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 /* 22*3f9d6ad7SLin Ling * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23fa9e4066Sahrens */ 24fa9e4066Sahrens 25fa9e4066Sahrens /* 2644cb6abcSbmc * DVA-based Adjustable Replacement Cache 27fa9e4066Sahrens * 28ea8dc4b6Seschrock * While much of the theory of operation used here is 29ea8dc4b6Seschrock * based on the self-tuning, low overhead replacement cache 30fa9e4066Sahrens * presented by Megiddo and Modha at FAST 2003, there are some 31fa9e4066Sahrens * significant differences: 32fa9e4066Sahrens * 33fa9e4066Sahrens * 1. The Megiddo and Modha model assumes any page is evictable. 34fa9e4066Sahrens * Pages in its cache cannot be "locked" into memory. This makes 35fa9e4066Sahrens * the eviction algorithm simple: evict the last page in the list. 36fa9e4066Sahrens * This also make the performance characteristics easy to reason 37fa9e4066Sahrens * about. Our cache is not so simple. At any given moment, some 38fa9e4066Sahrens * subset of the blocks in the cache are un-evictable because we 39fa9e4066Sahrens * have handed out a reference to them. Blocks are only evictable 40fa9e4066Sahrens * when there are no external references active. This makes 41fa9e4066Sahrens * eviction far more problematic: we choose to evict the evictable 42fa9e4066Sahrens * blocks that are the "lowest" in the list. 43fa9e4066Sahrens * 44fa9e4066Sahrens * There are times when it is not possible to evict the requested 45fa9e4066Sahrens * space. In these circumstances we are unable to adjust the cache 46fa9e4066Sahrens * size. To prevent the cache growing unbounded at these times we 47fa94a07fSbrendan * implement a "cache throttle" that slows the flow of new data 48fa94a07fSbrendan * into the cache until we can make space available. 49fa9e4066Sahrens * 50fa9e4066Sahrens * 2. The Megiddo and Modha model assumes a fixed cache size. 51fa9e4066Sahrens * Pages are evicted when the cache is full and there is a cache 52fa9e4066Sahrens * miss. Our model has a variable sized cache. It grows with 53fa94a07fSbrendan * high use, but also tries to react to memory pressure from the 54fa9e4066Sahrens * operating system: decreasing its size when system memory is 55fa9e4066Sahrens * tight. 56fa9e4066Sahrens * 57fa9e4066Sahrens * 3. The Megiddo and Modha model assumes a fixed page size. All 58fa9e4066Sahrens * elements of the cache are therefor exactly the same size. So 59fa9e4066Sahrens * when adjusting the cache size following a cache miss, its simply 60fa9e4066Sahrens * a matter of choosing a single page to evict. In our model, we 61fa9e4066Sahrens * have variable sized cache blocks (rangeing from 512 bytes to 62fa9e4066Sahrens * 128K bytes). We therefor choose a set of blocks to evict to make 63fa9e4066Sahrens * space for a cache miss that approximates as closely as possible 64fa9e4066Sahrens * the space used by the new block. 65fa9e4066Sahrens * 66fa9e4066Sahrens * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" 67fa9e4066Sahrens * by N. Megiddo & D. Modha, FAST 2003 68fa9e4066Sahrens */ 69fa9e4066Sahrens 70fa9e4066Sahrens /* 71fa9e4066Sahrens * The locking model: 72fa9e4066Sahrens * 73fa9e4066Sahrens * A new reference to a cache buffer can be obtained in two 74fa9e4066Sahrens * ways: 1) via a hash table lookup using the DVA as a key, 75fa94a07fSbrendan * or 2) via one of the ARC lists. The arc_read() interface 76fa9e4066Sahrens * uses method 1, while the internal arc algorithms for 77fa9e4066Sahrens * adjusting the cache use method 2. We therefor provide two 78fa9e4066Sahrens * types of locks: 1) the hash table lock array, and 2) the 79fa9e4066Sahrens * arc list locks. 80fa9e4066Sahrens * 81fa9e4066Sahrens * Buffers do not have their own mutexs, rather they rely on the 82fa9e4066Sahrens * hash table mutexs for the bulk of their protection (i.e. most 83fa9e4066Sahrens * fields in the arc_buf_hdr_t are protected by these mutexs). 84fa9e4066Sahrens * 85fa9e4066Sahrens * buf_hash_find() returns the appropriate mutex (held) when it 86fa9e4066Sahrens * locates the requested buffer in the hash table. It returns 87fa9e4066Sahrens * NULL for the mutex if the buffer was not in the table. 88fa9e4066Sahrens * 89fa9e4066Sahrens * buf_hash_remove() expects the appropriate hash mutex to be 90fa9e4066Sahrens * already held before it is invoked. 91fa9e4066Sahrens * 92fa9e4066Sahrens * Each arc state also has a mutex which is used to protect the 93fa9e4066Sahrens * buffer list associated with the state. When attempting to 94fa9e4066Sahrens * obtain a hash table lock while holding an arc list lock you 95fa9e4066Sahrens * must use: mutex_tryenter() to avoid deadlock. Also note that 9644eda4d7Smaybee * the active state mutex must be held before the ghost state mutex. 97fa9e4066Sahrens * 98ea8dc4b6Seschrock * Arc buffers may have an associated eviction callback function. 99ea8dc4b6Seschrock * This function will be invoked prior to removing the buffer (e.g. 100ea8dc4b6Seschrock * in arc_do_user_evicts()). Note however that the data associated 101ea8dc4b6Seschrock * with the buffer may be evicted prior to the callback. The callback 102ea8dc4b6Seschrock * must be made with *no locks held* (to prevent deadlock). Additionally, 103ea8dc4b6Seschrock * the users of callbacks must ensure that their private data is 104ea8dc4b6Seschrock * protected from simultaneous callbacks from arc_buf_evict() 105ea8dc4b6Seschrock * and arc_do_user_evicts(). 106ea8dc4b6Seschrock * 107fa9e4066Sahrens * Note that the majority of the performance stats are manipulated 108fa9e4066Sahrens * with atomic operations. 109fa94a07fSbrendan * 110fa94a07fSbrendan * The L2ARC uses the l2arc_buflist_mtx global mutex for the following: 111fa94a07fSbrendan * 112fa94a07fSbrendan * - L2ARC buflist creation 113fa94a07fSbrendan * - L2ARC buflist eviction 114fa94a07fSbrendan * - L2ARC write completion, which walks L2ARC buflists 115fa94a07fSbrendan * - ARC header destruction, as it removes from L2ARC buflists 116fa94a07fSbrendan * - ARC header release, as it removes from L2ARC buflists 117fa9e4066Sahrens */ 118fa9e4066Sahrens 119fa9e4066Sahrens #include <sys/spa.h> 120fa9e4066Sahrens #include <sys/zio.h> 121fa9e4066Sahrens #include <sys/zfs_context.h> 122fa9e4066Sahrens #include <sys/arc.h> 123fa9e4066Sahrens #include <sys/refcount.h> 124c5904d13Seschrock #include <sys/vdev.h> 125573ca77eSGeorge Wilson #include <sys/vdev_impl.h> 126fa9e4066Sahrens #ifdef _KERNEL 127fa9e4066Sahrens #include <sys/vmsystm.h> 128fa9e4066Sahrens #include <vm/anon.h> 129fa9e4066Sahrens #include <sys/fs/swapnode.h> 130033f9833Sek #include <sys/dnlc.h> 131fa9e4066Sahrens #endif 132fa9e4066Sahrens #include <sys/callb.h> 13344cb6abcSbmc #include <sys/kstat.h> 134b24ab676SJeff Bonwick #include <zfs_fletcher.h> 135fa9e4066Sahrens 136fa9e4066Sahrens static kmutex_t arc_reclaim_thr_lock; 137fa9e4066Sahrens static kcondvar_t arc_reclaim_thr_cv; /* used to signal reclaim thr */ 138fa9e4066Sahrens static uint8_t arc_thread_exit; 139fa9e4066Sahrens 1401ab7f2deSmaybee extern int zfs_write_limit_shift; 1411ab7f2deSmaybee extern uint64_t zfs_write_limit_max; 14205715f94SMark Maybee extern kmutex_t zfs_write_limit_lock; 1431ab7f2deSmaybee 144033f9833Sek #define ARC_REDUCE_DNLC_PERCENT 3 145033f9833Sek uint_t arc_reduce_dnlc_percent = ARC_REDUCE_DNLC_PERCENT; 146033f9833Sek 147fa9e4066Sahrens typedef enum arc_reclaim_strategy { 148fa9e4066Sahrens ARC_RECLAIM_AGGR, /* Aggressive reclaim strategy */ 149fa9e4066Sahrens ARC_RECLAIM_CONS /* Conservative reclaim strategy */ 150fa9e4066Sahrens } arc_reclaim_strategy_t; 151fa9e4066Sahrens 152fa9e4066Sahrens /* number of seconds before growing cache again */ 153fa9e4066Sahrens static int arc_grow_retry = 60; 154fa9e4066Sahrens 1555a98e54bSBrendan Gregg - Sun Microsystems /* shift of arc_c for calculating both min and max arc_p */ 1565a98e54bSBrendan Gregg - Sun Microsystems static int arc_p_min_shift = 4; 1575a98e54bSBrendan Gregg - Sun Microsystems 1585a98e54bSBrendan Gregg - Sun Microsystems /* log2(fraction of arc to reclaim) */ 1595a98e54bSBrendan Gregg - Sun Microsystems static int arc_shrink_shift = 5; 1605a98e54bSBrendan Gregg - Sun Microsystems 16113506d1eSmaybee /* 162b19a79ecSperrin * minimum lifespan of a prefetch block in clock ticks 163b19a79ecSperrin * (initialized in arc_init()) 16413506d1eSmaybee */ 165b19a79ecSperrin static int arc_min_prefetch_lifespan; 16613506d1eSmaybee 167fa9e4066Sahrens static int arc_dead; 168fa9e4066Sahrens 1693a737e0dSbrendan /* 1703a737e0dSbrendan * The arc has filled available memory and has now warmed up. 1713a737e0dSbrendan */ 1723a737e0dSbrendan static boolean_t arc_warm; 1733a737e0dSbrendan 174a2eea2e1Sahrens /* 175a2eea2e1Sahrens * These tunables are for performance analysis. 176a2eea2e1Sahrens */ 177a2eea2e1Sahrens uint64_t zfs_arc_max; 178a2eea2e1Sahrens uint64_t zfs_arc_min; 1791116048bSek uint64_t zfs_arc_meta_limit = 0; 1805a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_grow_retry = 0; 1815a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_shrink_shift = 0; 1825a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_p_min_shift = 0; 183a2eea2e1Sahrens 184fa9e4066Sahrens /* 185fa94a07fSbrendan * Note that buffers can be in one of 6 states: 186fa9e4066Sahrens * ARC_anon - anonymous (discussed below) 187ea8dc4b6Seschrock * ARC_mru - recently used, currently cached 188ea8dc4b6Seschrock * ARC_mru_ghost - recentely used, no longer in cache 189ea8dc4b6Seschrock * ARC_mfu - frequently used, currently cached 190ea8dc4b6Seschrock * ARC_mfu_ghost - frequently used, no longer in cache 191fa94a07fSbrendan * ARC_l2c_only - exists in L2ARC but not other states 1920e8c6158Smaybee * When there are no active references to the buffer, they are 1930e8c6158Smaybee * are linked onto a list in one of these arc states. These are 1940e8c6158Smaybee * the only buffers that can be evicted or deleted. Within each 1950e8c6158Smaybee * state there are multiple lists, one for meta-data and one for 1960e8c6158Smaybee * non-meta-data. Meta-data (indirect blocks, blocks of dnodes, 1970e8c6158Smaybee * etc.) is tracked separately so that it can be managed more 198fa94a07fSbrendan * explicitly: favored over data, limited explicitly. 199fa9e4066Sahrens * 200fa9e4066Sahrens * Anonymous buffers are buffers that are not associated with 201fa9e4066Sahrens * a DVA. These are buffers that hold dirty block copies 202fa9e4066Sahrens * before they are written to stable storage. By definition, 203ea8dc4b6Seschrock * they are "ref'd" and are considered part of arc_mru 204fa9e4066Sahrens * that cannot be freed. Generally, they will aquire a DVA 205ea8dc4b6Seschrock * as they are written and migrate onto the arc_mru list. 206fa94a07fSbrendan * 207fa94a07fSbrendan * The ARC_l2c_only state is for buffers that are in the second 208fa94a07fSbrendan * level ARC but no longer in any of the ARC_m* lists. The second 209fa94a07fSbrendan * level ARC itself may also contain buffers that are in any of 210fa94a07fSbrendan * the ARC_m* states - meaning that a buffer can exist in two 211fa94a07fSbrendan * places. The reason for the ARC_l2c_only state is to keep the 212fa94a07fSbrendan * buffer header in the hash table, so that reads that hit the 213fa94a07fSbrendan * second level ARC benefit from these fast lookups. 214fa9e4066Sahrens */ 215fa9e4066Sahrens 216fa9e4066Sahrens typedef struct arc_state { 2170e8c6158Smaybee list_t arcs_list[ARC_BUFC_NUMTYPES]; /* list of evictable buffers */ 2180e8c6158Smaybee uint64_t arcs_lsize[ARC_BUFC_NUMTYPES]; /* amount of evictable data */ 2190e8c6158Smaybee uint64_t arcs_size; /* total amount of data in this state */ 22044cb6abcSbmc kmutex_t arcs_mtx; 221fa9e4066Sahrens } arc_state_t; 222fa9e4066Sahrens 223fa94a07fSbrendan /* The 6 states: */ 224fa9e4066Sahrens static arc_state_t ARC_anon; 225ea8dc4b6Seschrock static arc_state_t ARC_mru; 226ea8dc4b6Seschrock static arc_state_t ARC_mru_ghost; 227ea8dc4b6Seschrock static arc_state_t ARC_mfu; 228ea8dc4b6Seschrock static arc_state_t ARC_mfu_ghost; 229fa94a07fSbrendan static arc_state_t ARC_l2c_only; 230fa9e4066Sahrens 23144cb6abcSbmc typedef struct arc_stats { 23244cb6abcSbmc kstat_named_t arcstat_hits; 23344cb6abcSbmc kstat_named_t arcstat_misses; 23444cb6abcSbmc kstat_named_t arcstat_demand_data_hits; 23544cb6abcSbmc kstat_named_t arcstat_demand_data_misses; 23644cb6abcSbmc kstat_named_t arcstat_demand_metadata_hits; 23744cb6abcSbmc kstat_named_t arcstat_demand_metadata_misses; 23844cb6abcSbmc kstat_named_t arcstat_prefetch_data_hits; 23944cb6abcSbmc kstat_named_t arcstat_prefetch_data_misses; 24044cb6abcSbmc kstat_named_t arcstat_prefetch_metadata_hits; 24144cb6abcSbmc kstat_named_t arcstat_prefetch_metadata_misses; 24244cb6abcSbmc kstat_named_t arcstat_mru_hits; 24344cb6abcSbmc kstat_named_t arcstat_mru_ghost_hits; 24444cb6abcSbmc kstat_named_t arcstat_mfu_hits; 24544cb6abcSbmc kstat_named_t arcstat_mfu_ghost_hits; 24644cb6abcSbmc kstat_named_t arcstat_deleted; 24744cb6abcSbmc kstat_named_t arcstat_recycle_miss; 24844cb6abcSbmc kstat_named_t arcstat_mutex_miss; 24944cb6abcSbmc kstat_named_t arcstat_evict_skip; 2505ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_cached; 2515ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_eligible; 2525ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_ineligible; 25344cb6abcSbmc kstat_named_t arcstat_hash_elements; 25444cb6abcSbmc kstat_named_t arcstat_hash_elements_max; 25544cb6abcSbmc kstat_named_t arcstat_hash_collisions; 25644cb6abcSbmc kstat_named_t arcstat_hash_chains; 25744cb6abcSbmc kstat_named_t arcstat_hash_chain_max; 25844cb6abcSbmc kstat_named_t arcstat_p; 25944cb6abcSbmc kstat_named_t arcstat_c; 26044cb6abcSbmc kstat_named_t arcstat_c_min; 26144cb6abcSbmc kstat_named_t arcstat_c_max; 26244cb6abcSbmc kstat_named_t arcstat_size; 263fa94a07fSbrendan kstat_named_t arcstat_hdr_size; 2645a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_data_size; 2655a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_other_size; 266fa94a07fSbrendan kstat_named_t arcstat_l2_hits; 267fa94a07fSbrendan kstat_named_t arcstat_l2_misses; 268fa94a07fSbrendan kstat_named_t arcstat_l2_feeds; 269fa94a07fSbrendan kstat_named_t arcstat_l2_rw_clash; 2705a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_l2_read_bytes; 2715a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_l2_write_bytes; 272fa94a07fSbrendan kstat_named_t arcstat_l2_writes_sent; 273fa94a07fSbrendan kstat_named_t arcstat_l2_writes_done; 274fa94a07fSbrendan kstat_named_t arcstat_l2_writes_error; 275fa94a07fSbrendan kstat_named_t arcstat_l2_writes_hdr_miss; 276fa94a07fSbrendan kstat_named_t arcstat_l2_evict_lock_retry; 277fa94a07fSbrendan kstat_named_t arcstat_l2_evict_reading; 278fa94a07fSbrendan kstat_named_t arcstat_l2_free_on_write; 279fa94a07fSbrendan kstat_named_t arcstat_l2_abort_lowmem; 280fa94a07fSbrendan kstat_named_t arcstat_l2_cksum_bad; 281fa94a07fSbrendan kstat_named_t arcstat_l2_io_error; 282fa94a07fSbrendan kstat_named_t arcstat_l2_size; 283fa94a07fSbrendan kstat_named_t arcstat_l2_hdr_size; 2841ab7f2deSmaybee kstat_named_t arcstat_memory_throttle_count; 28544cb6abcSbmc } arc_stats_t; 28644cb6abcSbmc 28744cb6abcSbmc static arc_stats_t arc_stats = { 28844cb6abcSbmc { "hits", KSTAT_DATA_UINT64 }, 28944cb6abcSbmc { "misses", KSTAT_DATA_UINT64 }, 29044cb6abcSbmc { "demand_data_hits", KSTAT_DATA_UINT64 }, 29144cb6abcSbmc { "demand_data_misses", KSTAT_DATA_UINT64 }, 29244cb6abcSbmc { "demand_metadata_hits", KSTAT_DATA_UINT64 }, 29344cb6abcSbmc { "demand_metadata_misses", KSTAT_DATA_UINT64 }, 29444cb6abcSbmc { "prefetch_data_hits", KSTAT_DATA_UINT64 }, 29544cb6abcSbmc { "prefetch_data_misses", KSTAT_DATA_UINT64 }, 29644cb6abcSbmc { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, 29744cb6abcSbmc { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, 29844cb6abcSbmc { "mru_hits", KSTAT_DATA_UINT64 }, 29944cb6abcSbmc { "mru_ghost_hits", KSTAT_DATA_UINT64 }, 30044cb6abcSbmc { "mfu_hits", KSTAT_DATA_UINT64 }, 30144cb6abcSbmc { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, 30244cb6abcSbmc { "deleted", KSTAT_DATA_UINT64 }, 30344cb6abcSbmc { "recycle_miss", KSTAT_DATA_UINT64 }, 30444cb6abcSbmc { "mutex_miss", KSTAT_DATA_UINT64 }, 30544cb6abcSbmc { "evict_skip", KSTAT_DATA_UINT64 }, 3065ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_cached", KSTAT_DATA_UINT64 }, 3075ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_eligible", KSTAT_DATA_UINT64 }, 3085ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, 30944cb6abcSbmc { "hash_elements", KSTAT_DATA_UINT64 }, 31044cb6abcSbmc { "hash_elements_max", KSTAT_DATA_UINT64 }, 31144cb6abcSbmc { "hash_collisions", KSTAT_DATA_UINT64 }, 31244cb6abcSbmc { "hash_chains", KSTAT_DATA_UINT64 }, 31344cb6abcSbmc { "hash_chain_max", KSTAT_DATA_UINT64 }, 31444cb6abcSbmc { "p", KSTAT_DATA_UINT64 }, 31544cb6abcSbmc { "c", KSTAT_DATA_UINT64 }, 31644cb6abcSbmc { "c_min", KSTAT_DATA_UINT64 }, 31744cb6abcSbmc { "c_max", KSTAT_DATA_UINT64 }, 318fa94a07fSbrendan { "size", KSTAT_DATA_UINT64 }, 319fa94a07fSbrendan { "hdr_size", KSTAT_DATA_UINT64 }, 3205a98e54bSBrendan Gregg - Sun Microsystems { "data_size", KSTAT_DATA_UINT64 }, 3215a98e54bSBrendan Gregg - Sun Microsystems { "other_size", KSTAT_DATA_UINT64 }, 322fa94a07fSbrendan { "l2_hits", KSTAT_DATA_UINT64 }, 323fa94a07fSbrendan { "l2_misses", KSTAT_DATA_UINT64 }, 324fa94a07fSbrendan { "l2_feeds", KSTAT_DATA_UINT64 }, 325fa94a07fSbrendan { "l2_rw_clash", KSTAT_DATA_UINT64 }, 3265a98e54bSBrendan Gregg - Sun Microsystems { "l2_read_bytes", KSTAT_DATA_UINT64 }, 3275a98e54bSBrendan Gregg - Sun Microsystems { "l2_write_bytes", KSTAT_DATA_UINT64 }, 328fa94a07fSbrendan { "l2_writes_sent", KSTAT_DATA_UINT64 }, 329fa94a07fSbrendan { "l2_writes_done", KSTAT_DATA_UINT64 }, 330fa94a07fSbrendan { "l2_writes_error", KSTAT_DATA_UINT64 }, 331fa94a07fSbrendan { "l2_writes_hdr_miss", KSTAT_DATA_UINT64 }, 332fa94a07fSbrendan { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, 333fa94a07fSbrendan { "l2_evict_reading", KSTAT_DATA_UINT64 }, 334fa94a07fSbrendan { "l2_free_on_write", KSTAT_DATA_UINT64 }, 335fa94a07fSbrendan { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, 336fa94a07fSbrendan { "l2_cksum_bad", KSTAT_DATA_UINT64 }, 337fa94a07fSbrendan { "l2_io_error", KSTAT_DATA_UINT64 }, 338fa94a07fSbrendan { "l2_size", KSTAT_DATA_UINT64 }, 3391ab7f2deSmaybee { "l2_hdr_size", KSTAT_DATA_UINT64 }, 3401ab7f2deSmaybee { "memory_throttle_count", KSTAT_DATA_UINT64 } 34144cb6abcSbmc }; 34244cb6abcSbmc 34344cb6abcSbmc #define ARCSTAT(stat) (arc_stats.stat.value.ui64) 34444cb6abcSbmc 34544cb6abcSbmc #define ARCSTAT_INCR(stat, val) \ 34644cb6abcSbmc atomic_add_64(&arc_stats.stat.value.ui64, (val)); 34744cb6abcSbmc 348b24ab676SJeff Bonwick #define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1) 34944cb6abcSbmc #define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1) 35044cb6abcSbmc 35144cb6abcSbmc #define ARCSTAT_MAX(stat, val) { \ 35244cb6abcSbmc uint64_t m; \ 35344cb6abcSbmc while ((val) > (m = arc_stats.stat.value.ui64) && \ 35444cb6abcSbmc (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ 35544cb6abcSbmc continue; \ 35644cb6abcSbmc } 35744cb6abcSbmc 35844cb6abcSbmc #define ARCSTAT_MAXSTAT(stat) \ 35944cb6abcSbmc ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64) 36044cb6abcSbmc 36144cb6abcSbmc /* 36244cb6abcSbmc * We define a macro to allow ARC hits/misses to be easily broken down by 36344cb6abcSbmc * two separate conditions, giving a total of four different subtypes for 36444cb6abcSbmc * each of hits and misses (so eight statistics total). 