enter(hash_lock); 715fa9e4066Sahrens for (fbuf = buf_hash_table.ht_table[idx], i = 0; fbuf != NULL; 716fa9e4066Sahrens fbuf = fbuf->b_hash_next, i++) { 717fa9e4066Sahrens if (BUF_EQUAL(buf->b_spa, &buf->b_dva, buf->b_birth, fbuf)) 718fa9e4066Sahrens return (fbuf); 719fa9e4066Sahrens } 720fa9e4066Sahrens 721fa9e4066Sahrens buf->b_hash_next = buf_hash_table.ht_table[idx]; 722fa9e4066Sahrens buf_hash_table.ht_table[idx] = buf; 723ea8dc4b6Seschrock buf->b_flags |= ARC_IN_HASH_TABLE; 724fa9e4066Sahrens 725fa9e4066Sahrens /* collect some hash table performance data */ 726fa9e4066Sahrens if (i > 0) { 72744cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_collisions); 728fa9e4066Sahrens if (i == 1) 72944cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_chains); 73044cb6abcSbmc 73144cb6abcSbmc ARCSTAT_MAX(arcstat_hash_chain_max, i); 732fa9e4066Sahrens } 73344cb6abcSbmc 73444cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_elements); 73544cb6abcSbmc ARCSTAT_MAXSTAT(arcstat_hash_elements); 736fa9e4066Sahrens 737fa9e4066Sahrens return (NULL); 738fa9e4066Sahrens } 739fa9e4066Sahrens 740fa9e4066Sahrens static void 741fa9e4066Sahrens buf_hash_remove(arc_buf_hdr_t *buf) 742fa9e4066Sahrens { 743fa9e4066Sahrens arc_buf_hdr_t *fbuf, **bufp; 744fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); 745fa9e4066Sahrens 746fa9e4066Sahrens ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); 747ea8dc4b6Seschrock ASSERT(HDR_IN_HASH_TABLE(buf)); 748fa9e4066Sahrens 749fa9e4066Sahrens bufp = &buf_hash_table.ht_table[idx]; 750fa9e4066Sahrens while ((fbuf = *bufp) != buf) { 751fa9e4066Sahrens ASSERT(fbuf != NULL); 752fa9e4066Sahrens bufp = &fbuf->b_hash_next; 753fa9e4066Sahrens } 754fa9e4066Sahrens *bufp = buf->b_hash_next; 755fa9e4066Sahrens buf->b_hash_next = NULL; 756ea8dc4b6Seschrock buf->b_flags &= ~ARC_IN_HASH_TABLE; 757fa9e4066Sahrens 758fa9e4066Sahrens /* collect some hash table performance data */ 75944cb6abcSbmc ARCSTAT_BUMPDOWN(arcstat_hash_elements); 76044cb6abcSbmc 761fa9e4066Sahrens if (buf_hash_table.ht_table[idx] && 762fa9e4066Sahrens buf_hash_table.ht_table[idx]->b_hash_next == NULL) 76344cb6abcSbmc ARCSTAT_BUMPDOWN(arcstat_hash_chains); 764fa9e4066Sahrens } 765fa9e4066Sahrens 766fa9e4066Sahrens /* 767fa9e4066Sahrens * Global data structures and functions for the buf kmem cache. 768fa9e4066Sahrens */ 769fa9e4066Sahrens static kmem_cache_t *hdr_cache; 770fa9e4066Sahrens static kmem_cache_t *buf_cache; 771fa9e4066Sahrens 772fa9e4066Sahrens static void 773fa9e4066Sahrens buf_fini(void) 774fa9e4066Sahrens { 775fa9e4066Sahrens int i; 776fa9e4066Sahrens 777fa9e4066Sahrens kmem_free(buf_hash_table.ht_table, 778fa9e4066Sahrens (buf_hash_table.ht_mask + 1) * sizeof (void *)); 779fa9e4066Sahrens for (i = 0; i < BUF_LOCKS; i++) 780fa9e4066Sahrens mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock); 781fa9e4066Sahrens kmem_cache_destroy(hdr_cache); 782fa9e4066Sahrens kmem_cache_destroy(buf_cache); 783fa9e4066Sahrens } 784fa9e4066Sahrens 785fa9e4066Sahrens /* 786fa9e4066Sahrens * Constructor callback - called when the cache is empty 787fa9e4066Sahrens * and a new buf is requested. 788fa9e4066Sahrens */ 789fa9e4066Sahrens /* ARGSUSED */ 790fa9e4066Sahrens static int 791fa9e4066Sahrens hdr_cons(void *vbuf, void *unused, int kmflag) 792fa9e4066Sahrens { 793fa9e4066Sahrens arc_buf_hdr_t *buf = vbuf; 794fa9e4066Sahrens 795fa9e4066Sahrens bzero(buf, sizeof (arc_buf_hdr_t)); 796fa9e4066Sahrens refcount_create(&buf->b_refcnt); 797fa9e4066Sahrens cv_init(&buf->b_cv, NULL, CV_DEFAULT, NULL); 798c25056deSgw mutex_init(&buf->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); 7995a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); 800fa94a07fSbrendan 801fa9e4066Sahrens return (0); 802fa9e4066Sahrens } 803fa9e4066Sahrens 8046f83844dSMark Maybee /* ARGSUSED */ 8056f83844dSMark Maybee static int 8066f83844dSMark Maybee buf_cons(void *vbuf, void *unused, int kmflag) 8076f83844dSMark Maybee { 8086f83844dSMark Maybee arc_buf_t *buf = vbuf; 8096f83844dSMark Maybee 8106f83844dSMark Maybee bzero(buf, sizeof (arc_buf_t)); 8113f9d6ad7SLin Ling mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL); 8123f9d6ad7SLin Ling rw_init(&buf->b_data_lock, NULL, RW_DEFAULT, NULL); 8135a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); 8145a98e54bSBrendan Gregg - Sun Microsystems 8156f83844dSMark Maybee return (0); 8166f83844dSMark Maybee } 8176f83844dSMark Maybee 818fa9e4066Sahrens /* 819fa9e4066Sahrens * Destructor callback - called when a cached buf is 820fa9e4066Sahrens * no longer required. 821fa9e4066Sahrens */ 822fa9e4066Sahrens /* ARGSUSED */ 823fa9e4066Sahrens static void 824fa9e4066Sahrens hdr_dest(void *vbuf, void *unused) 825fa9e4066Sahrens { 826fa9e4066Sahrens arc_buf_hdr_t *buf = vbuf; 827fa9e4066Sahrens 828b24ab676SJeff Bonwick ASSERT(BUF_EMPTY(buf)); 829fa9e4066Sahrens refcount_destroy(&buf->b_refcnt); 830fa9e4066Sahrens cv_destroy(&buf->b_cv); 831c25056deSgw mutex_destroy(&buf->b_freeze_lock); 8325a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); 833fa9e4066Sahrens } 834fa9e4066Sahrens 8356f83844dSMark Maybee /* ARGSUSED */ 8366f83844dSMark Maybee static void 8376f83844dSMark Maybee buf_dest(void *vbuf, void *unused) 8386f83844dSMark Maybee { 8396f83844dSMark Maybee arc_buf_t *buf = vbuf; 8406f83844dSMark Maybee 8413f9d6ad7SLin Ling mutex_destroy(&buf->b_evict_lock); 8423f9d6ad7SLin Ling rw_destroy(&buf->b_data_lock); 8435a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); 8446f83844dSMark Maybee } 8456f83844dSMark Maybee 846fa9e4066Sahrens /* 847fa9e4066Sahrens * Reclaim callback -- invoked when memory is low. 848fa9e4066Sahrens */ 849fa9e4066Sahrens /* ARGSUSED */ 850fa9e4066Sahrens static void 851fa9e4066Sahrens hdr_recl(void *unused) 852fa9e4066Sahrens { 853fa9e4066Sahrens dprintf("hdr_recl called\n"); 85449e3519aSmaybee /* 85549e3519aSmaybee * umem calls the reclaim func when we destroy the buf cache, 85649e3519aSmaybee * which is after we do arc_fini(). 85749e3519aSmaybee */ 85849e3519aSmaybee if (!arc_dead) 85949e3519aSmaybee cv_signal(&arc_reclaim_thr_cv); 860fa9e4066Sahrens } 861fa9e4066Sahrens 862fa9e4066Sahrens static void 863fa9e4066Sahrens buf_init(void) 864fa9e4066Sahrens { 865fa9e4066Sahrens uint64_t *ct; 866ea8dc4b6Seschrock uint64_t hsize = 1ULL << 12; 867fa9e4066Sahrens int i, j; 868fa9e4066Sahrens 869fa9e4066Sahrens /* 870fa9e4066Sahrens * The hash table is big enough to fill all of physical memory 871ea8dc4b6Seschrock * with an average 64K block size. The table will take up 872ea8dc4b6Seschrock * totalmem*sizeof(void*)/64K (eg. 128KB/GB with 8-byte pointers). 873fa9e4066Sahrens */ 874ea8dc4b6Seschrock while (hsize * 65536 < physmem * PAGESIZE) 875fa9e4066Sahrens hsize <<= 1; 876ea8dc4b6Seschrock retry: 877fa9e4066Sahrens buf_hash_table.ht_mask = hsize - 1; 878ea8dc4b6Seschrock buf_hash_table.ht_table = 879ea8dc4b6Seschrock kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); 880ea8dc4b6Seschrock if (buf_hash_table.ht_table == NULL) { 881ea8dc4b6Seschrock ASSERT(hsize > (1ULL << 8)); 882ea8dc4b6Seschrock hsize >>= 1; 883ea8dc4b6Seschrock goto retry; 884ea8dc4b6Seschrock } 885fa9e4066Sahrens 886fa9e4066Sahrens hdr_cache = kmem_cache_create("arc_buf_hdr_t", sizeof (arc_buf_hdr_t), 887fa9e4066Sahrens 0, hdr_cons, hdr_dest, hdr_recl, NULL, NULL, 0); 888fa9e4066Sahrens buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), 8896f83844dSMark Maybee 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); 890fa9e4066Sahrens 891fa9e4066Sahrens for (i = 0; i < 256; i++) 892fa9e4066Sahrens for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) 893fa9e4066Sahrens *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); 894fa9e4066Sahrens 895fa9e4066Sahrens for (i = 0; i < BUF_LOCKS; i++) { 896fa9e4066Sahrens mutex_init(&buf_hash_table.ht_locks[i].ht_lock, 897fa9e4066Sahrens NULL, MUTEX_DEFAULT, NULL); 898fa9e4066Sahrens } 899fa9e4066Sahrens } 900fa9e4066Sahrens 901fa9e4066Sahrens #define ARC_MINTIME (hz>>4) /* 62 ms */ 902fa9e4066Sahrens 9036b4acc8bSahrens static void 9046b4acc8bSahrens arc_cksum_verify(arc_buf_t *buf) 9056b4acc8bSahrens { 9066b4acc8bSahrens zio_cksum_t zc; 9076b4acc8bSahrens 908cc60fd72Sahrens if (!(zfs_flags & ZFS_DEBUG_MODIFY)) 9096b4acc8bSahrens return; 9106b4acc8bSahrens 9116b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9123ccfa83cSahrens if (buf->b_hdr->b_freeze_cksum == NULL || 9133ccfa83cSahrens (buf->b_hdr->b_flags & ARC_IO_ERROR)) { 9146b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9156b4acc8bSahrens return; 9166b4acc8bSahrens } 9176b4acc8bSahrens fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); 9186b4acc8bSahrens if (!ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc)) 9196b4acc8bSahrens panic("buffer modified while frozen!"); 9206b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9216b4acc8bSahrens } 9226b4acc8bSahrens 923fa94a07fSbrendan static int 924fa94a07fSbrendan arc_cksum_equal(arc_buf_t *buf) 925fa94a07fSbrendan { 926fa94a07fSbrendan zio_cksum_t zc; 927fa94a07fSbrendan int equal; 928fa94a07fSbrendan 929fa94a07fSbrendan mutex_enter(&buf->b_hdr->b_freeze_lock); 930fa94a07fSbrendan fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); 931fa94a07fSbrendan equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc); 932fa94a07fSbrendan mutex_exit(&buf->b_hdr->b_freeze_lock); 933fa94a07fSbrendan 934fa94a07fSbrendan return (equal); 935fa94a07fSbrendan } 936fa94a07fSbrendan 9376b4acc8bSahrens static void 938fa94a07fSbrendan arc_cksum_compute(arc_buf_t *buf, boolean_t force) 9396b4acc8bSahrens { 940fa94a07fSbrendan if (!force && !(zfs_flags & ZFS_DEBUG_MODIFY)) 9416b4acc8bSahrens return; 9426b4acc8bSahrens 9436b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9446b4acc8bSahrens if (buf->b_hdr->b_freeze_cksum != NULL) { 9456b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9466b4acc8bSahrens return; 9476b4acc8bSahrens } 9486b4acc8bSahrens buf->b_hdr->b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), KM_SLEEP); 9496b4acc8bSahrens fletcher_2_native(buf->b_data, buf->b_hdr->b_size, 9506b4acc8bSahrens buf->b_hdr->b_freeze_cksum); 9516b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9526b4acc8bSahrens } 9536b4acc8bSahrens 9546b4acc8bSahrens void 9556b4acc8bSahrens arc_buf_thaw(arc_buf_t *buf) 9566b4acc8bSahrens { 957fa94a07fSbrendan if (zfs_flags & ZFS_DEBUG_MODIFY) { 958fa94a07fSbrendan if (buf->b_hdr->b_state != arc_anon) 959fa94a07fSbrendan panic("modifying non-anon buffer!"); 960fa94a07fSbrendan if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS) 961fa94a07fSbrendan panic("modifying buffer while i/o in progress!"); 962fa94a07fSbrendan arc_cksum_verify(buf); 963fa94a07fSbrendan } 9646b4acc8bSahrens 9656b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9666b4acc8bSahrens if (buf->b_hdr->b_freeze_cksum != NULL) { 9676b4acc8bSahrens kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 9686b4acc8bSahrens buf->b_hdr->b_freeze_cksum = NULL; 9696b4acc8bSahrens } 9703f9d6ad7SLin Ling 9713f9d6ad7SLin Ling if (zfs_flags & ZFS_DEBUG_MODIFY) { 9723f9d6ad7SLin Ling if (buf->b_hdr->b_thawed) 9733f9d6ad7SLin Ling kmem_free(buf->b_hdr->b_thawed, 1); 9743f9d6ad7SLin Ling buf->b_hdr->b_thawed = kmem_alloc(1, KM_SLEEP); 9753f9d6ad7SLin Ling } 9763f9d6ad7SLin Ling 9776b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9786b4acc8bSahrens } 9796b4acc8bSahrens 9806b4acc8bSahrens void 9816b4acc8bSahrens arc_buf_freeze(arc_buf_t *buf) 9826b4acc8bSahrens { 9833f9d6ad7SLin Ling kmutex_t *hash_lock; 9843f9d6ad7SLin Ling 985cc60fd72Sahrens if (!(zfs_flags & ZFS_DEBUG_MODIFY)) 986cc60fd72Sahrens return; 987cc60fd72Sahrens 9883f9d6ad7SLin Ling hash_lock = HDR_LOCK(buf->b_hdr); 9893f9d6ad7SLin Ling mutex_enter(hash_lock); 9903f9d6ad7SLin Ling 9916b4acc8bSahrens ASSERT(buf->b_hdr->b_freeze_cksum != NULL || 99244cb6abcSbmc buf->b_hdr->b_state == arc_anon); 993fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 9943f9d6ad7SLin Ling mutex_exit(hash_lock); 9956b4acc8bSahrens } 9966b4acc8bSahrens 997fa9e4066Sahrens static void 998fa9e4066Sahrens add_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) 999fa9e4066Sahrens { 1000fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 1001fa9e4066Sahrens 1002fa9e4066Sahrens if ((refcount_add(&ab->b_refcnt, tag) == 1) && 100344cb6abcSbmc (ab->b_state != arc_anon)) { 1004c0a81264Sek uint64_t delta = ab->b_size * ab->b_datacnt; 10050e8c6158Smaybee list_t *list = &ab->b_state->arcs_list[ab->b_type]; 10060e8c6158Smaybee uint64_t *size = &ab->b_state->arcs_lsize[ab->b_type]; 1007fa9e4066Sahrens 100844cb6abcSbmc ASSERT(!MUTEX_HELD(&ab->b_state->arcs_mtx)); 100944cb6abcSbmc mutex_enter(&ab->b_state->arcs_mtx); 1010fa9e4066Sahrens ASSERT(list_link_active(&ab->b_arc_node)); 10110e8c6158Smaybee list_remove(list, ab); 1012ea8dc4b6Seschrock if (GHOST_STATE(ab->b_state)) { 1013ea8dc4b6Seschrock ASSERT3U(ab->b_datacnt, ==, 0); 1014ea8dc4b6Seschrock ASSERT3P(ab->b_buf, ==, NULL); 1015ea8dc4b6Seschrock delta = ab->b_size; 1016ea8dc4b6Seschrock } 1017ea8dc4b6Seschrock ASSERT(delta > 0); 10180e8c6158Smaybee ASSERT3U(*size, >=, delta); 10190e8c6158Smaybee atomic_add_64(size, -delta); 102044cb6abcSbmc mutex_exit(&ab->b_state->arcs_mtx); 1021088f3894Sahrens /* remove the prefetch flag if we get a reference */ 102213506d1eSmaybee if (ab->b_flags & ARC_PREFETCH) 102313506d1eSmaybee ab->b_flags &= ~ARC_PREFETCH; 1024fa9e4066Sahrens } 1025fa9e4066Sahrens } 1026fa9e4066Sahrens 1027fa9e4066Sahrens static int 1028fa9e4066Sahrens remove_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) 1029fa9e4066Sahrens { 1030fa9e4066Sahrens int cnt; 103144cb6abcSbmc arc_state_t *state = ab->b_state; 1032fa9e4066Sahrens 103344cb6abcSbmc ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); 103444cb6abcSbmc ASSERT(!GHOST_STATE(state)); 1035fa9e4066Sahrens 1036fa9e4066Sahrens if (((cnt = refcount_remove(&ab->b_refcnt, tag)) == 0) && 103744cb6abcSbmc (state != arc_anon)) { 10380e8c6158Smaybee uint64_t *size = &state->arcs_lsize[ab->b_type]; 10390e8c6158Smaybee 104044cb6abcSbmc ASSERT(!MUTEX_HELD(&state->arcs_mtx)); 104144cb6abcSbmc mutex_enter(&state->arcs_mtx); 1042fa9e4066Sahrens ASSERT(!list_link_active(&ab->b_arc_node)); 10430e8c6158Smaybee list_insert_head(&state->arcs_list[ab->b_type], ab); 1044ea8dc4b6Seschrock ASSERT(ab->b_datacnt > 0); 10450e8c6158Smaybee atomic_add_64(size, ab->b_size * ab->b_datacnt); 104644cb6abcSbmc mutex_exit(&state->arcs_mtx); 1047fa9e4066Sahrens } 1048fa9e4066Sahrens return (cnt); 1049fa9e4066Sahrens } 1050fa9e4066Sahrens 1051fa9e4066Sahrens /* 1052fa9e4066Sahrens * Move the supplied buffer to the indicated state. The mutex 1053fa9e4066Sahrens * for the buffer must be held by the caller. 1054fa9e4066Sahrens */ 1055fa9e4066Sahrens static void 1056ea8dc4b6Seschrock arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock) 1057fa9e4066Sahrens { 1058ea8dc4b6Seschrock arc_state_t *old_state = ab->b_state; 1059c0a81264Sek int64_t refcnt = refcount_count(&ab->b_refcnt); 1060c0a81264Sek uint64_t from_delta, to_delta; 1061fa9e4066Sahrens 1062fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 1063ea8dc4b6Seschrock ASSERT(new_state != old_state); 1064ea8dc4b6Seschrock ASSERT(refcnt == 0 || ab->b_datacnt > 0); 1065ea8dc4b6Seschrock ASSERT(ab->b_datacnt == 0 || !GHOST_STATE(new_state)); 1066b24ab676SJeff Bonwick ASSERT(ab->b_datacnt <= 1 || old_state != arc_anon); 1067ea8dc4b6Seschrock 1068ea8dc4b6Seschrock from_delta = to_delta = ab->b_datacnt * ab->b_size; 1069fa9e4066Sahrens 1070fa9e4066Sahrens /* 1071fa9e4066Sahrens * If this buffer is evictable, transfer it from the 1072fa9e4066Sahrens * old state list to the new state list. 1073fa9e4066Sahrens */ 1074ea8dc4b6Seschrock if (refcnt == 0) { 107544cb6abcSbmc if (old_state != arc_anon) { 107644cb6abcSbmc int use_mutex = !MUTEX_HELD(&old_state->arcs_mtx); 10770e8c6158Smaybee uint64_t *size = &old_state->arcs_lsize[ab->b_type]; 1078ea8dc4b6Seschrock 1079ea8dc4b6Seschrock if (use_mutex) 108044cb6abcSbmc mutex_enter(&old_state->arcs_mtx); 1081fa9e4066Sahrens 1082fa9e4066Sahrens ASSERT(list_link_active(&ab->b_arc_node)); 10830e8c6158Smaybee list_remove(&old_state->arcs_list[ab->b_type], ab); 1084ea8dc4b6Seschrock 108513506d1eSmaybee /* 108613506d1eSmaybee * If prefetching out of the ghost cache, 10873f9d6ad7SLin Ling * we will have a non-zero datacnt. 108813506d1eSmaybee */ 108913506d1eSmaybee if (GHOST_STATE(old_state) && ab->b_datacnt == 0) { 109013506d1eSmaybee /* ghost elements have a ghost size */ 1091ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 1092ea8dc4b6Seschrock from_delta = ab->b_size; 1093ea8dc4b6Seschrock } 10940e8c6158Smaybee ASSERT3U(*size, >=, from_delta); 10950e8c6158Smaybee atomic_add_64(size, -from_delta); 1096ea8dc4b6Seschrock 1097ea8dc4b6Seschrock if (use_mutex) 109844cb6abcSbmc mutex_exit(&old_state->arcs_mtx); 1099fa9e4066Sahrens } 110044cb6abcSbmc if (new_state != arc_anon) { 110144cb6abcSbmc int use_mutex = !MUTEX_HELD(&new_state->arcs_mtx); 11020e8c6158Smaybee uint64_t *size = &new_state->arcs_lsize[ab->b_type]; 1103fa9e4066Sahrens 1104ea8dc4b6Seschrock if (use_mutex) 110544cb6abcSbmc mutex_enter(&new_state->arcs_mtx); 1106ea8dc4b6Seschrock 11070e8c6158Smaybee list_insert_head(&new_state->arcs_list[ab->b_type], ab); 1108ea8dc4b6Seschrock 1109ea8dc4b6Seschrock /* ghost elements have a ghost size */ 1110ea8dc4b6Seschrock if (GHOST_STATE(new_state)) { 1111ea8dc4b6Seschrock ASSERT(ab->b_datacnt == 0); 1112ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 1113ea8dc4b6Seschrock to_delta = ab->b_size; 1114ea8dc4b6Seschrock } 11150e8c6158Smaybee atomic_add_64(size, to_delta); 1116ea8dc4b6Seschrock 1117ea8dc4b6Seschrock if (use_mutex) 111844cb6abcSbmc mutex_exit(&new_state->arcs_mtx); 1119fa9e4066Sahrens } 1120fa9e4066Sahrens } 1121fa9e4066Sahrens 1122fa9e4066Sahrens ASSERT(!BUF_EMPTY(ab)); 11233f9d6ad7SLin Ling if (new_state == arc_anon && HDR_IN_HASH_TABLE(ab)) 1124fa9e4066Sahrens buf_hash_remove(ab); 1125fa9e4066Sahrens 1126ea8dc4b6Seschrock /* adjust state sizes */ 1127ea8dc4b6Seschrock if (to_delta) 112844cb6abcSbmc atomic_add_64(&new_state->arcs_size, to_delta); 1129ea8dc4b6Seschrock if (from_delta) { 113044cb6abcSbmc ASSERT3U(old_state->arcs_size, >=, from_delta); 113144cb6abcSbmc atomic_add_64(&old_state->arcs_size, -from_delta); 1132fa9e4066Sahrens } 1133fa9e4066Sahrens ab->b_state = new_state; 1134fa94a07fSbrendan 1135fa94a07fSbrendan /* adjust l2arc hdr stats */ 1136fa94a07fSbrendan if (new_state == arc_l2c_only) 1137fa94a07fSbrendan l2arc_hdr_stat_add(); 1138fa94a07fSbrendan else if (old_state == arc_l2c_only) 1139fa94a07fSbrendan l2arc_hdr_stat_remove(); 1140fa9e4066Sahrens } 1141fa9e4066Sahrens 11420e8c6158Smaybee void 11435a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(uint64_t space, arc_space_type_t type) 11440e8c6158Smaybee { 11455a98e54bSBrendan Gregg - Sun Microsystems ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); 11465a98e54bSBrendan Gregg - Sun Microsystems 11475a98e54bSBrendan Gregg - Sun Microsystems switch (type) { 11485a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_DATA: 11495a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, space); 11505a98e54bSBrendan Gregg - Sun Microsystems break; 11515a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_OTHER: 11525a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_other_size, space); 11535a98e54bSBrendan Gregg - Sun Microsystems break; 11545a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_HDRS: 11555a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_hdr_size, space); 11565a98e54bSBrendan Gregg - Sun Microsystems break; 11575a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_L2HDRS: 11585a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_hdr_size, space); 11595a98e54bSBrendan Gregg - Sun Microsystems break; 11605a98e54bSBrendan Gregg - Sun Microsystems } 11615a98e54bSBrendan Gregg - Sun Microsystems 11620e8c6158Smaybee atomic_add_64(&arc_meta_used, space); 11630e8c6158Smaybee atomic_add_64(&arc_size, space); 11640e8c6158Smaybee } 11650e8c6158Smaybee 11660e8c6158Smaybee void 11675a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(uint64_t space, arc_space_type_t type) 11680e8c6158Smaybee { 11695a98e54bSBrendan Gregg - Sun Microsystems ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); 11705a98e54bSBrendan Gregg - Sun Microsystems 11715a98e54bSBrendan Gregg - Sun Microsystems switch (type) { 11725a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_DATA: 11735a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, -space); 11745a98e54bSBrendan Gregg - Sun Microsystems break; 11755a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_OTHER: 11765a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_other_size, -space); 11775a98e54bSBrendan Gregg - Sun Microsystems break; 11785a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_HDRS: 11795a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_hdr_size, -space); 11805a98e54bSBrendan Gregg - Sun Microsystems break; 11815a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_L2HDRS: 11825a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_hdr_size, -space); 11835a98e54bSBrendan Gregg - Sun Microsystems break; 11845a98e54bSBrendan Gregg - Sun Microsystems } 11855a98e54bSBrendan Gregg - Sun Microsystems 11860e8c6158Smaybee ASSERT(arc_meta_used >= space); 11870e8c6158Smaybee if (arc_meta_max < arc_meta_used) 11880e8c6158Smaybee arc_meta_max = arc_meta_used; 11890e8c6158Smaybee atomic_add_64(&arc_meta_used, -space); 11900e8c6158Smaybee ASSERT(arc_size >= space); 11910e8c6158Smaybee atomic_add_64(&arc_size, -space); 11920e8c6158Smaybee } 11930e8c6158Smaybee 11940e8c6158Smaybee void * 11950e8c6158Smaybee arc_data_buf_alloc(uint64_t size) 11960e8c6158Smaybee { 11970e8c6158Smaybee if (arc_evict_needed(ARC_BUFC_DATA)) 11980e8c6158Smaybee cv_signal(&arc_reclaim_thr_cv); 11990e8c6158Smaybee atomic_add_64(&arc_size, size); 12000e8c6158Smaybee return (zio_data_buf_alloc(size)); 12010e8c6158Smaybee } 12020e8c6158Smaybee 12030e8c6158Smaybee void 12040e8c6158Smaybee arc_data_buf_free(void *buf, uint64_t size) 12050e8c6158Smaybee { 12060e8c6158Smaybee zio_data_buf_free(buf, size); 12070e8c6158Smaybee ASSERT(arc_size >= size); 12080e8c6158Smaybee atomic_add_64(&arc_size, -size); 12090e8c6158Smaybee } 12100e8c6158Smaybee 1211fa9e4066Sahrens arc_buf_t * 1212ad23a2dbSjohansen arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type) 1213fa9e4066Sahrens { 1214fa9e4066Sahrens arc_buf_hdr_t *hdr; 1215fa9e4066Sahrens arc_buf_t *buf; 1216fa9e4066Sahrens 1217fa9e4066Sahrens ASSERT3U(size, >, 0); 12181ab7f2deSmaybee hdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 1219fa9e4066Sahrens ASSERT(BUF_EMPTY(hdr)); 1220fa9e4066Sahrens hdr->b_size = size; 1221ad23a2dbSjohansen hdr->b_type = type; 1222e9103aaeSGarrett D'Amore hdr->b_spa = spa_load_guid(spa); 122344cb6abcSbmc hdr->b_state = arc_anon; 1224fa9e4066Sahrens hdr->b_arc_access = 0; 12251ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 1226fa9e4066Sahrens buf->b_hdr = hdr; 122744eda4d7Smaybee buf->b_data = NULL; 1228ea8dc4b6Seschrock buf->b_efunc = NULL; 1229ea8dc4b6Seschrock buf->b_private = NULL; 1230fa9e4066Sahrens buf->b_next = NULL; 1231fa9e4066Sahrens hdr->b_buf = buf; 123244eda4d7Smaybee arc_get_data_buf(buf); 1233ea8dc4b6Seschrock hdr->b_datacnt = 1; 1234fa9e4066Sahrens hdr->b_flags = 0; 1235fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt)); 1236fa9e4066Sahrens (void) refcount_add(&hdr->b_refcnt, tag); 1237fa9e4066Sahrens 1238fa9e4066Sahrens return (buf); 1239fa9e4066Sahrens } 1240fa9e4066Sahrens 12412fdbea25SAleksandr Guzovskiy static char *arc_onloan_tag = "onloan"; 12422fdbea25SAleksandr Guzovskiy 12432fdbea25SAleksandr Guzovskiy /* 12442fdbea25SAleksandr Guzovskiy * Loan out an anonymous arc buffer. Loaned buffers are not counted as in 12452fdbea25SAleksandr Guzovskiy * flight data by arc_tempreserve_space() until they are "returned". Loaned 12462fdbea25SAleksandr Guzovskiy * buffers must be returned to the arc before they can be used by the DMU or 12472fdbea25SAleksandr Guzovskiy * freed. 