36544cb6abcSbmc */ 36644cb6abcSbmc #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ 36744cb6abcSbmc if (cond1) { \ 36844cb6abcSbmc if (cond2) { \ 36944cb6abcSbmc ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ 37044cb6abcSbmc } else { \ 37144cb6abcSbmc ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ 37244cb6abcSbmc } \ 37344cb6abcSbmc } else { \ 37444cb6abcSbmc if (cond2) { \ 37544cb6abcSbmc ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ 37644cb6abcSbmc } else { \ 37744cb6abcSbmc ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ 37844cb6abcSbmc } \ 37944cb6abcSbmc } 38044cb6abcSbmc 38144cb6abcSbmc kstat_t *arc_ksp; 382b24ab676SJeff Bonwick static arc_state_t *arc_anon; 38344cb6abcSbmc static arc_state_t *arc_mru; 38444cb6abcSbmc static arc_state_t *arc_mru_ghost; 38544cb6abcSbmc static arc_state_t *arc_mfu; 38644cb6abcSbmc static arc_state_t *arc_mfu_ghost; 387fa94a07fSbrendan static arc_state_t *arc_l2c_only; 38844cb6abcSbmc 38944cb6abcSbmc /* 39044cb6abcSbmc * There are several ARC variables that are critical to export as kstats -- 39144cb6abcSbmc * but we don't want to have to grovel around in the kstat whenever we wish to 39244cb6abcSbmc * manipulate them. For these variables, we therefore define them to be in 39344cb6abcSbmc * terms of the statistic variable. This assures that we are not introducing 39444cb6abcSbmc * the possibility of inconsistency by having shadow copies of the variables, 39544cb6abcSbmc * while still allowing the code to be readable. 39644cb6abcSbmc */ 39744cb6abcSbmc #define arc_size ARCSTAT(arcstat_size) /* actual total arc size */ 39844cb6abcSbmc #define arc_p ARCSTAT(arcstat_p) /* target size of MRU */ 39944cb6abcSbmc #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ 40044cb6abcSbmc #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ 40144cb6abcSbmc #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ 40244cb6abcSbmc 40344cb6abcSbmc static int arc_no_grow; /* Don't try to grow cache size */ 40444cb6abcSbmc static uint64_t arc_tempreserve; 4052fdbea25SAleksandr Guzovskiy static uint64_t arc_loaned_bytes; 4060e8c6158Smaybee static uint64_t arc_meta_used; 4070e8c6158Smaybee static uint64_t arc_meta_limit; 4080e8c6158Smaybee static uint64_t arc_meta_max = 0; 409fa9e4066Sahrens 410fa94a07fSbrendan typedef struct l2arc_buf_hdr l2arc_buf_hdr_t; 411fa94a07fSbrendan 412fa9e4066Sahrens typedef struct arc_callback arc_callback_t; 413fa9e4066Sahrens 414fa9e4066Sahrens struct arc_callback { 415fa9e4066Sahrens void *acb_private; 416c717a561Smaybee arc_done_func_t *acb_done; 417fa9e4066Sahrens arc_buf_t *acb_buf; 418fa9e4066Sahrens zio_t *acb_zio_dummy; 419fa9e4066Sahrens arc_callback_t *acb_next; 420fa9e4066Sahrens }; 421fa9e4066Sahrens 422c717a561Smaybee typedef struct arc_write_callback arc_write_callback_t; 423c717a561Smaybee 424c717a561Smaybee struct arc_write_callback { 425c717a561Smaybee void *awcb_private; 426c717a561Smaybee arc_done_func_t *awcb_ready; 427c717a561Smaybee arc_done_func_t *awcb_done; 428c717a561Smaybee arc_buf_t *awcb_buf; 429c717a561Smaybee }; 430c717a561Smaybee 431fa9e4066Sahrens struct arc_buf_hdr { 432fa9e4066Sahrens /* protected by hash lock */ 433fa9e4066Sahrens dva_t b_dva; 434fa9e4066Sahrens uint64_t b_birth; 435fa9e4066Sahrens uint64_t b_cksum0; 436fa9e4066Sahrens 4376b4acc8bSahrens kmutex_t b_freeze_lock; 4386b4acc8bSahrens zio_cksum_t *b_freeze_cksum; 439*3f9d6ad7SLin Ling void *b_thawed; 4406b4acc8bSahrens 441fa9e4066Sahrens arc_buf_hdr_t *b_hash_next; 442fa9e4066Sahrens arc_buf_t *b_buf; 443fa9e4066Sahrens uint32_t b_flags; 444ea8dc4b6Seschrock uint32_t b_datacnt; 445fa9e4066Sahrens 446fa9e4066Sahrens arc_callback_t *b_acb; 447ad23a2dbSjohansen kcondvar_t b_cv; 448ad23a2dbSjohansen 449ad23a2dbSjohansen /* immutable */ 450ad23a2dbSjohansen arc_buf_contents_t b_type; 451ad23a2dbSjohansen uint64_t b_size; 452ac05c741SMark Maybee uint64_t b_spa; 453fa9e4066Sahrens 454fa9e4066Sahrens /* protected by arc state mutex */ 455fa9e4066Sahrens arc_state_t *b_state; 456fa9e4066Sahrens list_node_t b_arc_node; 457fa9e4066Sahrens 458fa9e4066Sahrens /* updated atomically */ 459fa9e4066Sahrens clock_t b_arc_access; 460fa9e4066Sahrens 461fa9e4066Sahrens /* self protecting */ 462fa9e4066Sahrens refcount_t b_refcnt; 463fa94a07fSbrendan 464fa94a07fSbrendan l2arc_buf_hdr_t *b_l2hdr; 465fa94a07fSbrendan list_node_t b_l2node; 466fa9e4066Sahrens }; 467fa9e4066Sahrens 468ea8dc4b6Seschrock static arc_buf_t *arc_eviction_list; 469ea8dc4b6Seschrock static kmutex_t arc_eviction_mtx; 47040d7d650Smaybee static arc_buf_hdr_t arc_eviction_hdr; 47144eda4d7Smaybee static void arc_get_data_buf(arc_buf_t *buf); 47244eda4d7Smaybee static void arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock); 4730e8c6158Smaybee static int arc_evict_needed(arc_buf_contents_t type); 474ac05c741SMark Maybee static void arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes); 475ea8dc4b6Seschrock 4765ea40c06SBrendan Gregg - Sun Microsystems static boolean_t l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab); 4775ea40c06SBrendan Gregg - Sun Microsystems 478ea8dc4b6Seschrock #define GHOST_STATE(state) \ 479fa94a07fSbrendan ((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \ 480fa94a07fSbrendan (state) == arc_l2c_only) 481ea8dc4b6Seschrock 482fa9e4066Sahrens /* 483fa9e4066Sahrens * Private ARC flags. These flags are private ARC only flags that will show up 484fa9e4066Sahrens * in b_flags in the arc_hdr_buf_t. Some flags are publicly declared, and can 485fa9e4066Sahrens * be passed in as arc_flags in things like arc_read. However, these flags 486fa9e4066Sahrens * should never be passed and should only be set by ARC code. When adding new 487fa9e4066Sahrens * public flags, make sure not to smash the private ones. 488fa9e4066Sahrens */ 489fa9e4066Sahrens 490ea8dc4b6Seschrock #define ARC_IN_HASH_TABLE (1 << 9) /* this buffer is hashed */ 491fa9e4066Sahrens #define ARC_IO_IN_PROGRESS (1 << 10) /* I/O in progress for buf */ 492fa9e4066Sahrens #define ARC_IO_ERROR (1 << 11) /* I/O failed for buf */ 493fa9e4066Sahrens #define ARC_FREED_IN_READ (1 << 12) /* buf freed while in read */ 494ea8dc4b6Seschrock #define ARC_BUF_AVAILABLE (1 << 13) /* block not in active use */ 49513506d1eSmaybee #define ARC_INDIRECT (1 << 14) /* this is an indirect block */ 496fa94a07fSbrendan #define ARC_FREE_IN_PROGRESS (1 << 15) /* hdr about to be freed */ 4973baa08fcSek #define ARC_L2_WRITING (1 << 16) /* L2ARC write in progress */ 4983baa08fcSek #define ARC_L2_EVICTED (1 << 17) /* evicted during I/O */ 4993baa08fcSek #define ARC_L2_WRITE_HEAD (1 << 18) /* head of write list */ 500fa9e4066Sahrens 501ea8dc4b6Seschrock #define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_IN_HASH_TABLE) 502fa9e4066Sahrens #define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS) 503fa9e4066Sahrens #define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_IO_ERROR) 5045a98e54bSBrendan Gregg - Sun Microsystems #define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_PREFETCH) 505fa9e4066Sahrens #define HDR_FREED_IN_READ(hdr) ((hdr)->b_flags & ARC_FREED_IN_READ) 506ea8dc4b6Seschrock #define HDR_BUF_AVAILABLE(hdr) ((hdr)->b_flags & ARC_BUF_AVAILABLE) 507fa94a07fSbrendan #define HDR_FREE_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FREE_IN_PROGRESS) 5083baa08fcSek #define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_L2CACHE) 5093a737e0dSbrendan #define HDR_L2_READING(hdr) ((hdr)->b_flags & ARC_IO_IN_PROGRESS && \ 5103a737e0dSbrendan (hdr)->b_l2hdr != NULL) 511fa94a07fSbrendan #define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_L2_WRITING) 512fa94a07fSbrendan #define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_L2_EVICTED) 513fa94a07fSbrendan #define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_L2_WRITE_HEAD) 514fa9e4066Sahrens 515e6c728e1Sbrendan /* 516e6c728e1Sbrendan * Other sizes 517e6c728e1Sbrendan */ 518e6c728e1Sbrendan 519e6c728e1Sbrendan #define HDR_SIZE ((int64_t)sizeof (arc_buf_hdr_t)) 520e6c728e1Sbrendan #define L2HDR_SIZE ((int64_t)sizeof (l2arc_buf_hdr_t)) 521e6c728e1Sbrendan 522fa9e4066Sahrens /* 523fa9e4066Sahrens * Hash table routines 524fa9e4066Sahrens */ 525fa9e4066Sahrens 526fa9e4066Sahrens #define HT_LOCK_PAD 64 527fa9e4066Sahrens 528fa9e4066Sahrens struct ht_lock { 529fa9e4066Sahrens kmutex_t ht_lock; 530fa9e4066Sahrens #ifdef _KERNEL 531fa9e4066Sahrens unsigned char pad[(HT_LOCK_PAD - sizeof (kmutex_t))]; 532fa9e4066Sahrens #endif 533fa9e4066Sahrens }; 534fa9e4066Sahrens 535fa9e4066Sahrens #define BUF_LOCKS 256 536fa9e4066Sahrens typedef struct buf_hash_table { 537fa9e4066Sahrens uint64_t ht_mask; 538fa9e4066Sahrens arc_buf_hdr_t **ht_table; 539fa9e4066Sahrens struct ht_lock ht_locks[BUF_LOCKS]; 540fa9e4066Sahrens } buf_hash_table_t; 541fa9e4066Sahrens 542fa9e4066Sahrens static buf_hash_table_t buf_hash_table; 543fa9e4066Sahrens 544fa9e4066Sahrens #define BUF_HASH_INDEX(spa, dva, birth) \ 545fa9e4066Sahrens (buf_hash(spa, dva, birth) & buf_hash_table.ht_mask) 546fa9e4066Sahrens #define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)]) 547fa9e4066Sahrens #define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock)) 548*3f9d6ad7SLin Ling #define HDR_LOCK(hdr) \ 549*3f9d6ad7SLin Ling (BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth))) 550fa9e4066Sahrens 551fa9e4066Sahrens uint64_t zfs_crc64_table[256]; 552fa9e4066Sahrens 553fa94a07fSbrendan /* 554fa94a07fSbrendan * Level 2 ARC 555fa94a07fSbrendan */ 556fa94a07fSbrendan 557fa94a07fSbrendan #define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */ 5585a98e54bSBrendan Gregg - Sun Microsystems #define L2ARC_HEADROOM 2 /* num of writes */ 5595a98e54bSBrendan Gregg - Sun Microsystems #define L2ARC_FEED_SECS 1 /* caching interval secs */ 5605a98e54bSBrendan Gregg - Sun Microsystems #define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */ 561fa94a07fSbrendan 562fa94a07fSbrendan #define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent) 563fa94a07fSbrendan #define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done) 564fa94a07fSbrendan 565fa94a07fSbrendan /* 566fa94a07fSbrendan * L2ARC Performance Tunables 567fa94a07fSbrendan */ 568fa94a07fSbrendan uint64_t l2arc_write_max = L2ARC_WRITE_SIZE; /* default max write size */ 5693a737e0dSbrendan uint64_t l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra write during warmup */ 570fa94a07fSbrendan uint64_t l2arc_headroom = L2ARC_HEADROOM; /* number of dev writes */ 571fa94a07fSbrendan uint64_t l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */ 5725a98e54bSBrendan Gregg - Sun Microsystems uint64_t l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval milliseconds */ 573fa94a07fSbrendan boolean_t l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ 5745a98e54bSBrendan Gregg - Sun Microsystems boolean_t l2arc_feed_again = B_TRUE; /* turbo warmup */ 5755a98e54bSBrendan Gregg - Sun Microsystems boolean_t l2arc_norw = B_TRUE; /* no reads during writes */ 576fa94a07fSbrendan 577fa94a07fSbrendan /* 578fa94a07fSbrendan * L2ARC Internals 579fa94a07fSbrendan */ 580fa94a07fSbrendan typedef struct l2arc_dev { 581fa94a07fSbrendan vdev_t *l2ad_vdev; /* vdev */ 582fa94a07fSbrendan spa_t *l2ad_spa; /* spa */ 583fa94a07fSbrendan uint64_t l2ad_hand; /* next write location */ 584fa94a07fSbrendan uint64_t l2ad_write; /* desired write size, bytes */ 5853a737e0dSbrendan uint64_t l2ad_boost; /* warmup write boost, bytes */ 586fa94a07fSbrendan uint64_t l2ad_start; /* first addr on device */ 587fa94a07fSbrendan uint64_t l2ad_end; /* last addr on device */ 588fa94a07fSbrendan uint64_t l2ad_evict; /* last addr eviction reached */ 589fa94a07fSbrendan boolean_t l2ad_first; /* first sweep through */ 5905a98e54bSBrendan Gregg - Sun Microsystems boolean_t l2ad_writing; /* currently writing */ 591fa94a07fSbrendan list_t *l2ad_buflist; /* buffer list */ 592fa94a07fSbrendan list_node_t l2ad_node; /* device list node */ 593fa94a07fSbrendan } l2arc_dev_t; 594fa94a07fSbrendan 595fa94a07fSbrendan static list_t L2ARC_dev_list; /* device list */ 596fa94a07fSbrendan static list_t *l2arc_dev_list; /* device list pointer */ 597fa94a07fSbrendan static kmutex_t l2arc_dev_mtx; /* device list mutex */ 598fa94a07fSbrendan static l2arc_dev_t *l2arc_dev_last; /* last device used */ 599fa94a07fSbrendan static kmutex_t l2arc_buflist_mtx; /* mutex for all buflists */ 600fa94a07fSbrendan static list_t L2ARC_free_on_write; /* free after write buf list */ 601fa94a07fSbrendan static list_t *l2arc_free_on_write; /* free after write list ptr */ 602fa94a07fSbrendan static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */ 603fa94a07fSbrendan static uint64_t l2arc_ndev; /* number of devices */ 604fa94a07fSbrendan 605fa94a07fSbrendan typedef struct l2arc_read_callback { 606fa94a07fSbrendan arc_buf_t *l2rcb_buf; /* read buffer */ 607fa94a07fSbrendan spa_t *l2rcb_spa; /* spa */ 608fa94a07fSbrendan blkptr_t l2rcb_bp; /* original blkptr */ 609fa94a07fSbrendan zbookmark_t l2rcb_zb; /* original bookmark */ 610fa94a07fSbrendan int l2rcb_flags; /* original flags */ 611fa94a07fSbrendan } l2arc_read_callback_t; 612fa94a07fSbrendan 613fa94a07fSbrendan typedef struct l2arc_write_callback { 614fa94a07fSbrendan l2arc_dev_t *l2wcb_dev; /* device info */ 615fa94a07fSbrendan arc_buf_hdr_t *l2wcb_head; /* head of write buflist */ 616fa94a07fSbrendan } l2arc_write_callback_t; 617fa94a07fSbrendan 618fa94a07fSbrendan struct l2arc_buf_hdr { 619fa94a07fSbrendan /* protected by arc_buf_hdr mutex */ 620fa94a07fSbrendan l2arc_dev_t *b_dev; /* L2ARC device */ 621f9d8334fSGeorge Wilson uint64_t b_daddr; /* disk address, offset byte */ 622fa94a07fSbrendan }; 623fa94a07fSbrendan 624fa94a07fSbrendan typedef struct l2arc_data_free { 625fa94a07fSbrendan /* protected by l2arc_free_on_write_mtx */ 626fa94a07fSbrendan void *l2df_data; 627fa94a07fSbrendan size_t l2df_size; 628fa94a07fSbrendan void (*l2df_func)(void *, size_t); 629fa94a07fSbrendan list_node_t l2df_list_node; 630fa94a07fSbrendan } l2arc_data_free_t; 631fa94a07fSbrendan 632fa94a07fSbrendan static kmutex_t l2arc_feed_thr_lock; 633fa94a07fSbrendan static kcondvar_t l2arc_feed_thr_cv; 634fa94a07fSbrendan static uint8_t l2arc_thread_exit; 635fa94a07fSbrendan 636fa94a07fSbrendan static void l2arc_read_done(zio_t *zio); 637fa94a07fSbrendan static void l2arc_hdr_stat_add(void); 638fa94a07fSbrendan static void l2arc_hdr_stat_remove(void); 639fa94a07fSbrendan 640fa9e4066Sahrens static uint64_t 641ac05c741SMark Maybee buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth) 642fa9e4066Sahrens { 643fa9e4066Sahrens uint8_t *vdva = (uint8_t *)dva; 644fa9e4066Sahrens uint64_t crc = -1ULL; 645fa9e4066Sahrens int i; 646fa9e4066Sahrens 647fa9e4066Sahrens ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY); 648fa9e4066Sahrens 649fa9e4066Sahrens for (i = 0; i < sizeof (dva_t); i++) 650fa9e4066Sahrens crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ vdva[i]) & 0xFF]; 651fa9e4066Sahrens 652ac05c741SMark Maybee crc ^= (spa>>8) ^ birth; 653fa9e4066Sahrens 654fa9e4066Sahrens return (crc); 655fa9e4066Sahrens } 656fa9e4066Sahrens 657fa9e4066Sahrens #define BUF_EMPTY(buf) \ 658fa9e4066Sahrens ((buf)->b_dva.dva_word[0] == 0 && \ 659fa9e4066Sahrens (buf)->b_dva.dva_word[1] == 0 && \ 660fa9e4066Sahrens (buf)->b_birth == 0) 661fa9e4066Sahrens 662fa9e4066Sahrens #define BUF_EQUAL(spa, dva, birth, buf) \ 663fa9e4066Sahrens ((buf)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \ 664fa9e4066Sahrens ((buf)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \ 665fa9e4066Sahrens ((buf)->b_birth == birth) && ((buf)->b_spa == spa) 666fa9e4066Sahrens 667*3f9d6ad7SLin Ling static void 668*3f9d6ad7SLin Ling buf_discard_identity(arc_buf_hdr_t *hdr) 669*3f9d6ad7SLin Ling { 670*3f9d6ad7SLin Ling hdr->b_dva.dva_word[0] = 0; 671*3f9d6ad7SLin Ling hdr->b_dva.dva_word[1] = 0; 672*3f9d6ad7SLin Ling hdr->b_birth = 0; 673*3f9d6ad7SLin Ling hdr->b_cksum0 = 0; 674*3f9d6ad7SLin Ling } 675*3f9d6ad7SLin Ling 676fa9e4066Sahrens static arc_buf_hdr_t * 677ac05c741SMark Maybee buf_hash_find(uint64_t spa, const dva_t *dva, uint64_t birth, kmutex_t **lockp) 678fa9e4066Sahrens { 679fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); 680fa9e4066Sahrens kmutex_t *hash_lock = BUF_HASH_LOCK(idx); 681fa9e4066Sahrens arc_buf_hdr_t *buf; 682fa9e4066Sahrens 683fa9e4066Sahrens mutex_enter(hash_lock); 684fa9e4066Sahrens for (buf = buf_hash_table.ht_table[idx]; buf != NULL; 685fa9e4066Sahrens buf = buf->b_hash_next) { 686fa9e4066Sahrens if (BUF_EQUAL(spa, dva, birth, buf)) { 687fa9e4066Sahrens *lockp = hash_lock; 688fa9e4066Sahrens return (buf); 689fa9e4066Sahrens } 690fa9e4066Sahrens } 691fa9e4066Sahrens mutex_exit(hash_lock); 692fa9e4066Sahrens *lockp = NULL; 693fa9e4066Sahrens return (NULL); 694fa9e4066Sahrens } 695fa9e4066Sahrens 696fa9e4066Sahrens /* 697fa9e4066Sahrens * Insert an entry into the hash table. If there is already an element 698fa9e4066Sahrens * equal to elem in the hash table, then the already existing element 699fa9e4066Sahrens * will be returned and the new element will not be inserted. 700fa9e4066Sahrens * Otherwise returns NULL. 701fa9e4066Sahrens */ 702fa9e4066Sahrens static arc_buf_hdr_t * 703fa9e4066Sahrens buf_hash_insert(arc_buf_hdr_t *buf, kmutex_t **lockp) 704fa9e4066Sahrens { 705fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); 706fa9e4066Sahrens kmutex_t *hash_lock = BUF_HASH_LOCK(idx); 707fa9e4066Sahrens arc_buf_hdr_t *fbuf; 70844cb6abcSbmc uint32_t i; 709fa9e4066Sahrens 710ea8dc4b6Seschrock ASSERT(!HDR_IN_HASH_TABLE(buf)); 711fa9e4066Sahrens *lockp = hash_lock; 712fa9e4066Sahrens mutex_enter(hash_lock); 713fa9e4066Sahrens for (fbuf = buf_hash_table.ht_table[idx], i = 0; fbuf != NULL; 714fa9e4066Sahrens fbuf = fbuf->b_hash_next, i++) { 715fa9e4066Sahrens if (BUF_EQUAL(buf->b_spa, &buf->b_dva, buf->b_birth, fbuf)) 716fa9e4066Sahrens return (fbuf); 717fa9e4066Sahrens } 718fa9e4066Sahrens 719fa9e4066Sahrens buf->b_hash_next = buf_hash_table.ht_table[idx]; 720fa9e4066Sahrens buf_hash_table.ht_table[idx] = buf; 721ea8dc4b6Seschrock buf->b_flags |= ARC_IN_HASH_TABLE; 722fa9e4066Sahrens 723fa9e4066Sahrens /* collect some hash table performance data */ 724fa9e4066Sahrens if (i > 0) { 72544cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_collisions); 726fa9e4066Sahrens if (i == 1) 72744cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_chains); 72844cb6abcSbmc 72944cb6abcSbmc ARCSTAT_MAX(arcstat_hash_chain_max, i); 730fa9e4066Sahrens } 73144cb6abcSbmc 73244cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_elements); 73344cb6abcSbmc ARCSTAT_MAXSTAT(arcstat_hash_elements); 734fa9e4066Sahrens 735fa9e4066Sahrens return (NULL); 736fa9e4066Sahrens } 737fa9e4066Sahrens 738fa9e4066Sahrens static void 739fa9e4066Sahrens buf_hash_remove(arc_buf_hdr_t *buf) 740fa9e4066Sahrens { 741fa9e4066Sahrens arc_buf_hdr_t *fbuf, **bufp; 742fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); 743fa9e4066Sahrens 744fa9e4066Sahrens ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); 745ea8dc4b6Seschrock ASSERT(HDR_IN_HASH_TABLE(buf)); 746fa9e4066Sahrens 747fa9e4066Sahrens bufp = &buf_hash_table.ht_table[idx]; 748fa9e4066Sahrens while ((fbuf = *bufp) != buf) { 749fa9e4066Sahrens ASSERT(fbuf != NULL); 750fa9e4066Sahrens bufp = &fbuf->b_hash_next; 751fa9e4066Sahrens } 752fa9e4066Sahrens *bufp = buf->b_hash_next; 753fa9e4066Sahrens buf->b_hash_next = NULL; 754ea8dc4b6Seschrock buf->b_flags &= ~ARC_IN_HASH_TABLE; 755fa9e4066Sahrens 756fa9e4066Sahrens /* collect some hash table performance data */ 75744cb6abcSbmc ARCSTAT_BUMPDOWN(arcstat_hash_elements); 75844cb6abcSbmc 759fa9e4066Sahrens if (buf_hash_table.ht_table[idx] && 760fa9e4066Sahrens buf_hash_table.ht_table[idx]->b_hash_next == NULL) 76144cb6abcSbmc ARCSTAT_BUMPDOWN(arcstat_hash_chains); 762fa9e4066Sahrens } 763fa9e4066Sahrens 764fa9e4066Sahrens /* 765fa9e4066Sahrens * Global data structures and functions for the buf kmem cache. 766fa9e4066Sahrens */ 767fa9e4066Sahrens static kmem_cache_t *hdr_cache; 768fa9e4066Sahrens static kmem_cache_t *buf_cache; 769fa9e4066Sahrens 770fa9e4066Sahrens static void 771fa9e4066Sahrens buf_fini(void) 772fa9e4066Sahrens { 773fa9e4066Sahrens int i; 774fa9e4066Sahrens 775fa9e4066Sahrens kmem_free(buf_hash_table.ht_table, 776fa9e4066Sahrens (buf_hash_table.ht_mask + 1) * sizeof (void *)); 777fa9e4066Sahrens for (i = 0; i < BUF_LOCKS; i++) 778fa9e4066Sahrens mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock); 779fa9e4066Sahrens kmem_cache_destroy(hdr_cache); 780fa9e4066Sahrens kmem_cache_destroy(buf_cache); 781fa9e4066Sahrens } 782fa9e4066Sahrens 783fa9e4066Sahrens /* 784fa9e4066Sahrens * Constructor callback - called when the cache is empty 785fa9e4066Sahrens * and a new buf is requested. 786fa9e4066Sahrens */ 787fa9e4066Sahrens /* ARGSUSED */ 788fa9e4066Sahrens static int 789fa9e4066Sahrens hdr_cons(void *vbuf, void *unused, int kmflag) 790fa9e4066Sahrens { 791fa9e4066Sahrens arc_buf_hdr_t *buf = vbuf; 792fa9e4066Sahrens 793fa9e4066Sahrens bzero(buf, sizeof (arc_buf_hdr_t)); 794fa9e4066Sahrens refcount_create(&buf->b_refcnt); 795fa9e4066Sahrens cv_init(&buf->b_cv, NULL, CV_DEFAULT, NULL); 796c25056deSgw mutex_init(&buf->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); 7975a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); 798fa94a07fSbrendan 799fa9e4066Sahrens return (0); 800fa9e4066Sahrens } 801fa9e4066Sahrens 8026f83844dSMark Maybee /* ARGSUSED */ 8036f83844dSMark Maybee static int 8046f83844dSMark Maybee buf_cons(void *vbuf, void *unused, int kmflag) 8056f83844dSMark Maybee { 8066f83844dSMark Maybee arc_buf_t *buf = vbuf; 8076f83844dSMark Maybee 8086f83844dSMark Maybee bzero(buf, sizeof (arc_buf_t)); 809*3f9d6ad7SLin Ling mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL); 810*3f9d6ad7SLin Ling rw_init(&buf->b_data_lock, NULL, RW_DEFAULT, NULL); 8115a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); 8125a98e54bSBrendan Gregg - Sun Microsystems 8136f83844dSMark Maybee return (0); 8146f83844dSMark Maybee } 8156f83844dSMark Maybee 816fa9e4066Sahrens /* 817fa9e4066Sahrens * Destructor callback - called when a cached buf is 818fa9e4066Sahrens * no longer required. 819fa9e4066Sahrens */ 820fa9e4066Sahrens /* ARGSUSED */ 821fa9e4066Sahrens static void 822fa9e4066Sahrens hdr_dest(void *vbuf, void *unused) 823fa9e4066Sahrens { 824fa9e4066Sahrens arc_buf_hdr_t *buf = vbuf; 825fa9e4066Sahrens 826b24ab676SJeff Bonwick ASSERT(BUF_EMPTY(buf)); 827fa9e4066Sahrens refcount_destroy(&buf->b_refcnt); 828fa9e4066Sahrens cv_destroy(&buf->b_cv); 829c25056deSgw mutex_destroy(&buf->b_freeze_lock); 8305a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); 831fa9e4066Sahrens } 832fa9e4066Sahrens 8336f83844dSMark Maybee /* ARGSUSED */ 8346f83844dSMark Maybee static void 8356f83844dSMark Maybee buf_dest(void *vbuf, void *unused) 8366f83844dSMark Maybee { 8376f83844dSMark Maybee arc_buf_t *buf = vbuf; 8386f83844dSMark Maybee 839*3f9d6ad7SLin Ling mutex_destroy(&buf->b_evict_lock); 840*3f9d6ad7SLin Ling rw_destroy(&buf->b_data_lock); 8415a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); 8426f83844dSMark Maybee } 8436f83844dSMark Maybee 844fa9e4066Sahrens /* 845fa9e4066Sahrens * Reclaim callback -- invoked when memory is low. 846fa9e4066Sahrens */ 847fa9e4066Sahrens /* ARGSUSED */ 848fa9e4066Sahrens static void 849fa9e4066Sahrens hdr_recl(void *unused) 850fa9e4066Sahrens { 851fa9e4066Sahrens dprintf("hdr_recl called\n"); 85249e3519aSmaybee /* 85349e3519aSmaybee * umem calls the reclaim func when we destroy the buf cache, 85449e3519aSmaybee * which is after we do arc_fini(). 85549e3519aSmaybee */ 85649e3519aSmaybee if (!arc_dead) 85749e3519aSmaybee cv_signal(&arc_reclaim_thr_cv); 858fa9e4066Sahrens } 859fa9e4066Sahrens 860fa9e4066Sahrens static void 861fa9e4066Sahrens buf_init(void) 862fa9e4066Sahrens { 863fa9e4066Sahrens uint64_t *ct; 864ea8dc4b6Seschrock uint64_t hsize = 1ULL << 12; 865fa9e4066Sahrens int i, j; 866fa9e4066Sahrens 867fa9e4066Sahrens /* 868fa9e4066Sahrens * The hash table is big enough to fill all of physical memory 869ea8dc4b6Seschrock * with an average 64K block size. The table will take up 870ea8dc4b6Seschrock * totalmem*sizeof(void*)/64K (eg. 128KB/GB with 8-byte pointers). 871fa9e4066Sahrens */ 872ea8dc4b6Seschrock while (hsize * 65536 < physmem * PAGESIZE) 873fa9e4066Sahrens hsize <<= 1; 874ea8dc4b6Seschrock retry: 875fa9e4066Sahrens buf_hash_table.ht_mask = hsize - 1; 876ea8dc4b6Seschrock buf_hash_table.ht_table = 877ea8dc4b6Seschrock kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); 878ea8dc4b6Seschrock if (buf_hash_table.ht_table == NULL) { 879ea8dc4b6Seschrock ASSERT(hsize > (1ULL << 8)); 880ea8dc4b6Seschrock hsize >>= 1; 881ea8dc4b6Seschrock goto retry; 882ea8dc4b6Seschrock } 883fa9e4066Sahrens 884fa9e4066Sahrens hdr_cache = kmem_cache_create("arc_buf_hdr_t", sizeof (arc_buf_hdr_t), 885fa9e4066Sahrens 0, hdr_cons, hdr_dest, hdr_recl, NULL, NULL, 0); 886fa9e4066Sahrens buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), 8876f83844dSMark Maybee 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); 888fa9e4066Sahrens 889fa9e4066Sahrens for (i = 0; i < 256; i++) 890fa9e4066Sahrens for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) 891fa9e4066Sahrens *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); 892fa9e4066Sahrens 893fa9e4066Sahrens for (i = 0; i < BUF_LOCKS; i++) { 894fa9e4066Sahrens mutex_init(&buf_hash_table.ht_locks[i].ht_lock, 895fa9e4066Sahrens NULL, MUTEX_DEFAULT, NULL); 896fa9e4066Sahrens } 897fa9e4066Sahrens } 898fa9e4066Sahrens 899fa9e4066Sahrens #define ARC_MINTIME (hz>>4) /* 62 ms */ 900fa9e4066Sahrens 9016b4acc8bSahrens static void 9026b4acc8bSahrens arc_cksum_verify(arc_buf_t *buf) 9036b4acc8bSahrens { 9046b4acc8bSahrens zio_cksum_t zc; 9056b4acc8bSahrens 906cc60fd72Sahrens if (!(zfs_flags & ZFS_DEBUG_MODIFY)) 9076b4acc8bSahrens return; 9086b4acc8bSahrens 9096b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9103ccfa83cSahrens if (buf->b_hdr->b_freeze_cksum == NULL || 9113ccfa83cSahrens (buf->b_hdr->b_flags & ARC_IO_ERROR)) { 9126b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9136b4acc8bSahrens return; 9146b4acc8bSahrens } 9156b4acc8bSahrens fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); 9166b4acc8bSahrens if (!ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc)) 9176b4acc8bSahrens panic("buffer modified while frozen!"); 9186b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9196b4acc8bSahrens } 9206b4acc8bSahrens 921fa94a07fSbrendan static int 922fa94a07fSbrendan arc_cksum_equal(arc_buf_t *buf) 923fa94a07fSbrendan { 924fa94a07fSbrendan zio_cksum_t zc; 925fa94a07fSbrendan int equal; 926fa94a07fSbrendan 927fa94a07fSbrendan mutex_enter(&buf->b_hdr->b_freeze_lock); 928fa94a07fSbrendan fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); 929fa94a07fSbrendan equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc); 930fa94a07fSbrendan mutex_exit(&buf->b_hdr->b_freeze_lock); 931fa94a07fSbrendan 932fa94a07fSbrendan return (equal); 933fa94a07fSbrendan } 934fa94a07fSbrendan 9356b4acc8bSahrens static void 936fa94a07fSbrendan arc_cksum_compute(arc_buf_t *buf, boolean_t force) 9376b4acc8bSahrens { 938fa94a07fSbrendan if (!force && !(zfs_flags & ZFS_DEBUG_MODIFY)) 9396b4acc8bSahrens return; 9406b4acc8bSahrens 9416b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9426b4acc8bSahrens if (buf->b_hdr->b_freeze_cksum != NULL) { 9436b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9446b4acc8bSahrens return; 9456b4acc8bSahrens } 9466b4acc8bSahrens buf->b_hdr->b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), KM_SLEEP); 9476b4acc8bSahrens fletcher_2_native(buf->b_data, buf->b_hdr->b_size, 9486b4acc8bSahrens buf->b_hdr->b_freeze_cksum); 9496b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9506b4acc8bSahrens } 9516b4acc8bSahrens 9526b4acc8bSahrens void 9536b4acc8bSahrens arc_buf_thaw(arc_buf_t *buf) 9546b4acc8bSahrens { 955*3f9d6ad7SLin Ling kmutex_t *hash_lock; 956*3f9d6ad7SLin Ling 957*3f9d6ad7SLin Ling hash_lock = HDR_LOCK(buf->b_hdr); 958*3f9d6ad7SLin Ling mutex_enter(hash_lock); 959*3f9d6ad7SLin Ling 960fa94a07fSbrendan if (zfs_flags & ZFS_DEBUG_MODIFY) { 961fa94a07fSbrendan if (buf->b_hdr->b_state != arc_anon) 962fa94a07fSbrendan panic("modifying non-anon buffer!"); 963fa94a07fSbrendan if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS) 964fa94a07fSbrendan panic("modifying buffer while i/o in progress!"); 965fa94a07fSbrendan arc_cksum_verify(buf); 966fa94a07fSbrendan } 9676b4acc8bSahrens 9686b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9696b4acc8bSahrens if (buf->b_hdr->b_freeze_cksum != NULL) { 9706b4acc8bSahrens kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 9716b4acc8bSahrens buf->b_hdr->b_freeze_cksum = NULL; 9726b4acc8bSahrens } 973*3f9d6ad7SLin Ling 974*3f9d6ad7SLin Ling if (zfs_flags & ZFS_DEBUG_MODIFY) { 975*3f9d6ad7SLin Ling if (buf->b_hdr->b_thawed) 976*3f9d6ad7SLin Ling kmem_free(buf->b_hdr->b_thawed, 1); 977*3f9d6ad7SLin Ling buf->b_hdr->b_thawed = kmem_alloc(1, KM_SLEEP); 978*3f9d6ad7SLin Ling } 979*3f9d6ad7SLin Ling 9806b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 981*3f9d6ad7SLin Ling mutex_exit(hash_lock); 9826b4acc8bSahrens } 9836b4acc8bSahrens 9846b4acc8bSahrens void 9856b4acc8bSahrens arc_buf_freeze(arc_buf_t *buf) 9866b4acc8bSahrens { 987*3f9d6ad7SLin Ling kmutex_t *hash_lock; 988*3f9d6ad7SLin Ling 989cc60fd72Sahrens if (!(zfs_flags & ZFS_DEBUG_MODIFY)) 990cc60fd72Sahrens return; 991cc60fd72Sahrens 992*3f9d6ad7SLin Ling hash_lock = HDR_LOCK(buf->b_hdr); 993*3f9d6ad7SLin Ling mutex_enter(hash_lock); 994*3f9d6ad7SLin Ling 9956b4acc8bSahrens ASSERT(buf->b_hdr->b_freeze_cksum != NULL || 99644cb6abcSbmc buf->b_hdr->b_state == arc_anon); 997fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 998*3f9d6ad7SLin Ling mutex_exit(hash_lock); 9996b4acc8bSahrens } 10006b4acc8bSahrens 1001fa9e4066Sahrens static void 1002fa9e4066Sahrens add_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) 1003fa9e4066Sahrens { 1004fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 1005fa9e4066Sahrens 1006fa9e4066Sahrens if ((refcount_add(&ab->b_refcnt, tag) == 1) && 100744cb6abcSbmc (ab->b_state != arc_anon)) { 1008c0a81264Sek uint64_t delta = ab->b_size * ab->b_datacnt; 10090e8c6158Smaybee list_t *list = &ab->b_state->arcs_list[ab->b_type]; 10100e8c6158Smaybee uint64_t *size = &ab->b_state->arcs_lsize[ab->b_type]; 1011fa9e4066Sahrens 101244cb6abcSbmc ASSERT(!MUTEX_HELD(&ab->b_state->arcs_mtx)); 101344cb6abcSbmc mutex_enter(&ab->b_state->arcs_mtx); 1014fa9e4066Sahrens ASSERT(list_link_active(&ab->b_arc_node)); 10150e8c6158Smaybee list_remove(list, ab); 1016ea8dc4b6Seschrock if (GHOST_STATE(ab->b_state)) { 1017ea8dc4b6Seschrock ASSERT3U(ab->b_datacnt, ==, 0); 1018ea8dc4b6Seschrock ASSERT3P(ab->b_buf, ==, NULL); 1019ea8dc4b6Seschrock delta = ab->b_size; 1020ea8dc4b6Seschrock } 1021ea8dc4b6Seschrock ASSERT(delta > 0); 10220e8c6158Smaybee ASSERT3U(*size, >=, delta); 10230e8c6158Smaybee atomic_add_64(size, -delta); 102444cb6abcSbmc mutex_exit(&ab->b_state->arcs_mtx); 1025088f3894Sahrens /* remove the prefetch flag if we get a reference */ 102613506d1eSmaybee if (ab->b_flags & ARC_PREFETCH) 102713506d1eSmaybee ab->b_flags &= ~ARC_PREFETCH; 1028fa9e4066Sahrens } 1029fa9e4066Sahrens } 1030fa9e4066Sahrens 1031fa9e4066Sahrens static int 1032fa9e4066Sahrens remove_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) 1033fa9e4066Sahrens { 1034fa9e4066Sahrens int cnt; 103544cb6abcSbmc arc_state_t *state = ab->b_state; 1036fa9e4066Sahrens 103744cb6abcSbmc ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); 103844cb6abcSbmc ASSERT(!GHOST_STATE(state)); 1039fa9e4066Sahrens 1040fa9e4066Sahrens if (((cnt = refcount_remove(&ab->b_refcnt, tag)) == 0) && 104144cb6abcSbmc (state != arc_anon)) { 10420e8c6158Smaybee uint64_t *size = &state->arcs_lsize[ab->b_type]; 10430e8c6158Smaybee 104444cb6abcSbmc ASSERT(!MUTEX_HELD(&state->arcs_mtx)); 104544cb6abcSbmc mutex_enter(&state->arcs_mtx); 1046fa9e4066Sahrens ASSERT(!list_link_active(&ab->b_arc_node)); 10470e8c6158Smaybee list_insert_head(&state->arcs_list[ab->b_type], ab); 1048ea8dc4b6Seschrock ASSERT(ab->b_datacnt > 0); 10490e8c6158Smaybee atomic_add_64(size, ab->b_size * ab->b_datacnt); 105044cb6abcSbmc mutex_exit(&state->arcs_mtx); 1051fa9e4066Sahrens } 1052fa9e4066Sahrens return (cnt); 1053fa9e4066Sahrens } 1054fa9e4066Sahrens 1055fa9e4066Sahrens /* 1056fa9e4066Sahrens * Move the supplied buffer to the indicated state. The mutex 1057fa9e4066Sahrens * for the buffer must be held by the caller. 