12482fdbea25SAleksandr Guzovskiy */ 12492fdbea25SAleksandr Guzovskiy arc_buf_t * 12502fdbea25SAleksandr Guzovskiy arc_loan_buf(spa_t *spa, int size) 12512fdbea25SAleksandr Guzovskiy { 12522fdbea25SAleksandr Guzovskiy arc_buf_t *buf; 12532fdbea25SAleksandr Guzovskiy 12542fdbea25SAleksandr Guzovskiy buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA); 12552fdbea25SAleksandr Guzovskiy 12562fdbea25SAleksandr Guzovskiy atomic_add_64(&arc_loaned_bytes, size); 12572fdbea25SAleksandr Guzovskiy return (buf); 12582fdbea25SAleksandr Guzovskiy } 12592fdbea25SAleksandr Guzovskiy 12602fdbea25SAleksandr Guzovskiy /* 12612fdbea25SAleksandr Guzovskiy * Return a loaned arc buffer to the arc. 12622fdbea25SAleksandr Guzovskiy */ 12632fdbea25SAleksandr Guzovskiy void 12642fdbea25SAleksandr Guzovskiy arc_return_buf(arc_buf_t *buf, void *tag) 12652fdbea25SAleksandr Guzovskiy { 12662fdbea25SAleksandr Guzovskiy arc_buf_hdr_t *hdr = buf->b_hdr; 12672fdbea25SAleksandr Guzovskiy 12682fdbea25SAleksandr Guzovskiy ASSERT(buf->b_data != NULL); 1269c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_add(&hdr->b_refcnt, tag); 1270c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_remove(&hdr->b_refcnt, arc_onloan_tag); 12712fdbea25SAleksandr Guzovskiy 12722fdbea25SAleksandr Guzovskiy atomic_add_64(&arc_loaned_bytes, -hdr->b_size); 12732fdbea25SAleksandr Guzovskiy } 12742fdbea25SAleksandr Guzovskiy 1275c242f9a0Schunli zhang - Sun Microsystems - Irvine United States /* Detach an arc_buf from a dbuf (tag) */ 1276c242f9a0Schunli zhang - Sun Microsystems - Irvine United States void 1277c242f9a0Schunli zhang - Sun Microsystems - Irvine United States arc_loan_inuse_buf(arc_buf_t *buf, void *tag) 1278c242f9a0Schunli zhang - Sun Microsystems - Irvine United States { 1279c242f9a0Schunli zhang - Sun Microsystems - Irvine United States arc_buf_hdr_t *hdr; 1280c242f9a0Schunli zhang - Sun Microsystems - Irvine United States 1281c242f9a0Schunli zhang - Sun Microsystems - Irvine United States ASSERT(buf->b_data != NULL); 1282c242f9a0Schunli zhang - Sun Microsystems - Irvine United States hdr = buf->b_hdr; 1283c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_add(&hdr->b_refcnt, arc_onloan_tag); 1284c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_remove(&hdr->b_refcnt, tag); 1285c242f9a0Schunli zhang - Sun Microsystems - Irvine United States buf->b_efunc = NULL; 1286c242f9a0Schunli zhang - Sun Microsystems - Irvine United States buf->b_private = NULL; 1287c242f9a0Schunli zhang - Sun Microsystems - Irvine United States 1288c242f9a0Schunli zhang - Sun Microsystems - Irvine United States atomic_add_64(&arc_loaned_bytes, hdr->b_size); 1289c242f9a0Schunli zhang - Sun Microsystems - Irvine United States } 1290c242f9a0Schunli zhang - Sun Microsystems - Irvine United States 129144eda4d7Smaybee static arc_buf_t * 129244eda4d7Smaybee arc_buf_clone(arc_buf_t *from) 1293ea8dc4b6Seschrock { 129444eda4d7Smaybee arc_buf_t *buf; 129544eda4d7Smaybee arc_buf_hdr_t *hdr = from->b_hdr; 129644eda4d7Smaybee uint64_t size = hdr->b_size; 1297ea8dc4b6Seschrock 1298b24ab676SJeff Bonwick ASSERT(hdr->b_state != arc_anon); 1299b24ab676SJeff Bonwick 13001ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 130144eda4d7Smaybee buf->b_hdr = hdr; 130244eda4d7Smaybee buf->b_data = NULL; 130344eda4d7Smaybee buf->b_efunc = NULL; 130444eda4d7Smaybee buf->b_private = NULL; 130544eda4d7Smaybee buf->b_next = hdr->b_buf; 130644eda4d7Smaybee hdr->b_buf = buf; 130744eda4d7Smaybee arc_get_data_buf(buf); 130844eda4d7Smaybee bcopy(from->b_data, buf->b_data, size); 130944eda4d7Smaybee hdr->b_datacnt += 1; 131044eda4d7Smaybee return (buf); 1311ea8dc4b6Seschrock } 1312ea8dc4b6Seschrock 1313ea8dc4b6Seschrock void 1314ea8dc4b6Seschrock arc_buf_add_ref(arc_buf_t *buf, void* tag) 1315ea8dc4b6Seschrock { 131640d7d650Smaybee arc_buf_hdr_t *hdr; 1317ea8dc4b6Seschrock kmutex_t *hash_lock; 1318ea8dc4b6Seschrock 13199b23f181Smaybee /* 13206f83844dSMark Maybee * Check to see if this buffer is evicted. Callers 13216f83844dSMark Maybee * must verify b_data != NULL to know if the add_ref 13226f83844dSMark Maybee * was successful. 13239b23f181Smaybee */ 13243f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 13256f83844dSMark Maybee if (buf->b_data == NULL) { 13263f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 13279b23f181Smaybee return; 132840d7d650Smaybee } 13293f9d6ad7SLin Ling hash_lock = HDR_LOCK(buf->b_hdr); 13309b23f181Smaybee mutex_enter(hash_lock); 13313f9d6ad7SLin Ling hdr = buf->b_hdr; 13323f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 13333f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1334ea8dc4b6Seschrock 133544cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 1336ea8dc4b6Seschrock add_reference(hdr, hash_lock, tag); 13375a98e54bSBrendan Gregg - Sun Microsystems DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); 133844eda4d7Smaybee arc_access(hdr, hash_lock); 133944eda4d7Smaybee mutex_exit(hash_lock); 134044cb6abcSbmc ARCSTAT_BUMP(arcstat_hits); 134144cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 134244cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 134344cb6abcSbmc data, metadata, hits); 1344ea8dc4b6Seschrock } 1345ea8dc4b6Seschrock 1346fa94a07fSbrendan /* 1347fa94a07fSbrendan * Free the arc data buffer. If it is an l2arc write in progress, 1348fa94a07fSbrendan * the buffer is placed on l2arc_free_on_write to be freed later. 1349fa94a07fSbrendan */ 1350fa94a07fSbrendan static void 1351fa94a07fSbrendan arc_buf_data_free(arc_buf_hdr_t *hdr, void (*free_func)(void *, size_t), 1352fa94a07fSbrendan void *data, size_t size) 1353fa94a07fSbrendan { 1354fa94a07fSbrendan if (HDR_L2_WRITING(hdr)) { 1355fa94a07fSbrendan l2arc_data_free_t *df; 1356fa94a07fSbrendan df = kmem_alloc(sizeof (l2arc_data_free_t), KM_SLEEP); 1357fa94a07fSbrendan df->l2df_data = data; 1358fa94a07fSbrendan df->l2df_size = size; 1359fa94a07fSbrendan df->l2df_func = free_func; 1360fa94a07fSbrendan mutex_enter(&l2arc_free_on_write_mtx); 1361fa94a07fSbrendan list_insert_head(l2arc_free_on_write, df); 1362fa94a07fSbrendan mutex_exit(&l2arc_free_on_write_mtx); 1363fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_free_on_write); 1364fa94a07fSbrendan } else { 1365fa94a07fSbrendan free_func(data, size); 1366fa94a07fSbrendan } 1367fa94a07fSbrendan } 1368fa94a07fSbrendan 1369ea8dc4b6Seschrock static void 137044eda4d7Smaybee arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all) 1371ea8dc4b6Seschrock { 1372ea8dc4b6Seschrock arc_buf_t **bufp; 1373ea8dc4b6Seschrock 1374ea8dc4b6Seschrock /* free up data associated with the buf */ 1375ea8dc4b6Seschrock if (buf->b_data) { 1376ea8dc4b6Seschrock arc_state_t *state = buf->b_hdr->b_state; 1377ea8dc4b6Seschrock uint64_t size = buf->b_hdr->b_size; 1378ad23a2dbSjohansen arc_buf_contents_t type = buf->b_hdr->b_type; 1379ea8dc4b6Seschrock 13806b4acc8bSahrens arc_cksum_verify(buf); 1381b24ab676SJeff Bonwick 138244eda4d7Smaybee if (!recycle) { 1383ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 1384fa94a07fSbrendan arc_buf_data_free(buf->b_hdr, zio_buf_free, 1385fa94a07fSbrendan buf->b_data, size); 13865a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(size, ARC_SPACE_DATA); 1387ad23a2dbSjohansen } else { 1388ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 1389fa94a07fSbrendan arc_buf_data_free(buf->b_hdr, 1390fa94a07fSbrendan zio_data_buf_free, buf->b_data, size); 13915a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, -size); 13920e8c6158Smaybee atomic_add_64(&arc_size, -size); 1393ad23a2dbSjohansen } 139444eda4d7Smaybee } 1395ea8dc4b6Seschrock if (list_link_active(&buf->b_hdr->b_arc_node)) { 13960e8c6158Smaybee uint64_t *cnt = &state->arcs_lsize[type]; 13970e8c6158Smaybee 1398ea8dc4b6Seschrock ASSERT(refcount_is_zero(&buf->b_hdr->b_refcnt)); 139944cb6abcSbmc ASSERT(state != arc_anon); 14000e8c6158Smaybee 14010e8c6158Smaybee ASSERT3U(*cnt, >=, size); 14020e8c6158Smaybee atomic_add_64(cnt, -size); 1403ea8dc4b6Seschrock } 140444cb6abcSbmc ASSERT3U(state->arcs_size, >=, size); 140544cb6abcSbmc atomic_add_64(&state->arcs_size, -size); 1406ea8dc4b6Seschrock buf->b_data = NULL; 1407ea8dc4b6Seschrock ASSERT(buf->b_hdr->b_datacnt > 0); 1408ea8dc4b6Seschrock buf->b_hdr->b_datacnt -= 1; 1409ea8dc4b6Seschrock } 1410ea8dc4b6Seschrock 1411ea8dc4b6Seschrock /* only remove the buf if requested */ 1412ea8dc4b6Seschrock if (!all) 1413ea8dc4b6Seschrock return; 1414ea8dc4b6Seschrock 1415ea8dc4b6Seschrock /* remove the buf from the hdr list */ 1416ea8dc4b6Seschrock for (bufp = &buf->b_hdr->b_buf; *bufp != buf; bufp = &(*bufp)->b_next) 1417ea8dc4b6Seschrock continue; 1418ea8dc4b6Seschrock *bufp = buf->b_next; 14193f9d6ad7SLin Ling buf->b_next = NULL; 1420ea8dc4b6Seschrock 1421ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 1422ea8dc4b6Seschrock 1423ea8dc4b6Seschrock /* clean up the buf */ 1424ea8dc4b6Seschrock buf->b_hdr = NULL; 1425ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 1426ea8dc4b6Seschrock } 1427ea8dc4b6Seschrock 1428fa9e4066Sahrens static void 1429ea8dc4b6Seschrock arc_hdr_destroy(arc_buf_hdr_t *hdr) 1430fa9e4066Sahrens { 1431fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt)); 143244cb6abcSbmc ASSERT3P(hdr->b_state, ==, arc_anon); 1433ea8dc4b6Seschrock ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 1434b24ab676SJeff Bonwick l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr; 1435fa9e4066Sahrens 1436b24ab676SJeff Bonwick if (l2hdr != NULL) { 1437b24ab676SJeff Bonwick boolean_t buflist_held = MUTEX_HELD(&l2arc_buflist_mtx); 1438b24ab676SJeff Bonwick /* 1439b24ab676SJeff Bonwick * To prevent arc_free() and l2arc_evict() from 1440b24ab676SJeff Bonwick * attempting to free the same buffer at the same time, 1441b24ab676SJeff Bonwick * a FREE_IN_PROGRESS flag is given to arc_free() to 1442b24ab676SJeff Bonwick * give it priority. l2arc_evict() can't destroy this 1443b24ab676SJeff Bonwick * header while we are waiting on l2arc_buflist_mtx. 1444b24ab676SJeff Bonwick * 1445b24ab676SJeff Bonwick * The hdr may be removed from l2ad_buflist before we 1446b24ab676SJeff Bonwick * grab l2arc_buflist_mtx, so b_l2hdr is rechecked. 1447b24ab676SJeff Bonwick */ 1448b24ab676SJeff Bonwick if (!buflist_held) { 1449fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 1450b24ab676SJeff Bonwick l2hdr = hdr->b_l2hdr; 1451fa94a07fSbrendan } 1452b24ab676SJeff Bonwick 1453b24ab676SJeff Bonwick if (l2hdr != NULL) { 1454b24ab676SJeff Bonwick list_remove(l2hdr->b_dev->l2ad_buflist, hdr); 1455b24ab676SJeff Bonwick ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size); 1456b24ab676SJeff Bonwick kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); 1457b24ab676SJeff Bonwick if (hdr->b_state == arc_l2c_only) 1458b24ab676SJeff Bonwick l2arc_hdr_stat_remove(); 1459b24ab676SJeff Bonwick hdr->b_l2hdr = NULL; 1460b24ab676SJeff Bonwick } 1461b24ab676SJeff Bonwick 1462b24ab676SJeff Bonwick if (!buflist_held) 1463b24ab676SJeff Bonwick mutex_exit(&l2arc_buflist_mtx); 1464fa94a07fSbrendan } 1465fa94a07fSbrendan 1466fa9e4066Sahrens if (!BUF_EMPTY(hdr)) { 1467ea8dc4b6Seschrock ASSERT(!HDR_IN_HASH_TABLE(hdr)); 14683f9d6ad7SLin Ling buf_discard_identity(hdr); 1469fa9e4066Sahrens } 1470ea8dc4b6Seschrock while (hdr->b_buf) { 1471fa9e4066Sahrens arc_buf_t *buf = hdr->b_buf; 1472fa9e4066Sahrens 1473ea8dc4b6Seschrock if (buf->b_efunc) { 1474ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 14753f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 1476ea8dc4b6Seschrock ASSERT(buf->b_hdr != NULL); 147744eda4d7Smaybee arc_buf_destroy(hdr->b_buf, FALSE, FALSE); 1478ea8dc4b6Seschrock hdr->b_buf = buf->b_next; 147940d7d650Smaybee buf->b_hdr = &arc_eviction_hdr; 1480ea8dc4b6Seschrock buf->b_next = arc_eviction_list; 1481ea8dc4b6Seschrock arc_eviction_list = buf; 14823f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1483ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1484ea8dc4b6Seschrock } else { 148544eda4d7Smaybee arc_buf_destroy(hdr->b_buf, FALSE, TRUE); 1486ea8dc4b6Seschrock } 1487fa9e4066Sahrens } 14886b4acc8bSahrens if (hdr->b_freeze_cksum != NULL) { 14896b4acc8bSahrens kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 14906b4acc8bSahrens hdr->b_freeze_cksum = NULL; 14916b4acc8bSahrens } 14923f9d6ad7SLin Ling if (hdr->b_thawed) { 14933f9d6ad7SLin Ling kmem_free(hdr->b_thawed, 1); 14943f9d6ad7SLin Ling hdr->b_thawed = NULL; 14953f9d6ad7SLin Ling } 1496ea8dc4b6Seschrock 1497fa9e4066Sahrens ASSERT(!list_link_active(&hdr->b_arc_node)); 1498fa9e4066Sahrens ASSERT3P(hdr->b_hash_next, ==, NULL); 1499fa9e4066Sahrens ASSERT3P(hdr->b_acb, ==, NULL); 1500fa9e4066Sahrens kmem_cache_free(hdr_cache, hdr); 1501fa9e4066Sahrens } 1502fa9e4066Sahrens 1503fa9e4066Sahrens void 1504fa9e4066Sahrens arc_buf_free(arc_buf_t *buf, void *tag) 1505fa9e4066Sahrens { 1506fa9e4066Sahrens arc_buf_hdr_t *hdr = buf->b_hdr; 150744cb6abcSbmc int hashed = hdr->b_state != arc_anon; 1508fa9e4066Sahrens 1509ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 1510ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 1511ea8dc4b6Seschrock 1512ea8dc4b6Seschrock if (hashed) { 1513ea8dc4b6Seschrock kmutex_t *hash_lock = HDR_LOCK(hdr); 1514ea8dc4b6Seschrock 1515ea8dc4b6Seschrock mutex_enter(hash_lock); 15163f9d6ad7SLin Ling hdr = buf->b_hdr; 15173f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 15183f9d6ad7SLin Ling 1519ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 1520b24ab676SJeff Bonwick if (hdr->b_datacnt > 1) { 152144eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1522b24ab676SJeff Bonwick } else { 1523b24ab676SJeff Bonwick ASSERT(buf == hdr->b_buf); 1524b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 1525ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 1526b24ab676SJeff Bonwick } 1527fa9e4066Sahrens mutex_exit(hash_lock); 1528ea8dc4b6Seschrock } else if (HDR_IO_IN_PROGRESS(hdr)) { 1529ea8dc4b6Seschrock int destroy_hdr; 1530ea8dc4b6Seschrock /* 1531ea8dc4b6Seschrock * We are in the middle of an async write. Don't destroy 1532ea8dc4b6Seschrock * this buffer unless the write completes before we finish 1533ea8dc4b6Seschrock * decrementing the reference count. 1534ea8dc4b6Seschrock */ 1535ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1536ea8dc4b6Seschrock (void) remove_reference(hdr, NULL, tag); 1537ea8dc4b6Seschrock ASSERT(refcount_is_zero(&hdr->b_refcnt)); 1538ea8dc4b6Seschrock destroy_hdr = !HDR_IO_IN_PROGRESS(hdr); 1539ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1540ea8dc4b6Seschrock if (destroy_hdr) 1541ea8dc4b6Seschrock arc_hdr_destroy(hdr); 1542ea8dc4b6Seschrock } else { 15433f9d6ad7SLin Ling if (remove_reference(hdr, NULL, tag) > 0) 154444eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 15453f9d6ad7SLin Ling else 1546ea8dc4b6Seschrock arc_hdr_destroy(hdr); 1547fa9e4066Sahrens } 1548ea8dc4b6Seschrock } 1549fa9e4066Sahrens 1550ea8dc4b6Seschrock int 1551ea8dc4b6Seschrock arc_buf_remove_ref(arc_buf_t *buf, void* tag) 1552ea8dc4b6Seschrock { 1553ea8dc4b6Seschrock arc_buf_hdr_t *hdr = buf->b_hdr; 1554ea8dc4b6Seschrock kmutex_t *hash_lock = HDR_LOCK(hdr); 1555ea8dc4b6Seschrock int no_callback = (buf->b_efunc == NULL); 1556fa9e4066Sahrens 155744cb6abcSbmc if (hdr->b_state == arc_anon) { 1558b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 1559ea8dc4b6Seschrock arc_buf_free(buf, tag); 1560ea8dc4b6Seschrock return (no_callback); 1561ea8dc4b6Seschrock } 1562ea8dc4b6Seschrock 1563ea8dc4b6Seschrock mutex_enter(hash_lock); 15643f9d6ad7SLin Ling hdr = buf->b_hdr; 15653f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 156644cb6abcSbmc ASSERT(hdr->b_state != arc_anon); 1567ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 1568ea8dc4b6Seschrock 1569ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 1570ea8dc4b6Seschrock if (hdr->b_datacnt > 1) { 1571ea8dc4b6Seschrock if (no_callback) 157244eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1573ea8dc4b6Seschrock } else if (no_callback) { 1574ea8dc4b6Seschrock ASSERT(hdr->b_buf == buf && buf->b_next == NULL); 1575b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 1576ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 1577ea8dc4b6Seschrock } 1578ea8dc4b6Seschrock ASSERT(no_callback || hdr->b_datacnt > 1 || 1579ea8dc4b6Seschrock refcount_is_zero(&hdr->b_refcnt)); 1580ea8dc4b6Seschrock mutex_exit(hash_lock); 1581ea8dc4b6Seschrock return (no_callback); 1582fa9e4066Sahrens } 1583fa9e4066Sahrens 1584fa9e4066Sahrens int 1585fa9e4066Sahrens arc_buf_size(arc_buf_t *buf) 1586fa9e4066Sahrens { 1587fa9e4066Sahrens return (buf->b_hdr->b_size); 1588fa9e4066Sahrens } 1589fa9e4066Sahrens 1590fa9e4066Sahrens /* 1591fa9e4066Sahrens * Evict buffers from list until we've removed the specified number of 1592fa9e4066Sahrens * bytes. Move the removed buffers to the appropriate evict state. 159344eda4d7Smaybee * If the recycle flag is set, then attempt to "recycle" a buffer: 159444eda4d7Smaybee * - look for a buffer to evict that is `bytes' long. 159544eda4d7Smaybee * - return the data block from this buffer rather than freeing it. 159644eda4d7Smaybee * This flag is used by callers that are trying to make space for a 159744eda4d7Smaybee * new buffer in a full arc cache. 1598874395d5Smaybee * 1599874395d5Smaybee * This function makes a "best effort". It skips over any buffers 1600874395d5Smaybee * it can't get a hash_lock on, and so may not catch all candidates. 1601874395d5Smaybee * It may also return without evicting as much space as requested. 1602fa9e4066Sahrens */ 160344eda4d7Smaybee static void * 1604ac05c741SMark Maybee arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle, 1605ad23a2dbSjohansen arc_buf_contents_t type) 1606fa9e4066Sahrens { 1607fa9e4066Sahrens arc_state_t *evicted_state; 160844eda4d7Smaybee uint64_t bytes_evicted = 0, skipped = 0, missed = 0; 16093fa51506Smaybee arc_buf_hdr_t *ab, *ab_prev = NULL; 16100e8c6158Smaybee list_t *list = &state->arcs_list[type]; 1611fa9e4066Sahrens kmutex_t *hash_lock; 161244eda4d7Smaybee boolean_t have_lock; 16133fa51506Smaybee void *stolen = NULL; 1614fa9e4066Sahrens 161544cb6abcSbmc ASSERT(state == arc_mru || state == arc_mfu); 1616fa9e4066Sahrens 161744cb6abcSbmc evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; 1618fa9e4066Sahrens 161944cb6abcSbmc mutex_enter(&state->arcs_mtx); 162044cb6abcSbmc mutex_enter(&evicted_state->arcs_mtx); 1621fa9e4066Sahrens 16220e8c6158Smaybee for (ab = list_tail(list); ab; ab = ab_prev) { 16230e8c6158Smaybee ab_prev = list_prev(list, ab); 162413506d1eSmaybee /* prefetch buffers have a minimum lifespan */ 162544eda4d7Smaybee if (HDR_IO_IN_PROGRESS(ab) || 1626874395d5Smaybee (spa && ab->b_spa != spa) || 162744eda4d7Smaybee (ab->b_flags & (ARC_PREFETCH|ARC_INDIRECT) && 1628d3d50737SRafael Vanoni ddi_get_lbolt() - ab->b_arc_access < 1629d3d50737SRafael Vanoni arc_min_prefetch_lifespan)) { 163013506d1eSmaybee skipped++; 163113506d1eSmaybee continue; 163213506d1eSmaybee } 16333fa51506Smaybee /* "lookahead" for better eviction candidate */ 16343fa51506Smaybee if (recycle && ab->b_size != bytes && 16353fa51506Smaybee ab_prev && ab_prev->b_size == bytes) 163644eda4d7Smaybee continue; 1637fa9e4066Sahrens hash_lock = HDR_LOCK(ab); 163844eda4d7Smaybee have_lock = MUTEX_HELD(hash_lock); 163944eda4d7Smaybee if (have_lock || mutex_tryenter(hash_lock)) { 1640fa9e4066Sahrens ASSERT3U(refcount_count(&ab->b_refcnt), ==, 0); 1641ea8dc4b6Seschrock ASSERT(ab->b_datacnt > 0); 1642ea8dc4b6Seschrock while (ab->b_buf) { 1643ea8dc4b6Seschrock arc_buf_t *buf = ab->b_buf; 16443f9d6ad7SLin Ling if (!mutex_tryenter(&buf->b_evict_lock)) { 16456f83844dSMark Maybee missed += 1; 16466f83844dSMark Maybee break; 16476f83844dSMark Maybee } 164844eda4d7Smaybee if (buf->b_data) { 1649ea8dc4b6Seschrock bytes_evicted += ab->b_size; 1650ad23a2dbSjohansen if (recycle && ab->b_type == type && 1651fa94a07fSbrendan ab->b_size == bytes && 1652fa94a07fSbrendan !HDR_L2_WRITING(ab)) { 16533fa51506Smaybee stolen = buf->b_data; 16543fa51506Smaybee recycle = FALSE; 16553fa51506Smaybee } 165644eda4d7Smaybee } 1657ea8dc4b6Seschrock if (buf->b_efunc) { 1658ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 16593fa51506Smaybee arc_buf_destroy(buf, 16603fa51506Smaybee buf->b_data == stolen, FALSE); 1661ea8dc4b6Seschrock ab->b_buf = buf->b_next; 166240d7d650Smaybee buf->b_hdr = &arc_eviction_hdr; 1663ea8dc4b6Seschrock buf->b_next = arc_eviction_list; 1664ea8dc4b6Seschrock arc_eviction_list = buf; 1665ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 16663f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1667ea8dc4b6Seschrock } else { 16683f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 16693fa51506Smaybee arc_buf_destroy(buf, 16703fa51506Smaybee buf->b_data == stolen, TRUE); 1671ea8dc4b6Seschrock } 1672ea8dc4b6Seschrock } 16735ea40c06SBrendan Gregg - Sun Microsystems 16745ea40c06SBrendan Gregg - Sun Microsystems if (ab->b_l2hdr) { 16755ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_evict_l2_cached, 16765ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16775ea40c06SBrendan Gregg - Sun Microsystems } else { 16785ea40c06SBrendan Gregg - Sun Microsystems if (l2arc_write_eligible(ab->b_spa, ab)) { 16795ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_evict_l2_eligible, 16805ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16815ea40c06SBrendan Gregg - Sun Microsystems } else { 16825ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR( 16835ea40c06SBrendan Gregg - Sun Microsystems arcstat_evict_l2_ineligible, 16845ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16855ea40c06SBrendan Gregg - Sun Microsystems } 16865ea40c06SBrendan Gregg - Sun Microsystems } 16875ea40c06SBrendan Gregg - Sun Microsystems 16886f83844dSMark Maybee if (ab->b_datacnt == 0) { 16896f83844dSMark Maybee arc_change_state(evicted_state, ab, hash_lock); 16906f83844dSMark Maybee ASSERT(HDR_IN_HASH_TABLE(ab)); 16916f83844dSMark Maybee ab->b_flags |= ARC_IN_HASH_TABLE; 16926f83844dSMark Maybee ab->b_flags &= ~ARC_BUF_AVAILABLE; 16936f83844dSMark Maybee DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab); 16946f83844dSMark Maybee } 169544eda4d7Smaybee if (!have_lock) 169644eda4d7Smaybee mutex_exit(hash_lock); 1697ea8dc4b6Seschrock if (bytes >= 0 && bytes_evicted >= bytes) 1698fa9e4066Sahrens break; 1699fa9e4066Sahrens } else { 170044eda4d7Smaybee missed += 1; 1701fa9e4066Sahrens } 1702fa9e4066Sahrens } 170344cb6abcSbmc 170444cb6abcSbmc mutex_exit(&evicted_state->arcs_mtx); 170544cb6abcSbmc mutex_exit(&state->arcs_mtx); 1706fa9e4066Sahrens 1707fa9e4066Sahrens if (bytes_evicted < bytes) 1708fa9e4066Sahrens dprintf("only evicted %lld bytes from %x", 1709fa9e4066Sahrens (longlong_t)bytes_evicted, state); 1710fa9e4066Sahrens 171144eda4d7Smaybee if (skipped) 171244cb6abcSbmc ARCSTAT_INCR(arcstat_evict_skip, skipped); 171344cb6abcSbmc 171444eda4d7Smaybee if (missed) 171544cb6abcSbmc ARCSTAT_INCR(arcstat_mutex_miss, missed); 1716f4d2e9e6Smaybee 1717f4d2e9e6Smaybee /* 1718f4d2e9e6Smaybee * We have just evicted some date into the ghost state, make 1719f4d2e9e6Smaybee * sure we also adjust the ghost state size if necessary. 