1058fa9e4066Sahrens */ 1059fa9e4066Sahrens static void 1060ea8dc4b6Seschrock arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock) 1061fa9e4066Sahrens { 1062ea8dc4b6Seschrock arc_state_t *old_state = ab->b_state; 1063c0a81264Sek int64_t refcnt = refcount_count(&ab->b_refcnt); 1064c0a81264Sek uint64_t from_delta, to_delta; 1065fa9e4066Sahrens 1066fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 1067ea8dc4b6Seschrock ASSERT(new_state != old_state); 1068ea8dc4b6Seschrock ASSERT(refcnt == 0 || ab->b_datacnt > 0); 1069ea8dc4b6Seschrock ASSERT(ab->b_datacnt == 0 || !GHOST_STATE(new_state)); 1070b24ab676SJeff Bonwick ASSERT(ab->b_datacnt <= 1 || old_state != arc_anon); 1071ea8dc4b6Seschrock 1072ea8dc4b6Seschrock from_delta = to_delta = ab->b_datacnt * ab->b_size; 1073fa9e4066Sahrens 1074fa9e4066Sahrens /* 1075fa9e4066Sahrens * If this buffer is evictable, transfer it from the 1076fa9e4066Sahrens * old state list to the new state list. 1077fa9e4066Sahrens */ 1078ea8dc4b6Seschrock if (refcnt == 0) { 107944cb6abcSbmc if (old_state != arc_anon) { 108044cb6abcSbmc int use_mutex = !MUTEX_HELD(&old_state->arcs_mtx); 10810e8c6158Smaybee uint64_t *size = &old_state->arcs_lsize[ab->b_type]; 1082ea8dc4b6Seschrock 1083ea8dc4b6Seschrock if (use_mutex) 108444cb6abcSbmc mutex_enter(&old_state->arcs_mtx); 1085fa9e4066Sahrens 1086fa9e4066Sahrens ASSERT(list_link_active(&ab->b_arc_node)); 10870e8c6158Smaybee list_remove(&old_state->arcs_list[ab->b_type], ab); 1088ea8dc4b6Seschrock 108913506d1eSmaybee /* 109013506d1eSmaybee * If prefetching out of the ghost cache, 1091*3f9d6ad7SLin Ling * we will have a non-zero datacnt. 109213506d1eSmaybee */ 109313506d1eSmaybee if (GHOST_STATE(old_state) && ab->b_datacnt == 0) { 109413506d1eSmaybee /* ghost elements have a ghost size */ 1095ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 1096ea8dc4b6Seschrock from_delta = ab->b_size; 1097ea8dc4b6Seschrock } 10980e8c6158Smaybee ASSERT3U(*size, >=, from_delta); 10990e8c6158Smaybee atomic_add_64(size, -from_delta); 1100ea8dc4b6Seschrock 1101ea8dc4b6Seschrock if (use_mutex) 110244cb6abcSbmc mutex_exit(&old_state->arcs_mtx); 1103fa9e4066Sahrens } 110444cb6abcSbmc if (new_state != arc_anon) { 110544cb6abcSbmc int use_mutex = !MUTEX_HELD(&new_state->arcs_mtx); 11060e8c6158Smaybee uint64_t *size = &new_state->arcs_lsize[ab->b_type]; 1107fa9e4066Sahrens 1108ea8dc4b6Seschrock if (use_mutex) 110944cb6abcSbmc mutex_enter(&new_state->arcs_mtx); 1110ea8dc4b6Seschrock 11110e8c6158Smaybee list_insert_head(&new_state->arcs_list[ab->b_type], ab); 1112ea8dc4b6Seschrock 1113ea8dc4b6Seschrock /* ghost elements have a ghost size */ 1114ea8dc4b6Seschrock if (GHOST_STATE(new_state)) { 1115ea8dc4b6Seschrock ASSERT(ab->b_datacnt == 0); 1116ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 1117ea8dc4b6Seschrock to_delta = ab->b_size; 1118ea8dc4b6Seschrock } 11190e8c6158Smaybee atomic_add_64(size, to_delta); 1120ea8dc4b6Seschrock 1121ea8dc4b6Seschrock if (use_mutex) 112244cb6abcSbmc mutex_exit(&new_state->arcs_mtx); 1123fa9e4066Sahrens } 1124fa9e4066Sahrens } 1125fa9e4066Sahrens 1126fa9e4066Sahrens ASSERT(!BUF_EMPTY(ab)); 1127*3f9d6ad7SLin Ling if (new_state == arc_anon && HDR_IN_HASH_TABLE(ab)) 1128fa9e4066Sahrens buf_hash_remove(ab); 1129fa9e4066Sahrens 1130ea8dc4b6Seschrock /* adjust state sizes */ 1131ea8dc4b6Seschrock if (to_delta) 113244cb6abcSbmc atomic_add_64(&new_state->arcs_size, to_delta); 1133ea8dc4b6Seschrock if (from_delta) { 113444cb6abcSbmc ASSERT3U(old_state->arcs_size, >=, from_delta); 113544cb6abcSbmc atomic_add_64(&old_state->arcs_size, -from_delta); 1136fa9e4066Sahrens } 1137fa9e4066Sahrens ab->b_state = new_state; 1138fa94a07fSbrendan 1139fa94a07fSbrendan /* adjust l2arc hdr stats */ 1140fa94a07fSbrendan if (new_state == arc_l2c_only) 1141fa94a07fSbrendan l2arc_hdr_stat_add(); 1142fa94a07fSbrendan else if (old_state == arc_l2c_only) 1143fa94a07fSbrendan l2arc_hdr_stat_remove(); 1144fa9e4066Sahrens } 1145fa9e4066Sahrens 11460e8c6158Smaybee void 11475a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(uint64_t space, arc_space_type_t type) 11480e8c6158Smaybee { 11495a98e54bSBrendan Gregg - Sun Microsystems ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); 11505a98e54bSBrendan Gregg - Sun Microsystems 11515a98e54bSBrendan Gregg - Sun Microsystems switch (type) { 11525a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_DATA: 11535a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, space); 11545a98e54bSBrendan Gregg - Sun Microsystems break; 11555a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_OTHER: 11565a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_other_size, space); 11575a98e54bSBrendan Gregg - Sun Microsystems break; 11585a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_HDRS: 11595a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_hdr_size, space); 11605a98e54bSBrendan Gregg - Sun Microsystems break; 11615a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_L2HDRS: 11625a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_hdr_size, space); 11635a98e54bSBrendan Gregg - Sun Microsystems break; 11645a98e54bSBrendan Gregg - Sun Microsystems } 11655a98e54bSBrendan Gregg - Sun Microsystems 11660e8c6158Smaybee atomic_add_64(&arc_meta_used, space); 11670e8c6158Smaybee atomic_add_64(&arc_size, space); 11680e8c6158Smaybee } 11690e8c6158Smaybee 11700e8c6158Smaybee void 11715a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(uint64_t space, arc_space_type_t type) 11720e8c6158Smaybee { 11735a98e54bSBrendan Gregg - Sun Microsystems ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); 11745a98e54bSBrendan Gregg - Sun Microsystems 11755a98e54bSBrendan Gregg - Sun Microsystems switch (type) { 11765a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_DATA: 11775a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, -space); 11785a98e54bSBrendan Gregg - Sun Microsystems break; 11795a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_OTHER: 11805a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_other_size, -space); 11815a98e54bSBrendan Gregg - Sun Microsystems break; 11825a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_HDRS: 11835a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_hdr_size, -space); 11845a98e54bSBrendan Gregg - Sun Microsystems break; 11855a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_L2HDRS: 11865a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_hdr_size, -space); 11875a98e54bSBrendan Gregg - Sun Microsystems break; 11885a98e54bSBrendan Gregg - Sun Microsystems } 11895a98e54bSBrendan Gregg - Sun Microsystems 11900e8c6158Smaybee ASSERT(arc_meta_used >= space); 11910e8c6158Smaybee if (arc_meta_max < arc_meta_used) 11920e8c6158Smaybee arc_meta_max = arc_meta_used; 11930e8c6158Smaybee atomic_add_64(&arc_meta_used, -space); 11940e8c6158Smaybee ASSERT(arc_size >= space); 11950e8c6158Smaybee atomic_add_64(&arc_size, -space); 11960e8c6158Smaybee } 11970e8c6158Smaybee 11980e8c6158Smaybee void * 11990e8c6158Smaybee arc_data_buf_alloc(uint64_t size) 12000e8c6158Smaybee { 12010e8c6158Smaybee if (arc_evict_needed(ARC_BUFC_DATA)) 12020e8c6158Smaybee cv_signal(&arc_reclaim_thr_cv); 12030e8c6158Smaybee atomic_add_64(&arc_size, size); 12040e8c6158Smaybee return (zio_data_buf_alloc(size)); 12050e8c6158Smaybee } 12060e8c6158Smaybee 12070e8c6158Smaybee void 12080e8c6158Smaybee arc_data_buf_free(void *buf, uint64_t size) 12090e8c6158Smaybee { 12100e8c6158Smaybee zio_data_buf_free(buf, size); 12110e8c6158Smaybee ASSERT(arc_size >= size); 12120e8c6158Smaybee atomic_add_64(&arc_size, -size); 12130e8c6158Smaybee } 12140e8c6158Smaybee 1215fa9e4066Sahrens arc_buf_t * 1216ad23a2dbSjohansen arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type) 1217fa9e4066Sahrens { 1218fa9e4066Sahrens arc_buf_hdr_t *hdr; 1219fa9e4066Sahrens arc_buf_t *buf; 1220fa9e4066Sahrens 1221fa9e4066Sahrens ASSERT3U(size, >, 0); 12221ab7f2deSmaybee hdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 1223fa9e4066Sahrens ASSERT(BUF_EMPTY(hdr)); 1224fa9e4066Sahrens hdr->b_size = size; 1225ad23a2dbSjohansen hdr->b_type = type; 1226ac05c741SMark Maybee hdr->b_spa = spa_guid(spa); 122744cb6abcSbmc hdr->b_state = arc_anon; 1228fa9e4066Sahrens hdr->b_arc_access = 0; 12291ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 1230fa9e4066Sahrens buf->b_hdr = hdr; 123144eda4d7Smaybee buf->b_data = NULL; 1232ea8dc4b6Seschrock buf->b_efunc = NULL; 1233ea8dc4b6Seschrock buf->b_private = NULL; 1234fa9e4066Sahrens buf->b_next = NULL; 1235fa9e4066Sahrens hdr->b_buf = buf; 123644eda4d7Smaybee arc_get_data_buf(buf); 1237ea8dc4b6Seschrock hdr->b_datacnt = 1; 1238fa9e4066Sahrens hdr->b_flags = 0; 1239fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt)); 1240fa9e4066Sahrens (void) refcount_add(&hdr->b_refcnt, tag); 1241fa9e4066Sahrens 1242fa9e4066Sahrens return (buf); 1243fa9e4066Sahrens } 1244fa9e4066Sahrens 12452fdbea25SAleksandr Guzovskiy static char *arc_onloan_tag = "onloan"; 12462fdbea25SAleksandr Guzovskiy 12472fdbea25SAleksandr Guzovskiy /* 12482fdbea25SAleksandr Guzovskiy * Loan out an anonymous arc buffer. Loaned buffers are not counted as in 12492fdbea25SAleksandr Guzovskiy * flight data by arc_tempreserve_space() until they are "returned". Loaned 12502fdbea25SAleksandr Guzovskiy * buffers must be returned to the arc before they can be used by the DMU or 12512fdbea25SAleksandr Guzovskiy * freed. 12522fdbea25SAleksandr Guzovskiy */ 12532fdbea25SAleksandr Guzovskiy arc_buf_t * 12542fdbea25SAleksandr Guzovskiy arc_loan_buf(spa_t *spa, int size) 12552fdbea25SAleksandr Guzovskiy { 12562fdbea25SAleksandr Guzovskiy arc_buf_t *buf; 12572fdbea25SAleksandr Guzovskiy 12582fdbea25SAleksandr Guzovskiy buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA); 12592fdbea25SAleksandr Guzovskiy 12602fdbea25SAleksandr Guzovskiy atomic_add_64(&arc_loaned_bytes, size); 12612fdbea25SAleksandr Guzovskiy return (buf); 12622fdbea25SAleksandr Guzovskiy } 12632fdbea25SAleksandr Guzovskiy 12642fdbea25SAleksandr Guzovskiy /* 12652fdbea25SAleksandr Guzovskiy * Return a loaned arc buffer to the arc. 12662fdbea25SAleksandr Guzovskiy */ 12672fdbea25SAleksandr Guzovskiy void 12682fdbea25SAleksandr Guzovskiy arc_return_buf(arc_buf_t *buf, void *tag) 12692fdbea25SAleksandr Guzovskiy { 12702fdbea25SAleksandr Guzovskiy arc_buf_hdr_t *hdr = buf->b_hdr; 12712fdbea25SAleksandr Guzovskiy 12722fdbea25SAleksandr Guzovskiy ASSERT(buf->b_data != NULL); 1273c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_add(&hdr->b_refcnt, tag); 1274c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_remove(&hdr->b_refcnt, arc_onloan_tag); 12752fdbea25SAleksandr Guzovskiy 12762fdbea25SAleksandr Guzovskiy atomic_add_64(&arc_loaned_bytes, -hdr->b_size); 12772fdbea25SAleksandr Guzovskiy } 12782fdbea25SAleksandr Guzovskiy 1279c242f9a0Schunli zhang - Sun Microsystems - Irvine United States /* Detach an arc_buf from a dbuf (tag) */ 1280c242f9a0Schunli zhang - Sun Microsystems - Irvine United States void 1281c242f9a0Schunli zhang - Sun Microsystems - Irvine United States arc_loan_inuse_buf(arc_buf_t *buf, void *tag) 1282c242f9a0Schunli zhang - Sun Microsystems - Irvine United States { 1283c242f9a0Schunli zhang - Sun Microsystems - Irvine United States arc_buf_hdr_t *hdr; 1284c242f9a0Schunli zhang - Sun Microsystems - Irvine United States 1285c242f9a0Schunli zhang - Sun Microsystems - Irvine United States ASSERT(buf->b_data != NULL); 1286c242f9a0Schunli zhang - Sun Microsystems - Irvine United States hdr = buf->b_hdr; 1287c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_add(&hdr->b_refcnt, arc_onloan_tag); 1288c242f9a0Schunli zhang - Sun Microsystems - Irvine United States (void) refcount_remove(&hdr->b_refcnt, tag); 1289c242f9a0Schunli zhang - Sun Microsystems - Irvine United States buf->b_efunc = NULL; 1290c242f9a0Schunli zhang - Sun Microsystems - Irvine United States buf->b_private = NULL; 1291c242f9a0Schunli zhang - Sun Microsystems - Irvine United States 1292c242f9a0Schunli zhang - Sun Microsystems - Irvine United States atomic_add_64(&arc_loaned_bytes, hdr->b_size); 1293c242f9a0Schunli zhang - Sun Microsystems - Irvine United States } 1294c242f9a0Schunli zhang - Sun Microsystems - Irvine United States 129544eda4d7Smaybee static arc_buf_t * 129644eda4d7Smaybee arc_buf_clone(arc_buf_t *from) 1297ea8dc4b6Seschrock { 129844eda4d7Smaybee arc_buf_t *buf; 129944eda4d7Smaybee arc_buf_hdr_t *hdr = from->b_hdr; 130044eda4d7Smaybee uint64_t size = hdr->b_size; 1301ea8dc4b6Seschrock 1302b24ab676SJeff Bonwick ASSERT(hdr->b_state != arc_anon); 1303b24ab676SJeff Bonwick 13041ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 130544eda4d7Smaybee buf->b_hdr = hdr; 130644eda4d7Smaybee buf->b_data = NULL; 130744eda4d7Smaybee buf->b_efunc = NULL; 130844eda4d7Smaybee buf->b_private = NULL; 130944eda4d7Smaybee buf->b_next = hdr->b_buf; 131044eda4d7Smaybee hdr->b_buf = buf; 131144eda4d7Smaybee arc_get_data_buf(buf); 131244eda4d7Smaybee bcopy(from->b_data, buf->b_data, size); 131344eda4d7Smaybee hdr->b_datacnt += 1; 131444eda4d7Smaybee return (buf); 1315ea8dc4b6Seschrock } 1316ea8dc4b6Seschrock 1317ea8dc4b6Seschrock void 1318ea8dc4b6Seschrock arc_buf_add_ref(arc_buf_t *buf, void* tag) 1319ea8dc4b6Seschrock { 132040d7d650Smaybee arc_buf_hdr_t *hdr; 1321ea8dc4b6Seschrock kmutex_t *hash_lock; 1322ea8dc4b6Seschrock 13239b23f181Smaybee /* 13246f83844dSMark Maybee * Check to see if this buffer is evicted. Callers 13256f83844dSMark Maybee * must verify b_data != NULL to know if the add_ref 13266f83844dSMark Maybee * was successful. 13279b23f181Smaybee */ 1328*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 13296f83844dSMark Maybee if (buf->b_data == NULL) { 1330*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 13319b23f181Smaybee return; 133240d7d650Smaybee } 1333*3f9d6ad7SLin Ling hash_lock = HDR_LOCK(buf->b_hdr); 13349b23f181Smaybee mutex_enter(hash_lock); 1335*3f9d6ad7SLin Ling hdr = buf->b_hdr; 1336*3f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 1337*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1338ea8dc4b6Seschrock 133944cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 1340ea8dc4b6Seschrock add_reference(hdr, hash_lock, tag); 13415a98e54bSBrendan Gregg - Sun Microsystems DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); 134244eda4d7Smaybee arc_access(hdr, hash_lock); 134344eda4d7Smaybee mutex_exit(hash_lock); 134444cb6abcSbmc ARCSTAT_BUMP(arcstat_hits); 134544cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 134644cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 134744cb6abcSbmc data, metadata, hits); 1348ea8dc4b6Seschrock } 1349ea8dc4b6Seschrock 1350fa94a07fSbrendan /* 1351fa94a07fSbrendan * Free the arc data buffer. If it is an l2arc write in progress, 1352fa94a07fSbrendan * the buffer is placed on l2arc_free_on_write to be freed later. 