1720f4d2e9e6Smaybee */ 1721f4d2e9e6Smaybee if (arc_no_grow && 1722f4d2e9e6Smaybee arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size > arc_c) { 1723f4d2e9e6Smaybee int64_t mru_over = arc_anon->arcs_size + arc_mru->arcs_size + 1724f4d2e9e6Smaybee arc_mru_ghost->arcs_size - arc_c; 1725f4d2e9e6Smaybee 1726f4d2e9e6Smaybee if (mru_over > 0 && arc_mru_ghost->arcs_lsize[type] > 0) { 1727f4d2e9e6Smaybee int64_t todelete = 1728f4d2e9e6Smaybee MIN(arc_mru_ghost->arcs_lsize[type], mru_over); 1729874395d5Smaybee arc_evict_ghost(arc_mru_ghost, NULL, todelete); 1730f4d2e9e6Smaybee } else if (arc_mfu_ghost->arcs_lsize[type] > 0) { 1731f4d2e9e6Smaybee int64_t todelete = MIN(arc_mfu_ghost->arcs_lsize[type], 1732f4d2e9e6Smaybee arc_mru_ghost->arcs_size + 1733f4d2e9e6Smaybee arc_mfu_ghost->arcs_size - arc_c); 1734874395d5Smaybee arc_evict_ghost(arc_mfu_ghost, NULL, todelete); 1735f4d2e9e6Smaybee } 1736f4d2e9e6Smaybee } 173744cb6abcSbmc 17383fa51506Smaybee return (stolen); 1739fa9e4066Sahrens } 1740fa9e4066Sahrens 1741fa9e4066Sahrens /* 1742fa9e4066Sahrens * Remove buffers from list until we've removed the specified number of 1743fa9e4066Sahrens * bytes. Destroy the buffers that are removed. 1744fa9e4066Sahrens */ 1745fa9e4066Sahrens static void 1746ac05c741SMark Maybee arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes) 1747fa9e4066Sahrens { 1748fa9e4066Sahrens arc_buf_hdr_t *ab, *ab_prev; 1749b802aa8cSSanjeev Bagewadi arc_buf_hdr_t marker = { 0 }; 17500e8c6158Smaybee list_t *list = &state->arcs_list[ARC_BUFC_DATA]; 1751fa9e4066Sahrens kmutex_t *hash_lock; 1752ea8dc4b6Seschrock uint64_t bytes_deleted = 0; 1753c0a81264Sek uint64_t bufs_skipped = 0; 1754fa9e4066Sahrens 1755ea8dc4b6Seschrock ASSERT(GHOST_STATE(state)); 1756fa9e4066Sahrens top: 175744cb6abcSbmc mutex_enter(&state->arcs_mtx); 17580e8c6158Smaybee for (ab = list_tail(list); ab; ab = ab_prev) { 17590e8c6158Smaybee ab_prev = list_prev(list, ab); 1760874395d5Smaybee if (spa && ab->b_spa != spa) 1761874395d5Smaybee continue; 1762b802aa8cSSanjeev Bagewadi 1763b802aa8cSSanjeev Bagewadi /* ignore markers */ 1764b802aa8cSSanjeev Bagewadi if (ab->b_spa == 0) 1765b802aa8cSSanjeev Bagewadi continue; 1766b802aa8cSSanjeev Bagewadi 1767fa9e4066Sahrens hash_lock = HDR_LOCK(ab); 17687e453561SWilliam Gorrell /* caller may be trying to modify this buffer, skip it */ 17697e453561SWilliam Gorrell if (MUTEX_HELD(hash_lock)) 17707e453561SWilliam Gorrell continue; 17717e453561SWilliam Gorrell if (mutex_tryenter(hash_lock)) { 177213506d1eSmaybee ASSERT(!HDR_IO_IN_PROGRESS(ab)); 1773ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 177444cb6abcSbmc ARCSTAT_BUMP(arcstat_deleted); 1775fa9e4066Sahrens bytes_deleted += ab->b_size; 1776fa94a07fSbrendan 1777fa94a07fSbrendan if (ab->b_l2hdr != NULL) { 1778fa94a07fSbrendan /* 1779fa94a07fSbrendan * This buffer is cached on the 2nd Level ARC; 1780fa94a07fSbrendan * don't destroy the header. 1781fa94a07fSbrendan */ 1782fa94a07fSbrendan arc_change_state(arc_l2c_only, ab, hash_lock); 17837e453561SWilliam Gorrell mutex_exit(hash_lock); 1784fa94a07fSbrendan } else { 1785fa94a07fSbrendan arc_change_state(arc_anon, ab, hash_lock); 17867e453561SWilliam Gorrell mutex_exit(hash_lock); 1787fa94a07fSbrendan arc_hdr_destroy(ab); 1788fa94a07fSbrendan } 1789fa94a07fSbrendan 1790ea8dc4b6Seschrock DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, ab); 1791fa9e4066Sahrens if (bytes >= 0 && bytes_deleted >= bytes) 1792fa9e4066Sahrens break; 1793b802aa8cSSanjeev Bagewadi } else if (bytes < 0) { 1794b802aa8cSSanjeev Bagewadi /* 1795b802aa8cSSanjeev Bagewadi * Insert a list marker and then wait for the 1796b802aa8cSSanjeev Bagewadi * hash lock to become available. Once its 1797b802aa8cSSanjeev Bagewadi * available, restart from where we left off. 1798b802aa8cSSanjeev Bagewadi */ 1799b802aa8cSSanjeev Bagewadi list_insert_after(list, ab, &marker); 1800b802aa8cSSanjeev Bagewadi mutex_exit(&state->arcs_mtx); 1801b802aa8cSSanjeev Bagewadi mutex_enter(hash_lock); 1802b802aa8cSSanjeev Bagewadi mutex_exit(hash_lock); 1803b802aa8cSSanjeev Bagewadi mutex_enter(&state->arcs_mtx); 1804b802aa8cSSanjeev Bagewadi ab_prev = list_prev(list, &marker); 1805b802aa8cSSanjeev Bagewadi list_remove(list, &marker); 1806b802aa8cSSanjeev Bagewadi } else 1807fa9e4066Sahrens bufs_skipped += 1; 1808fa9e4066Sahrens } 180944cb6abcSbmc mutex_exit(&state->arcs_mtx); 1810fa9e4066Sahrens 18110e8c6158Smaybee if (list == &state->arcs_list[ARC_BUFC_DATA] && 18120e8c6158Smaybee (bytes < 0 || bytes_deleted < bytes)) { 18130e8c6158Smaybee list = &state->arcs_list[ARC_BUFC_METADATA]; 18140e8c6158Smaybee goto top; 18150e8c6158Smaybee } 18160e8c6158Smaybee 1817fa9e4066Sahrens if (bufs_skipped) { 181844cb6abcSbmc ARCSTAT_INCR(arcstat_mutex_miss, bufs_skipped); 1819fa9e4066Sahrens ASSERT(bytes >= 0); 1820fa9e4066Sahrens } 1821fa9e4066Sahrens 1822fa9e4066Sahrens if (bytes_deleted < bytes) 1823fa9e4066Sahrens dprintf("only deleted %lld bytes from %p", 1824fa9e4066Sahrens (longlong_t)bytes_deleted, state); 1825fa9e4066Sahrens } 1826fa9e4066Sahrens 1827fa9e4066Sahrens static void 1828fa9e4066Sahrens arc_adjust(void) 1829fa9e4066Sahrens { 18305a98e54bSBrendan Gregg - Sun Microsystems int64_t adjustment, delta; 1831fa9e4066Sahrens 18325a98e54bSBrendan Gregg - Sun Microsystems /* 18335a98e54bSBrendan Gregg - Sun Microsystems * Adjust MRU size 18345a98e54bSBrendan Gregg - Sun Microsystems */ 18355a98e54bSBrendan Gregg - Sun Microsystems 18363e4e8481STom Erickson adjustment = MIN((int64_t)(arc_size - arc_c), 18373e4e8481STom Erickson (int64_t)(arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used - 18383e4e8481STom Erickson arc_p)); 1839fa9e4066Sahrens 18405a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_DATA] > 0) { 18415a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_DATA], adjustment); 18425a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mru, NULL, delta, FALSE, ARC_BUFC_DATA); 18435a98e54bSBrendan Gregg - Sun Microsystems adjustment -= delta; 18440e8c6158Smaybee } 18450e8c6158Smaybee 18465a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { 18475a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); 18485a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mru, NULL, delta, FALSE, 1849874395d5Smaybee ARC_BUFC_METADATA); 1850fa9e4066Sahrens } 1851fa9e4066Sahrens 18525a98e54bSBrendan Gregg - Sun Microsystems /* 18535a98e54bSBrendan Gregg - Sun Microsystems * Adjust MFU size 18545a98e54bSBrendan Gregg - Sun Microsystems */ 1855fa9e4066Sahrens 18565a98e54bSBrendan Gregg - Sun Microsystems adjustment = arc_size - arc_c; 18575a98e54bSBrendan Gregg - Sun Microsystems 18585a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_DATA] > 0) { 18595a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(adjustment, arc_mfu->arcs_lsize[ARC_BUFC_DATA]); 18605a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mfu, NULL, delta, FALSE, ARC_BUFC_DATA); 18615a98e54bSBrendan Gregg - Sun Microsystems adjustment -= delta; 1862fa9e4066Sahrens } 1863fa9e4066Sahrens 18645a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { 18655a98e54bSBrendan Gregg - Sun Microsystems int64_t delta = MIN(adjustment, 18665a98e54bSBrendan Gregg - Sun Microsystems arc_mfu->arcs_lsize[ARC_BUFC_METADATA]); 18675a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mfu, NULL, delta, FALSE, 18685a98e54bSBrendan Gregg - Sun Microsystems ARC_BUFC_METADATA); 18695a98e54bSBrendan Gregg - Sun Microsystems } 1870fa9e4066Sahrens 18715a98e54bSBrendan Gregg - Sun Microsystems /* 18725a98e54bSBrendan Gregg - Sun Microsystems * Adjust ghost lists 18735a98e54bSBrendan Gregg - Sun Microsystems */ 1874fa9e4066Sahrens 18755a98e54bSBrendan Gregg - Sun Microsystems adjustment = arc_mru->arcs_size + arc_mru_ghost->arcs_size - arc_c; 1876fa9e4066Sahrens 18775a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru_ghost->arcs_size > 0) { 18785a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru_ghost->arcs_size, adjustment); 18795a98e54bSBrendan Gregg - Sun Microsystems arc_evict_ghost(arc_mru_ghost, NULL, delta); 18805a98e54bSBrendan Gregg - Sun Microsystems } 18810e8c6158Smaybee 18825a98e54bSBrendan Gregg - Sun Microsystems adjustment = 18835a98e54bSBrendan Gregg - Sun Microsystems arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size - arc_c; 18845a98e54bSBrendan Gregg - Sun Microsystems 18855a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu_ghost->arcs_size > 0) { 18865a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mfu_ghost->arcs_size, adjustment); 18875a98e54bSBrendan Gregg - Sun Microsystems arc_evict_ghost(arc_mfu_ghost, NULL, delta); 1888fa9e4066Sahrens } 1889fa9e4066Sahrens } 1890fa9e4066Sahrens 1891ea8dc4b6Seschrock static void 1892ea8dc4b6Seschrock arc_do_user_evicts(void) 1893ea8dc4b6Seschrock { 1894ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1895ea8dc4b6Seschrock while (arc_eviction_list != NULL) { 1896ea8dc4b6Seschrock arc_buf_t *buf = arc_eviction_list; 1897ea8dc4b6Seschrock arc_eviction_list = buf->b_next; 18983f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 1899ea8dc4b6Seschrock buf->b_hdr = NULL; 19003f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1901ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1902ea8dc4b6Seschrock 1903dd6ef538Smaybee if (buf->b_efunc != NULL) 1904dd6ef538Smaybee VERIFY(buf->b_efunc(buf) == 0); 1905ea8dc4b6Seschrock 1906ea8dc4b6Seschrock buf->b_efunc = NULL; 1907ea8dc4b6Seschrock buf->b_private = NULL; 1908ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 1909ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1910ea8dc4b6Seschrock } 1911ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1912ea8dc4b6Seschrock } 1913ea8dc4b6Seschrock 1914fa9e4066Sahrens /* 1915874395d5Smaybee * Flush all *evictable* data from the cache for the given spa. 1916fa9e4066Sahrens * NOTE: this will not touch "active" (i.e. referenced) data. 1917fa9e4066Sahrens */ 1918fa9e4066Sahrens void 1919874395d5Smaybee arc_flush(spa_t *spa) 1920fa9e4066Sahrens { 1921ac05c741SMark Maybee uint64_t guid = 0; 1922ac05c741SMark Maybee 1923ac05c741SMark Maybee if (spa) 1924e9103aaeSGarrett D'Amore guid = spa_load_guid(spa); 1925ac05c741SMark Maybee 1926874395d5Smaybee while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) { 1927ac05c741SMark Maybee (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA); 1928874395d5Smaybee if (spa) 1929874395d5Smaybee break; 1930874395d5Smaybee } 1931874395d5Smaybee while (list_head(&arc_mru->arcs_list[ARC_BUFC_METADATA])) { 1932ac05c741SMark Maybee (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_METADATA); 1933874395d5Smaybee if (spa) 1934874395d5Smaybee break; 1935874395d5Smaybee } 1936874395d5Smaybee while (list_head(&arc_mfu->arcs_list[ARC_BUFC_DATA])) { 1937ac05c741SMark Maybee (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_DATA); 1938874395d5Smaybee if (spa) 1939874395d5Smaybee break; 1940874395d5Smaybee } 1941874395d5Smaybee while (list_head(&arc_mfu->arcs_list[ARC_BUFC_METADATA])) { 1942ac05c741SMark Maybee (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_METADATA); 1943874395d5Smaybee if (spa) 1944874395d5Smaybee break; 1945874395d5Smaybee } 1946874395d5Smaybee 1947ac05c741SMark Maybee arc_evict_ghost(arc_mru_ghost, guid, -1); 1948ac05c741SMark Maybee arc_evict_ghost(arc_mfu_ghost, guid, -1); 1949ea8dc4b6Seschrock 1950ea8dc4b6Seschrock mutex_enter(&arc_reclaim_thr_lock); 1951ea8dc4b6Seschrock arc_do_user_evicts(); 1952ea8dc4b6Seschrock mutex_exit(&arc_reclaim_thr_lock); 1953874395d5Smaybee ASSERT(spa || arc_eviction_list == NULL); 1954fa9e4066Sahrens } 1955fa9e4066Sahrens 1956fa9e4066Sahrens void 195749e3519aSmaybee arc_shrink(void) 1958fa9e4066Sahrens { 195944cb6abcSbmc if (arc_c > arc_c_min) { 196049e3519aSmaybee uint64_t to_free; 1961fa9e4066Sahrens 19623cff2f43Sstans #ifdef _KERNEL 196344cb6abcSbmc to_free = MAX(arc_c >> arc_shrink_shift, ptob(needfree)); 19643cff2f43Sstans #else 196544cb6abcSbmc to_free = arc_c >> arc_shrink_shift; 19663cff2f43Sstans #endif 196744cb6abcSbmc if (arc_c > arc_c_min + to_free) 196844cb6abcSbmc atomic_add_64(&arc_c, -to_free); 196949e3519aSmaybee else 197044cb6abcSbmc arc_c = arc_c_min; 197144cb6abcSbmc 197244cb6abcSbmc atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift)); 197344cb6abcSbmc if (arc_c > arc_size) 197444cb6abcSbmc arc_c = MAX(arc_size, arc_c_min); 197544cb6abcSbmc if (arc_p > arc_c) 197644cb6abcSbmc arc_p = (arc_c >> 1); 197744cb6abcSbmc ASSERT(arc_c >= arc_c_min); 197844cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 197949e3519aSmaybee } 1980fa9e4066Sahrens 198144cb6abcSbmc if (arc_size > arc_c) 198249e3519aSmaybee arc_adjust(); 1983fa9e4066Sahrens } 1984fa9e4066Sahrens 198594dd93aeSGeorge Wilson /* 198694dd93aeSGeorge Wilson * Determine if the system is under memory pressure and is asking 198794dd93aeSGeorge Wilson * to reclaim memory. A return value of 1 indicates that the system 198894dd93aeSGeorge Wilson * is under memory pressure and that the arc should adjust accordingly. 198994dd93aeSGeorge Wilson */ 1990fa9e4066Sahrens static int 1991fa9e4066Sahrens arc_reclaim_needed(void) 1992fa9e4066Sahrens { 1993fa9e4066Sahrens uint64_t extra; 1994fa9e4066Sahrens 1995fa9e4066Sahrens #ifdef _KERNEL 19963cff2f43Sstans 19973cff2f43Sstans if (needfree) 19983cff2f43Sstans return (1); 19993cff2f43Sstans 2000fa9e4066Sahrens /* 2001fa9e4066Sahrens * take 'desfree' extra pages, so we reclaim sooner, rather than later 2002fa9e4066Sahrens */ 2003fa9e4066Sahrens extra = desfree; 2004fa9e4066Sahrens 2005fa9e4066Sahrens /* 2006fa9e4066Sahrens * check that we're out of range of the pageout scanner. It starts to 2007fa9e4066Sahrens * schedule paging if freemem is less than lotsfree and needfree. 2008fa9e4066Sahrens * lotsfree is the high-water mark for pageout, and needfree is the 2009fa9e4066Sahrens * number of needed free pages. We add extra pages here to make sure 2010fa9e4066Sahrens * the scanner doesn't start up while we're freeing memory. 2011fa9e4066Sahrens */ 2012fa9e4066Sahrens if (freemem < lotsfree + needfree + extra) 2013fa9e4066Sahrens return (1); 2014fa9e4066Sahrens 2015fa9e4066Sahrens /* 2016fa9e4066Sahrens * check to make sure that swapfs has enough space so that anon 2017fa94a07fSbrendan * reservations can still succeed. anon_resvmem() checks that the 2018fa9e4066Sahrens * availrmem is greater than swapfs_minfree, and the number of reserved 2019fa9e4066Sahrens * swap pages. We also add a bit of extra here just to prevent 2020fa9e4066Sahrens * circumstances from getting really dire. 2021fa9e4066Sahrens */ 2022fa9e4066Sahrens if (availrmem < swapfs_minfree + swapfs_reserve + extra) 2023fa9e4066Sahrens return (1); 2024fa9e4066Sahrens 20255dc8af33Smaybee #if defined(__i386) 2026fa9e4066Sahrens /* 2027fa9e4066Sahrens * If we're on an i386 platform, it's possible that we'll exhaust the 2028fa9e4066Sahrens * kernel heap space before we ever run out of available physical 2029fa9e4066Sahrens * memory. Most checks of the size of the heap_area compare against 2030fa9e4066Sahrens * tune.t_minarmem, which is the minimum available real memory that we 2031fa9e4066Sahrens * can have in the system. However, this is generally fixed at 25 pages 2032fa9e4066Sahrens * which is so low that it's useless. In this comparison, we seek to 2033fa9e4066Sahrens * calculate the total heap-size, and reclaim if more than 3/4ths of the 2034fa94a07fSbrendan * heap is allocated. (Or, in the calculation, if less than 1/4th is 2035fa9e4066Sahrens * free) 2036fa9e4066Sahrens */ 203794dd93aeSGeorge Wilson if (vmem_size(heap_arena, VMEM_FREE) < 203894dd93aeSGeorge Wilson (vmem_size(heap_arena, VMEM_FREE | VMEM_ALLOC) >> 2)) 2039fa9e4066Sahrens return (1); 2040fa9e4066Sahrens #endif 2041fa9e4066Sahrens 204294dd93aeSGeorge Wilson /* 204394dd93aeSGeorge Wilson * If zio data pages are being allocated out of a separate heap segment, 204494dd93aeSGeorge Wilson * then enforce that the size of available vmem for this arena remains 204594dd93aeSGeorge Wilson * above about 1/16th free. 204694dd93aeSGeorge Wilson * 204794dd93aeSGeorge Wilson * Note: The 1/16th arena free requirement was put in place 204894dd93aeSGeorge Wilson * to aggressively evict memory from the arc in order to avoid 204994dd93aeSGeorge Wilson * memory fragmentation issues. 205094dd93aeSGeorge Wilson */ 205194dd93aeSGeorge Wilson if (zio_arena != NULL && 205294dd93aeSGeorge Wilson vmem_size(zio_arena, VMEM_FREE) < 205394dd93aeSGeorge Wilson (vmem_size(zio_arena, VMEM_ALLOC) >> 4)) 205494dd93aeSGeorge Wilson return (1); 2055fa9e4066Sahrens #else 2056fa9e4066Sahrens if (spa_get_random(100) == 0) 2057fa9e4066Sahrens return (1); 2058fa9e4066Sahrens #endif 2059fa9e4066Sahrens return (0); 2060fa9e4066Sahrens } 2061fa9e4066Sahrens 2062fa9e4066Sahrens static void 2063fa9e4066Sahrens arc_kmem_reap_now(arc_reclaim_strategy_t strat) 2064fa9e4066Sahrens { 2065fa9e4066Sahrens size_t i; 2066fa9e4066Sahrens kmem_cache_t *prev_cache = NULL; 2067ad23a2dbSjohansen kmem_cache_t *prev_data_cache = NULL; 2068fa9e4066Sahrens extern kmem_cache_t *zio_buf_cache[]; 2069ad23a2dbSjohansen extern kmem_cache_t *zio_data_buf_cache[]; 2070fa9e4066Sahrens 2071033f9833Sek #ifdef _KERNEL 20720e8c6158Smaybee if (arc_meta_used >= arc_meta_limit) { 20730e8c6158Smaybee /* 20740e8c6158Smaybee * We are exceeding our meta-data cache limit. 20750e8c6158Smaybee * Purge some DNLC entries to release holds on meta-data. 20760e8c6158Smaybee */ 20770e8c6158Smaybee dnlc_reduce_cache((void *)(uintptr_t)arc_reduce_dnlc_percent); 20780e8c6158Smaybee } 20795dc8af33Smaybee #if defined(__i386) 20805dc8af33Smaybee /* 20815dc8af33Smaybee * Reclaim unused memory from all kmem caches. 20825dc8af33Smaybee */ 20835dc8af33Smaybee kmem_reap(); 20845dc8af33Smaybee #endif 2085033f9833Sek #endif 2086033f9833Sek 2087fa9e4066Sahrens /* 2088fa94a07fSbrendan * An aggressive reclamation will shrink the cache size as well as 2089ea8dc4b6Seschrock * reap free buffers from the arc kmem caches. 2090fa9e4066Sahrens */ 2091fa9e4066Sahrens if (strat == ARC_RECLAIM_AGGR) 209249e3519aSmaybee arc_shrink(); 2093fa9e4066Sahrens 2094fa9e4066Sahrens for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { 2095fa9e4066Sahrens if (zio_buf_cache[i] != prev_cache) { 2096fa9e4066Sahrens prev_cache = zio_buf_cache[i]; 2097fa9e4066Sahrens kmem_cache_reap_now(zio_buf_cache[i]); 2098fa9e4066Sahrens } 2099ad23a2dbSjohansen if (zio_data_buf_cache[i] != prev_data_cache) { 2100ad23a2dbSjohansen prev_data_cache = zio_data_buf_cache[i]; 2101ad23a2dbSjohansen kmem_cache_reap_now(zio_data_buf_cache[i]); 2102ad23a2dbSjohansen } 2103fa9e4066Sahrens } 2104ea8dc4b6Seschrock kmem_cache_reap_now(buf_cache); 2105ea8dc4b6Seschrock kmem_cache_reap_now(hdr_cache); 210694dd93aeSGeorge Wilson 210794dd93aeSGeorge Wilson /* 210894dd93aeSGeorge Wilson * Ask the vmem areana to reclaim unused memory from its 210994dd93aeSGeorge Wilson * quantum caches. 211094dd93aeSGeorge Wilson */ 211194dd93aeSGeorge Wilson if (zio_arena != NULL && strat == ARC_RECLAIM_AGGR) 211294dd93aeSGeorge Wilson vmem_qcache_reap(zio_arena); 2113fa9e4066Sahrens } 2114fa9e4066Sahrens 2115fa9e4066Sahrens static void 2116fa9e4066Sahrens arc_reclaim_thread(void) 2117fa9e4066Sahrens { 2118fa9e4066Sahrens clock_t growtime = 0; 2119fa9e4066Sahrens arc_reclaim_strategy_t last_reclaim = ARC_RECLAIM_CONS; 2120fa9e4066Sahrens callb_cpr_t cpr; 2121fa9e4066Sahrens 2122fa9e4066Sahrens CALLB_CPR_INIT(&cpr, &arc_reclaim_thr_lock, callb_generic_cpr, FTAG); 2123fa9e4066Sahrens 2124fa9e4066Sahrens mutex_enter(&arc_reclaim_thr_lock); 2125fa9e4066Sahrens while (arc_thread_exit == 0) { 2126fa9e4066Sahrens if (arc_reclaim_needed()) { 2127fa9e4066Sahrens 212844cb6abcSbmc if (arc_no_grow) { 2129fa9e4066Sahrens if (last_reclaim == ARC_RECLAIM_CONS) { 2130fa9e4066Sahrens last_reclaim = ARC_RECLAIM_AGGR; 2131fa9e4066Sahrens } else { 2132fa9e4066Sahrens last_reclaim = ARC_RECLAIM_CONS; 2133fa9e4066Sahrens } 2134fa9e4066Sahrens } else { 213544cb6abcSbmc arc_no_grow = TRUE; 2136fa9e4066Sahrens last_reclaim = ARC_RECLAIM_AGGR; 2137fa9e4066Sahrens membar_producer(); 2138fa9e4066Sahrens } 2139fa9e4066Sahrens 2140fa9e4066Sahrens /* reset the growth delay for every reclaim */ 2141d3d50737SRafael Vanoni growtime = ddi_get_lbolt() + (arc_grow_retry * hz); 2142fa9e4066Sahrens 2143fa9e4066Sahrens arc_kmem_reap_now(last_reclaim); 21443a737e0dSbrendan arc_warm = B_TRUE; 2145fa9e4066Sahrens 2146d3d50737SRafael Vanoni } else if (arc_no_grow && ddi_get_lbolt() >= growtime) { 214744cb6abcSbmc arc_no_grow = FALSE; 2148fa9e4066Sahrens } 2149fa9e4066Sahrens 21503e4e8481STom Erickson arc_adjust(); 2151641fbdaeSmaybee 2152ea8dc4b6Seschrock if (arc_eviction_list != NULL) 2153ea8dc4b6Seschrock arc_do_user_evicts(); 2154ea8dc4b6Seschrock 2155fa9e4066Sahrens /* block until needed, or one second, whichever is shorter */ 2156fa9e4066Sahrens CALLB_CPR_SAFE_BEGIN(&cpr); 2157fa9e4066Sahrens (void) cv_timedwait(&arc_reclaim_thr_cv, 2158d3d50737SRafael Vanoni &arc_reclaim_thr_lock, (ddi_get_lbolt() + hz)); 2159fa9e4066Sahrens CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_thr_lock); 2160fa9e4066Sahrens } 2161fa9e4066Sahrens 2162fa9e4066Sahrens arc_thread_exit = 0; 2163fa9e4066Sahrens cv_broadcast(&arc_reclaim_thr_cv); 2164fa9e4066Sahrens CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_thr_lock */ 2165fa9e4066Sahrens thread_exit(); 2166fa9e4066Sahrens } 2167fa9e4066Sahrens 2168ea8dc4b6Seschrock /* 2169ea8dc4b6Seschrock * Adapt arc info given the number of bytes we are trying to add and 2170ea8dc4b6Seschrock * the state that we are comming from. This function is only called 2171ea8dc4b6Seschrock * when we are adding new content to the cache. 2172ea8dc4b6Seschrock */ 2173fa9e4066Sahrens static void 2174ea8dc4b6Seschrock arc_adapt(int bytes, arc_state_t *state) 2175fa9e4066Sahrens { 2176ea8dc4b6Seschrock int mult; 21775a98e54bSBrendan Gregg - Sun Microsystems uint64_t arc_p_min = (arc_c >> arc_p_min_shift); 2178ea8dc4b6Seschrock 2179fa94a07fSbrendan if (state == arc_l2c_only) 2180fa94a07fSbrendan return; 2181fa94a07fSbrendan 2182ea8dc4b6Seschrock ASSERT(bytes > 0); 2183fa9e4066Sahrens /* 2184ea8dc4b6Seschrock * Adapt the target size of the MRU list: 2185ea8dc4b6Seschrock * - if we just hit in the MRU ghost list, then increase 2186ea8dc4b6Seschrock * the target size of the MRU list. 2187ea8dc4b6Seschrock * - if we just hit in the MFU ghost list, then increase 2188ea8dc4b6Seschrock * the target size of the MFU list by decreasing the 2189ea8dc4b6Seschrock * target size of the MRU list. 2190fa9e4066Sahrens */ 219144cb6abcSbmc if (state == arc_mru_ghost) { 219244cb6abcSbmc mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ? 219344cb6abcSbmc 1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size)); 21943e4e8481STom Erickson mult = MIN(mult, 10); /* avoid wild arc_p adjustment */ 2195ea8dc4b6Seschrock 21965a98e54bSBrendan Gregg - Sun Microsystems arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); 219744cb6abcSbmc } else if (state == arc_mfu_ghost) { 21985a98e54bSBrendan Gregg - Sun Microsystems uint64_t delta; 21995a98e54bSBrendan Gregg - Sun Microsystems 220044cb6abcSbmc mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ? 