1353fa94a07fSbrendan */ 1354fa94a07fSbrendan static void 1355fa94a07fSbrendan arc_buf_data_free(arc_buf_hdr_t *hdr, void (*free_func)(void *, size_t), 1356fa94a07fSbrendan void *data, size_t size) 1357fa94a07fSbrendan { 1358fa94a07fSbrendan if (HDR_L2_WRITING(hdr)) { 1359fa94a07fSbrendan l2arc_data_free_t *df; 1360fa94a07fSbrendan df = kmem_alloc(sizeof (l2arc_data_free_t), KM_SLEEP); 1361fa94a07fSbrendan df->l2df_data = data; 1362fa94a07fSbrendan df->l2df_size = size; 1363fa94a07fSbrendan df->l2df_func = free_func; 1364fa94a07fSbrendan mutex_enter(&l2arc_free_on_write_mtx); 1365fa94a07fSbrendan list_insert_head(l2arc_free_on_write, df); 1366fa94a07fSbrendan mutex_exit(&l2arc_free_on_write_mtx); 1367fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_free_on_write); 1368fa94a07fSbrendan } else { 1369fa94a07fSbrendan free_func(data, size); 1370fa94a07fSbrendan } 1371fa94a07fSbrendan } 1372fa94a07fSbrendan 1373ea8dc4b6Seschrock static void 137444eda4d7Smaybee arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all) 1375ea8dc4b6Seschrock { 1376ea8dc4b6Seschrock arc_buf_t **bufp; 1377ea8dc4b6Seschrock 1378ea8dc4b6Seschrock /* free up data associated with the buf */ 1379ea8dc4b6Seschrock if (buf->b_data) { 1380ea8dc4b6Seschrock arc_state_t *state = buf->b_hdr->b_state; 1381ea8dc4b6Seschrock uint64_t size = buf->b_hdr->b_size; 1382ad23a2dbSjohansen arc_buf_contents_t type = buf->b_hdr->b_type; 1383ea8dc4b6Seschrock 13846b4acc8bSahrens arc_cksum_verify(buf); 1385b24ab676SJeff Bonwick 138644eda4d7Smaybee if (!recycle) { 1387ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 1388fa94a07fSbrendan arc_buf_data_free(buf->b_hdr, zio_buf_free, 1389fa94a07fSbrendan buf->b_data, size); 13905a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(size, ARC_SPACE_DATA); 1391ad23a2dbSjohansen } else { 1392ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 1393fa94a07fSbrendan arc_buf_data_free(buf->b_hdr, 1394fa94a07fSbrendan zio_data_buf_free, buf->b_data, size); 13955a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, -size); 13960e8c6158Smaybee atomic_add_64(&arc_size, -size); 1397ad23a2dbSjohansen } 139844eda4d7Smaybee } 1399ea8dc4b6Seschrock if (list_link_active(&buf->b_hdr->b_arc_node)) { 14000e8c6158Smaybee uint64_t *cnt = &state->arcs_lsize[type]; 14010e8c6158Smaybee 1402ea8dc4b6Seschrock ASSERT(refcount_is_zero(&buf->b_hdr->b_refcnt)); 140344cb6abcSbmc ASSERT(state != arc_anon); 14040e8c6158Smaybee 14050e8c6158Smaybee ASSERT3U(*cnt, >=, size); 14060e8c6158Smaybee atomic_add_64(cnt, -size); 1407ea8dc4b6Seschrock } 140844cb6abcSbmc ASSERT3U(state->arcs_size, >=, size); 140944cb6abcSbmc atomic_add_64(&state->arcs_size, -size); 1410ea8dc4b6Seschrock buf->b_data = NULL; 1411ea8dc4b6Seschrock ASSERT(buf->b_hdr->b_datacnt > 0); 1412ea8dc4b6Seschrock buf->b_hdr->b_datacnt -= 1; 1413ea8dc4b6Seschrock } 1414ea8dc4b6Seschrock 1415ea8dc4b6Seschrock /* only remove the buf if requested */ 1416ea8dc4b6Seschrock if (!all) 1417ea8dc4b6Seschrock return; 1418ea8dc4b6Seschrock 1419ea8dc4b6Seschrock /* remove the buf from the hdr list */ 1420ea8dc4b6Seschrock for (bufp = &buf->b_hdr->b_buf; *bufp != buf; bufp = &(*bufp)->b_next) 1421ea8dc4b6Seschrock continue; 1422ea8dc4b6Seschrock *bufp = buf->b_next; 1423*3f9d6ad7SLin Ling buf->b_next = NULL; 1424ea8dc4b6Seschrock 1425ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 1426ea8dc4b6Seschrock 1427ea8dc4b6Seschrock /* clean up the buf */ 1428ea8dc4b6Seschrock buf->b_hdr = NULL; 1429ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 1430ea8dc4b6Seschrock } 1431ea8dc4b6Seschrock 1432fa9e4066Sahrens static void 1433ea8dc4b6Seschrock arc_hdr_destroy(arc_buf_hdr_t *hdr) 1434fa9e4066Sahrens { 1435fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt)); 143644cb6abcSbmc ASSERT3P(hdr->b_state, ==, arc_anon); 1437ea8dc4b6Seschrock ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 1438b24ab676SJeff Bonwick l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr; 1439fa9e4066Sahrens 1440b24ab676SJeff Bonwick if (l2hdr != NULL) { 1441b24ab676SJeff Bonwick boolean_t buflist_held = MUTEX_HELD(&l2arc_buflist_mtx); 1442b24ab676SJeff Bonwick /* 1443b24ab676SJeff Bonwick * To prevent arc_free() and l2arc_evict() from 1444b24ab676SJeff Bonwick * attempting to free the same buffer at the same time, 1445b24ab676SJeff Bonwick * a FREE_IN_PROGRESS flag is given to arc_free() to 1446b24ab676SJeff Bonwick * give it priority. l2arc_evict() can't destroy this 1447b24ab676SJeff Bonwick * header while we are waiting on l2arc_buflist_mtx. 1448b24ab676SJeff Bonwick * 1449b24ab676SJeff Bonwick * The hdr may be removed from l2ad_buflist before we 1450b24ab676SJeff Bonwick * grab l2arc_buflist_mtx, so b_l2hdr is rechecked. 1451b24ab676SJeff Bonwick */ 1452b24ab676SJeff Bonwick if (!buflist_held) { 1453fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 1454b24ab676SJeff Bonwick l2hdr = hdr->b_l2hdr; 1455fa94a07fSbrendan } 1456b24ab676SJeff Bonwick 1457b24ab676SJeff Bonwick if (l2hdr != NULL) { 1458b24ab676SJeff Bonwick list_remove(l2hdr->b_dev->l2ad_buflist, hdr); 1459b24ab676SJeff Bonwick ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size); 1460b24ab676SJeff Bonwick kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); 1461b24ab676SJeff Bonwick if (hdr->b_state == arc_l2c_only) 1462b24ab676SJeff Bonwick l2arc_hdr_stat_remove(); 1463b24ab676SJeff Bonwick hdr->b_l2hdr = NULL; 1464b24ab676SJeff Bonwick } 1465b24ab676SJeff Bonwick 1466b24ab676SJeff Bonwick if (!buflist_held) 1467b24ab676SJeff Bonwick mutex_exit(&l2arc_buflist_mtx); 1468fa94a07fSbrendan } 1469fa94a07fSbrendan 1470fa9e4066Sahrens if (!BUF_EMPTY(hdr)) { 1471ea8dc4b6Seschrock ASSERT(!HDR_IN_HASH_TABLE(hdr)); 1472*3f9d6ad7SLin Ling buf_discard_identity(hdr); 1473fa9e4066Sahrens } 1474ea8dc4b6Seschrock while (hdr->b_buf) { 1475fa9e4066Sahrens arc_buf_t *buf = hdr->b_buf; 1476fa9e4066Sahrens 1477ea8dc4b6Seschrock if (buf->b_efunc) { 1478ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1479*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 1480ea8dc4b6Seschrock ASSERT(buf->b_hdr != NULL); 148144eda4d7Smaybee arc_buf_destroy(hdr->b_buf, FALSE, FALSE); 1482ea8dc4b6Seschrock hdr->b_buf = buf->b_next; 148340d7d650Smaybee buf->b_hdr = &arc_eviction_hdr; 1484ea8dc4b6Seschrock buf->b_next = arc_eviction_list; 1485ea8dc4b6Seschrock arc_eviction_list = buf; 1486*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1487ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1488ea8dc4b6Seschrock } else { 148944eda4d7Smaybee arc_buf_destroy(hdr->b_buf, FALSE, TRUE); 1490ea8dc4b6Seschrock } 1491fa9e4066Sahrens } 14926b4acc8bSahrens if (hdr->b_freeze_cksum != NULL) { 14936b4acc8bSahrens kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 14946b4acc8bSahrens hdr->b_freeze_cksum = NULL; 14956b4acc8bSahrens } 1496*3f9d6ad7SLin Ling if (hdr->b_thawed) { 1497*3f9d6ad7SLin Ling kmem_free(hdr->b_thawed, 1); 1498*3f9d6ad7SLin Ling hdr->b_thawed = NULL; 1499*3f9d6ad7SLin Ling } 1500ea8dc4b6Seschrock 1501fa9e4066Sahrens ASSERT(!list_link_active(&hdr->b_arc_node)); 1502fa9e4066Sahrens ASSERT3P(hdr->b_hash_next, ==, NULL); 1503fa9e4066Sahrens ASSERT3P(hdr->b_acb, ==, NULL); 1504fa9e4066Sahrens kmem_cache_free(hdr_cache, hdr); 1505fa9e4066Sahrens } 1506fa9e4066Sahrens 1507fa9e4066Sahrens void 1508fa9e4066Sahrens arc_buf_free(arc_buf_t *buf, void *tag) 1509fa9e4066Sahrens { 1510fa9e4066Sahrens arc_buf_hdr_t *hdr = buf->b_hdr; 151144cb6abcSbmc int hashed = hdr->b_state != arc_anon; 1512fa9e4066Sahrens 1513ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 1514ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 1515ea8dc4b6Seschrock 1516ea8dc4b6Seschrock if (hashed) { 1517ea8dc4b6Seschrock kmutex_t *hash_lock = HDR_LOCK(hdr); 1518ea8dc4b6Seschrock 1519ea8dc4b6Seschrock mutex_enter(hash_lock); 1520*3f9d6ad7SLin Ling hdr = buf->b_hdr; 1521*3f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 1522*3f9d6ad7SLin Ling 1523ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 1524b24ab676SJeff Bonwick if (hdr->b_datacnt > 1) { 152544eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1526b24ab676SJeff Bonwick } else { 1527b24ab676SJeff Bonwick ASSERT(buf == hdr->b_buf); 1528b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 1529ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 1530b24ab676SJeff Bonwick } 1531fa9e4066Sahrens mutex_exit(hash_lock); 1532ea8dc4b6Seschrock } else if (HDR_IO_IN_PROGRESS(hdr)) { 1533ea8dc4b6Seschrock int destroy_hdr; 1534ea8dc4b6Seschrock /* 1535ea8dc4b6Seschrock * We are in the middle of an async write. Don't destroy 1536ea8dc4b6Seschrock * this buffer unless the write completes before we finish 1537ea8dc4b6Seschrock * decrementing the reference count. 1538ea8dc4b6Seschrock */ 1539ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1540ea8dc4b6Seschrock (void) remove_reference(hdr, NULL, tag); 1541ea8dc4b6Seschrock ASSERT(refcount_is_zero(&hdr->b_refcnt)); 1542ea8dc4b6Seschrock destroy_hdr = !HDR_IO_IN_PROGRESS(hdr); 1543ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1544ea8dc4b6Seschrock if (destroy_hdr) 1545ea8dc4b6Seschrock arc_hdr_destroy(hdr); 1546ea8dc4b6Seschrock } else { 1547*3f9d6ad7SLin Ling if (remove_reference(hdr, NULL, tag) > 0) 154844eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1549*3f9d6ad7SLin Ling else 1550ea8dc4b6Seschrock arc_hdr_destroy(hdr); 1551fa9e4066Sahrens } 1552ea8dc4b6Seschrock } 1553fa9e4066Sahrens 1554ea8dc4b6Seschrock int 1555ea8dc4b6Seschrock arc_buf_remove_ref(arc_buf_t *buf, void* tag) 1556ea8dc4b6Seschrock { 1557ea8dc4b6Seschrock arc_buf_hdr_t *hdr = buf->b_hdr; 1558ea8dc4b6Seschrock kmutex_t *hash_lock = HDR_LOCK(hdr); 1559ea8dc4b6Seschrock int no_callback = (buf->b_efunc == NULL); 1560fa9e4066Sahrens 156144cb6abcSbmc if (hdr->b_state == arc_anon) { 1562b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 1563ea8dc4b6Seschrock arc_buf_free(buf, tag); 1564ea8dc4b6Seschrock return (no_callback); 1565ea8dc4b6Seschrock } 1566ea8dc4b6Seschrock 1567ea8dc4b6Seschrock mutex_enter(hash_lock); 1568*3f9d6ad7SLin Ling hdr = buf->b_hdr; 1569*3f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 157044cb6abcSbmc ASSERT(hdr->b_state != arc_anon); 1571ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 1572ea8dc4b6Seschrock 1573ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 1574ea8dc4b6Seschrock if (hdr->b_datacnt > 1) { 1575ea8dc4b6Seschrock if (no_callback) 157644eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1577ea8dc4b6Seschrock } else if (no_callback) { 1578ea8dc4b6Seschrock ASSERT(hdr->b_buf == buf && buf->b_next == NULL); 1579b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 1580ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 1581ea8dc4b6Seschrock } 1582ea8dc4b6Seschrock ASSERT(no_callback || hdr->b_datacnt > 1 || 1583ea8dc4b6Seschrock refcount_is_zero(&hdr->b_refcnt)); 1584ea8dc4b6Seschrock mutex_exit(hash_lock); 1585ea8dc4b6Seschrock return (no_callback); 1586fa9e4066Sahrens } 1587fa9e4066Sahrens 1588fa9e4066Sahrens int 1589fa9e4066Sahrens arc_buf_size(arc_buf_t *buf) 1590fa9e4066Sahrens { 1591fa9e4066Sahrens return (buf->b_hdr->b_size); 1592fa9e4066Sahrens } 1593fa9e4066Sahrens 1594fa9e4066Sahrens /* 1595fa9e4066Sahrens * Evict buffers from list until we've removed the specified number of 1596fa9e4066Sahrens * bytes. Move the removed buffers to the appropriate evict state. 159744eda4d7Smaybee * If the recycle flag is set, then attempt to "recycle" a buffer: 159844eda4d7Smaybee * - look for a buffer to evict that is `bytes' long. 159944eda4d7Smaybee * - return the data block from this buffer rather than freeing it. 160044eda4d7Smaybee * This flag is used by callers that are trying to make space for a 160144eda4d7Smaybee * new buffer in a full arc cache. 1602874395d5Smaybee * 1603874395d5Smaybee * This function makes a "best effort". It skips over any buffers 1604874395d5Smaybee * it can't get a hash_lock on, and so may not catch all candidates. 1605874395d5Smaybee * It may also return without evicting as much space as requested. 1606fa9e4066Sahrens */ 160744eda4d7Smaybee static void * 1608ac05c741SMark Maybee arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle, 1609ad23a2dbSjohansen arc_buf_contents_t type) 1610fa9e4066Sahrens { 1611fa9e4066Sahrens arc_state_t *evicted_state; 161244eda4d7Smaybee uint64_t bytes_evicted = 0, skipped = 0, missed = 0; 16133fa51506Smaybee arc_buf_hdr_t *ab, *ab_prev = NULL; 16140e8c6158Smaybee list_t *list = &state->arcs_list[type]; 1615fa9e4066Sahrens kmutex_t *hash_lock; 161644eda4d7Smaybee boolean_t have_lock; 16173fa51506Smaybee void *stolen = NULL; 1618fa9e4066Sahrens 161944cb6abcSbmc ASSERT(state == arc_mru || state == arc_mfu); 1620fa9e4066Sahrens 162144cb6abcSbmc evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; 1622fa9e4066Sahrens 162344cb6abcSbmc mutex_enter(&state->arcs_mtx); 162444cb6abcSbmc mutex_enter(&evicted_state->arcs_mtx); 1625fa9e4066Sahrens 16260e8c6158Smaybee for (ab = list_tail(list); ab; ab = ab_prev) { 16270e8c6158Smaybee ab_prev = list_prev(list, ab); 162813506d1eSmaybee /* prefetch buffers have a minimum lifespan */ 162944eda4d7Smaybee if (HDR_IO_IN_PROGRESS(ab) || 1630874395d5Smaybee (spa && ab->b_spa != spa) || 163144eda4d7Smaybee (ab->b_flags & (ARC_PREFETCH|ARC_INDIRECT) && 1632d3d50737SRafael Vanoni ddi_get_lbolt() - ab->b_arc_access < 1633d3d50737SRafael Vanoni arc_min_prefetch_lifespan)) { 163413506d1eSmaybee skipped++; 163513506d1eSmaybee continue; 163613506d1eSmaybee } 16373fa51506Smaybee /* "lookahead" for better eviction candidate */ 16383fa51506Smaybee if (recycle && ab->b_size != bytes && 16393fa51506Smaybee ab_prev && ab_prev->b_size == bytes) 164044eda4d7Smaybee continue; 1641fa9e4066Sahrens hash_lock = HDR_LOCK(ab); 164244eda4d7Smaybee have_lock = MUTEX_HELD(hash_lock); 164344eda4d7Smaybee if (have_lock || mutex_tryenter(hash_lock)) { 1644fa9e4066Sahrens ASSERT3U(refcount_count(&ab->b_refcnt), ==, 0); 1645ea8dc4b6Seschrock ASSERT(ab->b_datacnt > 0); 1646ea8dc4b6Seschrock while (ab->b_buf) { 1647ea8dc4b6Seschrock arc_buf_t *buf = ab->b_buf; 1648*3f9d6ad7SLin Ling if (!mutex_tryenter(&buf->b_evict_lock)) { 16496f83844dSMark Maybee missed += 1; 16506f83844dSMark Maybee break; 16516f83844dSMark Maybee } 165244eda4d7Smaybee if (buf->b_data) { 1653ea8dc4b6Seschrock bytes_evicted += ab->b_size; 1654ad23a2dbSjohansen if (recycle && ab->b_type == type && 1655fa94a07fSbrendan ab->b_size == bytes && 1656fa94a07fSbrendan !HDR_L2_WRITING(ab)) { 16573fa51506Smaybee stolen = buf->b_data; 16583fa51506Smaybee recycle = FALSE; 16593fa51506Smaybee } 166044eda4d7Smaybee } 1661ea8dc4b6Seschrock if (buf->b_efunc) { 1662ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 16633fa51506Smaybee arc_buf_destroy(buf, 16643fa51506Smaybee buf->b_data == stolen, FALSE); 1665ea8dc4b6Seschrock ab->b_buf = buf->b_next; 166640d7d650Smaybee buf->b_hdr = &arc_eviction_hdr; 1667ea8dc4b6Seschrock buf->b_next = arc_eviction_list; 1668ea8dc4b6Seschrock arc_eviction_list = buf; 1669ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1670*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1671ea8dc4b6Seschrock } else { 1672*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 16733fa51506Smaybee arc_buf_destroy(buf, 16743fa51506Smaybee buf->b_data == stolen, TRUE); 1675ea8dc4b6Seschrock } 1676ea8dc4b6Seschrock } 16775ea40c06SBrendan Gregg - Sun Microsystems 16785ea40c06SBrendan Gregg - Sun Microsystems if (ab->b_l2hdr) { 16795ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_evict_l2_cached, 16805ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16815ea40c06SBrendan Gregg - Sun Microsystems } else { 16825ea40c06SBrendan Gregg - Sun Microsystems if (l2arc_write_eligible(ab->b_spa, ab)) { 16835ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_evict_l2_eligible, 16845ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16855ea40c06SBrendan Gregg - Sun Microsystems } else { 16865ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR( 16875ea40c06SBrendan Gregg - Sun Microsystems arcstat_evict_l2_ineligible, 16885ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16895ea40c06SBrendan Gregg - Sun Microsystems } 16905ea40c06SBrendan Gregg - Sun Microsystems } 16915ea40c06SBrendan Gregg - Sun Microsystems 16926f83844dSMark Maybee if (ab->b_datacnt == 0) { 16936f83844dSMark Maybee arc_change_state(evicted_state, ab, hash_lock); 16946f83844dSMark Maybee ASSERT(HDR_IN_HASH_TABLE(ab)); 16956f83844dSMark Maybee ab->b_flags |= ARC_IN_HASH_TABLE; 16966f83844dSMark Maybee ab->b_flags &= ~ARC_BUF_AVAILABLE; 16976f83844dSMark Maybee DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab); 16986f83844dSMark Maybee } 169944eda4d7Smaybee if (!have_lock) 170044eda4d7Smaybee mutex_exit(hash_lock); 1701ea8dc4b6Seschrock if (bytes >= 0 && bytes_evicted >= bytes) 1702fa9e4066Sahrens break; 1703fa9e4066Sahrens } else { 170444eda4d7Smaybee missed += 1; 1705fa9e4066Sahrens } 1706fa9e4066Sahrens } 170744cb6abcSbmc 170844cb6abcSbmc mutex_exit(&evicted_state->arcs_mtx); 170944cb6abcSbmc mutex_exit(&state->arcs_mtx); 1710fa9e4066Sahrens 1711fa9e4066Sahrens if (bytes_evicted < bytes) 1712fa9e4066Sahrens dprintf("only evicted %lld bytes from %x", 1713fa9e4066Sahrens (longlong_t)bytes_evicted, state); 1714fa9e4066Sahrens 171544eda4d7Smaybee if (skipped) 171644cb6abcSbmc ARCSTAT_INCR(arcstat_evict_skip, skipped); 171744cb6abcSbmc 171844eda4d7Smaybee if (missed) 171944cb6abcSbmc ARCSTAT_INCR(arcstat_mutex_miss, missed); 1720f4d2e9e6Smaybee 1721f4d2e9e6Smaybee /* 1722f4d2e9e6Smaybee * We have just evicted some date into the ghost state, make 1723f4d2e9e6Smaybee * sure we also adjust the ghost state size if necessary. 1724f4d2e9e6Smaybee */ 1725f4d2e9e6Smaybee if (arc_no_grow && 1726f4d2e9e6Smaybee arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size > arc_c) { 1727f4d2e9e6Smaybee int64_t mru_over = arc_anon->arcs_size + arc_mru->arcs_size + 1728f4d2e9e6Smaybee arc_mru_ghost->arcs_size - arc_c; 1729f4d2e9e6Smaybee 1730f4d2e9e6Smaybee if (mru_over > 0 && arc_mru_ghost->arcs_lsize[type] > 0) { 1731f4d2e9e6Smaybee int64_t todelete = 1732f4d2e9e6Smaybee MIN(arc_mru_ghost->arcs_lsize[type], mru_over); 1733874395d5Smaybee arc_evict_ghost(arc_mru_ghost, NULL, todelete); 1734f4d2e9e6Smaybee } else if (arc_mfu_ghost->arcs_lsize[type] > 0) { 1735f4d2e9e6Smaybee int64_t todelete = MIN(arc_mfu_ghost->arcs_lsize[type], 1736f4d2e9e6Smaybee arc_mru_ghost->arcs_size + 1737f4d2e9e6Smaybee arc_mfu_ghost->arcs_size - arc_c); 1738874395d5Smaybee arc_evict_ghost(arc_mfu_ghost, NULL, todelete); 1739f4d2e9e6Smaybee } 1740f4d2e9e6Smaybee } 174144cb6abcSbmc 17423fa51506Smaybee return (stolen); 1743fa9e4066Sahrens } 1744fa9e4066Sahrens 1745fa9e4066Sahrens /* 1746fa9e4066Sahrens * Remove buffers from list until we've removed the specified number of 1747fa9e4066Sahrens * bytes. Destroy the buffers that are removed. 