220144cb6abcSbmc 1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size)); 22023e4e8481STom Erickson mult = MIN(mult, 10); 2203ea8dc4b6Seschrock 22045a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(bytes * mult, arc_p); 22055a98e54bSBrendan Gregg - Sun Microsystems arc_p = MAX(arc_p_min, arc_p - delta); 2206ea8dc4b6Seschrock } 220744cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 2208fa9e4066Sahrens 2209fa9e4066Sahrens if (arc_reclaim_needed()) { 2210fa9e4066Sahrens cv_signal(&arc_reclaim_thr_cv); 2211fa9e4066Sahrens return; 2212fa9e4066Sahrens } 2213fa9e4066Sahrens 221444cb6abcSbmc if (arc_no_grow) 2215fa9e4066Sahrens return; 2216fa9e4066Sahrens 221744cb6abcSbmc if (arc_c >= arc_c_max) 2218ea8dc4b6Seschrock return; 2219ea8dc4b6Seschrock 2220fa9e4066Sahrens /* 2221ea8dc4b6Seschrock * If we're within (2 * maxblocksize) bytes of the target 2222ea8dc4b6Seschrock * cache size, increment the target cache size 2223fa9e4066Sahrens */ 222444cb6abcSbmc if (arc_size > arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) { 222544cb6abcSbmc atomic_add_64(&arc_c, (int64_t)bytes); 222644cb6abcSbmc if (arc_c > arc_c_max) 222744cb6abcSbmc arc_c = arc_c_max; 222844cb6abcSbmc else if (state == arc_anon) 222944cb6abcSbmc atomic_add_64(&arc_p, (int64_t)bytes); 223044cb6abcSbmc if (arc_p > arc_c) 223144cb6abcSbmc arc_p = arc_c; 2232fa9e4066Sahrens } 223344cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 2234fa9e4066Sahrens } 2235fa9e4066Sahrens 2236fa9e4066Sahrens /* 2237ea8dc4b6Seschrock * Check if the cache has reached its limits and eviction is required 2238ea8dc4b6Seschrock * prior to insert. 2239fa9e4066Sahrens */ 2240fa9e4066Sahrens static int 22410e8c6158Smaybee arc_evict_needed(arc_buf_contents_t type) 2242fa9e4066Sahrens { 22430e8c6158Smaybee if (type == ARC_BUFC_METADATA && arc_meta_used >= arc_meta_limit) 22440e8c6158Smaybee return (1); 22450e8c6158Smaybee 2246fa9e4066Sahrens if (arc_reclaim_needed()) 2247fa9e4066Sahrens return (1); 2248fa9e4066Sahrens 224944cb6abcSbmc return (arc_size > arc_c); 2250fa9e4066Sahrens } 2251fa9e4066Sahrens 2252fa9e4066Sahrens /* 225344eda4d7Smaybee * The buffer, supplied as the first argument, needs a data block. 225444eda4d7Smaybee * So, if we are at cache max, determine which cache should be victimized. 225544eda4d7Smaybee * We have the following cases: 2256fa9e4066Sahrens * 225744cb6abcSbmc * 1. Insert for MRU, p > sizeof(arc_anon + arc_mru) -> 2258fa9e4066Sahrens * In this situation if we're out of space, but the resident size of the MFU is 2259fa9e4066Sahrens * under the limit, victimize the MFU cache to satisfy this insertion request. 2260fa9e4066Sahrens * 226144cb6abcSbmc * 2. Insert for MRU, p <= sizeof(arc_anon + arc_mru) -> 2262fa9e4066Sahrens * Here, we've used up all of the available space for the MRU, so we need to 2263fa9e4066Sahrens * evict from our own cache instead. Evict from the set of resident MRU 2264fa9e4066Sahrens * entries. 2265fa9e4066Sahrens * 226644cb6abcSbmc * 3. Insert for MFU (c - p) > sizeof(arc_mfu) -> 2267fa9e4066Sahrens * c minus p represents the MFU space in the cache, since p is the size of the 2268fa9e4066Sahrens * cache that is dedicated to the MRU. In this situation there's still space on 2269fa9e4066Sahrens * the MFU side, so the MRU side needs to be victimized. 2270fa9e4066Sahrens * 227144cb6abcSbmc * 4. Insert for MFU (c - p) < sizeof(arc_mfu) -> 2272fa9e4066Sahrens * MFU's resident set is consuming more space than it has been allotted. In 2273fa9e4066Sahrens * this situation, we must victimize our own cache, the MFU, for this insertion. 2274fa9e4066Sahrens */ 2275fa9e4066Sahrens static void 227644eda4d7Smaybee arc_get_data_buf(arc_buf_t *buf) 2277fa9e4066Sahrens { 2278ad23a2dbSjohansen arc_state_t *state = buf->b_hdr->b_state; 2279ad23a2dbSjohansen uint64_t size = buf->b_hdr->b_size; 2280ad23a2dbSjohansen arc_buf_contents_t type = buf->b_hdr->b_type; 2281fa9e4066Sahrens 228244eda4d7Smaybee arc_adapt(size, state); 2283fa9e4066Sahrens 228444eda4d7Smaybee /* 228544eda4d7Smaybee * We have not yet reached cache maximum size, 228644eda4d7Smaybee * just allocate a new buffer. 228744eda4d7Smaybee */ 22880e8c6158Smaybee if (!arc_evict_needed(type)) { 2289ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 2290ad23a2dbSjohansen buf->b_data = zio_buf_alloc(size); 22915a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(size, ARC_SPACE_DATA); 2292ad23a2dbSjohansen } else { 2293ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 2294ad23a2dbSjohansen buf->b_data = zio_data_buf_alloc(size); 22955a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, size); 22960e8c6158Smaybee atomic_add_64(&arc_size, size); 2297ad23a2dbSjohansen } 229844eda4d7Smaybee goto out; 229944eda4d7Smaybee } 230044eda4d7Smaybee 230144eda4d7Smaybee /* 230244eda4d7Smaybee * If we are prefetching from the mfu ghost list, this buffer 230344eda4d7Smaybee * will end up on the mru list; so steal space from there. 230444eda4d7Smaybee */ 230544cb6abcSbmc if (state == arc_mfu_ghost) 230644cb6abcSbmc state = buf->b_hdr->b_flags & ARC_PREFETCH ? arc_mru : arc_mfu; 230744cb6abcSbmc else if (state == arc_mru_ghost) 230844cb6abcSbmc state = arc_mru; 230944cb6abcSbmc 231044cb6abcSbmc if (state == arc_mru || state == arc_anon) { 231144cb6abcSbmc uint64_t mru_used = arc_anon->arcs_size + arc_mru->arcs_size; 23125a98e54bSBrendan Gregg - Sun Microsystems state = (arc_mfu->arcs_lsize[type] >= size && 23130e8c6158Smaybee arc_p > mru_used) ? arc_mfu : arc_mru; 2314fa9e4066Sahrens } else { 231544eda4d7Smaybee /* MFU cases */ 231644cb6abcSbmc uint64_t mfu_space = arc_c - arc_p; 23175a98e54bSBrendan Gregg - Sun Microsystems state = (arc_mru->arcs_lsize[type] >= size && 23180e8c6158Smaybee mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu; 231944eda4d7Smaybee } 2320874395d5Smaybee if ((buf->b_data = arc_evict(state, NULL, size, TRUE, type)) == NULL) { 2321ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 2322ad23a2dbSjohansen buf->b_data = zio_buf_alloc(size); 23235a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(size, ARC_SPACE_DATA); 2324ad23a2dbSjohansen } else { 2325ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 2326ad23a2dbSjohansen buf->b_data = zio_data_buf_alloc(size); 23275a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, size); 23280e8c6158Smaybee atomic_add_64(&arc_size, size); 2329ad23a2dbSjohansen } 233044cb6abcSbmc ARCSTAT_BUMP(arcstat_recycle_miss); 233144eda4d7Smaybee } 233244eda4d7Smaybee ASSERT(buf->b_data != NULL); 233344eda4d7Smaybee out: 233444eda4d7Smaybee /* 233544eda4d7Smaybee * Update the state size. Note that ghost states have a 233644eda4d7Smaybee * "ghost size" and so don't need to be updated. 233744eda4d7Smaybee */ 233844eda4d7Smaybee if (!GHOST_STATE(buf->b_hdr->b_state)) { 233944eda4d7Smaybee arc_buf_hdr_t *hdr = buf->b_hdr; 234044eda4d7Smaybee 234144cb6abcSbmc atomic_add_64(&hdr->b_state->arcs_size, size); 234244eda4d7Smaybee if (list_link_active(&hdr->b_arc_node)) { 234344eda4d7Smaybee ASSERT(refcount_is_zero(&hdr->b_refcnt)); 23440e8c6158Smaybee atomic_add_64(&hdr->b_state->arcs_lsize[type], size); 2345fa9e4066Sahrens } 2346641fbdaeSmaybee /* 2347641fbdaeSmaybee * If we are growing the cache, and we are adding anonymous 234844cb6abcSbmc * data, and we have outgrown arc_p, update arc_p 2349641fbdaeSmaybee */ 235044cb6abcSbmc if (arc_size < arc_c && hdr->b_state == arc_anon && 235144cb6abcSbmc arc_anon->arcs_size + arc_mru->arcs_size > arc_p) 235244cb6abcSbmc arc_p = MIN(arc_c, arc_p + size); 2353fa9e4066Sahrens } 2354fa9e4066Sahrens } 2355fa9e4066Sahrens 2356fa9e4066Sahrens /* 2357fa9e4066Sahrens * This routine is called whenever a buffer is accessed. 2358ea8dc4b6Seschrock * NOTE: the hash lock is dropped in this function. 2359fa9e4066Sahrens */ 2360fa9e4066Sahrens static void 236144eda4d7Smaybee arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock) 2362fa9e4066Sahrens { 2363d3d50737SRafael Vanoni clock_t now; 2364d3d50737SRafael Vanoni 2365fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 2366fa9e4066Sahrens 236744cb6abcSbmc if (buf->b_state == arc_anon) { 2368fa9e4066Sahrens /* 2369fa9e4066Sahrens * This buffer is not in the cache, and does not 2370fa9e4066Sahrens * appear in our "ghost" list. Add the new buffer 2371fa9e4066Sahrens * to the MRU state. 2372fa9e4066Sahrens */ 2373fa9e4066Sahrens 2374fa9e4066Sahrens ASSERT(buf->b_arc_access == 0); 2375d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2376ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); 237744cb6abcSbmc arc_change_state(arc_mru, buf, hash_lock); 2378fa9e4066Sahrens 237944cb6abcSbmc } else if (buf->b_state == arc_mru) { 2380d3d50737SRafael Vanoni now = ddi_get_lbolt(); 2381d3d50737SRafael Vanoni 2382fa9e4066Sahrens /* 238313506d1eSmaybee * If this buffer is here because of a prefetch, then either: 238413506d1eSmaybee * - clear the flag if this is a "referencing" read 238513506d1eSmaybee * (any subsequent access will bump this into the MFU state). 238613506d1eSmaybee * or 238713506d1eSmaybee * - move the buffer to the head of the list if this is 238813506d1eSmaybee * another prefetch (to make it less likely to be evicted). 2389fa9e4066Sahrens */ 2390fa9e4066Sahrens if ((buf->b_flags & ARC_PREFETCH) != 0) { 239113506d1eSmaybee if (refcount_count(&buf->b_refcnt) == 0) { 239213506d1eSmaybee ASSERT(list_link_active(&buf->b_arc_node)); 239313506d1eSmaybee } else { 239413506d1eSmaybee buf->b_flags &= ~ARC_PREFETCH; 239544cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_hits); 239613506d1eSmaybee } 2397d3d50737SRafael Vanoni buf->b_arc_access = now; 2398fa9e4066Sahrens return; 2399fa9e4066Sahrens } 2400fa9e4066Sahrens 2401fa9e4066Sahrens /* 2402fa9e4066Sahrens * This buffer has been "accessed" only once so far, 2403fa9e4066Sahrens * but it is still in the cache. Move it to the MFU 2404fa9e4066Sahrens * state. 2405fa9e4066Sahrens */ 2406d3d50737SRafael Vanoni if (now > buf->b_arc_access + ARC_MINTIME) { 2407fa9e4066Sahrens /* 2408fa9e4066Sahrens * More than 125ms have passed since we 2409fa9e4066Sahrens * instantiated this buffer. Move it to the 2410fa9e4066Sahrens * most frequently used state. 2411fa9e4066Sahrens */ 2412d3d50737SRafael Vanoni buf->b_arc_access = now; 2413ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 241444cb6abcSbmc arc_change_state(arc_mfu, buf, hash_lock); 2415fa9e4066Sahrens } 241644cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_hits); 241744cb6abcSbmc } else if (buf->b_state == arc_mru_ghost) { 2418fa9e4066Sahrens arc_state_t *new_state; 2419fa9e4066Sahrens /* 2420fa9e4066Sahrens * This buffer has been "accessed" recently, but 2421fa9e4066Sahrens * was evicted from the cache. Move it to the 2422fa9e4066Sahrens * MFU state. 2423fa9e4066Sahrens */ 2424fa9e4066Sahrens 2425fa9e4066Sahrens if (buf->b_flags & ARC_PREFETCH) { 242644cb6abcSbmc new_state = arc_mru; 242713506d1eSmaybee if (refcount_count(&buf->b_refcnt) > 0) 242813506d1eSmaybee buf->b_flags &= ~ARC_PREFETCH; 2429ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); 2430fa9e4066Sahrens } else { 243144cb6abcSbmc new_state = arc_mfu; 2432ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 2433fa9e4066Sahrens } 2434fa9e4066Sahrens 2435d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2436fa9e4066Sahrens arc_change_state(new_state, buf, hash_lock); 2437fa9e4066Sahrens 243844cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_ghost_hits); 243944cb6abcSbmc } else if (buf->b_state == arc_mfu) { 2440fa9e4066Sahrens /* 2441fa9e4066Sahrens * This buffer has been accessed more than once and is 2442fa9e4066Sahrens * still in the cache. Keep it in the MFU state. 2443fa9e4066Sahrens * 244413506d1eSmaybee * NOTE: an add_reference() that occurred when we did 244513506d1eSmaybee * the arc_read() will have kicked this off the list. 244613506d1eSmaybee * If it was a prefetch, we will explicitly move it to 244713506d1eSmaybee * the head of the list now. 2448fa9e4066Sahrens */ 244913506d1eSmaybee if ((buf->b_flags & ARC_PREFETCH) != 0) { 245013506d1eSmaybee ASSERT(refcount_count(&buf->b_refcnt) == 0); 245113506d1eSmaybee ASSERT(list_link_active(&buf->b_arc_node)); 245213506d1eSmaybee } 245344cb6abcSbmc ARCSTAT_BUMP(arcstat_mfu_hits); 2454d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 245544cb6abcSbmc } else if (buf->b_state == arc_mfu_ghost) { 245644cb6abcSbmc arc_state_t *new_state = arc_mfu; 2457fa9e4066Sahrens /* 2458fa9e4066Sahrens * This buffer has been accessed more than once but has 2459fa9e4066Sahrens * been evicted from the cache. Move it back to the 2460fa9e4066Sahrens * MFU state. 2461fa9e4066Sahrens */ 2462fa9e4066Sahrens 246313506d1eSmaybee if (buf->b_flags & ARC_PREFETCH) { 246413506d1eSmaybee /* 246513506d1eSmaybee * This is a prefetch access... 246613506d1eSmaybee * move this block back to the MRU state. 246713506d1eSmaybee */ 246813506d1eSmaybee ASSERT3U(refcount_count(&buf->b_refcnt), ==, 0); 246944cb6abcSbmc new_state = arc_mru; 247013506d1eSmaybee } 247113506d1eSmaybee 2472d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2473ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 247413506d1eSmaybee arc_change_state(new_state, buf, hash_lock); 2475fa9e4066Sahrens 247644cb6abcSbmc ARCSTAT_BUMP(arcstat_mfu_ghost_hits); 2477fa94a07fSbrendan } else if (buf->b_state == arc_l2c_only) { 2478fa94a07fSbrendan /* 2479fa94a07fSbrendan * This buffer is on the 2nd Level ARC. 2480fa94a07fSbrendan */ 2481fa94a07fSbrendan 2482d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2483fa94a07fSbrendan DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 2484fa94a07fSbrendan arc_change_state(arc_mfu, buf, hash_lock); 2485fa9e4066Sahrens } else { 2486fa9e4066Sahrens ASSERT(!"invalid arc state"); 2487fa9e4066Sahrens } 2488fa9e4066Sahrens } 2489fa9e4066Sahrens 2490fa9e4066Sahrens /* a generic arc_done_func_t which you can use */ 2491fa9e4066Sahrens /* ARGSUSED */ 2492fa9e4066Sahrens void 2493fa9e4066Sahrens arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg) 2494fa9e4066Sahrens { 24953f9d6ad7SLin Ling if (zio == NULL || zio->io_error == 0) 24963f9d6ad7SLin Ling bcopy(buf->b_data, arg, buf->b_hdr->b_size); 2497ea8dc4b6Seschrock VERIFY(arc_buf_remove_ref(buf, arg) == 1); 2498fa9e4066Sahrens } 2499fa9e4066Sahrens 25000e8c6158Smaybee /* a generic arc_done_func_t */ 2501fa9e4066Sahrens void 2502fa9e4066Sahrens arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg) 2503fa9e4066Sahrens { 2504fa9e4066Sahrens arc_buf_t **bufp = arg; 2505fa9e4066Sahrens if (zio && zio->io_error) { 2506ea8dc4b6Seschrock VERIFY(arc_buf_remove_ref(buf, arg) == 1); 2507fa9e4066Sahrens *bufp = NULL; 2508fa9e4066Sahrens } else { 2509fa9e4066Sahrens *bufp = buf; 25103f9d6ad7SLin Ling ASSERT(buf->b_data); 2511fa9e4066Sahrens } 2512fa9e4066Sahrens } 2513fa9e4066Sahrens 2514fa9e4066Sahrens static void 2515fa9e4066Sahrens arc_read_done(zio_t *zio) 2516fa9e4066Sahrens { 2517bbf4a8dfSmaybee arc_buf_hdr_t *hdr, *found; 2518fa9e4066Sahrens arc_buf_t *buf; 2519fa9e4066Sahrens arc_buf_t *abuf; /* buffer we're assigning to callback */ 2520fa9e4066Sahrens kmutex_t *hash_lock; 2521fa9e4066Sahrens arc_callback_t *callback_list, *acb; 2522fa9e4066Sahrens int freeable = FALSE; 2523fa9e4066Sahrens 2524fa9e4066Sahrens buf = zio->io_private; 2525fa9e4066Sahrens hdr = buf->b_hdr; 2526fa9e4066Sahrens 2527bbf4a8dfSmaybee /* 2528bbf4a8dfSmaybee * The hdr was inserted into hash-table and removed from lists 2529bbf4a8dfSmaybee * prior to starting I/O. We should find this header, since 2530bbf4a8dfSmaybee * it's in the hash table, and it should be legit since it's 2531bbf4a8dfSmaybee * not possible to evict it during the I/O. The only possible 2532bbf4a8dfSmaybee * reason for it not to be found is if we were freed during the 2533bbf4a8dfSmaybee * read. 2534bbf4a8dfSmaybee */ 2535ac05c741SMark Maybee found = buf_hash_find(hdr->b_spa, &hdr->b_dva, hdr->b_birth, 25366b4acc8bSahrens &hash_lock); 2537fa9e4066Sahrens 2538bbf4a8dfSmaybee ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) && hash_lock == NULL) || 2539fa94a07fSbrendan (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || 2540fa94a07fSbrendan (found == hdr && HDR_L2_READING(hdr))); 2541fa94a07fSbrendan 25423a737e0dSbrendan hdr->b_flags &= ~ARC_L2_EVICTED; 2543fa94a07fSbrendan if (l2arc_noprefetch && (hdr->b_flags & ARC_PREFETCH)) 25443baa08fcSek hdr->b_flags &= ~ARC_L2CACHE; 2545fa9e4066Sahrens 2546fa9e4066Sahrens /* byteswap if necessary */ 2547fa9e4066Sahrens callback_list = hdr->b_acb; 2548fa9e4066Sahrens ASSERT(callback_list != NULL); 25498e0f0d3dSWilliam Gorrell if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) { 2550ad135b5dSChristopher Siden dmu_object_byteswap_t bswap = 2551ad135b5dSChristopher Siden DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp)); 2552088f3894Sahrens arc_byteswap_func_t *func = BP_GET_LEVEL(zio->io_bp) > 0 ? 2553088f3894Sahrens byteswap_uint64_array : 2554ad135b5dSChristopher Siden dmu_ot_byteswap[bswap].ob_func; 2555088f3894Sahrens func(buf->b_data, hdr->b_size); 2556088f3894Sahrens } 2557fa9e4066Sahrens 2558fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 25596b4acc8bSahrens 2560b24ab676SJeff Bonwick if (hash_lock && zio->io_error == 0 && hdr->b_state == arc_anon) { 2561b24ab676SJeff Bonwick /* 2562b24ab676SJeff Bonwick * Only call arc_access on anonymous buffers. This is because 2563b24ab676SJeff Bonwick * if we've issued an I/O for an evicted buffer, we've already 2564b24ab676SJeff Bonwick * called arc_access (to prevent any simultaneous readers from 2565b24ab676SJeff Bonwick * getting confused). 2566b24ab676SJeff Bonwick */ 2567b24ab676SJeff Bonwick arc_access(hdr, hash_lock); 2568b24ab676SJeff Bonwick } 2569b24ab676SJeff Bonwick 2570fa9e4066Sahrens /* create copies of the data buffer for the callers */ 2571fa9e4066Sahrens abuf = buf; 2572fa9e4066Sahrens for (acb = callback_list; acb; acb = acb->acb_next) { 2573fa9e4066Sahrens if (acb->acb_done) { 257444eda4d7Smaybee if (abuf == NULL) 257544eda4d7Smaybee abuf = arc_buf_clone(buf); 2576fa9e4066Sahrens acb->acb_buf = abuf; 2577fa9e4066Sahrens abuf = NULL; 2578fa9e4066Sahrens } 2579fa9e4066Sahrens } 2580fa9e4066Sahrens hdr->b_acb = NULL; 2581fa9e4066Sahrens hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 2582ea8dc4b6Seschrock ASSERT(!HDR_BUF_AVAILABLE(hdr)); 2583b24ab676SJeff Bonwick if (abuf == buf) { 2584b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 2585b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 2586ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 2587b24ab676SJeff Bonwick } 2588fa9e4066Sahrens 2589fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt) || callback_list != NULL); 2590fa9e4066Sahrens 2591fa9e4066Sahrens if (zio->io_error != 0) { 2592fa9e4066Sahrens hdr->b_flags |= ARC_IO_ERROR; 259344cb6abcSbmc if (hdr->b_state != arc_anon) 259444cb6abcSbmc arc_change_state(arc_anon, hdr, hash_lock); 2595ea8dc4b6Seschrock if (HDR_IN_HASH_TABLE(hdr)) 2596ea8dc4b6Seschrock buf_hash_remove(hdr); 2597fa9e4066Sahrens freeable = refcount_is_zero(&hdr->b_refcnt); 2598fa9e4066Sahrens } 2599fa9e4066Sahrens 2600ea8dc4b6Seschrock /* 260113506d1eSmaybee * Broadcast before we drop the hash_lock to avoid the possibility 260213506d1eSmaybee * that the hdr (and hence the cv) might be freed before we get to 260313506d1eSmaybee * the cv_broadcast(). 2604ea8dc4b6Seschrock */ 2605ea8dc4b6Seschrock cv_broadcast(&hdr->b_cv); 2606ea8dc4b6Seschrock 2607bbf4a8dfSmaybee if (hash_lock) { 260844eda4d7Smaybee mutex_exit(hash_lock); 2609fa9e4066Sahrens } else { 2610fa9e4066Sahrens /* 2611fa9e4066Sahrens * This block was freed while we waited for the read to 2612fa9e4066Sahrens * complete. It has been removed from the hash table and 2613fa9e4066Sahrens * moved to the anonymous state (so that it won't show up 2614fa9e4066Sahrens * in the cache). 2615fa9e4066Sahrens */ 261644cb6abcSbmc ASSERT3P(hdr->b_state, ==, arc_anon); 2617fa9e4066Sahrens freeable = refcount_is_zero(&hdr->b_refcnt); 2618fa9e4066Sahrens } 2619fa9e4066Sahrens 2620fa9e4066Sahrens /* execute each callback and free its structure */ 2621fa9e4066Sahrens while ((acb = callback_list) != NULL) { 2622fa9e4066Sahrens if (acb->acb_done) 2623fa9e4066Sahrens acb->acb_done(zio, acb->acb_buf, acb->acb_private); 2624fa9e4066Sahrens 2625fa9e4066Sahrens if (acb->acb_zio_dummy != NULL) { 2626fa9e4066Sahrens acb->acb_zio_dummy->io_error = zio->io_error; 2627fa9e4066Sahrens zio_nowait(acb->acb_zio_dummy); 2628fa9e4066Sahrens } 2629fa9e4066Sahrens 2630fa9e4066Sahrens callback_list = acb->acb_next; 2631fa9e4066Sahrens kmem_free(acb, sizeof (arc_callback_t)); 2632fa9e4066Sahrens } 2633fa9e4066Sahrens 2634fa9e4066Sahrens if (freeable) 2635ea8dc4b6Seschrock arc_hdr_destroy(hdr); 2636fa9e4066Sahrens } 2637fa9e4066Sahrens 2638fa9e4066Sahrens /* 2639*fc98fea5SBart Coddens * "Read" the block at the specified DVA (in bp) via the 2640fa9e4066Sahrens * cache. If the block is found in the cache, invoke the provided 2641fa9e4066Sahrens * callback immediately and return. Note that the `zio' parameter 2642fa9e4066Sahrens * in the callback will be NULL in this case, since no IO was 2643fa9e4066Sahrens * required. If the block is not in the cache pass the read request 2644fa9e4066Sahrens * on to the spa with a substitute callback function, so that the 2645fa9e4066Sahrens * requested block will be added to the cache. 2646fa9e4066Sahrens * 2647fa9e4066Sahrens * If a read request arrives for a block that has a read in-progress, 2648fa9e4066Sahrens * either wait for the in-progress read to complete (and return the 2649fa9e4066Sahrens * results); or, if this is a read with a "done" func, add a record 2650fa9e4066Sahrens * to the read to invoke the "done" func when the read completes, 2651fa9e4066Sahrens * and return; or just return. 2652fa9e4066Sahrens * 2653fa9e4066Sahrens * arc_read_done() will invoke all the requested "done" functions 2654fa9e4066Sahrens * for readers of this block. 2655088f3894Sahrens * 2656088f3894Sahrens * Normal callers should use arc_read and pass the arc buffer and offset 2657088f3894Sahrens * for the bp. But if you know you don't need locking, you can use 26588ad10dceSSuhasini Peddada * arc_read_bp. 2659fa9e4066Sahrens */ 2660fa9e4066Sahrens int 2661b24ab676SJeff Bonwick arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_buf_t *pbuf, 26623baa08fcSek arc_done_func_t *done, void *private, int priority, int zio_flags, 2663088f3894Sahrens uint32_t *arc_flags, const zbookmark_t *zb) 2664088f3894Sahrens { 2665088f3894Sahrens int err; 2666088f3894Sahrens 26673f9d6ad7SLin Ling if (pbuf == NULL) { 26683f9d6ad7SLin Ling /* 26693f9d6ad7SLin Ling * XXX This happens from traverse callback funcs, for 26703f9d6ad7SLin Ling * the objset_phys_t block. 26713f9d6ad7SLin Ling */ 26723f9d6ad7SLin Ling return (arc_read_nolock(pio, spa, bp, done, private, priority, 26733f9d6ad7SLin Ling zio_flags, arc_flags, zb)); 26743f9d6ad7SLin Ling } 26753f9d6ad7SLin Ling 2676088f3894Sahrens ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt)); 2677088f3894Sahrens ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size); 26783f9d6ad7SLin Ling rw_enter(&pbuf->b_data_lock, RW_READER); 2679088f3894Sahrens 2680088f3894Sahrens err = arc_read_nolock(pio, spa, bp, done, private, priority, 26813baa08fcSek zio_flags, arc_flags, zb); 26823f9d6ad7SLin Ling rw_exit(&pbuf->b_data_lock); 268314843421SMatthew Ahrens 2684088f3894Sahrens return (err); 2685088f3894Sahrens } 2686088f3894Sahrens 2687088f3894Sahrens int 2688b24ab676SJeff Bonwick arc_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bp, 26893baa08fcSek arc_done_func_t *done, void *private, int priority, int zio_flags, 2690088f3894Sahrens uint32_t *arc_flags, const zbookmark_t *zb) 2691fa9e4066Sahrens { 2692fa9e4066Sahrens arc_buf_hdr_t *hdr; 2693fa9e4066Sahrens arc_buf_t *buf; 2694fa9e4066Sahrens kmutex_t *hash_lock; 2695fa94a07fSbrendan zio_t *rzio; 2696e9103aaeSGarrett D'Amore uint64_t guid = spa_load_guid(spa); 2697fa9e4066Sahrens 2698fa9e4066Sahrens top: 2699b24ab676SJeff Bonwick hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), 2700b24ab676SJeff Bonwick &hash_lock); 2701ea8dc4b6Seschrock if (hdr && hdr->b_datacnt > 0) { 2702fa9e4066Sahrens 270313506d1eSmaybee *arc_flags |= ARC_CACHED; 270413506d1eSmaybee 2705fa9e4066Sahrens if (HDR_IO_IN_PROGRESS(hdr)) { 270613506d1eSmaybee 270713506d1eSmaybee if (*arc_flags & ARC_WAIT) { 270813506d1eSmaybee cv_wait(&hdr->b_cv, hash_lock); 270913506d1eSmaybee mutex_exit(hash_lock); 271013506d1eSmaybee goto top; 271113506d1eSmaybee } 271213506d1eSmaybee ASSERT(*arc_flags & ARC_NOWAIT); 271313506d1eSmaybee 271413506d1eSmaybee if (done) { 2715fa9e4066Sahrens arc_callback_t *acb = NULL; 2716fa9e4066Sahrens 2717fa9e4066Sahrens acb = kmem_zalloc(sizeof (arc_callback_t), 2718fa9e4066Sahrens KM_SLEEP); 2719fa9e4066Sahrens acb->acb_done = done; 2720fa9e4066Sahrens acb->acb_private = private; 2721fa9e4066Sahrens if (pio != NULL) 2722fa9e4066Sahrens acb->acb_zio_dummy = zio_null(pio, 2723a3f829aeSBill Moore spa, NULL, NULL, NULL, zio_flags); 2724fa9e4066Sahrens 2725fa9e4066Sahrens ASSERT(acb->acb_done != NULL); 2726fa9e4066Sahrens acb->acb_next = hdr->b_acb; 2727fa9e4066Sahrens hdr->b_acb = acb; 2728fa9e4066Sahrens add_reference(hdr, hash_lock, private); 2729fa9e4066Sahrens mutex_exit(hash_lock); 2730fa9e4066Sahrens return (0); 2731fa9e4066Sahrens } 2732fa9e4066Sahrens mutex_exit(hash_lock); 2733fa9e4066Sahrens return (0); 2734fa9e4066Sahrens } 2735fa9e4066Sahrens 273644cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 2737fa9e4066Sahrens 2738ea8dc4b6Seschrock if (done) { 273944eda4d7Smaybee add_reference(hdr, hash_lock, private); 2740ea8dc4b6Seschrock /* 2741ea8dc4b6Seschrock * If this block is already in use, create a new 2742ea8dc4b6Seschrock * copy of the data so that we will be guaranteed 2743ea8dc4b6Seschrock * that arc_release() will always succeed. 2744ea8dc4b6Seschrock */ 2745fa9e4066Sahrens buf = hdr->b_buf; 2746ea8dc4b6Seschrock ASSERT(buf); 2747ea8dc4b6Seschrock ASSERT(buf->b_data); 274844eda4d7Smaybee if (HDR_BUF_AVAILABLE(hdr)) { 2749ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 2750ea8dc4b6Seschrock hdr->b_flags &= ~ARC_BUF_AVAILABLE; 275144eda4d7Smaybee } else { 275244eda4d7Smaybee buf = arc_buf_clone(buf); 2753ea8dc4b6Seschrock } 2754b24ab676SJeff Bonwick 275513506d1eSmaybee } else if (*arc_flags & ARC_PREFETCH && 275613506d1eSmaybee refcount_count(&hdr->b_refcnt) == 0) { 275713506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 2758fa9e4066Sahrens } 2759fa9e4066Sahrens DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); 276044eda4d7Smaybee arc_access(hdr, hash_lock); 27613baa08fcSek if (*arc_flags & ARC_L2CACHE) 27623baa08fcSek hdr->b_flags |= ARC_L2CACHE; 276344eda4d7Smaybee mutex_exit(hash_lock); 276444cb6abcSbmc ARCSTAT_BUMP(arcstat_hits); 276544cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 276644cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 276744cb6abcSbmc data, metadata, hits); 276844cb6abcSbmc 2769fa9e4066Sahrens if (done) 2770fa9e4066Sahrens done(NULL, buf, private); 2771fa9e4066Sahrens } else { 2772fa9e4066Sahrens uint64_t size = BP_GET_LSIZE(bp); 2773fa9e4066Sahrens arc_callback_t *acb; 27743a737e0dSbrendan vdev_t *vd = NULL; 2775f9d8334fSGeorge Wilson uint64_t addr; 27765a98e54bSBrendan Gregg - Sun Microsystems boolean_t devw = B_FALSE; 2777fa9e4066Sahrens 2778fa9e4066Sahrens if (hdr == NULL) { 2779fa9e4066Sahrens /* this block is not in the cache */ 2780fa9e4066Sahrens arc_buf_hdr_t *exists; 2781ad23a2dbSjohansen arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); 2782ad23a2dbSjohansen buf = arc_buf_alloc(spa, size, private, type); 2783fa9e4066Sahrens hdr = buf->b_hdr; 2784fa9e4066Sahrens hdr->b_dva = *BP_IDENTITY(bp); 2785b24ab676SJeff Bonwick hdr->b_birth = BP_PHYSICAL_BIRTH(bp); 2786fa9e4066Sahrens hdr->b_cksum0 = bp->blk_cksum.zc_word[0]; 2787fa9e4066Sahrens exists = buf_hash_insert(hdr, &hash_lock); 2788fa9e4066Sahrens if (exists) { 2789fa9e4066Sahrens /* somebody beat us to the hash insert */ 2790fa9e4066Sahrens mutex_exit(hash_lock); 27913f9d6ad7SLin Ling buf_discard_identity(hdr); 2792ea8dc4b6Seschrock (void) arc_buf_remove_ref(buf, private); 2793fa9e4066Sahrens goto top; /* restart the IO request */ 2794fa9e4066Sahrens } 279513506d1eSmaybee /* if this is a prefetch, we don't have a reference */ 279613506d1eSmaybee if (*arc_flags & ARC_PREFETCH) { 279713506d1eSmaybee (void) remove_reference(hdr, hash_lock, 279813506d1eSmaybee private); 279913506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 280013506d1eSmaybee } 28013baa08fcSek if (*arc_flags & ARC_L2CACHE) 28023baa08fcSek hdr->b_flags |= ARC_L2CACHE; 280313506d1eSmaybee if (BP_GET_LEVEL(bp) > 0) 280413506d1eSmaybee hdr->b_flags |= ARC_INDIRECT; 2805fa9e4066Sahrens } else { 2806fa9e4066Sahrens /* this block is in the ghost cache */ 2807ea8dc4b6Seschrock ASSERT(GHOST_STATE(hdr->b_state)); 2808ea8dc4b6Seschrock ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 280913506d1eSmaybee ASSERT3U(refcount_count(&hdr->b_refcnt), ==, 0); 2810ea8dc4b6Seschrock ASSERT(hdr->b_buf == NULL); 281113506d1eSmaybee 281213506d1eSmaybee /* if this is a prefetch, we don't have a reference */ 281313506d1eSmaybee if (*arc_flags & ARC_PREFETCH) 281413506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 281513506d1eSmaybee else 281613506d1eSmaybee add_reference(hdr, hash_lock, private); 28173baa08fcSek if (*arc_flags & ARC_L2CACHE) 28183baa08fcSek hdr->b_flags |= ARC_L2CACHE; 28191ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 2820fa9e4066Sahrens buf->b_hdr = hdr; 282144eda4d7Smaybee buf->b_data = NULL; 2822ea8dc4b6Seschrock buf->b_efunc = NULL; 2823ea8dc4b6Seschrock buf->b_private = NULL; 2824fa9e4066Sahrens buf->b_next = NULL; 2825fa9e4066Sahrens hdr->b_buf = buf; 2826ea8dc4b6Seschrock ASSERT(hdr->b_datacnt == 0); 2827ea8dc4b6Seschrock hdr->b_datacnt = 1; 28285614b00aSWilliam Gorrell arc_get_data_buf(buf); 28297e453561SWilliam Gorrell arc_access(hdr, hash_lock); 2830fa9e4066Sahrens } 2831fa9e4066Sahrens 28325614b00aSWilliam Gorrell ASSERT(!GHOST_STATE(hdr->b_state)); 28335614b00aSWilliam Gorrell 2834fa9e4066Sahrens acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP); 2835fa9e4066Sahrens acb->acb_done = done; 2836fa9e4066Sahrens acb->acb_private = private; 2837fa9e4066Sahrens 2838fa9e4066Sahrens ASSERT(hdr->b_acb == NULL); 2839fa9e4066Sahrens hdr->b_acb = acb; 2840fa9e4066Sahrens hdr->b_flags |= ARC_IO_IN_PROGRESS; 2841fa9e4066Sahrens 2842e14bb325SJeff Bonwick if (HDR_L2CACHE(hdr) && hdr->b_l2hdr != NULL && 2843e14bb325SJeff Bonwick (vd = hdr->b_l2hdr->b_dev->l2ad_vdev) != NULL) { 28445a98e54bSBrendan Gregg - Sun Microsystems devw = hdr->b_l2hdr->b_dev->l2ad_writing; 28453a737e0dSbrendan addr = hdr->b_l2hdr->b_daddr; 2846e14bb325SJeff Bonwick /* 2847e14bb325SJeff Bonwick * Lock out device removal. 2848e14bb325SJeff Bonwick */ 2849e14bb325SJeff Bonwick if (vdev_is_dead(vd) || 2850e14bb325SJeff Bonwick !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) 2851e14bb325SJeff Bonwick vd = NULL; 28523a737e0dSbrendan } 28533a737e0dSbrendan 28543a737e0dSbrendan mutex_exit(hash_lock); 28553a737e0dSbrendan 2856fa9e4066Sahrens ASSERT3U(hdr->b_size, ==, size); 28575c28183bSBrendan Gregg - Sun Microsystems DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, 28585c28183bSBrendan Gregg - Sun Microsystems uint64_t, size, zbookmark_t *, zb); 285944cb6abcSbmc ARCSTAT_BUMP(arcstat_misses); 286044cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 286144cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 286244cb6abcSbmc data, metadata, misses); 2863ea8dc4b6Seschrock 28645a98e54bSBrendan Gregg - Sun Microsystems if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) { 2865fa94a07fSbrendan /* 2866fa94a07fSbrendan * Read from the L2ARC if the following are true: 28673a737e0dSbrendan * 1. The L2ARC vdev was previously cached. 28683a737e0dSbrendan * 2. This buffer still has L2ARC metadata. 28693a737e0dSbrendan * 3. This buffer isn't currently writing to the L2ARC. 28703a737e0dSbrendan * 4. The L2ARC entry wasn't evicted, which may 28713a737e0dSbrendan * also have invalidated the vdev. 28725a98e54bSBrendan Gregg - Sun Microsystems * 5. This isn't prefetch and l2arc_noprefetch is set. 2873fa94a07fSbrendan */ 2874e14bb325SJeff Bonwick if (hdr->b_l2hdr != NULL && 28755a98e54bSBrendan Gregg - Sun Microsystems !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && 28765a98e54bSBrendan Gregg - Sun Microsystems !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { 2877fa94a07fSbrendan l2arc_read_callback_t *cb; 2878fa94a07fSbrendan 2879c5904d13Seschrock DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); 2880c5904d13Seschrock ARCSTAT_BUMP(arcstat_l2_hits); 2881c5904d13Seschrock 2882fa94a07fSbrendan cb = kmem_zalloc(sizeof (l2arc_read_callback_t), 2883fa94a07fSbrendan KM_SLEEP); 2884fa94a07fSbrendan cb->l2rcb_buf = buf; 2885fa94a07fSbrendan cb->l2rcb_spa = spa; 2886fa94a07fSbrendan cb->l2rcb_bp = *bp; 2887fa94a07fSbrendan cb->l2rcb_zb = *zb; 28883baa08fcSek cb->l2rcb_flags = zio_flags; 2889fa94a07fSbrendan 2890fa94a07fSbrendan /* 2891e14bb325SJeff Bonwick * l2arc read. The SCL_L2ARC lock will be 2892e14bb325SJeff Bonwick * released by l2arc_read_done(). 2893fa94a07fSbrendan */ 2894fa94a07fSbrendan rzio = zio_read_phys(pio, vd, addr, size, 2895fa94a07fSbrendan buf->b_data, ZIO_CHECKSUM_OFF, 28963baa08fcSek l2arc_read_done, cb, priority, zio_flags | 289749cf58c0SBrendan Gregg - Sun Microsystems ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | 2898e14bb325SJeff Bonwick ZIO_FLAG_DONT_PROPAGATE | 2899e14bb325SJeff Bonwick ZIO_FLAG_DONT_RETRY, B_FALSE); 2900fa94a07fSbrendan DTRACE_PROBE2(l2arc__read, vdev_t *, vd, 2901fa94a07fSbrendan zio_t *, rzio); 29025a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_read_bytes, size); 2903fa94a07fSbrendan 29043a737e0dSbrendan if (*arc_flags & ARC_NOWAIT) { 29053a737e0dSbrendan zio_nowait(rzio); 29063a737e0dSbrendan return (0); 29073a737e0dSbrendan } 2908fa94a07fSbrendan 29093a737e0dSbrendan ASSERT(*arc_flags & ARC_WAIT); 29103a737e0dSbrendan if (zio_wait(rzio) == 0) 29113a737e0dSbrendan return (0); 29123a737e0dSbrendan 29133a737e0dSbrendan /* l2arc read error; goto zio_read() */ 2914fa94a07fSbrendan } else { 2915fa94a07fSbrendan DTRACE_PROBE1(l2arc__miss, 2916fa94a07fSbrendan arc_buf_hdr_t *, hdr); 2917fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_misses); 2918fa94a07fSbrendan if (HDR_L2_WRITING(hdr)) 2919fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_rw_clash); 2920e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, vd); 2921fa94a07fSbrendan } 29225a98e54bSBrendan Gregg - Sun Microsystems } else { 292376a25fafSBill Moore if (vd != NULL) 292476a25fafSBill Moore spa_config_exit(spa, SCL_L2ARC, vd); 29255a98e54bSBrendan Gregg - Sun Microsystems if (l2arc_ndev != 0) { 29265a98e54bSBrendan Gregg - Sun Microsystems DTRACE_PROBE1(l2arc__miss, 29275a98e54bSBrendan Gregg - Sun Microsystems arc_buf_hdr_t *, hdr); 29285a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_BUMP(arcstat_l2_misses); 29295a98e54bSBrendan Gregg - Sun Microsystems } 2930fa94a07fSbrendan } 2931c5904d13Seschrock 2932fa9e4066Sahrens rzio = zio_read(pio, spa, bp, buf->b_data, size, 29333baa08fcSek arc_read_done, buf, priority, zio_flags, zb); 2934fa9e4066Sahrens 293513506d1eSmaybee if (*arc_flags & ARC_WAIT) 2936fa9e4066Sahrens return (zio_wait(rzio)); 2937fa9e4066Sahrens 293813506d1eSmaybee ASSERT(*arc_flags & ARC_NOWAIT); 2939fa9e4066Sahrens zio_nowait(rzio); 2940fa9e4066Sahrens } 2941fa9e4066Sahrens return (0); 2942fa9e4066Sahrens } 2943fa9e4066Sahrens 2944ea8dc4b6Seschrock void 2945ea8dc4b6Seschrock arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private) 2946ea8dc4b6Seschrock { 2947ea8dc4b6Seschrock ASSERT(buf->b_hdr != NULL); 294844cb6abcSbmc ASSERT(buf->b_hdr->b_state != arc_anon); 2949ea8dc4b6Seschrock ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt) || func == NULL); 2950b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 2951b24ab676SJeff Bonwick ASSERT(!HDR_BUF_AVAILABLE(buf->b_hdr)); 2952b24ab676SJeff Bonwick 2953ea8dc4b6Seschrock buf->b_efunc = func; 2954ea8dc4b6Seschrock buf->b_private = private; 2955ea8dc4b6Seschrock } 2956ea8dc4b6Seschrock 2957ea8dc4b6Seschrock /* 2958ea8dc4b6Seschrock * This is used by the DMU to let the ARC know that a buffer is 2959ea8dc4b6Seschrock * being evicted, so the ARC should clean up. If this arc buf 2960ea8dc4b6Seschrock * is not yet in the evicted state, it will be put there. 2961ea8dc4b6Seschrock */ 2962ea8dc4b6Seschrock int 2963ea8dc4b6Seschrock arc_buf_evict(arc_buf_t *buf) 2964ea8dc4b6Seschrock { 296540d7d650Smaybee arc_buf_hdr_t *hdr; 2966ea8dc4b6Seschrock kmutex_t *hash_lock; 2967ea8dc4b6Seschrock arc_buf_t **bufp; 2968ea8dc4b6Seschrock 29693f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 297040d7d650Smaybee hdr = buf->b_hdr; 2971ea8dc4b6Seschrock if (hdr == NULL) { 2972ea8dc4b6Seschrock /* 2973ea8dc4b6Seschrock * We are in arc_do_user_evicts(). 2974ea8dc4b6Seschrock */ 2975ea8dc4b6Seschrock ASSERT(buf->b_data == NULL); 29763f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 2977ea8dc4b6Seschrock return (0); 29786f83844dSMark Maybee } else if (buf->b_data == NULL) { 29796f83844dSMark Maybee arc_buf_t copy = *buf; /* structure assignment */ 29809b23f181Smaybee /* 29816f83844dSMark Maybee * We are on the eviction list; process this buffer now 29826f83844dSMark Maybee * but let arc_do_user_evicts() do the reaping. 29839b23f181Smaybee */ 29846f83844dSMark Maybee buf->b_efunc = NULL; 29853f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 29866f83844dSMark Maybee VERIFY(copy.b_efunc(©) == 0); 29876f83844dSMark Maybee return (1); 29889b23f181Smaybee } 29896f83844dSMark Maybee hash_lock = HDR_LOCK(hdr); 29906f83844dSMark Maybee mutex_enter(hash_lock); 29913f9d6ad7SLin Ling hdr = buf->b_hdr; 29923f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 29939b23f181Smaybee 29949b23f181Smaybee ASSERT3U(refcount_count(&hdr->b_refcnt), <, hdr->b_datacnt); 299544cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 2996ea8dc4b6Seschrock 2997ea8dc4b6Seschrock /* 2998ea8dc4b6Seschrock * Pull this buffer off of the hdr 2999ea8dc4b6Seschrock */ 3000ea8dc4b6Seschrock bufp = &hdr->b_buf; 3001ea8dc4b6Seschrock while (*bufp != buf) 3002ea8dc4b6Seschrock bufp = &(*bufp)->b_next; 3003ea8dc4b6Seschrock *bufp = buf->b_next; 3004ea8dc4b6Seschrock 3005ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 300644eda4d7Smaybee arc_buf_destroy(buf, FALSE, FALSE); 3007ea8dc4b6Seschrock 3008ea8dc4b6Seschrock if (hdr->b_datacnt == 0) { 3009ea8dc4b6Seschrock arc_state_t *old_state = hdr->b_state; 3010ea8dc4b6Seschrock arc_state_t *evicted_state; 3011ea8dc4b6Seschrock 30123f9d6ad7SLin Ling ASSERT(hdr->b_buf == NULL); 3013ea8dc4b6Seschrock ASSERT(refcount_is_zero(&hdr->b_refcnt)); 3014ea8dc4b6Seschrock 3015ea8dc4b6Seschrock evicted_state = 301644cb6abcSbmc (old_state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; 3017ea8dc4b6Seschrock 301844cb6abcSbmc mutex_enter(&old_state->arcs_mtx); 301944cb6abcSbmc mutex_enter(&evicted_state->arcs_mtx); 3020ea8dc4b6Seschrock 3021ea8dc4b6Seschrock arc_change_state(evicted_state, hdr, hash_lock); 3022ea8dc4b6Seschrock ASSERT(HDR_IN_HASH_TABLE(hdr)); 3023fa94a07fSbrendan hdr->b_flags |= ARC_IN_HASH_TABLE; 3024fa94a07fSbrendan hdr->b_flags &= ~ARC_BUF_AVAILABLE; 3025ea8dc4b6Seschrock 302644cb6abcSbmc mutex_exit(&evicted_state->arcs_mtx); 302744cb6abcSbmc mutex_exit(&old_state->arcs_mtx); 3028ea8dc4b6Seschrock } 3029ea8dc4b6Seschrock mutex_exit(hash_lock); 30303f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 3031dd6ef538Smaybee 3032ea8dc4b6Seschrock VERIFY(buf->b_efunc(buf) == 0); 3033ea8dc4b6Seschrock buf->b_efunc = NULL; 3034ea8dc4b6Seschrock buf->b_private = NULL; 3035ea8dc4b6Seschrock buf->b_hdr = NULL; 30363f9d6ad7SLin Ling buf->b_next = NULL; 3037ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 3038ea8dc4b6Seschrock return (1); 3039ea8dc4b6Seschrock } 3040ea8dc4b6Seschrock 3041fa9e4066Sahrens /* 3042fa9e4066Sahrens * Release this buffer from the cache. This must be done 3043fa9e4066Sahrens * after a read and prior to modifying the buffer contents. 3044fa9e4066Sahrens * If the buffer has more than one reference, we must make 3045088f3894Sahrens * a new hdr for the buffer. 3046fa9e4066Sahrens */ 3047fa9e4066Sahrens void 3048fa9e4066Sahrens arc_release(arc_buf_t *buf, void *tag) 3049fa9e4066Sahrens { 30506f83844dSMark Maybee arc_buf_hdr_t *hdr; 30513f9d6ad7SLin Ling kmutex_t *hash_lock = NULL; 30526f83844dSMark Maybee l2arc_buf_hdr_t *l2hdr; 3053fa94a07fSbrendan uint64_t buf_size; 3054fa9e4066Sahrens 30553f9d6ad7SLin Ling /* 30563f9d6ad7SLin Ling * It would be nice to assert that if it's DMU metadata (level > 30573f9d6ad7SLin Ling * 0 || it's the dnode file), then it must be syncing context. 30583f9d6ad7SLin Ling * But we don't know that information at this level. 30593f9d6ad7SLin Ling */ 30603f9d6ad7SLin Ling 30613f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 30626f83844dSMark Maybee hdr = buf->b_hdr; 30636f83844dSMark Maybee 3064fa9e4066Sahrens /* this buffer is not on any list */ 3065fa9e4066Sahrens ASSERT(refcount_count(&hdr->b_refcnt) > 0); 3066fa9e4066Sahrens 306744cb6abcSbmc if (hdr->b_state == arc_anon) { 3068fa9e4066Sahrens /* this buffer is already released */ 3069ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 30700a95608cSBrendan Gregg - Sun Microsystems } else { 30710a95608cSBrendan Gregg - Sun Microsystems hash_lock = HDR_LOCK(hdr); 30720a95608cSBrendan Gregg - Sun Microsystems mutex_enter(hash_lock); 30733f9d6ad7SLin Ling hdr = buf->b_hdr; 30743f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 3075fa9e4066Sahrens } 3076fa9e4066Sahrens 30776f83844dSMark Maybee l2hdr = hdr->b_l2hdr; 30786f83844dSMark Maybee if (l2hdr) { 30796f83844dSMark Maybee mutex_enter(&l2arc_buflist_mtx); 30806f83844dSMark Maybee hdr->b_l2hdr = NULL; 30816f83844dSMark Maybee buf_size = hdr->b_size; 30826f83844dSMark Maybee } 30836f83844dSMark Maybee 3084ea8dc4b6Seschrock /* 3085ea8dc4b6Seschrock * Do we have more than one buf? 3086ea8dc4b6Seschrock */ 30876f83844dSMark Maybee if (hdr->b_datacnt > 1) { 3088fa9e4066Sahrens arc_buf_hdr_t *nhdr; 3089fa9e4066Sahrens arc_buf_t **bufp; 3090fa9e4066Sahrens uint64_t blksz = hdr->b_size; 3091ac05c741SMark Maybee uint64_t spa = hdr->b_spa; 3092ad23a2dbSjohansen arc_buf_contents_t type = hdr->b_type; 3093fa94a07fSbrendan uint32_t flags = hdr->b_flags; 3094fa9e4066Sahrens 30956f83844dSMark Maybee ASSERT(hdr->b_buf != buf || buf->b_next != NULL); 3096fa9e4066Sahrens /* 30973f9d6ad7SLin Ling * Pull the data off of this hdr and attach it to 30983f9d6ad7SLin Ling * a new anonymous hdr. 3099fa9e4066Sahrens */ 3100ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 3101fa9e4066Sahrens bufp = &hdr->b_buf; 3102ea8dc4b6Seschrock while (*bufp != buf) 3103fa9e4066Sahrens bufp = &(*bufp)->b_next; 31043f9d6ad7SLin Ling *bufp = buf->b_next; 3105af2c4821Smaybee buf->b_next = NULL; 3106ea8dc4b6Seschrock 310744cb6abcSbmc ASSERT3U(hdr->b_state->arcs_size, >=, hdr->b_size); 310844cb6abcSbmc atomic_add_64(&hdr->b_state->arcs_size, -hdr->b_size); 3109ea8dc4b6Seschrock if (refcount_is_zero(&hdr->b_refcnt)) { 31100e8c6158Smaybee uint64_t *size = &hdr->b_state->arcs_lsize[hdr->b_type]; 31110e8c6158Smaybee ASSERT3U(*size, >=, hdr->b_size); 31120e8c6158Smaybee atomic_add_64(size, -hdr->b_size); 3113ea8dc4b6Seschrock } 3114ea8dc4b6Seschrock hdr->b_datacnt -= 1; 3115c717a561Smaybee arc_cksum_verify(buf); 3116ea8dc4b6Seschrock 3117fa9e4066Sahrens mutex_exit(hash_lock); 3118fa9e4066Sahrens 31191ab7f2deSmaybee nhdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 3120fa9e4066Sahrens nhdr->b_size = blksz; 3121fa9e4066Sahrens nhdr->b_spa = spa; 3122ad23a2dbSjohansen nhdr->b_type = type; 3123fa9e4066Sahrens nhdr->b_buf = buf; 312444cb6abcSbmc nhdr->b_state = arc_anon; 3125fa9e4066Sahrens nhdr->b_arc_access = 0; 3126fa94a07fSbrendan nhdr->b_flags = flags & ARC_L2_WRITING; 3127fa94a07fSbrendan nhdr->b_l2hdr = NULL; 3128ea8dc4b6Seschrock nhdr->b_datacnt = 1; 3129c717a561Smaybee nhdr->b_freeze_cksum = NULL; 3130fa9e4066Sahrens (void) refcount_add(&nhdr->b_refcnt, tag); 3131af2c4821Smaybee buf->b_hdr = nhdr; 31323f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 313344cb6abcSbmc atomic_add_64(&arc_anon->arcs_size, blksz); 3134fa9e4066Sahrens } else { 31353f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 3136ea8dc4b6Seschrock ASSERT(refcount_count(&hdr->b_refcnt) == 1); 3137fa9e4066Sahrens ASSERT(!list_link_active(&hdr->b_arc_node)); 3138fa9e4066Sahrens ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 31393f9d6ad7SLin Ling if (hdr->b_state != arc_anon) 31403f9d6ad7SLin Ling arc_change_state(arc_anon, hdr, hash_lock); 3141fa9e4066Sahrens hdr->b_arc_access = 0; 31423f9d6ad7SLin Ling if (hash_lock) 31433f9d6ad7SLin Ling mutex_exit(hash_lock); 3144fa94a07fSbrendan 31453f9d6ad7SLin Ling buf_discard_identity(hdr); 3146c717a561Smaybee arc_buf_thaw(buf); 3147fa9e4066Sahrens } 3148ea8dc4b6Seschrock buf->b_efunc = NULL; 3149ea8dc4b6Seschrock buf->b_private = NULL; 3150fa94a07fSbrendan 3151fa94a07fSbrendan if (l2hdr) { 3152fa94a07fSbrendan list_remove(l2hdr->b_dev->l2ad_buflist, hdr); 3153fa94a07fSbrendan kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); 3154fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, -buf_size); 3155fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 31566f83844dSMark Maybee } 3157fa9e4066Sahrens } 3158fa9e4066Sahrens 31593f9d6ad7SLin Ling /* 31603f9d6ad7SLin Ling * Release this buffer. If it does not match the provided BP, fill it 31613f9d6ad7SLin Ling * with that block's contents. 31623f9d6ad7SLin Ling */ 31633f9d6ad7SLin Ling /* ARGSUSED */ 31643f9d6ad7SLin Ling int 31653f9d6ad7SLin Ling arc_release_bp(arc_buf_t *buf, void *tag, blkptr_t *bp, spa_t *spa, 31663f9d6ad7SLin Ling zbookmark_t *zb) 31673f9d6ad7SLin Ling { 31683f9d6ad7SLin Ling arc_release(buf, tag); 31693f9d6ad7SLin Ling return (0); 31703f9d6ad7SLin Ling } 31713f9d6ad7SLin Ling 3172fa9e4066Sahrens int 3173fa9e4066Sahrens arc_released(arc_buf_t *buf) 3174fa9e4066Sahrens { 31756f83844dSMark Maybee int released; 31766f83844dSMark Maybee 31773f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 31786f83844dSMark Maybee released = (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon); 31793f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 31806f83844dSMark Maybee return (released); 3181ea8dc4b6Seschrock } 3182ea8dc4b6Seschrock 3183ea8dc4b6Seschrock int 3184ea8dc4b6Seschrock arc_has_callback(arc_buf_t *buf) 3185ea8dc4b6Seschrock { 31866f83844dSMark Maybee int callback; 31876f83844dSMark Maybee 31883f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 31896f83844dSMark Maybee callback = (buf->b_efunc != NULL); 31903f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 31916f83844dSMark Maybee return (callback); 3192fa9e4066Sahrens } 3193fa9e4066Sahrens 3194ea8dc4b6Seschrock #ifdef ZFS_DEBUG 3195ea8dc4b6Seschrock int 3196ea8dc4b6Seschrock arc_referenced(arc_buf_t *buf) 3197ea8dc4b6Seschrock { 31986f83844dSMark Maybee int referenced; 31996f83844dSMark Maybee 32003f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 32016f83844dSMark Maybee referenced = (refcount_count(&buf->b_hdr->b_refcnt)); 32023f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 32036f83844dSMark Maybee return (referenced); 3204ea8dc4b6Seschrock } 3205ea8dc4b6Seschrock #endif 3206ea8dc4b6Seschrock 3207c717a561Smaybee static void 3208c717a561Smaybee arc_write_ready(zio_t *zio) 3209c717a561Smaybee { 3210c717a561Smaybee arc_write_callback_t *callback = zio->io_private; 3211c717a561Smaybee arc_buf_t *buf = callback->awcb_buf; 32120a4e9518Sgw arc_buf_hdr_t *hdr = buf->b_hdr; 3213c717a561Smaybee 3214e14bb325SJeff Bonwick ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt)); 3215e14bb325SJeff Bonwick callback->awcb_ready(zio, buf, callback->awcb_private); 3216e14bb325SJeff Bonwick 32170a4e9518Sgw /* 32180a4e9518Sgw * If the IO is already in progress, then this is a re-write 3219e14bb325SJeff Bonwick * attempt, so we need to thaw and re-compute the cksum. 