1748fa9e4066Sahrens */ 1749fa9e4066Sahrens static void 1750ac05c741SMark Maybee arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes) 1751fa9e4066Sahrens { 1752fa9e4066Sahrens arc_buf_hdr_t *ab, *ab_prev; 17530e8c6158Smaybee list_t *list = &state->arcs_list[ARC_BUFC_DATA]; 1754fa9e4066Sahrens kmutex_t *hash_lock; 1755ea8dc4b6Seschrock uint64_t bytes_deleted = 0; 1756c0a81264Sek uint64_t bufs_skipped = 0; 1757fa9e4066Sahrens 1758ea8dc4b6Seschrock ASSERT(GHOST_STATE(state)); 1759fa9e4066Sahrens top: 176044cb6abcSbmc mutex_enter(&state->arcs_mtx); 17610e8c6158Smaybee for (ab = list_tail(list); ab; ab = ab_prev) { 17620e8c6158Smaybee ab_prev = list_prev(list, ab); 1763874395d5Smaybee if (spa && ab->b_spa != spa) 1764874395d5Smaybee continue; 1765fa9e4066Sahrens hash_lock = HDR_LOCK(ab); 17667e453561SWilliam Gorrell /* caller may be trying to modify this buffer, skip it */ 17677e453561SWilliam Gorrell if (MUTEX_HELD(hash_lock)) 17687e453561SWilliam Gorrell continue; 17697e453561SWilliam Gorrell if (mutex_tryenter(hash_lock)) { 177013506d1eSmaybee ASSERT(!HDR_IO_IN_PROGRESS(ab)); 1771ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 177244cb6abcSbmc ARCSTAT_BUMP(arcstat_deleted); 1773fa9e4066Sahrens bytes_deleted += ab->b_size; 1774fa94a07fSbrendan 1775fa94a07fSbrendan if (ab->b_l2hdr != NULL) { 1776fa94a07fSbrendan /* 1777fa94a07fSbrendan * This buffer is cached on the 2nd Level ARC; 1778fa94a07fSbrendan * don't destroy the header. 1779fa94a07fSbrendan */ 1780fa94a07fSbrendan arc_change_state(arc_l2c_only, ab, hash_lock); 17817e453561SWilliam Gorrell mutex_exit(hash_lock); 1782fa94a07fSbrendan } else { 1783fa94a07fSbrendan arc_change_state(arc_anon, ab, hash_lock); 17847e453561SWilliam Gorrell mutex_exit(hash_lock); 1785fa94a07fSbrendan arc_hdr_destroy(ab); 1786fa94a07fSbrendan } 1787fa94a07fSbrendan 1788ea8dc4b6Seschrock DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, ab); 1789fa9e4066Sahrens if (bytes >= 0 && bytes_deleted >= bytes) 1790fa9e4066Sahrens break; 1791fa9e4066Sahrens } else { 1792fa9e4066Sahrens if (bytes < 0) { 179344cb6abcSbmc mutex_exit(&state->arcs_mtx); 1794fa9e4066Sahrens mutex_enter(hash_lock); 1795fa9e4066Sahrens mutex_exit(hash_lock); 1796fa9e4066Sahrens goto top; 1797fa9e4066Sahrens } 1798fa9e4066Sahrens bufs_skipped += 1; 1799fa9e4066Sahrens } 1800fa9e4066Sahrens } 180144cb6abcSbmc mutex_exit(&state->arcs_mtx); 1802fa9e4066Sahrens 18030e8c6158Smaybee if (list == &state->arcs_list[ARC_BUFC_DATA] && 18040e8c6158Smaybee (bytes < 0 || bytes_deleted < bytes)) { 18050e8c6158Smaybee list = &state->arcs_list[ARC_BUFC_METADATA]; 18060e8c6158Smaybee goto top; 18070e8c6158Smaybee } 18080e8c6158Smaybee 1809fa9e4066Sahrens if (bufs_skipped) { 181044cb6abcSbmc ARCSTAT_INCR(arcstat_mutex_miss, bufs_skipped); 1811fa9e4066Sahrens ASSERT(bytes >= 0); 1812fa9e4066Sahrens } 1813fa9e4066Sahrens 1814fa9e4066Sahrens if (bytes_deleted < bytes) 1815fa9e4066Sahrens dprintf("only deleted %lld bytes from %p", 1816fa9e4066Sahrens (longlong_t)bytes_deleted, state); 1817fa9e4066Sahrens } 1818fa9e4066Sahrens 1819fa9e4066Sahrens static void 1820fa9e4066Sahrens arc_adjust(void) 1821fa9e4066Sahrens { 18225a98e54bSBrendan Gregg - Sun Microsystems int64_t adjustment, delta; 1823fa9e4066Sahrens 18245a98e54bSBrendan Gregg - Sun Microsystems /* 18255a98e54bSBrendan Gregg - Sun Microsystems * Adjust MRU size 18265a98e54bSBrendan Gregg - Sun Microsystems */ 18275a98e54bSBrendan Gregg - Sun Microsystems 18285a98e54bSBrendan Gregg - Sun Microsystems adjustment = MIN(arc_size - arc_c, 18295a98e54bSBrendan Gregg - Sun Microsystems arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used - arc_p); 1830fa9e4066Sahrens 18315a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_DATA] > 0) { 18325a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_DATA], adjustment); 18335a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mru, NULL, delta, FALSE, ARC_BUFC_DATA); 18345a98e54bSBrendan Gregg - Sun Microsystems adjustment -= delta; 18350e8c6158Smaybee } 18360e8c6158Smaybee 18375a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { 18385a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); 18395a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mru, NULL, delta, FALSE, 1840874395d5Smaybee ARC_BUFC_METADATA); 1841fa9e4066Sahrens } 1842fa9e4066Sahrens 18435a98e54bSBrendan Gregg - Sun Microsystems /* 18445a98e54bSBrendan Gregg - Sun Microsystems * Adjust MFU size 18455a98e54bSBrendan Gregg - Sun Microsystems */ 1846fa9e4066Sahrens 18475a98e54bSBrendan Gregg - Sun Microsystems adjustment = arc_size - arc_c; 18485a98e54bSBrendan Gregg - Sun Microsystems 18495a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_DATA] > 0) { 18505a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(adjustment, arc_mfu->arcs_lsize[ARC_BUFC_DATA]); 18515a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mfu, NULL, delta, FALSE, ARC_BUFC_DATA); 18525a98e54bSBrendan Gregg - Sun Microsystems adjustment -= delta; 1853fa9e4066Sahrens } 1854fa9e4066Sahrens 18555a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { 18565a98e54bSBrendan Gregg - Sun Microsystems int64_t delta = MIN(adjustment, 18575a98e54bSBrendan Gregg - Sun Microsystems arc_mfu->arcs_lsize[ARC_BUFC_METADATA]); 18585a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mfu, NULL, delta, FALSE, 18595a98e54bSBrendan Gregg - Sun Microsystems ARC_BUFC_METADATA); 18605a98e54bSBrendan Gregg - Sun Microsystems } 1861fa9e4066Sahrens 18625a98e54bSBrendan Gregg - Sun Microsystems /* 18635a98e54bSBrendan Gregg - Sun Microsystems * Adjust ghost lists 18645a98e54bSBrendan Gregg - Sun Microsystems */ 1865fa9e4066Sahrens 18665a98e54bSBrendan Gregg - Sun Microsystems adjustment = arc_mru->arcs_size + arc_mru_ghost->arcs_size - arc_c; 1867fa9e4066Sahrens 18685a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru_ghost->arcs_size > 0) { 18695a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru_ghost->arcs_size, adjustment); 18705a98e54bSBrendan Gregg - Sun Microsystems arc_evict_ghost(arc_mru_ghost, NULL, delta); 18715a98e54bSBrendan Gregg - Sun Microsystems } 18720e8c6158Smaybee 18735a98e54bSBrendan Gregg - Sun Microsystems adjustment = 18745a98e54bSBrendan Gregg - Sun Microsystems arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size - arc_c; 18755a98e54bSBrendan Gregg - Sun Microsystems 18765a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu_ghost->arcs_size > 0) { 18775a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mfu_ghost->arcs_size, adjustment); 18785a98e54bSBrendan Gregg - Sun Microsystems arc_evict_ghost(arc_mfu_ghost, NULL, delta); 1879fa9e4066Sahrens } 1880fa9e4066Sahrens } 1881fa9e4066Sahrens 1882ea8dc4b6Seschrock static void 1883ea8dc4b6Seschrock arc_do_user_evicts(void) 1884ea8dc4b6Seschrock { 1885ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1886ea8dc4b6Seschrock while (arc_eviction_list != NULL) { 1887ea8dc4b6Seschrock arc_buf_t *buf = arc_eviction_list; 1888ea8dc4b6Seschrock arc_eviction_list = buf->b_next; 1889*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 1890ea8dc4b6Seschrock buf->b_hdr = NULL; 1891*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 1892ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1893ea8dc4b6Seschrock 1894dd6ef538Smaybee if (buf->b_efunc != NULL) 1895dd6ef538Smaybee VERIFY(buf->b_efunc(buf) == 0); 1896ea8dc4b6Seschrock 1897ea8dc4b6Seschrock buf->b_efunc = NULL; 1898ea8dc4b6Seschrock buf->b_private = NULL; 1899ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 1900ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1901ea8dc4b6Seschrock } 1902ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1903ea8dc4b6Seschrock } 1904ea8dc4b6Seschrock 1905fa9e4066Sahrens /* 1906874395d5Smaybee * Flush all *evictable* data from the cache for the given spa. 1907fa9e4066Sahrens * NOTE: this will not touch "active" (i.e. referenced) data. 1908fa9e4066Sahrens */ 1909fa9e4066Sahrens void 1910874395d5Smaybee arc_flush(spa_t *spa) 1911fa9e4066Sahrens { 1912ac05c741SMark Maybee uint64_t guid = 0; 1913ac05c741SMark Maybee 1914ac05c741SMark Maybee if (spa) 1915ac05c741SMark Maybee guid = spa_guid(spa); 1916ac05c741SMark Maybee 1917874395d5Smaybee while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) { 1918ac05c741SMark Maybee (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA); 1919874395d5Smaybee if (spa) 1920874395d5Smaybee break; 1921874395d5Smaybee } 1922874395d5Smaybee while (list_head(&arc_mru->arcs_list[ARC_BUFC_METADATA])) { 1923ac05c741SMark Maybee (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_METADATA); 1924874395d5Smaybee if (spa) 1925874395d5Smaybee break; 1926874395d5Smaybee } 1927874395d5Smaybee while (list_head(&arc_mfu->arcs_list[ARC_BUFC_DATA])) { 1928ac05c741SMark Maybee (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_DATA); 1929874395d5Smaybee if (spa) 1930874395d5Smaybee break; 1931874395d5Smaybee } 1932874395d5Smaybee while (list_head(&arc_mfu->arcs_list[ARC_BUFC_METADATA])) { 1933ac05c741SMark Maybee (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_METADATA); 1934874395d5Smaybee if (spa) 1935874395d5Smaybee break; 1936874395d5Smaybee } 1937874395d5Smaybee 1938ac05c741SMark Maybee arc_evict_ghost(arc_mru_ghost, guid, -1); 1939ac05c741SMark Maybee arc_evict_ghost(arc_mfu_ghost, guid, -1); 1940ea8dc4b6Seschrock 1941ea8dc4b6Seschrock mutex_enter(&arc_reclaim_thr_lock); 1942ea8dc4b6Seschrock arc_do_user_evicts(); 1943ea8dc4b6Seschrock mutex_exit(&arc_reclaim_thr_lock); 1944874395d5Smaybee ASSERT(spa || arc_eviction_list == NULL); 1945fa9e4066Sahrens } 1946fa9e4066Sahrens 1947fa9e4066Sahrens void 194849e3519aSmaybee arc_shrink(void) 1949fa9e4066Sahrens { 195044cb6abcSbmc if (arc_c > arc_c_min) { 195149e3519aSmaybee uint64_t to_free; 1952fa9e4066Sahrens 19533cff2f43Sstans #ifdef _KERNEL 195444cb6abcSbmc to_free = MAX(arc_c >> arc_shrink_shift, ptob(needfree)); 19553cff2f43Sstans #else 195644cb6abcSbmc to_free = arc_c >> arc_shrink_shift; 19573cff2f43Sstans #endif 195844cb6abcSbmc if (arc_c > arc_c_min + to_free) 195944cb6abcSbmc atomic_add_64(&arc_c, -to_free); 196049e3519aSmaybee else 196144cb6abcSbmc arc_c = arc_c_min; 196244cb6abcSbmc 196344cb6abcSbmc atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift)); 196444cb6abcSbmc if (arc_c > arc_size) 196544cb6abcSbmc arc_c = MAX(arc_size, arc_c_min); 196644cb6abcSbmc if (arc_p > arc_c) 196744cb6abcSbmc arc_p = (arc_c >> 1); 196844cb6abcSbmc ASSERT(arc_c >= arc_c_min); 196944cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 197049e3519aSmaybee } 1971fa9e4066Sahrens 197244cb6abcSbmc if (arc_size > arc_c) 197349e3519aSmaybee arc_adjust(); 1974fa9e4066Sahrens } 1975fa9e4066Sahrens 1976fa9e4066Sahrens static int 1977fa9e4066Sahrens arc_reclaim_needed(void) 1978fa9e4066Sahrens { 1979fa9e4066Sahrens uint64_t extra; 1980fa9e4066Sahrens 1981fa9e4066Sahrens #ifdef _KERNEL 19823cff2f43Sstans 19833cff2f43Sstans if (needfree) 19843cff2f43Sstans return (1); 19853cff2f43Sstans 1986fa9e4066Sahrens /* 1987fa9e4066Sahrens * take 'desfree' extra pages, so we reclaim sooner, rather than later 1988fa9e4066Sahrens */ 1989fa9e4066Sahrens extra = desfree; 1990fa9e4066Sahrens 1991fa9e4066Sahrens /* 1992fa9e4066Sahrens * check that we're out of range of the pageout scanner. It starts to 1993fa9e4066Sahrens * schedule paging if freemem is less than lotsfree and needfree. 1994fa9e4066Sahrens * lotsfree is the high-water mark for pageout, and needfree is the 1995fa9e4066Sahrens * number of needed free pages. We add extra pages here to make sure 1996fa9e4066Sahrens * the scanner doesn't start up while we're freeing memory. 1997fa9e4066Sahrens */ 1998fa9e4066Sahrens if (freemem < lotsfree + needfree + extra) 1999fa9e4066Sahrens return (1); 2000fa9e4066Sahrens 2001fa9e4066Sahrens /* 2002fa9e4066Sahrens * check to make sure that swapfs has enough space so that anon 2003fa94a07fSbrendan * reservations can still succeed. anon_resvmem() checks that the 2004fa9e4066Sahrens * availrmem is greater than swapfs_minfree, and the number of reserved 2005fa9e4066Sahrens * swap pages. We also add a bit of extra here just to prevent 2006fa9e4066Sahrens * circumstances from getting really dire. 2007fa9e4066Sahrens */ 2008fa9e4066Sahrens if (availrmem < swapfs_minfree + swapfs_reserve + extra) 2009fa9e4066Sahrens return (1); 2010fa9e4066Sahrens 20115dc8af33Smaybee #if defined(__i386) 2012fa9e4066Sahrens /* 2013fa9e4066Sahrens * If we're on an i386 platform, it's possible that we'll exhaust the 2014fa9e4066Sahrens * kernel heap space before we ever run out of available physical 2015fa9e4066Sahrens * memory. Most checks of the size of the heap_area compare against 2016fa9e4066Sahrens * tune.t_minarmem, which is the minimum available real memory that we 2017fa9e4066Sahrens * can have in the system. However, this is generally fixed at 25 pages 2018fa9e4066Sahrens * which is so low that it's useless. In this comparison, we seek to 2019fa9e4066Sahrens * calculate the total heap-size, and reclaim if more than 3/4ths of the 2020fa94a07fSbrendan * heap is allocated. (Or, in the calculation, if less than 1/4th is 2021fa9e4066Sahrens * free) 2022fa9e4066Sahrens */ 2023fa9e4066Sahrens if (btop(vmem_size(heap_arena, VMEM_FREE)) < 2024fa9e4066Sahrens (btop(vmem_size(heap_arena, VMEM_FREE | VMEM_ALLOC)) >> 2)) 2025fa9e4066Sahrens return (1); 2026fa9e4066Sahrens #endif 2027fa9e4066Sahrens 2028fa9e4066Sahrens #else 2029fa9e4066Sahrens if (spa_get_random(100) == 0) 2030fa9e4066Sahrens return (1); 2031fa9e4066Sahrens #endif 2032fa9e4066Sahrens return (0); 2033fa9e4066Sahrens } 2034fa9e4066Sahrens 2035fa9e4066Sahrens static void 2036fa9e4066Sahrens arc_kmem_reap_now(arc_reclaim_strategy_t strat) 2037fa9e4066Sahrens { 2038fa9e4066Sahrens size_t i; 2039fa9e4066Sahrens kmem_cache_t *prev_cache = NULL; 2040ad23a2dbSjohansen kmem_cache_t *prev_data_cache = NULL; 2041fa9e4066Sahrens extern kmem_cache_t *zio_buf_cache[]; 2042ad23a2dbSjohansen extern kmem_cache_t *zio_data_buf_cache[]; 2043fa9e4066Sahrens 2044033f9833Sek #ifdef _KERNEL 20450e8c6158Smaybee if (arc_meta_used >= arc_meta_limit) { 20460e8c6158Smaybee /* 20470e8c6158Smaybee * We are exceeding our meta-data cache limit. 20480e8c6158Smaybee * Purge some DNLC entries to release holds on meta-data. 20490e8c6158Smaybee */ 20500e8c6158Smaybee dnlc_reduce_cache((void *)(uintptr_t)arc_reduce_dnlc_percent); 20510e8c6158Smaybee } 20525dc8af33Smaybee #if defined(__i386) 20535dc8af33Smaybee /* 20545dc8af33Smaybee * Reclaim unused memory from all kmem caches. 20555dc8af33Smaybee */ 20565dc8af33Smaybee kmem_reap(); 20575dc8af33Smaybee #endif 2058033f9833Sek #endif 2059033f9833Sek 2060fa9e4066Sahrens /* 2061fa94a07fSbrendan * An aggressive reclamation will shrink the cache size as well as 2062ea8dc4b6Seschrock * reap free buffers from the arc kmem caches. 2063fa9e4066Sahrens */ 2064fa9e4066Sahrens if (strat == ARC_RECLAIM_AGGR) 206549e3519aSmaybee arc_shrink(); 2066fa9e4066Sahrens 2067fa9e4066Sahrens for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { 2068fa9e4066Sahrens if (zio_buf_cache[i] != prev_cache) { 2069fa9e4066Sahrens prev_cache = zio_buf_cache[i]; 2070fa9e4066Sahrens kmem_cache_reap_now(zio_buf_cache[i]); 2071fa9e4066Sahrens } 2072ad23a2dbSjohansen if (zio_data_buf_cache[i] != prev_data_cache) { 2073ad23a2dbSjohansen prev_data_cache = zio_data_buf_cache[i]; 2074ad23a2dbSjohansen kmem_cache_reap_now(zio_data_buf_cache[i]); 2075ad23a2dbSjohansen } 2076fa9e4066Sahrens } 2077ea8dc4b6Seschrock kmem_cache_reap_now(buf_cache); 2078ea8dc4b6Seschrock kmem_cache_reap_now(hdr_cache); 2079fa9e4066Sahrens } 2080fa9e4066Sahrens 2081fa9e4066Sahrens static void 2082fa9e4066Sahrens arc_reclaim_thread(void) 2083fa9e4066Sahrens { 2084fa9e4066Sahrens clock_t growtime = 0; 2085fa9e4066Sahrens arc_reclaim_strategy_t last_reclaim = ARC_RECLAIM_CONS; 2086fa9e4066Sahrens callb_cpr_t cpr; 2087fa9e4066Sahrens 2088fa9e4066Sahrens CALLB_CPR_INIT(&cpr, &arc_reclaim_thr_lock, callb_generic_cpr, FTAG); 2089fa9e4066Sahrens 2090fa9e4066Sahrens mutex_enter(&arc_reclaim_thr_lock); 2091fa9e4066Sahrens while (arc_thread_exit == 0) { 2092fa9e4066Sahrens if (arc_reclaim_needed()) { 2093fa9e4066Sahrens 209444cb6abcSbmc if (arc_no_grow) { 2095fa9e4066Sahrens if (last_reclaim == ARC_RECLAIM_CONS) { 2096fa9e4066Sahrens last_reclaim = ARC_RECLAIM_AGGR; 2097fa9e4066Sahrens } else { 2098fa9e4066Sahrens last_reclaim = ARC_RECLAIM_CONS; 2099fa9e4066Sahrens } 2100fa9e4066Sahrens } else { 210144cb6abcSbmc arc_no_grow = TRUE; 2102fa9e4066Sahrens last_reclaim = ARC_RECLAIM_AGGR; 2103fa9e4066Sahrens membar_producer(); 2104fa9e4066Sahrens } 2105fa9e4066Sahrens 2106fa9e4066Sahrens /* reset the growth delay for every reclaim */ 2107d3d50737SRafael Vanoni growtime = ddi_get_lbolt() + (arc_grow_retry * hz); 2108fa9e4066Sahrens 2109fa9e4066Sahrens arc_kmem_reap_now(last_reclaim); 21103a737e0dSbrendan arc_warm = B_TRUE; 2111fa9e4066Sahrens 2112d3d50737SRafael Vanoni } else if (arc_no_grow && ddi_get_lbolt() >= growtime) { 211344cb6abcSbmc arc_no_grow = FALSE; 2114fa9e4066Sahrens } 2115fa9e4066Sahrens 211644cb6abcSbmc if (2 * arc_c < arc_size + 211744cb6abcSbmc arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size) 2118641fbdaeSmaybee arc_adjust(); 2119641fbdaeSmaybee 2120ea8dc4b6Seschrock if (arc_eviction_list != NULL) 2121ea8dc4b6Seschrock arc_do_user_evicts(); 2122ea8dc4b6Seschrock 2123fa9e4066Sahrens /* block until needed, or one second, whichever is shorter */ 2124fa9e4066Sahrens CALLB_CPR_SAFE_BEGIN(&cpr); 2125fa9e4066Sahrens (void) cv_timedwait(&arc_reclaim_thr_cv, 2126d3d50737SRafael Vanoni &arc_reclaim_thr_lock, (ddi_get_lbolt() + hz)); 2127fa9e4066Sahrens CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_thr_lock); 2128fa9e4066Sahrens } 2129fa9e4066Sahrens 2130fa9e4066Sahrens arc_thread_exit = 0; 2131fa9e4066Sahrens cv_broadcast(&arc_reclaim_thr_cv); 2132fa9e4066Sahrens CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_thr_lock */ 2133fa9e4066Sahrens thread_exit(); 2134fa9e4066Sahrens } 2135fa9e4066Sahrens 2136ea8dc4b6Seschrock /* 2137ea8dc4b6Seschrock * Adapt arc info given the number of bytes we are trying to add and 2138ea8dc4b6Seschrock * the state that we are comming from. This function is only called 2139ea8dc4b6Seschrock * when we are adding new content to the cache. 