3220e14bb325SJeff Bonwick * It is the responsibility of the callback to handle the 3221e14bb325SJeff Bonwick * accounting for any re-write attempt. 32220a4e9518Sgw */ 32230a4e9518Sgw if (HDR_IO_IN_PROGRESS(hdr)) { 32240a4e9518Sgw mutex_enter(&hdr->b_freeze_lock); 32250a4e9518Sgw if (hdr->b_freeze_cksum != NULL) { 32260a4e9518Sgw kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 32270a4e9518Sgw hdr->b_freeze_cksum = NULL; 32280a4e9518Sgw } 32290a4e9518Sgw mutex_exit(&hdr->b_freeze_lock); 32300a4e9518Sgw } 3231fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 32320a4e9518Sgw hdr->b_flags |= ARC_IO_IN_PROGRESS; 3233c717a561Smaybee } 3234c717a561Smaybee 3235fa9e4066Sahrens static void 3236fa9e4066Sahrens arc_write_done(zio_t *zio) 3237fa9e4066Sahrens { 3238c717a561Smaybee arc_write_callback_t *callback = zio->io_private; 3239c717a561Smaybee arc_buf_t *buf = callback->awcb_buf; 3240c717a561Smaybee arc_buf_hdr_t *hdr = buf->b_hdr; 3241fa9e4066Sahrens 3242b24ab676SJeff Bonwick ASSERT(hdr->b_acb == NULL); 3243b24ab676SJeff Bonwick 3244b24ab676SJeff Bonwick if (zio->io_error == 0) { 3245b24ab676SJeff Bonwick hdr->b_dva = *BP_IDENTITY(zio->io_bp); 3246b24ab676SJeff Bonwick hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); 3247b24ab676SJeff Bonwick hdr->b_cksum0 = zio->io_bp->blk_cksum.zc_word[0]; 3248b24ab676SJeff Bonwick } else { 3249b24ab676SJeff Bonwick ASSERT(BUF_EMPTY(hdr)); 3250b24ab676SJeff Bonwick } 3251fa9e4066Sahrens 3252ea8dc4b6Seschrock /* 3253ea8dc4b6Seschrock * If the block to be written was all-zero, we may have 3254ea8dc4b6Seschrock * compressed it away. In this case no write was performed 32553f9d6ad7SLin Ling * so there will be no dva/birth/checksum. The buffer must 32563f9d6ad7SLin Ling * therefore remain anonymous (and uncached). 3257ea8dc4b6Seschrock */ 3258fa9e4066Sahrens if (!BUF_EMPTY(hdr)) { 3259fa9e4066Sahrens arc_buf_hdr_t *exists; 3260fa9e4066Sahrens kmutex_t *hash_lock; 3261fa9e4066Sahrens 3262b24ab676SJeff Bonwick ASSERT(zio->io_error == 0); 3263b24ab676SJeff Bonwick 32646b4acc8bSahrens arc_cksum_verify(buf); 32656b4acc8bSahrens 3266fa9e4066Sahrens exists = buf_hash_insert(hdr, &hash_lock); 3267fa9e4066Sahrens if (exists) { 3268fa9e4066Sahrens /* 3269fa9e4066Sahrens * This can only happen if we overwrite for 3270fa9e4066Sahrens * sync-to-convergence, because we remove 3271fa9e4066Sahrens * buffers from the hash table when we arc_free(). 3272fa9e4066Sahrens */ 3273b24ab676SJeff Bonwick if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { 3274b24ab676SJeff Bonwick if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) 3275b24ab676SJeff Bonwick panic("bad overwrite, hdr=%p exists=%p", 3276b24ab676SJeff Bonwick (void *)hdr, (void *)exists); 3277b24ab676SJeff Bonwick ASSERT(refcount_is_zero(&exists->b_refcnt)); 3278b24ab676SJeff Bonwick arc_change_state(arc_anon, exists, hash_lock); 3279b24ab676SJeff Bonwick mutex_exit(hash_lock); 3280b24ab676SJeff Bonwick arc_hdr_destroy(exists); 3281b24ab676SJeff Bonwick exists = buf_hash_insert(hdr, &hash_lock); 3282b24ab676SJeff Bonwick ASSERT3P(exists, ==, NULL); 3283b24ab676SJeff Bonwick } else { 3284b24ab676SJeff Bonwick /* Dedup */ 3285b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 3286b24ab676SJeff Bonwick ASSERT(hdr->b_state == arc_anon); 3287b24ab676SJeff Bonwick ASSERT(BP_GET_DEDUP(zio->io_bp)); 3288b24ab676SJeff Bonwick ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); 3289ae46e4c7SMatthew Ahrens } 3290fa9e4066Sahrens } 3291ea8dc4b6Seschrock hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 3292088f3894Sahrens /* if it's not anon, we are doing a scrub */ 3293b24ab676SJeff Bonwick if (!exists && hdr->b_state == arc_anon) 3294088f3894Sahrens arc_access(hdr, hash_lock); 329544eda4d7Smaybee mutex_exit(hash_lock); 3296ea8dc4b6Seschrock } else { 3297ea8dc4b6Seschrock hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 3298fa9e4066Sahrens } 3299ea8dc4b6Seschrock 3300b24ab676SJeff Bonwick ASSERT(!refcount_is_zero(&hdr->b_refcnt)); 3301b24ab676SJeff Bonwick callback->awcb_done(zio, buf, callback->awcb_private); 3302fa9e4066Sahrens 3303c717a561Smaybee kmem_free(callback, sizeof (arc_write_callback_t)); 3304fa9e4066Sahrens } 3305fa9e4066Sahrens 3306c717a561Smaybee zio_t * 3307b24ab676SJeff Bonwick arc_write(zio_t *pio, spa_t *spa, uint64_t txg, 3308b24ab676SJeff Bonwick blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp, 3309b24ab676SJeff Bonwick arc_done_func_t *ready, arc_done_func_t *done, void *private, 3310b24ab676SJeff Bonwick int priority, int zio_flags, const zbookmark_t *zb) 3311fa9e4066Sahrens { 3312fa9e4066Sahrens arc_buf_hdr_t *hdr = buf->b_hdr; 3313c717a561Smaybee arc_write_callback_t *callback; 3314e14bb325SJeff Bonwick zio_t *zio; 3315fa9e4066Sahrens 3316e14bb325SJeff Bonwick ASSERT(ready != NULL); 3317b24ab676SJeff Bonwick ASSERT(done != NULL); 3318fa9e4066Sahrens ASSERT(!HDR_IO_ERROR(hdr)); 3319c5c6ffa0Smaybee ASSERT((hdr->b_flags & ARC_IO_IN_PROGRESS) == 0); 3320b24ab676SJeff Bonwick ASSERT(hdr->b_acb == NULL); 33213baa08fcSek if (l2arc) 33223baa08fcSek hdr->b_flags |= ARC_L2CACHE; 3323c717a561Smaybee callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP); 3324c717a561Smaybee callback->awcb_ready = ready; 3325c717a561Smaybee callback->awcb_done = done; 3326c717a561Smaybee callback->awcb_private = private; 3327c717a561Smaybee callback->awcb_buf = buf; 3328088f3894Sahrens 3329b24ab676SJeff Bonwick zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, zp, 3330e14bb325SJeff Bonwick arc_write_ready, arc_write_done, callback, priority, zio_flags, zb); 3331fa9e4066Sahrens 3332c717a561Smaybee return (zio); 3333fa9e4066Sahrens } 3334fa9e4066Sahrens 33351ab7f2deSmaybee static int 33362fdbea25SAleksandr Guzovskiy arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg) 33371ab7f2deSmaybee { 33381ab7f2deSmaybee #ifdef _KERNEL 33391ab7f2deSmaybee uint64_t available_memory = ptob(freemem); 33401ab7f2deSmaybee static uint64_t page_load = 0; 33411ab7f2deSmaybee static uint64_t last_txg = 0; 33421ab7f2deSmaybee 33431ab7f2deSmaybee #if defined(__i386) 33441ab7f2deSmaybee available_memory = 33451ab7f2deSmaybee MIN(available_memory, vmem_size(heap_arena, VMEM_FREE)); 33461ab7f2deSmaybee #endif 33471ab7f2deSmaybee if (available_memory >= zfs_write_limit_max) 33481ab7f2deSmaybee return (0); 33491ab7f2deSmaybee 33501ab7f2deSmaybee if (txg > last_txg) { 33511ab7f2deSmaybee last_txg = txg; 33521ab7f2deSmaybee page_load = 0; 33531ab7f2deSmaybee } 33541ab7f2deSmaybee /* 33551ab7f2deSmaybee * If we are in pageout, we know that memory is already tight, 33561ab7f2deSmaybee * the arc is already going to be evicting, so we just want to 33571ab7f2deSmaybee * continue to let page writes occur as quickly as possible. 33581ab7f2deSmaybee */ 33591ab7f2deSmaybee if (curproc == proc_pageout) { 33601ab7f2deSmaybee if (page_load > MAX(ptob(minfree), available_memory) / 4) 33611ab7f2deSmaybee return (ERESTART); 33621ab7f2deSmaybee /* Note: reserve is inflated, so we deflate */ 33631ab7f2deSmaybee page_load += reserve / 8; 33641ab7f2deSmaybee return (0); 33651ab7f2deSmaybee } else if (page_load > 0 && arc_reclaim_needed()) { 33661ab7f2deSmaybee /* memory is low, delay before restarting */ 33671ab7f2deSmaybee ARCSTAT_INCR(arcstat_memory_throttle_count, 1); 33681ab7f2deSmaybee return (EAGAIN); 33691ab7f2deSmaybee } 33701ab7f2deSmaybee page_load = 0; 33711ab7f2deSmaybee 33721ab7f2deSmaybee if (arc_size > arc_c_min) { 33731ab7f2deSmaybee uint64_t evictable_memory = 33741ab7f2deSmaybee arc_mru->arcs_lsize[ARC_BUFC_DATA] + 33751ab7f2deSmaybee arc_mru->arcs_lsize[ARC_BUFC_METADATA] + 33761ab7f2deSmaybee arc_mfu->arcs_lsize[ARC_BUFC_DATA] + 33771ab7f2deSmaybee arc_mfu->arcs_lsize[ARC_BUFC_METADATA]; 33781ab7f2deSmaybee available_memory += MIN(evictable_memory, arc_size - arc_c_min); 33791ab7f2deSmaybee } 33801ab7f2deSmaybee 33811ab7f2deSmaybee if (inflight_data > available_memory / 4) { 33821ab7f2deSmaybee ARCSTAT_INCR(arcstat_memory_throttle_count, 1); 33831ab7f2deSmaybee return (ERESTART); 33841ab7f2deSmaybee } 33851ab7f2deSmaybee #endif 33861ab7f2deSmaybee return (0); 33871ab7f2deSmaybee } 33881ab7f2deSmaybee 3389fa9e4066Sahrens void 33901ab7f2deSmaybee arc_tempreserve_clear(uint64_t reserve) 3391fa9e4066Sahrens { 33921ab7f2deSmaybee atomic_add_64(&arc_tempreserve, -reserve); 3393fa9e4066Sahrens ASSERT((int64_t)arc_tempreserve >= 0); 3394fa9e4066Sahrens } 3395fa9e4066Sahrens 3396fa9e4066Sahrens int 33971ab7f2deSmaybee arc_tempreserve_space(uint64_t reserve, uint64_t txg) 3398fa9e4066Sahrens { 33991ab7f2deSmaybee int error; 34002fdbea25SAleksandr Guzovskiy uint64_t anon_size; 34011ab7f2deSmaybee 3402fa9e4066Sahrens #ifdef ZFS_DEBUG 3403fa9e4066Sahrens /* 3404fa9e4066Sahrens * Once in a while, fail for no reason. Everything should cope. 3405fa9e4066Sahrens */ 3406fa9e4066Sahrens if (spa_get_random(10000) == 0) { 3407fa9e4066Sahrens dprintf("forcing random failure\n"); 3408fa9e4066Sahrens return (ERESTART); 3409fa9e4066Sahrens } 3410fa9e4066Sahrens #endif 34111ab7f2deSmaybee if (reserve > arc_c/4 && !arc_no_grow) 34121ab7f2deSmaybee arc_c = MIN(arc_c_max, reserve * 4); 34131ab7f2deSmaybee if (reserve > arc_c) 3414112fe045Smaybee return (ENOMEM); 3415112fe045Smaybee 34162fdbea25SAleksandr Guzovskiy /* 34172fdbea25SAleksandr Guzovskiy * Don't count loaned bufs as in flight dirty data to prevent long 34182fdbea25SAleksandr Guzovskiy * network delays from blocking transactions that are ready to be 34192fdbea25SAleksandr Guzovskiy * assigned to a txg. 34202fdbea25SAleksandr Guzovskiy */ 34212fdbea25SAleksandr Guzovskiy anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0); 34222fdbea25SAleksandr Guzovskiy 34231ab7f2deSmaybee /* 34241ab7f2deSmaybee * Writes will, almost always, require additional memory allocations 34251ab7f2deSmaybee * in order to compress/encrypt/etc the data. We therefor need to 34261ab7f2deSmaybee * make sure that there is sufficient available memory for this. 34271ab7f2deSmaybee */ 34282fdbea25SAleksandr Guzovskiy if (error = arc_memory_throttle(reserve, anon_size, txg)) 34291ab7f2deSmaybee return (error); 34301ab7f2deSmaybee 3431fa9e4066Sahrens /* 3432112fe045Smaybee * Throttle writes when the amount of dirty data in the cache 3433112fe045Smaybee * gets too large. We try to keep the cache less than half full 3434112fe045Smaybee * of dirty blocks so that our sync times don't grow too large. 3435112fe045Smaybee * Note: if two requests come in concurrently, we might let them 3436112fe045Smaybee * both succeed, when one of them should fail. Not a huge deal. 3437fa9e4066Sahrens */ 34382fdbea25SAleksandr Guzovskiy 34392fdbea25SAleksandr Guzovskiy if (reserve + arc_tempreserve + anon_size > arc_c / 2 && 34402fdbea25SAleksandr Guzovskiy anon_size > arc_c / 4) { 34410e8c6158Smaybee dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " 34420e8c6158Smaybee "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n", 34430e8c6158Smaybee arc_tempreserve>>10, 34440e8c6158Smaybee arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10, 34450e8c6158Smaybee arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10, 34461ab7f2deSmaybee reserve>>10, arc_c>>10); 3447fa9e4066Sahrens return (ERESTART); 3448fa9e4066Sahrens } 34491ab7f2deSmaybee atomic_add_64(&arc_tempreserve, reserve); 3450fa9e4066Sahrens return (0); 3451fa9e4066Sahrens } 3452fa9e4066Sahrens 3453fa9e4066Sahrens void 3454fa9e4066Sahrens arc_init(void) 3455fa9e4066Sahrens { 3456fa9e4066Sahrens mutex_init(&arc_reclaim_thr_lock, NULL, MUTEX_DEFAULT, NULL); 3457fa9e4066Sahrens cv_init(&arc_reclaim_thr_cv, NULL, CV_DEFAULT, NULL); 3458fa9e4066Sahrens 345913506d1eSmaybee /* Convert seconds to clock ticks */ 3460b19a79ecSperrin arc_min_prefetch_lifespan = 1 * hz; 346113506d1eSmaybee 3462fa9e4066Sahrens /* Start out with 1/8 of all memory */ 346344cb6abcSbmc arc_c = physmem * PAGESIZE / 8; 3464fa9e4066Sahrens 3465fa9e4066Sahrens #ifdef _KERNEL 3466fa9e4066Sahrens /* 3467fa9e4066Sahrens * On architectures where the physical memory can be larger 3468fa9e4066Sahrens * than the addressable space (intel in 32-bit mode), we may 3469fa9e4066Sahrens * need to limit the cache to 1/8 of VM size. 3470fa9e4066Sahrens */ 347144cb6abcSbmc arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8); 3472fa9e4066Sahrens #endif 3473fa9e4066Sahrens 3474112fe045Smaybee /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ 347544cb6abcSbmc arc_c_min = MAX(arc_c / 4, 64<<20); 3476112fe045Smaybee /* set max to 3/4 of all memory, or all but 1GB, whichever is more */ 347744cb6abcSbmc if (arc_c * 8 >= 1<<30) 347844cb6abcSbmc arc_c_max = (arc_c * 8) - (1<<30); 3479fa9e4066Sahrens else 348044cb6abcSbmc arc_c_max = arc_c_min; 348144cb6abcSbmc arc_c_max = MAX(arc_c * 6, arc_c_max); 3482a2eea2e1Sahrens 3483a2eea2e1Sahrens /* 3484a2eea2e1Sahrens * Allow the tunables to override our calculations if they are 3485a2eea2e1Sahrens * reasonable (ie. over 64MB) 3486a2eea2e1Sahrens */ 3487a2eea2e1Sahrens if (zfs_arc_max > 64<<20 && zfs_arc_max < physmem * PAGESIZE) 348844cb6abcSbmc arc_c_max = zfs_arc_max; 348944cb6abcSbmc if (zfs_arc_min > 64<<20 && zfs_arc_min <= arc_c_max) 349044cb6abcSbmc arc_c_min = zfs_arc_min; 3491a2eea2e1Sahrens 349244cb6abcSbmc arc_c = arc_c_max; 349344cb6abcSbmc arc_p = (arc_c >> 1); 3494fa9e4066Sahrens 34950e8c6158Smaybee /* limit meta-data to 1/4 of the arc capacity */ 34960e8c6158Smaybee arc_meta_limit = arc_c_max / 4; 34971116048bSek 34981116048bSek /* Allow the tunable to override if it is reasonable */ 34991116048bSek if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max) 35001116048bSek arc_meta_limit = zfs_arc_meta_limit; 35011116048bSek 35020e8c6158Smaybee if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0) 35030e8c6158Smaybee arc_c_min = arc_meta_limit / 2; 35040e8c6158Smaybee 35055a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_grow_retry > 0) 35065a98e54bSBrendan Gregg - Sun Microsystems arc_grow_retry = zfs_arc_grow_retry; 35075a98e54bSBrendan Gregg - Sun Microsystems 35085a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_shrink_shift > 0) 35095a98e54bSBrendan Gregg - Sun Microsystems arc_shrink_shift = zfs_arc_shrink_shift; 35105a98e54bSBrendan Gregg - Sun Microsystems 35115a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_p_min_shift > 0) 35125a98e54bSBrendan Gregg - Sun Microsystems arc_p_min_shift = zfs_arc_p_min_shift; 35135a98e54bSBrendan Gregg - Sun Microsystems 3514fa9e4066Sahrens /* if kmem_flags are set, lets try to use less memory */ 3515fa9e4066Sahrens if (kmem_debugging()) 351644cb6abcSbmc arc_c = arc_c / 2; 351744cb6abcSbmc if (arc_c < arc_c_min) 351844cb6abcSbmc arc_c = arc_c_min; 351944cb6abcSbmc 352044cb6abcSbmc arc_anon = &ARC_anon; 352144cb6abcSbmc arc_mru = &ARC_mru; 352244cb6abcSbmc arc_mru_ghost = &ARC_mru_ghost; 352344cb6abcSbmc arc_mfu = &ARC_mfu; 352444cb6abcSbmc arc_mfu_ghost = &ARC_mfu_ghost; 3525fa94a07fSbrendan arc_l2c_only = &ARC_l2c_only; 352644cb6abcSbmc arc_size = 0; 352744cb6abcSbmc 352844cb6abcSbmc mutex_init(&arc_anon->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 352944cb6abcSbmc mutex_init(&arc_mru->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 353044cb6abcSbmc mutex_init(&arc_mru_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 353144cb6abcSbmc mutex_init(&arc_mfu->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 353244cb6abcSbmc mutex_init(&arc_mfu_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 3533fa94a07fSbrendan mutex_init(&arc_l2c_only->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 353444cb6abcSbmc 35350e8c6158Smaybee list_create(&arc_mru->arcs_list[ARC_BUFC_METADATA], 35360e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35370e8c6158Smaybee list_create(&arc_mru->arcs_list[ARC_BUFC_DATA], 35380e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35390e8c6158Smaybee list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA], 35400e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35410e8c6158Smaybee list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA], 35420e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35430e8c6158Smaybee list_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA], 35440e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35450e8c6158Smaybee list_create(&arc_mfu->arcs_list[ARC_BUFC_DATA], 35460e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35470e8c6158Smaybee list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA], 35480e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35490e8c6158Smaybee list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA], 35500e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3551fa94a07fSbrendan list_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA], 3552fa94a07fSbrendan sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3553fa94a07fSbrendan list_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA], 3554fa94a07fSbrendan sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3555fa9e4066Sahrens 3556fa9e4066Sahrens buf_init(); 3557fa9e4066Sahrens 3558fa9e4066Sahrens arc_thread_exit = 0; 3559ea8dc4b6Seschrock arc_eviction_list = NULL; 3560ea8dc4b6Seschrock mutex_init(&arc_eviction_mtx, NULL, MUTEX_DEFAULT, NULL); 356140d7d650Smaybee bzero(&arc_eviction_hdr, sizeof (arc_buf_hdr_t)); 3562fa9e4066Sahrens 356344cb6abcSbmc arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, 356444cb6abcSbmc sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); 356544cb6abcSbmc 356644cb6abcSbmc if (arc_ksp != NULL) { 356744cb6abcSbmc arc_ksp->ks_data = &arc_stats; 356844cb6abcSbmc kstat_install(arc_ksp); 356944cb6abcSbmc } 357044cb6abcSbmc 3571fa9e4066Sahrens (void) thread_create(NULL, 0, arc_reclaim_thread, NULL, 0, &p0, 3572fa9e4066Sahrens TS_RUN, minclsyspri); 357349e3519aSmaybee 357449e3519aSmaybee arc_dead = FALSE; 35753a737e0dSbrendan arc_warm = B_FALSE; 35761ab7f2deSmaybee 35771ab7f2deSmaybee if (zfs_write_limit_max == 0) 357805715f94SMark Maybee zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift; 35791ab7f2deSmaybee else 35801ab7f2deSmaybee zfs_write_limit_shift = 0; 358105715f94SMark Maybee mutex_init(&zfs_write_limit_lock, NULL, MUTEX_DEFAULT, NULL); 3582fa9e4066Sahrens } 3583fa9e4066Sahrens 3584fa9e4066Sahrens void 3585fa9e4066Sahrens arc_fini(void) 3586fa9e4066Sahrens { 3587fa9e4066Sahrens mutex_enter(&arc_reclaim_thr_lock); 3588fa9e4066Sahrens arc_thread_exit = 1; 3589fa9e4066Sahrens while (arc_thread_exit != 0) 3590fa9e4066Sahrens cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock); 3591fa9e4066Sahrens mutex_exit(&arc_reclaim_thr_lock); 3592fa9e4066Sahrens 3593874395d5Smaybee arc_flush(NULL); 3594fa9e4066Sahrens 3595fa9e4066Sahrens arc_dead = TRUE; 3596fa9e4066Sahrens 359744cb6abcSbmc if (arc_ksp != NULL) { 359844cb6abcSbmc kstat_delete(arc_ksp); 359944cb6abcSbmc arc_ksp = NULL; 360044cb6abcSbmc } 360144cb6abcSbmc 3602ea8dc4b6Seschrock mutex_destroy(&arc_eviction_mtx); 3603fa9e4066Sahrens mutex_destroy(&arc_reclaim_thr_lock); 3604fa9e4066Sahrens cv_destroy(&arc_reclaim_thr_cv); 3605fa9e4066Sahrens 36060e8c6158Smaybee list_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]); 36070e8c6158Smaybee list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); 36080e8c6158Smaybee list_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]); 36090e8c6158Smaybee list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); 36100e8c6158Smaybee list_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]); 36110e8c6158Smaybee list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); 36120e8c6158Smaybee list_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]); 36130e8c6158Smaybee list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); 3614fa9e4066Sahrens 361544cb6abcSbmc mutex_destroy(&arc_anon->arcs_mtx); 361644cb6abcSbmc mutex_destroy(&arc_mru->arcs_mtx); 361744cb6abcSbmc mutex_destroy(&arc_mru_ghost->arcs_mtx); 361844cb6abcSbmc mutex_destroy(&arc_mfu->arcs_mtx); 361944cb6abcSbmc mutex_destroy(&arc_mfu_ghost->arcs_mtx); 3620b5e70f97SRicardo M. Correia mutex_destroy(&arc_l2c_only->arcs_mtx); 36215ad82045Snd 362205715f94SMark Maybee mutex_destroy(&zfs_write_limit_lock); 362305715f94SMark Maybee 3624fa9e4066Sahrens buf_fini(); 36252fdbea25SAleksandr Guzovskiy 36262fdbea25SAleksandr Guzovskiy ASSERT(arc_loaned_bytes == 0); 3627fa9e4066Sahrens } 3628fa94a07fSbrendan 3629fa94a07fSbrendan /* 3630fa94a07fSbrendan * Level 2 ARC 3631fa94a07fSbrendan * 3632fa94a07fSbrendan * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. 3633fa94a07fSbrendan * It uses dedicated storage devices to hold cached data, which are populated 3634fa94a07fSbrendan * using large infrequent writes. The main role of this cache is to boost 3635fa94a07fSbrendan * the performance of random read workloads. The intended L2ARC devices 3636fa94a07fSbrendan * include short-stroked disks, solid state disks, and other media with 3637fa94a07fSbrendan * substantially faster read latency than disk. 3638fa94a07fSbrendan * 3639fa94a07fSbrendan * +-----------------------+ 3640fa94a07fSbrendan * | ARC | 3641fa94a07fSbrendan * +-----------------------+ 3642fa94a07fSbrendan * | ^ ^ 3643fa94a07fSbrendan * | | | 3644fa94a07fSbrendan * l2arc_feed_thread() arc_read() 3645fa94a07fSbrendan * | | | 3646fa94a07fSbrendan * | l2arc read | 3647fa94a07fSbrendan * V | | 3648fa94a07fSbrendan * +---------------+ | 3649fa94a07fSbrendan * | L2ARC | | 3650fa94a07fSbrendan * +---------------+ | 3651fa94a07fSbrendan * | ^ | 3652fa94a07fSbrendan * l2arc_write() | | 3653fa94a07fSbrendan * | | | 3654fa94a07fSbrendan * V | | 3655fa94a07fSbrendan * +-------+ +-------+ 3656fa94a07fSbrendan * | vdev | | vdev | 3657fa94a07fSbrendan * | cache | | cache | 3658fa94a07fSbrendan * +-------+ +-------+ 3659fa94a07fSbrendan * +=========+ .-----. 3660fa94a07fSbrendan * : L2ARC : |-_____-| 3661fa94a07fSbrendan * : devices : | Disks | 3662fa94a07fSbrendan * +=========+ `-_____-' 3663fa94a07fSbrendan * 3664fa94a07fSbrendan * Read requests are satisfied from the following sources, in order: 3665fa94a07fSbrendan * 3666fa94a07fSbrendan * 1) ARC 3667fa94a07fSbrendan * 2) vdev cache of L2ARC devices 3668fa94a07fSbrendan * 3) L2ARC devices 3669fa94a07fSbrendan * 4) vdev cache of disks 3670fa94a07fSbrendan * 5) disks 3671fa94a07fSbrendan * 3672fa94a07fSbrendan * Some L2ARC device types exhibit extremely slow write performance. 3673fa94a07fSbrendan * To accommodate for this there are some significant differences between 3674fa94a07fSbrendan * the L2ARC and traditional cache design: 3675fa94a07fSbrendan * 3676fa94a07fSbrendan * 1. There is no eviction path from the ARC to the L2ARC. Evictions from 3677fa94a07fSbrendan * the ARC behave as usual, freeing buffers and placing headers on ghost 3678fa94a07fSbrendan * lists. The ARC does not send buffers to the L2ARC during eviction as 3679fa94a07fSbrendan * this would add inflated write latencies for all ARC memory pressure. 3680fa94a07fSbrendan * 3681fa94a07fSbrendan * 2. The L2ARC attempts to cache data from the ARC before it is evicted. 3682fa94a07fSbrendan * It does this by periodically scanning buffers from the eviction-end of 3683fa94a07fSbrendan * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are 3684fa94a07fSbrendan * not already there. It scans until a headroom of buffers is satisfied, 3685fa94a07fSbrendan * which itself is a buffer for ARC eviction. The thread that does this is 3686fa94a07fSbrendan * l2arc_feed_thread(), illustrated below; example sizes are included to 3687fa94a07fSbrendan * provide a better sense of ratio than this diagram: 3688fa94a07fSbrendan * 3689fa94a07fSbrendan * head --> tail 3690fa94a07fSbrendan * +---------------------+----------+ 3691fa94a07fSbrendan * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC 3692fa94a07fSbrendan * +---------------------+----------+ | o L2ARC eligible 3693fa94a07fSbrendan * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer 3694fa94a07fSbrendan * +---------------------+----------+ | 3695fa94a07fSbrendan * 15.9 Gbytes ^ 32 Mbytes | 3696fa94a07fSbrendan * headroom | 3697fa94a07fSbrendan * l2arc_feed_thread() 3698fa94a07fSbrendan * | 3699fa94a07fSbrendan * l2arc write hand <--[oooo]--' 3700fa94a07fSbrendan * | 8 Mbyte 3701fa94a07fSbrendan * | write max 3702fa94a07fSbrendan * V 3703fa94a07fSbrendan * +==============================+ 3704fa94a07fSbrendan * L2ARC dev |####|#|###|###| |####| ... | 3705fa94a07fSbrendan * +==============================+ 3706fa94a07fSbrendan * 32 Gbytes 3707fa94a07fSbrendan * 3708fa94a07fSbrendan * 3. If an ARC buffer is copied to the L2ARC but then hit instead of 3709fa94a07fSbrendan * evicted, then the L2ARC has cached a buffer much sooner than it probably 3710fa94a07fSbrendan * needed to, potentially wasting L2ARC device bandwidth and storage. It is 3711fa94a07fSbrendan * safe to say that this is an uncommon case, since buffers at the end of 3712fa94a07fSbrendan * the ARC lists have moved there due to inactivity. 3713fa94a07fSbrendan * 3714fa94a07fSbrendan * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, 3715fa94a07fSbrendan * then the L2ARC simply misses copying some buffers. This serves as a 3716fa94a07fSbrendan * pressure valve to prevent heavy read workloads from both stalling the ARC 3717fa94a07fSbrendan * with waits and clogging the L2ARC with writes. This also helps prevent 3718fa94a07fSbrendan * the potential for the L2ARC to churn if it attempts to cache content too 3719fa94a07fSbrendan * quickly, such as during backups of the entire pool. 3720fa94a07fSbrendan * 37213a737e0dSbrendan * 5. After system boot and before the ARC has filled main memory, there are 37223a737e0dSbrendan * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru 37233a737e0dSbrendan * lists can remain mostly static. Instead of searching from tail of these 37243a737e0dSbrendan * lists as pictured, the l2arc_feed_thread() will search from the list heads 37253a737e0dSbrendan * for eligible buffers, greatly increasing its chance of finding them. 37263a737e0dSbrendan * 37273a737e0dSbrendan * The L2ARC device write speed is also boosted during this time so that 37283a737e0dSbrendan * the L2ARC warms up faster. Since there have been no ARC evictions yet, 37293a737e0dSbrendan * there are no L2ARC reads, and no fear of degrading read performance 37303a737e0dSbrendan * through increased writes. 37313a737e0dSbrendan * 37323a737e0dSbrendan * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that 3733fa94a07fSbrendan * the vdev queue can aggregate them into larger and fewer writes. Each 3734fa94a07fSbrendan * device is written to in a rotor fashion, sweeping writes through 3735fa94a07fSbrendan * available space then repeating. 3736fa94a07fSbrendan * 37373a737e0dSbrendan * 7. The L2ARC does not store dirty content. It never needs to flush 3738fa94a07fSbrendan * write buffers back to disk based storage. 3739fa94a07fSbrendan * 37403a737e0dSbrendan * 8. If an ARC buffer is written (and dirtied) which also exists in the 3741fa94a07fSbrendan * L2ARC, the now stale L2ARC buffer is immediately dropped. 3742fa94a07fSbrendan * 3743fa94a07fSbrendan * The performance of the L2ARC can be tweaked by a number of tunables, which 3744fa94a07fSbrendan * may be necessary for different workloads: 3745fa94a07fSbrendan * 3746fa94a07fSbrendan * l2arc_write_max max write bytes per interval 37473a737e0dSbrendan * l2arc_write_boost extra write bytes during device warmup 3748fa94a07fSbrendan * l2arc_noprefetch skip caching prefetched buffers 3749fa94a07fSbrendan * l2arc_headroom number of max device writes to precache 3750fa94a07fSbrendan * l2arc_feed_secs seconds between L2ARC writing 3751fa94a07fSbrendan * 3752fa94a07fSbrendan * Tunables may be removed or added as future performance improvements are 3753fa94a07fSbrendan * integrated, and also may become zpool properties. 37545a98e54bSBrendan Gregg - Sun Microsystems * 37555a98e54bSBrendan Gregg - Sun Microsystems * There are three key functions that control how the L2ARC warms up: 37565a98e54bSBrendan Gregg - Sun Microsystems * 37575a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_eligible() check if a buffer is eligible to cache 37585a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_size() calculate how much to write 37595a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_interval() calculate sleep delay between writes 37605a98e54bSBrendan Gregg - Sun Microsystems * 37615a98e54bSBrendan Gregg - Sun Microsystems * These three functions determine what to write, how much, and how quickly 37625a98e54bSBrendan Gregg - Sun Microsystems * to send writes. 3763fa94a07fSbrendan */ 3764fa94a07fSbrendan 37655a98e54bSBrendan Gregg - Sun Microsystems static boolean_t 3766ac05c741SMark Maybee l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab) 37675a98e54bSBrendan Gregg - Sun Microsystems { 37685a98e54bSBrendan Gregg - Sun Microsystems /* 37695a98e54bSBrendan Gregg - Sun Microsystems * A buffer is *not* eligible for the L2ARC if it: 37705a98e54bSBrendan Gregg - Sun Microsystems * 1. belongs to a different spa. 37715ea40c06SBrendan Gregg - Sun Microsystems * 2. is already cached on the L2ARC. 37725ea40c06SBrendan Gregg - Sun Microsystems * 3. has an I/O in progress (it may be an incomplete read). 37735ea40c06SBrendan Gregg - Sun Microsystems * 4. is flagged not eligible (zfs property). 37745a98e54bSBrendan Gregg - Sun Microsystems */ 37755ea40c06SBrendan Gregg - Sun Microsystems if (ab->b_spa != spa_guid || ab->b_l2hdr != NULL || 37765a98e54bSBrendan Gregg - Sun Microsystems HDR_IO_IN_PROGRESS(ab) || !HDR_L2CACHE(ab)) 37775a98e54bSBrendan Gregg - Sun Microsystems return (B_FALSE); 37785a98e54bSBrendan Gregg - Sun Microsystems 37795a98e54bSBrendan Gregg - Sun Microsystems return (B_TRUE); 37805a98e54bSBrendan Gregg - Sun Microsystems } 37815a98e54bSBrendan Gregg - Sun Microsystems 37825a98e54bSBrendan Gregg - Sun Microsystems static uint64_t 37835a98e54bSBrendan Gregg - Sun Microsystems l2arc_write_size(l2arc_dev_t *dev) 37845a98e54bSBrendan Gregg - Sun Microsystems { 37855a98e54bSBrendan Gregg - Sun Microsystems uint64_t size; 37865a98e54bSBrendan Gregg - Sun Microsystems 37875a98e54bSBrendan Gregg - Sun Microsystems size = dev->l2ad_write; 37885a98e54bSBrendan Gregg - Sun Microsystems 37895a98e54bSBrendan Gregg - Sun Microsystems if (arc_warm == B_FALSE) 37905a98e54bSBrendan Gregg - Sun Microsystems size += dev->l2ad_boost; 37915a98e54bSBrendan Gregg - Sun Microsystems 37925a98e54bSBrendan Gregg - Sun Microsystems return (size); 37935a98e54bSBrendan Gregg - Sun Microsystems 37945a98e54bSBrendan Gregg - Sun Microsystems } 37955a98e54bSBrendan Gregg - Sun Microsystems 37965a98e54bSBrendan Gregg - Sun Microsystems static clock_t 37975a98e54bSBrendan Gregg - Sun Microsystems l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) 37985a98e54bSBrendan Gregg - Sun Microsystems { 3799d3d50737SRafael Vanoni clock_t interval, next, now; 38005a98e54bSBrendan Gregg - Sun Microsystems 38015a98e54bSBrendan Gregg - Sun Microsystems /* 38025a98e54bSBrendan Gregg - Sun Microsystems * If the ARC lists are busy, increase our write rate; if the 38035a98e54bSBrendan Gregg - Sun Microsystems * lists are stale, idle back. This is achieved by checking 38045a98e54bSBrendan Gregg - Sun Microsystems * how much we previously wrote - if it was more than half of 38055a98e54bSBrendan Gregg - Sun Microsystems * what we wanted, schedule the next write much sooner. 38065a98e54bSBrendan Gregg - Sun Microsystems */ 38075a98e54bSBrendan Gregg - Sun Microsystems if (l2arc_feed_again && wrote > (wanted / 2)) 38085a98e54bSBrendan Gregg - Sun Microsystems interval = (hz * l2arc_feed_min_ms) / 1000; 38095a98e54bSBrendan Gregg - Sun Microsystems else 38105a98e54bSBrendan Gregg - Sun Microsystems interval = hz * l2arc_feed_secs; 38115a98e54bSBrendan Gregg - Sun Microsystems 3812d3d50737SRafael Vanoni now = ddi_get_lbolt(); 3813d3d50737SRafael Vanoni next = MAX(now, MIN(now + interval, began + interval)); 38145a98e54bSBrendan Gregg - Sun Microsystems 38155a98e54bSBrendan Gregg - Sun Microsystems return (next); 38165a98e54bSBrendan Gregg - Sun Microsystems } 38175a98e54bSBrendan Gregg - Sun Microsystems 3818fa94a07fSbrendan static void 3819fa94a07fSbrendan l2arc_hdr_stat_add(void) 3820fa94a07fSbrendan { 3821e6c728e1Sbrendan ARCSTAT_INCR(arcstat_l2_hdr_size, HDR_SIZE + L2HDR_SIZE); 3822e6c728e1Sbrendan ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE); 3823fa94a07fSbrendan } 3824fa94a07fSbrendan 3825fa94a07fSbrendan static void 3826fa94a07fSbrendan l2arc_hdr_stat_remove(void) 3827fa94a07fSbrendan { 3828e6c728e1Sbrendan ARCSTAT_INCR(arcstat_l2_hdr_size, -(HDR_SIZE + L2HDR_SIZE)); 3829e6c728e1Sbrendan ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE); 3830fa94a07fSbrendan } 3831fa94a07fSbrendan 3832fa94a07fSbrendan /* 3833fa94a07fSbrendan * Cycle through L2ARC devices. This is how L2ARC load balances. 38343a737e0dSbrendan * If a device is returned, this also returns holding the spa config lock. 3835fa94a07fSbrendan */ 3836fa94a07fSbrendan static l2arc_dev_t * 3837fa94a07fSbrendan l2arc_dev_get_next(void) 3838fa94a07fSbrendan { 38393a737e0dSbrendan l2arc_dev_t *first, *next = NULL; 38403a737e0dSbrendan 38413a737e0dSbrendan /* 38423a737e0dSbrendan * Lock out the removal of spas (spa_namespace_lock), then removal 38433a737e0dSbrendan * of cache devices (l2arc_dev_mtx). Once a device has been selected, 38443a737e0dSbrendan * both locks will be dropped and a spa config lock held instead. 38453a737e0dSbrendan */ 38463a737e0dSbrendan mutex_enter(&spa_namespace_lock); 38473a737e0dSbrendan mutex_enter(&l2arc_dev_mtx); 3848fa94a07fSbrendan 3849c5904d13Seschrock /* if there are no vdevs, there is nothing to do */ 3850c5904d13Seschrock if (l2arc_ndev == 0) 38513a737e0dSbrendan goto out; 3852c5904d13Seschrock 3853c5904d13Seschrock first = NULL; 3854c5904d13Seschrock next = l2arc_dev_last; 3855c5904d13Seschrock do { 3856c5904d13Seschrock /* loop around the list looking for a non-faulted vdev */ 3857c5904d13Seschrock if (next == NULL) { 3858fa94a07fSbrendan next = list_head(l2arc_dev_list); 3859c5904d13Seschrock } else { 3860c5904d13Seschrock next = list_next(l2arc_dev_list, next); 3861c5904d13Seschrock if (next == NULL) 3862c5904d13Seschrock next = list_head(l2arc_dev_list); 3863c5904d13Seschrock } 3864c5904d13Seschrock 3865c5904d13Seschrock /* if we have come back to the start, bail out */ 3866c5904d13Seschrock if (first == NULL) 3867c5904d13Seschrock first = next; 3868c5904d13Seschrock else if (next == first) 3869c5904d13Seschrock break; 3870c5904d13Seschrock 3871c5904d13Seschrock } while (vdev_is_dead(next->l2ad_vdev)); 3872c5904d13Seschrock 3873c5904d13Seschrock /* if we were unable to find any usable vdevs, return NULL */ 3874c5904d13Seschrock if (vdev_is_dead(next->l2ad_vdev)) 38753a737e0dSbrendan next = NULL; 3876fa94a07fSbrendan 3877fa94a07fSbrendan l2arc_dev_last = next; 3878fa94a07fSbrendan 38793a737e0dSbrendan out: 38803a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 38813a737e0dSbrendan 38823a737e0dSbrendan /* 38833a737e0dSbrendan * Grab the config lock to prevent the 'next' device from being 38843a737e0dSbrendan * removed while we are writing to it. 38853a737e0dSbrendan */ 38863a737e0dSbrendan if (next != NULL) 3887e14bb325SJeff Bonwick spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); 38883a737e0dSbrendan mutex_exit(&spa_namespace_lock); 38893a737e0dSbrendan 3890fa94a07fSbrendan return (next); 3891fa94a07fSbrendan } 3892fa94a07fSbrendan 38933a737e0dSbrendan /* 38943a737e0dSbrendan * Free buffers that were tagged for destruction. 38953a737e0dSbrendan */ 38963a737e0dSbrendan static void 38973a737e0dSbrendan l2arc_do_free_on_write() 38983a737e0dSbrendan { 38993a737e0dSbrendan list_t *buflist; 39003a737e0dSbrendan l2arc_data_free_t *df, *df_prev; 39013a737e0dSbrendan 39023a737e0dSbrendan mutex_enter(&l2arc_free_on_write_mtx); 39033a737e0dSbrendan buflist = l2arc_free_on_write; 39043a737e0dSbrendan 39053a737e0dSbrendan for (df = list_tail(buflist); df; df = df_prev) { 39063a737e0dSbrendan df_prev = list_prev(buflist, df); 39073a737e0dSbrendan ASSERT(df->l2df_data != NULL); 39083a737e0dSbrendan ASSERT(df->l2df_func != NULL); 39093a737e0dSbrendan df->l2df_func(df->l2df_data, df->l2df_size); 39103a737e0dSbrendan list_remove(buflist, df); 39113a737e0dSbrendan kmem_free(df, sizeof (l2arc_data_free_t)); 39123a737e0dSbrendan } 39133a737e0dSbrendan 39143a737e0dSbrendan mutex_exit(&l2arc_free_on_write_mtx); 39153a737e0dSbrendan } 39163a737e0dSbrendan 3917fa94a07fSbrendan /* 3918fa94a07fSbrendan * A write to a cache device has completed. Update all headers to allow 3919fa94a07fSbrendan * reads from these buffers to begin. 3920fa94a07fSbrendan */ 3921fa94a07fSbrendan static void 3922fa94a07fSbrendan l2arc_write_done(zio_t *zio) 3923fa94a07fSbrendan { 3924fa94a07fSbrendan l2arc_write_callback_t *cb; 3925fa94a07fSbrendan l2arc_dev_t *dev; 3926fa94a07fSbrendan list_t *buflist; 3927fa94a07fSbrendan arc_buf_hdr_t *head, *ab, *ab_prev; 39283a737e0dSbrendan l2arc_buf_hdr_t *abl2; 3929fa94a07fSbrendan kmutex_t *hash_lock; 3930fa94a07fSbrendan 3931fa94a07fSbrendan cb = zio->io_private; 3932fa94a07fSbrendan ASSERT(cb != NULL); 3933fa94a07fSbrendan dev = cb->l2wcb_dev; 3934fa94a07fSbrendan ASSERT(dev != NULL); 3935fa94a07fSbrendan head = cb->l2wcb_head; 3936fa94a07fSbrendan ASSERT(head != NULL); 3937fa94a07fSbrendan buflist = dev->l2ad_buflist; 3938fa94a07fSbrendan ASSERT(buflist != NULL); 3939fa94a07fSbrendan DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, 3940fa94a07fSbrendan l2arc_write_callback_t *, cb); 3941fa94a07fSbrendan 3942fa94a07fSbrendan if (zio->io_error != 0) 3943fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_error); 3944fa94a07fSbrendan 3945fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 3946fa94a07fSbrendan 3947fa94a07fSbrendan /* 3948fa94a07fSbrendan * All writes completed, or an error was hit. 3949fa94a07fSbrendan */ 3950fa94a07fSbrendan for (ab = list_prev(buflist, head); ab; ab = ab_prev) { 3951fa94a07fSbrendan ab_prev = list_prev(buflist, ab); 3952fa94a07fSbrendan 3953fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 3954fa94a07fSbrendan if (!mutex_tryenter(hash_lock)) { 3955fa94a07fSbrendan /* 3956fa94a07fSbrendan * This buffer misses out. It may be in a stage 3957fa94a07fSbrendan * of eviction. Its ARC_L2_WRITING flag will be 3958fa94a07fSbrendan * left set, denying reads to this buffer. 3959fa94a07fSbrendan */ 3960fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_hdr_miss); 3961fa94a07fSbrendan continue; 3962fa94a07fSbrendan } 3963fa94a07fSbrendan 3964fa94a07fSbrendan if (zio->io_error != 0) { 3965fa94a07fSbrendan /* 39663a737e0dSbrendan * Error - drop L2ARC entry. 3967fa94a07fSbrendan */ 39683a737e0dSbrendan list_remove(buflist, ab); 39693a737e0dSbrendan abl2 = ab->b_l2hdr; 3970fa94a07fSbrendan ab->b_l2hdr = NULL; 39713a737e0dSbrendan kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); 39723a737e0dSbrendan ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); 3973fa94a07fSbrendan } 3974fa94a07fSbrendan 3975fa94a07fSbrendan /* 3976fa94a07fSbrendan * Allow ARC to begin reads to this L2ARC entry. 3977fa94a07fSbrendan */ 3978fa94a07fSbrendan ab->b_flags &= ~ARC_L2_WRITING; 3979fa94a07fSbrendan 3980fa94a07fSbrendan mutex_exit(hash_lock); 3981fa94a07fSbrendan } 3982fa94a07fSbrendan 3983fa94a07fSbrendan atomic_inc_64(&l2arc_writes_done); 3984fa94a07fSbrendan list_remove(buflist, head); 3985fa94a07fSbrendan kmem_cache_free(hdr_cache, head); 3986fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 3987fa94a07fSbrendan 39883a737e0dSbrendan l2arc_do_free_on_write(); 3989fa94a07fSbrendan 3990fa94a07fSbrendan kmem_free(cb, sizeof (l2arc_write_callback_t)); 3991fa94a07fSbrendan } 3992fa94a07fSbrendan 3993fa94a07fSbrendan /* 3994fa94a07fSbrendan * A read to a cache device completed. Validate buffer contents before 3995fa94a07fSbrendan * handing over to the regular ARC routines. 3996fa94a07fSbrendan */ 3997fa94a07fSbrendan static void 3998fa94a07fSbrendan l2arc_read_done(zio_t *zio) 3999fa94a07fSbrendan { 4000fa94a07fSbrendan l2arc_read_callback_t *cb; 4001fa94a07fSbrendan arc_buf_hdr_t *hdr; 4002fa94a07fSbrendan arc_buf_t *buf; 4003fa94a07fSbrendan kmutex_t *hash_lock; 40043a737e0dSbrendan int equal; 4005fa94a07fSbrendan 4006e14bb325SJeff Bonwick ASSERT(zio->io_vd != NULL); 4007e14bb325SJeff Bonwick ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); 4008e14bb325SJeff Bonwick 4009e14bb325SJeff Bonwick spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); 4010e14bb325SJeff Bonwick 4011fa94a07fSbrendan cb = zio->io_private; 4012fa94a07fSbrendan ASSERT(cb != NULL); 4013fa94a07fSbrendan buf = cb->l2rcb_buf; 4014fa94a07fSbrendan ASSERT(buf != NULL); 4015fa94a07fSbrendan 40163f9d6ad7SLin Ling hash_lock = HDR_LOCK(buf->b_hdr); 4017fa94a07fSbrendan mutex_enter(hash_lock); 40183f9d6ad7SLin Ling hdr = buf->b_hdr; 40193f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 4020fa94a07fSbrendan 4021fa94a07fSbrendan /* 4022fa94a07fSbrendan * Check this survived the L2ARC journey. 4023fa94a07fSbrendan */ 4024fa94a07fSbrendan equal = arc_cksum_equal(buf); 4025fa94a07fSbrendan if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) { 4026fa94a07fSbrendan mutex_exit(hash_lock); 4027fa94a07fSbrendan zio->io_private = buf; 4028e14bb325SJeff Bonwick zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ 4029e14bb325SJeff Bonwick zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ 4030fa94a07fSbrendan arc_read_done(zio); 4031fa94a07fSbrendan } else { 4032fa94a07fSbrendan mutex_exit(hash_lock); 4033fa94a07fSbrendan /* 4034fa94a07fSbrendan * Buffer didn't survive caching. Increment stats and 4035fa94a07fSbrendan * reissue to the original storage device. 4036fa94a07fSbrendan */ 40373a737e0dSbrendan if (zio->io_error != 0) { 4038fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_io_error); 40393a737e0dSbrendan } else { 40403a737e0dSbrendan zio->io_error = EIO; 40413a737e0dSbrendan } 4042fa94a07fSbrendan if (!equal) 4043fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_cksum_bad); 4044fa94a07fSbrendan 4045e14bb325SJeff Bonwick /* 4046e14bb325SJeff Bonwick * If there's no waiter, issue an async i/o to the primary 4047e14bb325SJeff Bonwick * storage now. If there *is* a waiter, the caller must 4048e14bb325SJeff Bonwick * issue the i/o in a context where it's OK to block. 4049e14bb325SJeff Bonwick */ 4050a3f829aeSBill Moore if (zio->io_waiter == NULL) { 4051a3f829aeSBill Moore zio_t *pio = zio_unique_parent(zio); 4052a3f829aeSBill Moore 4053a3f829aeSBill Moore ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); 4054a3f829aeSBill Moore 4055a3f829aeSBill Moore zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp, 4056e14bb325SJeff Bonwick buf->b_data, zio->io_size, arc_read_done, buf, 4057e14bb325SJeff Bonwick zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb)); 4058a3f829aeSBill Moore } 4059fa94a07fSbrendan } 4060fa94a07fSbrendan 4061fa94a07fSbrendan kmem_free(cb, sizeof (l2arc_read_callback_t)); 4062fa94a07fSbrendan } 4063fa94a07fSbrendan 4064fa94a07fSbrendan /* 4065fa94a07fSbrendan * This is the list priority from which the L2ARC will search for pages to 4066fa94a07fSbrendan * cache. This is used within loops (0..3) to cycle through lists in the 4067fa94a07fSbrendan * desired order. This order can have a significant effect on cache 4068fa94a07fSbrendan * performance. 4069fa94a07fSbrendan * 4070fa94a07fSbrendan * Currently the metadata lists are hit first, MFU then MRU, followed by 4071fa94a07fSbrendan * the data lists. This function returns a locked list, and also returns 4072fa94a07fSbrendan * the lock pointer. 4073fa94a07fSbrendan */ 4074fa94a07fSbrendan static list_t * 4075fa94a07fSbrendan l2arc_list_locked(int list_num, kmutex_t **lock) 4076fa94a07fSbrendan { 4077fa94a07fSbrendan list_t *list; 4078fa94a07fSbrendan 4079fa94a07fSbrendan ASSERT(list_num >= 0 && list_num <= 3); 4080fa94a07fSbrendan 4081fa94a07fSbrendan switch (list_num) { 4082fa94a07fSbrendan case 0: 4083fa94a07fSbrendan list = &arc_mfu->arcs_list[ARC_BUFC_METADATA]; 4084fa94a07fSbrendan *lock = &arc_mfu->arcs_mtx; 4085fa94a07fSbrendan break; 4086fa94a07fSbrendan case 1: 4087fa94a07fSbrendan list = &arc_mru->arcs_list[ARC_BUFC_METADATA]; 4088fa94a07fSbrendan *lock = &arc_mru->arcs_mtx; 4089fa94a07fSbrendan break; 4090fa94a07fSbrendan case 2: 4091fa94a07fSbrendan list = &arc_mfu->arcs_list[ARC_BUFC_DATA]; 4092fa94a07fSbrendan *lock = &arc_mfu->arcs_mtx; 4093fa94a07fSbrendan break; 4094fa94a07fSbrendan case 3: 4095fa94a07fSbrendan list = &arc_mru->arcs_list[ARC_BUFC_DATA]; 4096fa94a07fSbrendan *lock = &arc_mru->arcs_mtx; 4097fa94a07fSbrendan break; 4098fa94a07fSbrendan } 4099fa94a07fSbrendan 4100fa94a07fSbrendan ASSERT(!(MUTEX_HELD(*lock))); 4101fa94a07fSbrendan mutex_enter(*lock); 4102fa94a07fSbrendan return (list); 4103fa94a07fSbrendan } 4104fa94a07fSbrendan 4105fa94a07fSbrendan /* 4106fa94a07fSbrendan * Evict buffers from the device write hand to the distance specified in 4107fa94a07fSbrendan * bytes. This distance may span populated buffers, it may span nothing. 4108fa94a07fSbrendan * This is clearing a region on the L2ARC device ready for writing. 4109fa94a07fSbrendan * If the 'all' boolean is set, every buffer is evicted. 4110fa94a07fSbrendan */ 4111fa94a07fSbrendan static void 4112fa94a07fSbrendan l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) 4113fa94a07fSbrendan { 4114fa94a07fSbrendan list_t *buflist; 4115fa94a07fSbrendan l2arc_buf_hdr_t *abl2; 4116fa94a07fSbrendan arc_buf_hdr_t *ab, *ab_prev; 4117fa94a07fSbrendan kmutex_t *hash_lock; 4118fa94a07fSbrendan uint64_t taddr; 4119fa94a07fSbrendan 4120fa94a07fSbrendan buflist = dev->l2ad_buflist; 4121fa94a07fSbrendan 4122fa94a07fSbrendan if (buflist == NULL) 4123fa94a07fSbrendan return; 4124fa94a07fSbrendan 4125fa94a07fSbrendan if (!all && dev->l2ad_first) { 4126fa94a07fSbrendan /* 4127fa94a07fSbrendan * This is the first sweep through the device. There is 4128fa94a07fSbrendan * nothing to evict. 4129fa94a07fSbrendan */ 4130fa94a07fSbrendan return; 4131fa94a07fSbrendan } 4132fa94a07fSbrendan 41333a737e0dSbrendan if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) { 4134fa94a07fSbrendan /* 4135fa94a07fSbrendan * When nearing the end of the device, evict to the end 4136fa94a07fSbrendan * before the device write hand jumps to the start. 