2140ea8dc4b6Seschrock */ 2141fa9e4066Sahrens static void 2142ea8dc4b6Seschrock arc_adapt(int bytes, arc_state_t *state) 2143fa9e4066Sahrens { 2144ea8dc4b6Seschrock int mult; 21455a98e54bSBrendan Gregg - Sun Microsystems uint64_t arc_p_min = (arc_c >> arc_p_min_shift); 2146ea8dc4b6Seschrock 2147fa94a07fSbrendan if (state == arc_l2c_only) 2148fa94a07fSbrendan return; 2149fa94a07fSbrendan 2150ea8dc4b6Seschrock ASSERT(bytes > 0); 2151fa9e4066Sahrens /* 2152ea8dc4b6Seschrock * Adapt the target size of the MRU list: 2153ea8dc4b6Seschrock * - if we just hit in the MRU ghost list, then increase 2154ea8dc4b6Seschrock * the target size of the MRU list. 2155ea8dc4b6Seschrock * - if we just hit in the MFU ghost list, then increase 2156ea8dc4b6Seschrock * the target size of the MFU list by decreasing the 2157ea8dc4b6Seschrock * target size of the MRU list. 2158fa9e4066Sahrens */ 215944cb6abcSbmc if (state == arc_mru_ghost) { 216044cb6abcSbmc mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ? 216144cb6abcSbmc 1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size)); 2162ea8dc4b6Seschrock 21635a98e54bSBrendan Gregg - Sun Microsystems arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); 216444cb6abcSbmc } else if (state == arc_mfu_ghost) { 21655a98e54bSBrendan Gregg - Sun Microsystems uint64_t delta; 21665a98e54bSBrendan Gregg - Sun Microsystems 216744cb6abcSbmc mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ? 216844cb6abcSbmc 1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size)); 2169ea8dc4b6Seschrock 21705a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(bytes * mult, arc_p); 21715a98e54bSBrendan Gregg - Sun Microsystems arc_p = MAX(arc_p_min, arc_p - delta); 2172ea8dc4b6Seschrock } 217344cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 2174fa9e4066Sahrens 2175fa9e4066Sahrens if (arc_reclaim_needed()) { 2176fa9e4066Sahrens cv_signal(&arc_reclaim_thr_cv); 2177fa9e4066Sahrens return; 2178fa9e4066Sahrens } 2179fa9e4066Sahrens 218044cb6abcSbmc if (arc_no_grow) 2181fa9e4066Sahrens return; 2182fa9e4066Sahrens 218344cb6abcSbmc if (arc_c >= arc_c_max) 2184ea8dc4b6Seschrock return; 2185ea8dc4b6Seschrock 2186fa9e4066Sahrens /* 2187ea8dc4b6Seschrock * If we're within (2 * maxblocksize) bytes of the target 2188ea8dc4b6Seschrock * cache size, increment the target cache size 2189fa9e4066Sahrens */ 219044cb6abcSbmc if (arc_size > arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) { 219144cb6abcSbmc atomic_add_64(&arc_c, (int64_t)bytes); 219244cb6abcSbmc if (arc_c > arc_c_max) 219344cb6abcSbmc arc_c = arc_c_max; 219444cb6abcSbmc else if (state == arc_anon) 219544cb6abcSbmc atomic_add_64(&arc_p, (int64_t)bytes); 219644cb6abcSbmc if (arc_p > arc_c) 219744cb6abcSbmc arc_p = arc_c; 2198fa9e4066Sahrens } 219944cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 2200fa9e4066Sahrens } 2201fa9e4066Sahrens 2202fa9e4066Sahrens /* 2203ea8dc4b6Seschrock * Check if the cache has reached its limits and eviction is required 2204ea8dc4b6Seschrock * prior to insert. 2205fa9e4066Sahrens */ 2206fa9e4066Sahrens static int 22070e8c6158Smaybee arc_evict_needed(arc_buf_contents_t type) 2208fa9e4066Sahrens { 22090e8c6158Smaybee if (type == ARC_BUFC_METADATA && arc_meta_used >= arc_meta_limit) 22100e8c6158Smaybee return (1); 22110e8c6158Smaybee 22120e8c6158Smaybee #ifdef _KERNEL 22130e8c6158Smaybee /* 22140e8c6158Smaybee * If zio data pages are being allocated out of a separate heap segment, 22150e8c6158Smaybee * then enforce that the size of available vmem for this area remains 22160e8c6158Smaybee * above about 1/32nd free. 22170e8c6158Smaybee */ 22180e8c6158Smaybee if (type == ARC_BUFC_DATA && zio_arena != NULL && 22190e8c6158Smaybee vmem_size(zio_arena, VMEM_FREE) < 22200e8c6158Smaybee (vmem_size(zio_arena, VMEM_ALLOC) >> 5)) 22210e8c6158Smaybee return (1); 22220e8c6158Smaybee #endif 22230e8c6158Smaybee 2224fa9e4066Sahrens if (arc_reclaim_needed()) 2225fa9e4066Sahrens return (1); 2226fa9e4066Sahrens 222744cb6abcSbmc return (arc_size > arc_c); 2228fa9e4066Sahrens } 2229fa9e4066Sahrens 2230fa9e4066Sahrens /* 223144eda4d7Smaybee * The buffer, supplied as the first argument, needs a data block. 223244eda4d7Smaybee * So, if we are at cache max, determine which cache should be victimized. 223344eda4d7Smaybee * We have the following cases: 2234fa9e4066Sahrens * 223544cb6abcSbmc * 1. Insert for MRU, p > sizeof(arc_anon + arc_mru) -> 2236fa9e4066Sahrens * In this situation if we're out of space, but the resident size of the MFU is 2237fa9e4066Sahrens * under the limit, victimize the MFU cache to satisfy this insertion request. 2238fa9e4066Sahrens * 223944cb6abcSbmc * 2. Insert for MRU, p <= sizeof(arc_anon + arc_mru) -> 2240fa9e4066Sahrens * Here, we've used up all of the available space for the MRU, so we need to 2241fa9e4066Sahrens * evict from our own cache instead. Evict from the set of resident MRU 2242fa9e4066Sahrens * entries. 2243fa9e4066Sahrens * 224444cb6abcSbmc * 3. Insert for MFU (c - p) > sizeof(arc_mfu) -> 2245fa9e4066Sahrens * c minus p represents the MFU space in the cache, since p is the size of the 2246fa9e4066Sahrens * cache that is dedicated to the MRU. In this situation there's still space on 2247fa9e4066Sahrens * the MFU side, so the MRU side needs to be victimized. 2248fa9e4066Sahrens * 224944cb6abcSbmc * 4. Insert for MFU (c - p) < sizeof(arc_mfu) -> 2250fa9e4066Sahrens * MFU's resident set is consuming more space than it has been allotted. In 2251fa9e4066Sahrens * this situation, we must victimize our own cache, the MFU, for this insertion. 2252fa9e4066Sahrens */ 2253fa9e4066Sahrens static void 225444eda4d7Smaybee arc_get_data_buf(arc_buf_t *buf) 2255fa9e4066Sahrens { 2256ad23a2dbSjohansen arc_state_t *state = buf->b_hdr->b_state; 2257ad23a2dbSjohansen uint64_t size = buf->b_hdr->b_size; 2258ad23a2dbSjohansen arc_buf_contents_t type = buf->b_hdr->b_type; 2259fa9e4066Sahrens 226044eda4d7Smaybee arc_adapt(size, state); 2261fa9e4066Sahrens 226244eda4d7Smaybee /* 226344eda4d7Smaybee * We have not yet reached cache maximum size, 226444eda4d7Smaybee * just allocate a new buffer. 226544eda4d7Smaybee */ 22660e8c6158Smaybee if (!arc_evict_needed(type)) { 2267ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 2268ad23a2dbSjohansen buf->b_data = zio_buf_alloc(size); 22695a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(size, ARC_SPACE_DATA); 2270ad23a2dbSjohansen } else { 2271ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 2272ad23a2dbSjohansen buf->b_data = zio_data_buf_alloc(size); 22735a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, size); 22740e8c6158Smaybee atomic_add_64(&arc_size, size); 2275ad23a2dbSjohansen } 227644eda4d7Smaybee goto out; 227744eda4d7Smaybee } 227844eda4d7Smaybee 227944eda4d7Smaybee /* 228044eda4d7Smaybee * If we are prefetching from the mfu ghost list, this buffer 228144eda4d7Smaybee * will end up on the mru list; so steal space from there. 228244eda4d7Smaybee */ 228344cb6abcSbmc if (state == arc_mfu_ghost) 228444cb6abcSbmc state = buf->b_hdr->b_flags & ARC_PREFETCH ? arc_mru : arc_mfu; 228544cb6abcSbmc else if (state == arc_mru_ghost) 228644cb6abcSbmc state = arc_mru; 228744cb6abcSbmc 228844cb6abcSbmc if (state == arc_mru || state == arc_anon) { 228944cb6abcSbmc uint64_t mru_used = arc_anon->arcs_size + arc_mru->arcs_size; 22905a98e54bSBrendan Gregg - Sun Microsystems state = (arc_mfu->arcs_lsize[type] >= size && 22910e8c6158Smaybee arc_p > mru_used) ? arc_mfu : arc_mru; 2292fa9e4066Sahrens } else { 229344eda4d7Smaybee /* MFU cases */ 229444cb6abcSbmc uint64_t mfu_space = arc_c - arc_p; 22955a98e54bSBrendan Gregg - Sun Microsystems state = (arc_mru->arcs_lsize[type] >= size && 22960e8c6158Smaybee mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu; 229744eda4d7Smaybee } 2298874395d5Smaybee if ((buf->b_data = arc_evict(state, NULL, size, TRUE, type)) == NULL) { 2299ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 2300ad23a2dbSjohansen buf->b_data = zio_buf_alloc(size); 23015a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(size, ARC_SPACE_DATA); 2302ad23a2dbSjohansen } else { 2303ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 2304ad23a2dbSjohansen buf->b_data = zio_data_buf_alloc(size); 23055a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, size); 23060e8c6158Smaybee atomic_add_64(&arc_size, size); 2307ad23a2dbSjohansen } 230844cb6abcSbmc ARCSTAT_BUMP(arcstat_recycle_miss); 230944eda4d7Smaybee } 231044eda4d7Smaybee ASSERT(buf->b_data != NULL); 231144eda4d7Smaybee out: 231244eda4d7Smaybee /* 231344eda4d7Smaybee * Update the state size. Note that ghost states have a 231444eda4d7Smaybee * "ghost size" and so don't need to be updated. 231544eda4d7Smaybee */ 231644eda4d7Smaybee if (!GHOST_STATE(buf->b_hdr->b_state)) { 231744eda4d7Smaybee arc_buf_hdr_t *hdr = buf->b_hdr; 231844eda4d7Smaybee 231944cb6abcSbmc atomic_add_64(&hdr->b_state->arcs_size, size); 232044eda4d7Smaybee if (list_link_active(&hdr->b_arc_node)) { 232144eda4d7Smaybee ASSERT(refcount_is_zero(&hdr->b_refcnt)); 23220e8c6158Smaybee atomic_add_64(&hdr->b_state->arcs_lsize[type], size); 2323fa9e4066Sahrens } 2324641fbdaeSmaybee /* 2325641fbdaeSmaybee * If we are growing the cache, and we are adding anonymous 232644cb6abcSbmc * data, and we have outgrown arc_p, update arc_p 2327641fbdaeSmaybee */ 232844cb6abcSbmc if (arc_size < arc_c && hdr->b_state == arc_anon && 232944cb6abcSbmc arc_anon->arcs_size + arc_mru->arcs_size > arc_p) 233044cb6abcSbmc arc_p = MIN(arc_c, arc_p + size); 2331fa9e4066Sahrens } 2332fa9e4066Sahrens } 2333fa9e4066Sahrens 2334fa9e4066Sahrens /* 2335fa9e4066Sahrens * This routine is called whenever a buffer is accessed. 2336ea8dc4b6Seschrock * NOTE: the hash lock is dropped in this function. 2337fa9e4066Sahrens */ 2338fa9e4066Sahrens static void 233944eda4d7Smaybee arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock) 2340fa9e4066Sahrens { 2341d3d50737SRafael Vanoni clock_t now; 2342d3d50737SRafael Vanoni 2343fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 2344fa9e4066Sahrens 234544cb6abcSbmc if (buf->b_state == arc_anon) { 2346fa9e4066Sahrens /* 2347fa9e4066Sahrens * This buffer is not in the cache, and does not 2348fa9e4066Sahrens * appear in our "ghost" list. Add the new buffer 2349fa9e4066Sahrens * to the MRU state. 2350fa9e4066Sahrens */ 2351fa9e4066Sahrens 2352fa9e4066Sahrens ASSERT(buf->b_arc_access == 0); 2353d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2354ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); 235544cb6abcSbmc arc_change_state(arc_mru, buf, hash_lock); 2356fa9e4066Sahrens 235744cb6abcSbmc } else if (buf->b_state == arc_mru) { 2358d3d50737SRafael Vanoni now = ddi_get_lbolt(); 2359d3d50737SRafael Vanoni 2360fa9e4066Sahrens /* 236113506d1eSmaybee * If this buffer is here because of a prefetch, then either: 236213506d1eSmaybee * - clear the flag if this is a "referencing" read 236313506d1eSmaybee * (any subsequent access will bump this into the MFU state). 236413506d1eSmaybee * or 236513506d1eSmaybee * - move the buffer to the head of the list if this is 236613506d1eSmaybee * another prefetch (to make it less likely to be evicted). 2367fa9e4066Sahrens */ 2368fa9e4066Sahrens if ((buf->b_flags & ARC_PREFETCH) != 0) { 236913506d1eSmaybee if (refcount_count(&buf->b_refcnt) == 0) { 237013506d1eSmaybee ASSERT(list_link_active(&buf->b_arc_node)); 237113506d1eSmaybee } else { 237213506d1eSmaybee buf->b_flags &= ~ARC_PREFETCH; 237344cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_hits); 237413506d1eSmaybee } 2375d3d50737SRafael Vanoni buf->b_arc_access = now; 2376fa9e4066Sahrens return; 2377fa9e4066Sahrens } 2378fa9e4066Sahrens 2379fa9e4066Sahrens /* 2380fa9e4066Sahrens * This buffer has been "accessed" only once so far, 2381fa9e4066Sahrens * but it is still in the cache. Move it to the MFU 2382fa9e4066Sahrens * state. 2383fa9e4066Sahrens */ 2384d3d50737SRafael Vanoni if (now > buf->b_arc_access + ARC_MINTIME) { 2385fa9e4066Sahrens /* 2386fa9e4066Sahrens * More than 125ms have passed since we 2387fa9e4066Sahrens * instantiated this buffer. Move it to the 2388fa9e4066Sahrens * most frequently used state. 2389fa9e4066Sahrens */ 2390d3d50737SRafael Vanoni buf->b_arc_access = now; 2391ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 239244cb6abcSbmc arc_change_state(arc_mfu, buf, hash_lock); 2393fa9e4066Sahrens } 239444cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_hits); 239544cb6abcSbmc } else if (buf->b_state == arc_mru_ghost) { 2396fa9e4066Sahrens arc_state_t *new_state; 2397fa9e4066Sahrens /* 2398fa9e4066Sahrens * This buffer has been "accessed" recently, but 2399fa9e4066Sahrens * was evicted from the cache. Move it to the 2400fa9e4066Sahrens * MFU state. 2401fa9e4066Sahrens */ 2402fa9e4066Sahrens 2403fa9e4066Sahrens if (buf->b_flags & ARC_PREFETCH) { 240444cb6abcSbmc new_state = arc_mru; 240513506d1eSmaybee if (refcount_count(&buf->b_refcnt) > 0) 240613506d1eSmaybee buf->b_flags &= ~ARC_PREFETCH; 2407ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); 2408fa9e4066Sahrens } else { 240944cb6abcSbmc new_state = arc_mfu; 2410ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 2411fa9e4066Sahrens } 2412fa9e4066Sahrens 2413d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2414fa9e4066Sahrens arc_change_state(new_state, buf, hash_lock); 2415fa9e4066Sahrens 241644cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_ghost_hits); 241744cb6abcSbmc } else if (buf->b_state == arc_mfu) { 2418fa9e4066Sahrens /* 2419fa9e4066Sahrens * This buffer has been accessed more than once and is 2420fa9e4066Sahrens * still in the cache. Keep it in the MFU state. 2421fa9e4066Sahrens * 242213506d1eSmaybee * NOTE: an add_reference() that occurred when we did 242313506d1eSmaybee * the arc_read() will have kicked this off the list. 242413506d1eSmaybee * If it was a prefetch, we will explicitly move it to 242513506d1eSmaybee * the head of the list now. 2426fa9e4066Sahrens */ 242713506d1eSmaybee if ((buf->b_flags & ARC_PREFETCH) != 0) { 242813506d1eSmaybee ASSERT(refcount_count(&buf->b_refcnt) == 0); 242913506d1eSmaybee ASSERT(list_link_active(&buf->b_arc_node)); 243013506d1eSmaybee } 243144cb6abcSbmc ARCSTAT_BUMP(arcstat_mfu_hits); 2432d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 243344cb6abcSbmc } else if (buf->b_state == arc_mfu_ghost) { 243444cb6abcSbmc arc_state_t *new_state = arc_mfu; 2435fa9e4066Sahrens /* 2436fa9e4066Sahrens * This buffer has been accessed more than once but has 2437fa9e4066Sahrens * been evicted from the cache. Move it back to the 2438fa9e4066Sahrens * MFU state. 2439fa9e4066Sahrens */ 2440fa9e4066Sahrens 244113506d1eSmaybee if (buf->b_flags & ARC_PREFETCH) { 244213506d1eSmaybee /* 244313506d1eSmaybee * This is a prefetch access... 244413506d1eSmaybee * move this block back to the MRU state. 244513506d1eSmaybee */ 244613506d1eSmaybee ASSERT3U(refcount_count(&buf->b_refcnt), ==, 0); 244744cb6abcSbmc new_state = arc_mru; 244813506d1eSmaybee } 244913506d1eSmaybee 2450d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2451ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 245213506d1eSmaybee arc_change_state(new_state, buf, hash_lock); 2453fa9e4066Sahrens 245444cb6abcSbmc ARCSTAT_BUMP(arcstat_mfu_ghost_hits); 2455fa94a07fSbrendan } else if (buf->b_state == arc_l2c_only) { 2456fa94a07fSbrendan /* 2457fa94a07fSbrendan * This buffer is on the 2nd Level ARC. 2458fa94a07fSbrendan */ 2459fa94a07fSbrendan 2460d3d50737SRafael Vanoni buf->b_arc_access = ddi_get_lbolt(); 2461fa94a07fSbrendan DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 2462fa94a07fSbrendan arc_change_state(arc_mfu, buf, hash_lock); 2463fa9e4066Sahrens } else { 2464fa9e4066Sahrens ASSERT(!"invalid arc state"); 2465fa9e4066Sahrens } 2466fa9e4066Sahrens } 2467fa9e4066Sahrens 2468fa9e4066Sahrens /* a generic arc_done_func_t which you can use */ 2469fa9e4066Sahrens /* ARGSUSED */ 2470fa9e4066Sahrens void 2471fa9e4066Sahrens arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg) 2472fa9e4066Sahrens { 2473*3f9d6ad7SLin Ling if (zio == NULL || zio->io_error == 0) 2474*3f9d6ad7SLin Ling bcopy(buf->b_data, arg, buf->b_hdr->b_size); 2475ea8dc4b6Seschrock VERIFY(arc_buf_remove_ref(buf, arg) == 1); 2476fa9e4066Sahrens } 2477fa9e4066Sahrens 24780e8c6158Smaybee /* a generic arc_done_func_t */ 2479fa9e4066Sahrens void 2480fa9e4066Sahrens arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg) 2481fa9e4066Sahrens { 2482fa9e4066Sahrens arc_buf_t **bufp = arg; 2483fa9e4066Sahrens if (zio && zio->io_error) { 2484ea8dc4b6Seschrock VERIFY(arc_buf_remove_ref(buf, arg) == 1); 2485fa9e4066Sahrens *bufp = NULL; 2486fa9e4066Sahrens } else { 2487fa9e4066Sahrens *bufp = buf; 2488*3f9d6ad7SLin Ling ASSERT(buf->b_data); 2489fa9e4066Sahrens } 2490fa9e4066Sahrens } 2491fa9e4066Sahrens 2492fa9e4066Sahrens static void 2493fa9e4066Sahrens arc_read_done(zio_t *zio) 2494fa9e4066Sahrens { 2495bbf4a8dfSmaybee arc_buf_hdr_t *hdr, *found; 2496fa9e4066Sahrens arc_buf_t *buf; 2497fa9e4066Sahrens arc_buf_t *abuf; /* buffer we're assigning to callback */ 2498fa9e4066Sahrens kmutex_t *hash_lock; 2499fa9e4066Sahrens arc_callback_t *callback_list, *acb; 2500fa9e4066Sahrens int freeable = FALSE; 2501fa9e4066Sahrens 2502fa9e4066Sahrens buf = zio->io_private; 2503fa9e4066Sahrens hdr = buf->b_hdr; 2504fa9e4066Sahrens 2505bbf4a8dfSmaybee /* 2506bbf4a8dfSmaybee * The hdr was inserted into hash-table and removed from lists 2507bbf4a8dfSmaybee * prior to starting I/O. We should find this header, since 2508bbf4a8dfSmaybee * it's in the hash table, and it should be legit since it's 2509bbf4a8dfSmaybee * not possible to evict it during the I/O. The only possible 2510bbf4a8dfSmaybee * reason for it not to be found is if we were freed during the 2511bbf4a8dfSmaybee * read. 2512bbf4a8dfSmaybee */ 2513ac05c741SMark Maybee found = buf_hash_find(hdr->b_spa, &hdr->b_dva, hdr->b_birth, 25146b4acc8bSahrens &hash_lock); 2515fa9e4066Sahrens 2516bbf4a8dfSmaybee ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) && hash_lock == NULL) || 2517fa94a07fSbrendan (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || 2518fa94a07fSbrendan (found == hdr && HDR_L2_READING(hdr))); 2519fa94a07fSbrendan 25203a737e0dSbrendan hdr->b_flags &= ~ARC_L2_EVICTED; 2521fa94a07fSbrendan if (l2arc_noprefetch && (hdr->b_flags & ARC_PREFETCH)) 25223baa08fcSek hdr->b_flags &= ~ARC_L2CACHE; 2523fa9e4066Sahrens 2524fa9e4066Sahrens /* byteswap if necessary */ 2525fa9e4066Sahrens callback_list = hdr->b_acb; 2526fa9e4066Sahrens ASSERT(callback_list != NULL); 25278e0f0d3dSWilliam Gorrell if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) { 2528088f3894Sahrens arc_byteswap_func_t *func = BP_GET_LEVEL(zio->io_bp) > 0 ? 