4137fa94a07fSbrendan */ 4138fa94a07fSbrendan taddr = dev->l2ad_end; 4139fa94a07fSbrendan } else { 4140fa94a07fSbrendan taddr = dev->l2ad_hand + distance; 4141fa94a07fSbrendan } 4142fa94a07fSbrendan DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, 4143fa94a07fSbrendan uint64_t, taddr, boolean_t, all); 4144fa94a07fSbrendan 4145fa94a07fSbrendan top: 4146fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 4147fa94a07fSbrendan for (ab = list_tail(buflist); ab; ab = ab_prev) { 4148fa94a07fSbrendan ab_prev = list_prev(buflist, ab); 4149fa94a07fSbrendan 4150fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 4151fa94a07fSbrendan if (!mutex_tryenter(hash_lock)) { 4152fa94a07fSbrendan /* 4153fa94a07fSbrendan * Missed the hash lock. Retry. 4154fa94a07fSbrendan */ 4155fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); 4156fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4157fa94a07fSbrendan mutex_enter(hash_lock); 4158fa94a07fSbrendan mutex_exit(hash_lock); 4159fa94a07fSbrendan goto top; 4160fa94a07fSbrendan } 4161fa94a07fSbrendan 4162fa94a07fSbrendan if (HDR_L2_WRITE_HEAD(ab)) { 4163fa94a07fSbrendan /* 4164fa94a07fSbrendan * We hit a write head node. Leave it for 4165fa94a07fSbrendan * l2arc_write_done(). 4166fa94a07fSbrendan */ 4167fa94a07fSbrendan list_remove(buflist, ab); 4168fa94a07fSbrendan mutex_exit(hash_lock); 4169fa94a07fSbrendan continue; 4170fa94a07fSbrendan } 4171fa94a07fSbrendan 4172fa94a07fSbrendan if (!all && ab->b_l2hdr != NULL && 4173fa94a07fSbrendan (ab->b_l2hdr->b_daddr > taddr || 4174fa94a07fSbrendan ab->b_l2hdr->b_daddr < dev->l2ad_hand)) { 4175fa94a07fSbrendan /* 4176fa94a07fSbrendan * We've evicted to the target address, 4177fa94a07fSbrendan * or the end of the device. 4178fa94a07fSbrendan */ 4179fa94a07fSbrendan mutex_exit(hash_lock); 4180fa94a07fSbrendan break; 4181fa94a07fSbrendan } 4182fa94a07fSbrendan 4183fa94a07fSbrendan if (HDR_FREE_IN_PROGRESS(ab)) { 4184fa94a07fSbrendan /* 4185fa94a07fSbrendan * Already on the path to destruction. 4186fa94a07fSbrendan */ 4187fa94a07fSbrendan mutex_exit(hash_lock); 4188fa94a07fSbrendan continue; 4189fa94a07fSbrendan } 4190fa94a07fSbrendan 4191fa94a07fSbrendan if (ab->b_state == arc_l2c_only) { 4192fa94a07fSbrendan ASSERT(!HDR_L2_READING(ab)); 4193fa94a07fSbrendan /* 4194fa94a07fSbrendan * This doesn't exist in the ARC. Destroy. 4195fa94a07fSbrendan * arc_hdr_destroy() will call list_remove() 4196fa94a07fSbrendan * and decrement arcstat_l2_size. 4197fa94a07fSbrendan */ 4198fa94a07fSbrendan arc_change_state(arc_anon, ab, hash_lock); 4199fa94a07fSbrendan arc_hdr_destroy(ab); 4200fa94a07fSbrendan } else { 42013a737e0dSbrendan /* 42023a737e0dSbrendan * Invalidate issued or about to be issued 42033a737e0dSbrendan * reads, since we may be about to write 42043a737e0dSbrendan * over this location. 42053a737e0dSbrendan */ 42063a737e0dSbrendan if (HDR_L2_READING(ab)) { 42073a737e0dSbrendan ARCSTAT_BUMP(arcstat_l2_evict_reading); 42083a737e0dSbrendan ab->b_flags |= ARC_L2_EVICTED; 42093a737e0dSbrendan } 42103a737e0dSbrendan 4211fa94a07fSbrendan /* 4212fa94a07fSbrendan * Tell ARC this no longer exists in L2ARC. 4213fa94a07fSbrendan */ 4214fa94a07fSbrendan if (ab->b_l2hdr != NULL) { 4215fa94a07fSbrendan abl2 = ab->b_l2hdr; 4216fa94a07fSbrendan ab->b_l2hdr = NULL; 4217fa94a07fSbrendan kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); 4218fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); 4219fa94a07fSbrendan } 4220fa94a07fSbrendan list_remove(buflist, ab); 4221fa94a07fSbrendan 4222fa94a07fSbrendan /* 4223fa94a07fSbrendan * This may have been leftover after a 4224fa94a07fSbrendan * failed write. 4225fa94a07fSbrendan */ 4226fa94a07fSbrendan ab->b_flags &= ~ARC_L2_WRITING; 4227fa94a07fSbrendan } 4228fa94a07fSbrendan mutex_exit(hash_lock); 4229fa94a07fSbrendan } 4230fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4231fa94a07fSbrendan 4232b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, -(taddr - dev->l2ad_evict), 0, 0); 4233fa94a07fSbrendan dev->l2ad_evict = taddr; 4234fa94a07fSbrendan } 4235fa94a07fSbrendan 4236fa94a07fSbrendan /* 4237fa94a07fSbrendan * Find and write ARC buffers to the L2ARC device. 4238fa94a07fSbrendan * 4239fa94a07fSbrendan * An ARC_L2_WRITING flag is set so that the L2ARC buffers are not valid 4240fa94a07fSbrendan * for reading until they have completed writing. 4241fa94a07fSbrendan */ 42425a98e54bSBrendan Gregg - Sun Microsystems static uint64_t 42433a737e0dSbrendan l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) 4244fa94a07fSbrendan { 4245fa94a07fSbrendan arc_buf_hdr_t *ab, *ab_prev, *head; 4246fa94a07fSbrendan l2arc_buf_hdr_t *hdrl2; 4247fa94a07fSbrendan list_t *list; 42483a737e0dSbrendan uint64_t passed_sz, write_sz, buf_sz, headroom; 4249fa94a07fSbrendan void *buf_data; 4250fa94a07fSbrendan kmutex_t *hash_lock, *list_lock; 4251fa94a07fSbrendan boolean_t have_lock, full; 4252fa94a07fSbrendan l2arc_write_callback_t *cb; 4253fa94a07fSbrendan zio_t *pio, *wzio; 4254e9103aaeSGarrett D'Amore uint64_t guid = spa_load_guid(spa); 4255fa94a07fSbrendan 4256fa94a07fSbrendan ASSERT(dev->l2ad_vdev != NULL); 4257fa94a07fSbrendan 4258fa94a07fSbrendan pio = NULL; 4259fa94a07fSbrendan write_sz = 0; 4260fa94a07fSbrendan full = B_FALSE; 42611ab7f2deSmaybee head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 4262fa94a07fSbrendan head->b_flags |= ARC_L2_WRITE_HEAD; 4263fa94a07fSbrendan 4264fa94a07fSbrendan /* 4265fa94a07fSbrendan * Copy buffers for L2ARC writing. 4266fa94a07fSbrendan */ 4267fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 4268fa94a07fSbrendan for (int try = 0; try <= 3; try++) { 4269fa94a07fSbrendan list = l2arc_list_locked(try, &list_lock); 4270fa94a07fSbrendan passed_sz = 0; 4271fa94a07fSbrendan 42723a737e0dSbrendan /* 42733a737e0dSbrendan * L2ARC fast warmup. 42743a737e0dSbrendan * 42753a737e0dSbrendan * Until the ARC is warm and starts to evict, read from the 42763a737e0dSbrendan * head of the ARC lists rather than the tail. 42773a737e0dSbrendan */ 42783a737e0dSbrendan headroom = target_sz * l2arc_headroom; 42793a737e0dSbrendan if (arc_warm == B_FALSE) 42803a737e0dSbrendan ab = list_head(list); 42813a737e0dSbrendan else 42823a737e0dSbrendan ab = list_tail(list); 42833a737e0dSbrendan 42843a737e0dSbrendan for (; ab; ab = ab_prev) { 42853a737e0dSbrendan if (arc_warm == B_FALSE) 42863a737e0dSbrendan ab_prev = list_next(list, ab); 42873a737e0dSbrendan else 42883a737e0dSbrendan ab_prev = list_prev(list, ab); 4289fa94a07fSbrendan 4290fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 4291fa94a07fSbrendan have_lock = MUTEX_HELD(hash_lock); 4292fa94a07fSbrendan if (!have_lock && !mutex_tryenter(hash_lock)) { 4293fa94a07fSbrendan /* 4294fa94a07fSbrendan * Skip this buffer rather than waiting. 4295fa94a07fSbrendan */ 4296fa94a07fSbrendan continue; 4297fa94a07fSbrendan } 4298fa94a07fSbrendan 4299fa94a07fSbrendan passed_sz += ab->b_size; 4300fa94a07fSbrendan if (passed_sz > headroom) { 4301fa94a07fSbrendan /* 4302fa94a07fSbrendan * Searched too far. 4303fa94a07fSbrendan */ 4304fa94a07fSbrendan mutex_exit(hash_lock); 4305fa94a07fSbrendan break; 4306fa94a07fSbrendan } 4307fa94a07fSbrendan 4308ac05c741SMark Maybee if (!l2arc_write_eligible(guid, ab)) { 4309fa94a07fSbrendan mutex_exit(hash_lock); 4310fa94a07fSbrendan continue; 4311fa94a07fSbrendan } 4312fa94a07fSbrendan 4313fa94a07fSbrendan if ((write_sz + ab->b_size) > target_sz) { 4314fa94a07fSbrendan full = B_TRUE; 4315fa94a07fSbrendan mutex_exit(hash_lock); 4316fa94a07fSbrendan break; 4317fa94a07fSbrendan } 4318fa94a07fSbrendan 4319fa94a07fSbrendan if (pio == NULL) { 4320fa94a07fSbrendan /* 4321fa94a07fSbrendan * Insert a dummy header on the buflist so 4322fa94a07fSbrendan * l2arc_write_done() can find where the 4323fa94a07fSbrendan * write buffers begin without searching. 4324fa94a07fSbrendan */ 4325fa94a07fSbrendan list_insert_head(dev->l2ad_buflist, head); 4326fa94a07fSbrendan 4327fa94a07fSbrendan cb = kmem_alloc( 4328fa94a07fSbrendan sizeof (l2arc_write_callback_t), KM_SLEEP); 4329fa94a07fSbrendan cb->l2wcb_dev = dev; 4330fa94a07fSbrendan cb->l2wcb_head = head; 4331fa94a07fSbrendan pio = zio_root(spa, l2arc_write_done, cb, 4332fa94a07fSbrendan ZIO_FLAG_CANFAIL); 4333fa94a07fSbrendan } 4334fa94a07fSbrendan 4335fa94a07fSbrendan /* 4336fa94a07fSbrendan * Create and add a new L2ARC header. 4337fa94a07fSbrendan */ 4338fa94a07fSbrendan hdrl2 = kmem_zalloc(sizeof (l2arc_buf_hdr_t), KM_SLEEP); 4339fa94a07fSbrendan hdrl2->b_dev = dev; 4340fa94a07fSbrendan hdrl2->b_daddr = dev->l2ad_hand; 4341fa94a07fSbrendan 4342fa94a07fSbrendan ab->b_flags |= ARC_L2_WRITING; 4343fa94a07fSbrendan ab->b_l2hdr = hdrl2; 4344fa94a07fSbrendan list_insert_head(dev->l2ad_buflist, ab); 4345fa94a07fSbrendan buf_data = ab->b_buf->b_data; 4346fa94a07fSbrendan buf_sz = ab->b_size; 4347fa94a07fSbrendan 4348fa94a07fSbrendan /* 4349fa94a07fSbrendan * Compute and store the buffer cksum before 4350fa94a07fSbrendan * writing. On debug the cksum is verified first. 4351fa94a07fSbrendan */ 4352fa94a07fSbrendan arc_cksum_verify(ab->b_buf); 4353fa94a07fSbrendan arc_cksum_compute(ab->b_buf, B_TRUE); 4354fa94a07fSbrendan 4355fa94a07fSbrendan mutex_exit(hash_lock); 4356fa94a07fSbrendan 4357fa94a07fSbrendan wzio = zio_write_phys(pio, dev->l2ad_vdev, 4358fa94a07fSbrendan dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF, 4359fa94a07fSbrendan NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, 4360fa94a07fSbrendan ZIO_FLAG_CANFAIL, B_FALSE); 4361fa94a07fSbrendan 4362fa94a07fSbrendan DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, 4363fa94a07fSbrendan zio_t *, wzio); 4364fa94a07fSbrendan (void) zio_nowait(wzio); 4365fa94a07fSbrendan 4366e14bb325SJeff Bonwick /* 4367e14bb325SJeff Bonwick * Keep the clock hand suitably device-aligned. 4368e14bb325SJeff Bonwick */ 4369e14bb325SJeff Bonwick buf_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); 4370e14bb325SJeff Bonwick 4371fa94a07fSbrendan write_sz += buf_sz; 4372fa94a07fSbrendan dev->l2ad_hand += buf_sz; 4373fa94a07fSbrendan } 4374fa94a07fSbrendan 4375fa94a07fSbrendan mutex_exit(list_lock); 4376fa94a07fSbrendan 4377fa94a07fSbrendan if (full == B_TRUE) 4378fa94a07fSbrendan break; 4379fa94a07fSbrendan } 4380fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4381fa94a07fSbrendan 4382fa94a07fSbrendan if (pio == NULL) { 4383fa94a07fSbrendan ASSERT3U(write_sz, ==, 0); 4384fa94a07fSbrendan kmem_cache_free(hdr_cache, head); 43855a98e54bSBrendan Gregg - Sun Microsystems return (0); 4386fa94a07fSbrendan } 4387fa94a07fSbrendan 4388fa94a07fSbrendan ASSERT3U(write_sz, <=, target_sz); 4389fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_sent); 43905a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_write_bytes, write_sz); 4391fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, write_sz); 4392b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, write_sz, 0, 0); 4393fa94a07fSbrendan 4394fa94a07fSbrendan /* 4395fa94a07fSbrendan * Bump device hand to the device start if it is approaching the end. 4396fa94a07fSbrendan * l2arc_evict() will already have evicted ahead for this case. 4397fa94a07fSbrendan */ 43983a737e0dSbrendan if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) { 4399b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, 4400b24ab676SJeff Bonwick dev->l2ad_end - dev->l2ad_hand, 0, 0); 4401fa94a07fSbrendan dev->l2ad_hand = dev->l2ad_start; 4402fa94a07fSbrendan dev->l2ad_evict = dev->l2ad_start; 4403fa94a07fSbrendan dev->l2ad_first = B_FALSE; 4404fa94a07fSbrendan } 4405fa94a07fSbrendan 44065a98e54bSBrendan Gregg - Sun Microsystems dev->l2ad_writing = B_TRUE; 4407fa94a07fSbrendan (void) zio_wait(pio); 44085a98e54bSBrendan Gregg - Sun Microsystems dev->l2ad_writing = B_FALSE; 44095a98e54bSBrendan Gregg - Sun Microsystems 44105a98e54bSBrendan Gregg - Sun Microsystems return (write_sz); 4411fa94a07fSbrendan } 4412fa94a07fSbrendan 4413fa94a07fSbrendan /* 4414fa94a07fSbrendan * This thread feeds the L2ARC at regular intervals. This is the beating 4415fa94a07fSbrendan * heart of the L2ARC. 4416fa94a07fSbrendan */ 4417fa94a07fSbrendan static void 4418fa94a07fSbrendan l2arc_feed_thread(void) 4419fa94a07fSbrendan { 4420fa94a07fSbrendan callb_cpr_t cpr; 4421fa94a07fSbrendan l2arc_dev_t *dev; 4422fa94a07fSbrendan spa_t *spa; 44235a98e54bSBrendan Gregg - Sun Microsystems uint64_t size, wrote; 4424d3d50737SRafael Vanoni clock_t begin, next = ddi_get_lbolt(); 4425fa94a07fSbrendan 4426fa94a07fSbrendan CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); 4427fa94a07fSbrendan 4428fa94a07fSbrendan mutex_enter(&l2arc_feed_thr_lock); 4429fa94a07fSbrendan 4430fa94a07fSbrendan while (l2arc_thread_exit == 0) { 4431fa94a07fSbrendan CALLB_CPR_SAFE_BEGIN(&cpr); 4432fa94a07fSbrendan (void) cv_timedwait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock, 44335a98e54bSBrendan Gregg - Sun Microsystems next); 4434fa94a07fSbrendan CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); 4435d3d50737SRafael Vanoni next = ddi_get_lbolt() + hz; 4436fa94a07fSbrendan 44373a737e0dSbrendan /* 44383a737e0dSbrendan * Quick check for L2ARC devices. 44393a737e0dSbrendan */ 4440c5904d13Seschrock mutex_enter(&l2arc_dev_mtx); 44413a737e0dSbrendan if (l2arc_ndev == 0) { 44423a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 44433a737e0dSbrendan continue; 44443a737e0dSbrendan } 44453a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 4446d3d50737SRafael Vanoni begin = ddi_get_lbolt(); 4447c5904d13Seschrock 4448fa94a07fSbrendan /* 4449c5904d13Seschrock * This selects the next l2arc device to write to, and in 4450c5904d13Seschrock * doing so the next spa to feed from: dev->l2ad_spa. This 44513a737e0dSbrendan * will return NULL if there are now no l2arc devices or if 44523a737e0dSbrendan * they are all faulted. 44533a737e0dSbrendan * 44543a737e0dSbrendan * If a device is returned, its spa's config lock is also 44553a737e0dSbrendan * held to prevent device removal. l2arc_dev_get_next() 44563a737e0dSbrendan * will grab and release l2arc_dev_mtx. 4457fa94a07fSbrendan */ 44583a737e0dSbrendan if ((dev = l2arc_dev_get_next()) == NULL) 4459fa94a07fSbrendan continue; 44603a737e0dSbrendan 44613a737e0dSbrendan spa = dev->l2ad_spa; 44623a737e0dSbrendan ASSERT(spa != NULL); 4463fa94a07fSbrendan 4464f9af39baSGeorge Wilson /* 4465f9af39baSGeorge Wilson * If the pool is read-only then force the feed thread to 4466f9af39baSGeorge Wilson * sleep a little longer. 4467f9af39baSGeorge Wilson */ 4468f9af39baSGeorge Wilson if (!spa_writeable(spa)) { 4469f9af39baSGeorge Wilson next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz; 4470f9af39baSGeorge Wilson spa_config_exit(spa, SCL_L2ARC, dev); 4471f9af39baSGeorge Wilson continue; 4472f9af39baSGeorge Wilson } 4473f9af39baSGeorge Wilson 4474fa94a07fSbrendan /* 4475fa94a07fSbrendan * Avoid contributing to memory pressure. 4476fa94a07fSbrendan */ 4477fa94a07fSbrendan if (arc_reclaim_needed()) { 4478fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_abort_lowmem); 4479e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, dev); 4480fa94a07fSbrendan continue; 4481fa94a07fSbrendan } 4482fa94a07fSbrendan 4483fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_feeds); 4484fa94a07fSbrendan 44855a98e54bSBrendan Gregg - Sun Microsystems size = l2arc_write_size(dev); 44863a737e0dSbrendan 4487fa94a07fSbrendan /* 4488fa94a07fSbrendan * Evict L2ARC buffers that will be overwritten. 4489fa94a07fSbrendan */ 44903a737e0dSbrendan l2arc_evict(dev, size, B_FALSE); 4491fa94a07fSbrendan 4492fa94a07fSbrendan /* 4493fa94a07fSbrendan * Write ARC buffers. 4494fa94a07fSbrendan */ 44955a98e54bSBrendan Gregg - Sun Microsystems wrote = l2arc_write_buffers(spa, dev, size); 44965a98e54bSBrendan Gregg - Sun Microsystems 44975a98e54bSBrendan Gregg - Sun Microsystems /* 44985a98e54bSBrendan Gregg - Sun Microsystems * Calculate interval between writes. 44995a98e54bSBrendan Gregg - Sun Microsystems */ 45005a98e54bSBrendan Gregg - Sun Microsystems next = l2arc_write_interval(begin, size, wrote); 4501e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, dev); 4502fa94a07fSbrendan } 4503fa94a07fSbrendan 4504fa94a07fSbrendan l2arc_thread_exit = 0; 4505fa94a07fSbrendan cv_broadcast(&l2arc_feed_thr_cv); 4506fa94a07fSbrendan CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ 4507fa94a07fSbrendan thread_exit(); 4508fa94a07fSbrendan } 4509fa94a07fSbrendan 4510c5904d13Seschrock boolean_t 4511c5904d13Seschrock l2arc_vdev_present(vdev_t *vd) 4512c5904d13Seschrock { 4513c5904d13Seschrock l2arc_dev_t *dev; 4514c5904d13Seschrock 4515c5904d13Seschrock mutex_enter(&l2arc_dev_mtx); 4516c5904d13Seschrock for (dev = list_head(l2arc_dev_list); dev != NULL; 4517c5904d13Seschrock dev = list_next(l2arc_dev_list, dev)) { 4518c5904d13Seschrock if (dev->l2ad_vdev == vd) 4519c5904d13Seschrock break; 4520c5904d13Seschrock } 4521c5904d13Seschrock mutex_exit(&l2arc_dev_mtx); 4522c5904d13Seschrock 4523c5904d13Seschrock return (dev != NULL); 4524c5904d13Seschrock } 4525c5904d13Seschrock 4526fa94a07fSbrendan /* 4527fa94a07fSbrendan * Add a vdev for use by the L2ARC. By this point the spa has already 4528fa94a07fSbrendan * validated the vdev and opened it. 4529fa94a07fSbrendan */ 4530fa94a07fSbrendan void 4531573ca77eSGeorge Wilson l2arc_add_vdev(spa_t *spa, vdev_t *vd) 4532fa94a07fSbrendan { 4533fa94a07fSbrendan l2arc_dev_t *adddev; 4534fa94a07fSbrendan 4535c5904d13Seschrock ASSERT(!l2arc_vdev_present(vd)); 4536c5904d13Seschrock 4537fa94a07fSbrendan /* 4538fa94a07fSbrendan * Create a new l2arc device entry. 4539fa94a07fSbrendan */ 4540fa94a07fSbrendan adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); 4541fa94a07fSbrendan adddev->l2ad_spa = spa; 4542fa94a07fSbrendan adddev->l2ad_vdev = vd; 4543fa94a07fSbrendan adddev->l2ad_write = l2arc_write_max; 45443a737e0dSbrendan adddev->l2ad_boost = l2arc_write_boost; 4545573ca77eSGeorge Wilson adddev->l2ad_start = VDEV_LABEL_START_SIZE; 4546573ca77eSGeorge Wilson adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); 4547fa94a07fSbrendan adddev->l2ad_hand = adddev->l2ad_start; 4548fa94a07fSbrendan adddev->l2ad_evict = adddev->l2ad_start; 4549fa94a07fSbrendan adddev->l2ad_first = B_TRUE; 45505a98e54bSBrendan Gregg - Sun Microsystems adddev->l2ad_writing = B_FALSE; 4551fa94a07fSbrendan ASSERT3U(adddev->l2ad_write, >, 0); 4552fa94a07fSbrendan 4553fa94a07fSbrendan /* 4554fa94a07fSbrendan * This is a list of all ARC buffers that are still valid on the 4555fa94a07fSbrendan * device. 4556fa94a07fSbrendan */ 4557fa94a07fSbrendan adddev->l2ad_buflist = kmem_zalloc(sizeof (list_t), KM_SLEEP); 4558fa94a07fSbrendan list_create(adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), 4559fa94a07fSbrendan offsetof(arc_buf_hdr_t, b_l2node)); 4560fa94a07fSbrendan 4561b24ab676SJeff Bonwick vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); 4562fa94a07fSbrendan 4563fa94a07fSbrendan /* 4564fa94a07fSbrendan * Add device to global list 4565fa94a07fSbrendan */ 4566fa94a07fSbrendan mutex_enter(&l2arc_dev_mtx); 4567fa94a07fSbrendan list_insert_head(l2arc_dev_list, adddev); 4568fa94a07fSbrendan atomic_inc_64(&l2arc_ndev); 4569fa94a07fSbrendan mutex_exit(&l2arc_dev_mtx); 4570fa94a07fSbrendan } 4571fa94a07fSbrendan 4572fa94a07fSbrendan /* 4573fa94a07fSbrendan * Remove a vdev from the L2ARC. 4574fa94a07fSbrendan */ 4575fa94a07fSbrendan void 4576fa94a07fSbrendan l2arc_remove_vdev(vdev_t *vd) 4577fa94a07fSbrendan { 4578fa94a07fSbrendan l2arc_dev_t *dev, *nextdev, *remdev = NULL; 4579fa94a07fSbrendan 4580fa94a07fSbrendan /* 4581fa94a07fSbrendan * Find the device by vdev 4582fa94a07fSbrendan */ 4583fa94a07fSbrendan mutex_enter(&l2arc_dev_mtx); 4584fa94a07fSbrendan for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) { 4585fa94a07fSbrendan nextdev = list_next(l2arc_dev_list, dev); 4586fa94a07fSbrendan if (vd == dev->l2ad_vdev) { 4587fa94a07fSbrendan remdev = dev; 4588fa94a07fSbrendan break; 4589fa94a07fSbrendan } 4590fa94a07fSbrendan } 4591fa94a07fSbrendan ASSERT(remdev != NULL); 4592fa94a07fSbrendan 4593fa94a07fSbrendan /* 4594fa94a07fSbrendan * Remove device from global list 4595fa94a07fSbrendan */ 4596fa94a07fSbrendan list_remove(l2arc_dev_list, remdev); 4597fa94a07fSbrendan l2arc_dev_last = NULL; /* may have been invalidated */ 45983a737e0dSbrendan atomic_dec_64(&l2arc_ndev); 45993a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 4600fa94a07fSbrendan 4601fa94a07fSbrendan /* 4602fa94a07fSbrendan * Clear all buflists and ARC references. L2ARC device flush. 4603fa94a07fSbrendan */ 4604fa94a07fSbrendan l2arc_evict(remdev, 0, B_TRUE); 4605fa94a07fSbrendan list_destroy(remdev->l2ad_buflist); 4606fa94a07fSbrendan kmem_free(remdev->l2ad_buflist, sizeof (list_t)); 4607fa94a07fSbrendan kmem_free(remdev, sizeof (l2arc_dev_t)); 4608fa94a07fSbrendan } 4609fa94a07fSbrendan 4610fa94a07fSbrendan void 4611e14bb325SJeff Bonwick l2arc_init(void) 4612fa94a07fSbrendan { 4613fa94a07fSbrendan l2arc_thread_exit = 0; 4614fa94a07fSbrendan l2arc_ndev = 0; 4615fa94a07fSbrendan l2arc_writes_sent = 0; 4616fa94a07fSbrendan l2arc_writes_done = 0; 4617fa94a07fSbrendan 4618fa94a07fSbrendan mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); 4619fa94a07fSbrendan cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); 4620fa94a07fSbrendan mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); 4621fa94a07fSbrendan mutex_init(&l2arc_buflist_mtx, NULL, MUTEX_DEFAULT, NULL); 4622fa94a07fSbrendan mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); 4623fa94a07fSbrendan 4624fa94a07fSbrendan l2arc_dev_list = &L2ARC_dev_list; 4625fa94a07fSbrendan l2arc_free_on_write = &L2ARC_free_on_write; 4626fa94a07fSbrendan list_create(l2arc_dev_list, sizeof (l2arc_dev_t), 4627fa94a07fSbrendan offsetof(l2arc_dev_t, l2ad_node)); 4628fa94a07fSbrendan list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), 4629fa94a07fSbrendan offsetof(l2arc_data_free_t, l2df_list_node)); 4630fa94a07fSbrendan } 4631fa94a07fSbrendan 4632fa94a07fSbrendan void 4633e14bb325SJeff Bonwick l2arc_fini(void) 4634fa94a07fSbrendan { 46353a737e0dSbrendan /* 46363a737e0dSbrendan * This is called from dmu_fini(), which is called from spa_fini(); 46373a737e0dSbrendan * Because of this, we can assume that all l2arc devices have 46383a737e0dSbrendan * already been removed when the pools themselves were removed. 46393a737e0dSbrendan */ 46403a737e0dSbrendan 46413a737e0dSbrendan l2arc_do_free_on_write(); 46423a737e0dSbrendan 4643fa94a07fSbrendan mutex_destroy(&l2arc_feed_thr_lock); 4644fa94a07fSbrendan cv_destroy(&l2arc_feed_thr_cv); 4645fa94a07fSbrendan mutex_destroy(&l2arc_dev_mtx); 4646fa94a07fSbrendan mutex_destroy(&l2arc_buflist_mtx); 4647fa94a07fSbrendan mutex_destroy(&l2arc_free_on_write_mtx); 4648fa94a07fSbrendan 4649fa94a07fSbrendan list_destroy(l2arc_dev_list); 4650fa94a07fSbrendan list_destroy(l2arc_free_on_write); 4651fa94a07fSbrendan } 4652e14bb325SJeff Bonwick 4653e14bb325SJeff Bonwick void 4654e14bb325SJeff Bonwick l2arc_start(void) 4655e14bb325SJeff Bonwick { 46568ad4d6ddSJeff Bonwick if (!(spa_mode_global & FWRITE)) 4657e14bb325SJeff Bonwick return; 4658e14bb325SJeff Bonwick 4659e14bb325SJeff Bonwick (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, 4660e14bb325SJeff Bonwick TS_RUN, minclsyspri); 4661e14bb325SJeff Bonwick } 4662e14bb325SJeff Bonwick 4663e14bb325SJeff Bonwick void 4664e14bb325SJeff Bonwick l2arc_stop(void) 4665e14bb325SJeff Bonwick { 46668ad4d6ddSJeff Bonwick if (!(spa_mode_global & FWRITE)) 4667e14bb325SJeff Bonwick return; 4668e14bb325SJeff Bonwick 4669e14bb325SJeff Bonwick mutex_enter(&l2arc_feed_thr_lock); 4670e14bb325SJeff Bonwick cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ 4671e14bb325SJeff Bonwick l2arc_thread_exit = 1; 4672e14bb325SJeff Bonwick while (l2arc_thread_exit != 0) 4673e14bb325SJeff Bonwick cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); 4674e14bb325SJeff Bonwick mutex_exit(&l2arc_feed_thr_lock); 4675e14bb325SJeff Bonwick } 4676