2529088f3894Sahrens byteswap_uint64_array : 2530088f3894Sahrens dmu_ot[BP_GET_TYPE(zio->io_bp)].ot_byteswap; 2531088f3894Sahrens func(buf->b_data, hdr->b_size); 2532088f3894Sahrens } 2533fa9e4066Sahrens 2534fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 25356b4acc8bSahrens 2536b24ab676SJeff Bonwick if (hash_lock && zio->io_error == 0 && hdr->b_state == arc_anon) { 2537b24ab676SJeff Bonwick /* 2538b24ab676SJeff Bonwick * Only call arc_access on anonymous buffers. This is because 2539b24ab676SJeff Bonwick * if we've issued an I/O for an evicted buffer, we've already 2540b24ab676SJeff Bonwick * called arc_access (to prevent any simultaneous readers from 2541b24ab676SJeff Bonwick * getting confused). 2542b24ab676SJeff Bonwick */ 2543b24ab676SJeff Bonwick arc_access(hdr, hash_lock); 2544b24ab676SJeff Bonwick } 2545b24ab676SJeff Bonwick 2546fa9e4066Sahrens /* create copies of the data buffer for the callers */ 2547fa9e4066Sahrens abuf = buf; 2548fa9e4066Sahrens for (acb = callback_list; acb; acb = acb->acb_next) { 2549fa9e4066Sahrens if (acb->acb_done) { 255044eda4d7Smaybee if (abuf == NULL) 255144eda4d7Smaybee abuf = arc_buf_clone(buf); 2552fa9e4066Sahrens acb->acb_buf = abuf; 2553fa9e4066Sahrens abuf = NULL; 2554fa9e4066Sahrens } 2555fa9e4066Sahrens } 2556fa9e4066Sahrens hdr->b_acb = NULL; 2557fa9e4066Sahrens hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 2558ea8dc4b6Seschrock ASSERT(!HDR_BUF_AVAILABLE(hdr)); 2559b24ab676SJeff Bonwick if (abuf == buf) { 2560b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 2561b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 2562ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 2563b24ab676SJeff Bonwick } 2564fa9e4066Sahrens 2565fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt) || callback_list != NULL); 2566fa9e4066Sahrens 2567fa9e4066Sahrens if (zio->io_error != 0) { 2568fa9e4066Sahrens hdr->b_flags |= ARC_IO_ERROR; 256944cb6abcSbmc if (hdr->b_state != arc_anon) 257044cb6abcSbmc arc_change_state(arc_anon, hdr, hash_lock); 2571ea8dc4b6Seschrock if (HDR_IN_HASH_TABLE(hdr)) 2572ea8dc4b6Seschrock buf_hash_remove(hdr); 2573fa9e4066Sahrens freeable = refcount_is_zero(&hdr->b_refcnt); 2574fa9e4066Sahrens } 2575fa9e4066Sahrens 2576ea8dc4b6Seschrock /* 257713506d1eSmaybee * Broadcast before we drop the hash_lock to avoid the possibility 257813506d1eSmaybee * that the hdr (and hence the cv) might be freed before we get to 257913506d1eSmaybee * the cv_broadcast(). 2580ea8dc4b6Seschrock */ 2581ea8dc4b6Seschrock cv_broadcast(&hdr->b_cv); 2582ea8dc4b6Seschrock 2583bbf4a8dfSmaybee if (hash_lock) { 258444eda4d7Smaybee mutex_exit(hash_lock); 2585fa9e4066Sahrens } else { 2586fa9e4066Sahrens /* 2587fa9e4066Sahrens * This block was freed while we waited for the read to 2588fa9e4066Sahrens * complete. It has been removed from the hash table and 2589fa9e4066Sahrens * moved to the anonymous state (so that it won't show up 2590fa9e4066Sahrens * in the cache). 2591fa9e4066Sahrens */ 259244cb6abcSbmc ASSERT3P(hdr->b_state, ==, arc_anon); 2593fa9e4066Sahrens freeable = refcount_is_zero(&hdr->b_refcnt); 2594fa9e4066Sahrens } 2595fa9e4066Sahrens 2596fa9e4066Sahrens /* execute each callback and free its structure */ 2597fa9e4066Sahrens while ((acb = callback_list) != NULL) { 2598fa9e4066Sahrens if (acb->acb_done) 2599fa9e4066Sahrens acb->acb_done(zio, acb->acb_buf, acb->acb_private); 2600fa9e4066Sahrens 2601fa9e4066Sahrens if (acb->acb_zio_dummy != NULL) { 2602fa9e4066Sahrens acb->acb_zio_dummy->io_error = zio->io_error; 2603fa9e4066Sahrens zio_nowait(acb->acb_zio_dummy); 2604fa9e4066Sahrens } 2605fa9e4066Sahrens 2606fa9e4066Sahrens callback_list = acb->acb_next; 2607fa9e4066Sahrens kmem_free(acb, sizeof (arc_callback_t)); 2608fa9e4066Sahrens } 2609fa9e4066Sahrens 2610fa9e4066Sahrens if (freeable) 2611ea8dc4b6Seschrock arc_hdr_destroy(hdr); 2612fa9e4066Sahrens } 2613fa9e4066Sahrens 2614fa9e4066Sahrens /* 2615fa9e4066Sahrens * "Read" the block block at the specified DVA (in bp) via the 2616fa9e4066Sahrens * cache. If the block is found in the cache, invoke the provided 2617fa9e4066Sahrens * callback immediately and return. Note that the `zio' parameter 2618fa9e4066Sahrens * in the callback will be NULL in this case, since no IO was 2619fa9e4066Sahrens * required. If the block is not in the cache pass the read request 2620fa9e4066Sahrens * on to the spa with a substitute callback function, so that the 2621fa9e4066Sahrens * requested block will be added to the cache. 2622fa9e4066Sahrens * 2623fa9e4066Sahrens * If a read request arrives for a block that has a read in-progress, 2624fa9e4066Sahrens * either wait for the in-progress read to complete (and return the 2625fa9e4066Sahrens * results); or, if this is a read with a "done" func, add a record 2626fa9e4066Sahrens * to the read to invoke the "done" func when the read completes, 2627fa9e4066Sahrens * and return; or just return. 2628fa9e4066Sahrens * 2629fa9e4066Sahrens * arc_read_done() will invoke all the requested "done" functions 2630fa9e4066Sahrens * for readers of this block. 2631088f3894Sahrens * 2632088f3894Sahrens * Normal callers should use arc_read and pass the arc buffer and offset 2633088f3894Sahrens * for the bp. But if you know you don't need locking, you can use 26348ad10dceSSuhasini Peddada * arc_read_bp. 2635fa9e4066Sahrens */ 2636fa9e4066Sahrens int 2637b24ab676SJeff Bonwick arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_buf_t *pbuf, 26383baa08fcSek arc_done_func_t *done, void *private, int priority, int zio_flags, 2639088f3894Sahrens uint32_t *arc_flags, const zbookmark_t *zb) 2640088f3894Sahrens { 2641088f3894Sahrens int err; 2642088f3894Sahrens 2643*3f9d6ad7SLin Ling if (pbuf == NULL) { 2644*3f9d6ad7SLin Ling /* 2645*3f9d6ad7SLin Ling * XXX This happens from traverse callback funcs, for 2646*3f9d6ad7SLin Ling * the objset_phys_t block. 2647*3f9d6ad7SLin Ling */ 2648*3f9d6ad7SLin Ling return (arc_read_nolock(pio, spa, bp, done, private, priority, 2649*3f9d6ad7SLin Ling zio_flags, arc_flags, zb)); 2650*3f9d6ad7SLin Ling } 2651*3f9d6ad7SLin Ling 2652088f3894Sahrens ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt)); 2653088f3894Sahrens ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size); 2654*3f9d6ad7SLin Ling rw_enter(&pbuf->b_data_lock, RW_READER); 2655088f3894Sahrens 2656088f3894Sahrens err = arc_read_nolock(pio, spa, bp, done, private, priority, 26573baa08fcSek zio_flags, arc_flags, zb); 2658*3f9d6ad7SLin Ling rw_exit(&pbuf->b_data_lock); 265914843421SMatthew Ahrens 2660088f3894Sahrens return (err); 2661088f3894Sahrens } 2662088f3894Sahrens 2663088f3894Sahrens int 2664b24ab676SJeff Bonwick arc_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bp, 26653baa08fcSek arc_done_func_t *done, void *private, int priority, int zio_flags, 2666088f3894Sahrens uint32_t *arc_flags, const zbookmark_t *zb) 2667fa9e4066Sahrens { 2668fa9e4066Sahrens arc_buf_hdr_t *hdr; 2669fa9e4066Sahrens arc_buf_t *buf; 2670fa9e4066Sahrens kmutex_t *hash_lock; 2671fa94a07fSbrendan zio_t *rzio; 2672ac05c741SMark Maybee uint64_t guid = spa_guid(spa); 2673fa9e4066Sahrens 2674fa9e4066Sahrens top: 2675b24ab676SJeff Bonwick hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), 2676b24ab676SJeff Bonwick &hash_lock); 2677ea8dc4b6Seschrock if (hdr && hdr->b_datacnt > 0) { 2678fa9e4066Sahrens 267913506d1eSmaybee *arc_flags |= ARC_CACHED; 268013506d1eSmaybee 2681fa9e4066Sahrens if (HDR_IO_IN_PROGRESS(hdr)) { 268213506d1eSmaybee 268313506d1eSmaybee if (*arc_flags & ARC_WAIT) { 268413506d1eSmaybee cv_wait(&hdr->b_cv, hash_lock); 268513506d1eSmaybee mutex_exit(hash_lock); 268613506d1eSmaybee goto top; 268713506d1eSmaybee } 268813506d1eSmaybee ASSERT(*arc_flags & ARC_NOWAIT); 268913506d1eSmaybee 269013506d1eSmaybee if (done) { 2691fa9e4066Sahrens arc_callback_t *acb = NULL; 2692fa9e4066Sahrens 2693fa9e4066Sahrens acb = kmem_zalloc(sizeof (arc_callback_t), 2694fa9e4066Sahrens KM_SLEEP); 2695fa9e4066Sahrens acb->acb_done = done; 2696fa9e4066Sahrens acb->acb_private = private; 2697fa9e4066Sahrens if (pio != NULL) 2698fa9e4066Sahrens acb->acb_zio_dummy = zio_null(pio, 2699a3f829aeSBill Moore spa, NULL, NULL, NULL, zio_flags); 2700fa9e4066Sahrens 2701fa9e4066Sahrens ASSERT(acb->acb_done != NULL); 2702fa9e4066Sahrens acb->acb_next = hdr->b_acb; 2703fa9e4066Sahrens hdr->b_acb = acb; 2704fa9e4066Sahrens add_reference(hdr, hash_lock, private); 2705fa9e4066Sahrens mutex_exit(hash_lock); 2706fa9e4066Sahrens return (0); 2707fa9e4066Sahrens } 2708fa9e4066Sahrens mutex_exit(hash_lock); 2709fa9e4066Sahrens return (0); 2710fa9e4066Sahrens } 2711fa9e4066Sahrens 271244cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 2713fa9e4066Sahrens 2714ea8dc4b6Seschrock if (done) { 271544eda4d7Smaybee add_reference(hdr, hash_lock, private); 2716ea8dc4b6Seschrock /* 2717ea8dc4b6Seschrock * If this block is already in use, create a new 2718ea8dc4b6Seschrock * copy of the data so that we will be guaranteed 2719ea8dc4b6Seschrock * that arc_release() will always succeed. 2720ea8dc4b6Seschrock */ 2721fa9e4066Sahrens buf = hdr->b_buf; 2722ea8dc4b6Seschrock ASSERT(buf); 2723ea8dc4b6Seschrock ASSERT(buf->b_data); 272444eda4d7Smaybee if (HDR_BUF_AVAILABLE(hdr)) { 2725ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 2726ea8dc4b6Seschrock hdr->b_flags &= ~ARC_BUF_AVAILABLE; 272744eda4d7Smaybee } else { 272844eda4d7Smaybee buf = arc_buf_clone(buf); 2729ea8dc4b6Seschrock } 2730b24ab676SJeff Bonwick 273113506d1eSmaybee } else if (*arc_flags & ARC_PREFETCH && 273213506d1eSmaybee refcount_count(&hdr->b_refcnt) == 0) { 273313506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 2734fa9e4066Sahrens } 2735fa9e4066Sahrens DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); 273644eda4d7Smaybee arc_access(hdr, hash_lock); 27373baa08fcSek if (*arc_flags & ARC_L2CACHE) 27383baa08fcSek hdr->b_flags |= ARC_L2CACHE; 273944eda4d7Smaybee mutex_exit(hash_lock); 274044cb6abcSbmc ARCSTAT_BUMP(arcstat_hits); 274144cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 274244cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 274344cb6abcSbmc data, metadata, hits); 274444cb6abcSbmc 2745fa9e4066Sahrens if (done) 2746fa9e4066Sahrens done(NULL, buf, private); 2747fa9e4066Sahrens } else { 2748fa9e4066Sahrens uint64_t size = BP_GET_LSIZE(bp); 2749fa9e4066Sahrens arc_callback_t *acb; 27503a737e0dSbrendan vdev_t *vd = NULL; 2751f9d8334fSGeorge Wilson uint64_t addr; 27525a98e54bSBrendan Gregg - Sun Microsystems boolean_t devw = B_FALSE; 2753fa9e4066Sahrens 2754fa9e4066Sahrens if (hdr == NULL) { 2755fa9e4066Sahrens /* this block is not in the cache */ 2756fa9e4066Sahrens arc_buf_hdr_t *exists; 2757ad23a2dbSjohansen arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); 2758ad23a2dbSjohansen buf = arc_buf_alloc(spa, size, private, type); 2759fa9e4066Sahrens hdr = buf->b_hdr; 2760fa9e4066Sahrens hdr->b_dva = *BP_IDENTITY(bp); 2761b24ab676SJeff Bonwick hdr->b_birth = BP_PHYSICAL_BIRTH(bp); 2762fa9e4066Sahrens hdr->b_cksum0 = bp->blk_cksum.zc_word[0]; 2763fa9e4066Sahrens exists = buf_hash_insert(hdr, &hash_lock); 2764fa9e4066Sahrens if (exists) { 2765fa9e4066Sahrens /* somebody beat us to the hash insert */ 2766fa9e4066Sahrens mutex_exit(hash_lock); 2767*3f9d6ad7SLin Ling buf_discard_identity(hdr); 2768ea8dc4b6Seschrock (void) arc_buf_remove_ref(buf, private); 2769fa9e4066Sahrens goto top; /* restart the IO request */ 2770fa9e4066Sahrens } 277113506d1eSmaybee /* if this is a prefetch, we don't have a reference */ 277213506d1eSmaybee if (*arc_flags & ARC_PREFETCH) { 277313506d1eSmaybee (void) remove_reference(hdr, hash_lock, 277413506d1eSmaybee private); 277513506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 277613506d1eSmaybee } 27773baa08fcSek if (*arc_flags & ARC_L2CACHE) 27783baa08fcSek hdr->b_flags |= ARC_L2CACHE; 277913506d1eSmaybee if (BP_GET_LEVEL(bp) > 0) 278013506d1eSmaybee hdr->b_flags |= ARC_INDIRECT; 2781fa9e4066Sahrens } else { 2782fa9e4066Sahrens /* this block is in the ghost cache */ 2783ea8dc4b6Seschrock ASSERT(GHOST_STATE(hdr->b_state)); 2784ea8dc4b6Seschrock ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 278513506d1eSmaybee ASSERT3U(refcount_count(&hdr->b_refcnt), ==, 0); 2786ea8dc4b6Seschrock ASSERT(hdr->b_buf == NULL); 278713506d1eSmaybee 278813506d1eSmaybee /* if this is a prefetch, we don't have a reference */ 278913506d1eSmaybee if (*arc_flags & ARC_PREFETCH) 279013506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 279113506d1eSmaybee else 279213506d1eSmaybee add_reference(hdr, hash_lock, private); 27933baa08fcSek if (*arc_flags & ARC_L2CACHE) 27943baa08fcSek hdr->b_flags |= ARC_L2CACHE; 27951ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 2796fa9e4066Sahrens buf->b_hdr = hdr; 279744eda4d7Smaybee buf->b_data = NULL; 2798ea8dc4b6Seschrock buf->b_efunc = NULL; 2799ea8dc4b6Seschrock buf->b_private = NULL; 2800fa9e4066Sahrens buf->b_next = NULL; 2801fa9e4066Sahrens hdr->b_buf = buf; 2802ea8dc4b6Seschrock ASSERT(hdr->b_datacnt == 0); 2803ea8dc4b6Seschrock hdr->b_datacnt = 1; 28045614b00aSWilliam Gorrell arc_get_data_buf(buf); 28057e453561SWilliam Gorrell arc_access(hdr, hash_lock); 2806fa9e4066Sahrens } 2807fa9e4066Sahrens 28085614b00aSWilliam Gorrell ASSERT(!GHOST_STATE(hdr->b_state)); 28095614b00aSWilliam Gorrell 2810fa9e4066Sahrens acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP); 2811fa9e4066Sahrens acb->acb_done = done; 2812fa9e4066Sahrens acb->acb_private = private; 2813fa9e4066Sahrens 2814fa9e4066Sahrens ASSERT(hdr->b_acb == NULL); 2815fa9e4066Sahrens hdr->b_acb = acb; 2816fa9e4066Sahrens hdr->b_flags |= ARC_IO_IN_PROGRESS; 2817fa9e4066Sahrens 2818e14bb325SJeff Bonwick if (HDR_L2CACHE(hdr) && hdr->b_l2hdr != NULL && 2819e14bb325SJeff Bonwick (vd = hdr->b_l2hdr->b_dev->l2ad_vdev) != NULL) { 28205a98e54bSBrendan Gregg - Sun Microsystems devw = hdr->b_l2hdr->b_dev->l2ad_writing; 28213a737e0dSbrendan addr = hdr->b_l2hdr->b_daddr; 2822e14bb325SJeff Bonwick /* 2823e14bb325SJeff Bonwick * Lock out device removal. 2824e14bb325SJeff Bonwick */ 2825e14bb325SJeff Bonwick if (vdev_is_dead(vd) || 2826e14bb325SJeff Bonwick !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) 2827e14bb325SJeff Bonwick vd = NULL; 28283a737e0dSbrendan } 28293a737e0dSbrendan 28303a737e0dSbrendan mutex_exit(hash_lock); 28313a737e0dSbrendan 2832fa9e4066Sahrens ASSERT3U(hdr->b_size, ==, size); 28335c28183bSBrendan Gregg - Sun Microsystems DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, 28345c28183bSBrendan Gregg - Sun Microsystems uint64_t, size, zbookmark_t *, zb); 283544cb6abcSbmc ARCSTAT_BUMP(arcstat_misses); 283644cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 283744cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 283844cb6abcSbmc data, metadata, misses); 2839ea8dc4b6Seschrock 28405a98e54bSBrendan Gregg - Sun Microsystems if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) { 2841fa94a07fSbrendan /* 2842fa94a07fSbrendan * Read from the L2ARC if the following are true: 28433a737e0dSbrendan * 1. The L2ARC vdev was previously cached. 28443a737e0dSbrendan * 2. This buffer still has L2ARC metadata. 28453a737e0dSbrendan * 3. This buffer isn't currently writing to the L2ARC. 28463a737e0dSbrendan * 4. The L2ARC entry wasn't evicted, which may 28473a737e0dSbrendan * also have invalidated the vdev. 28485a98e54bSBrendan Gregg - Sun Microsystems * 5. This isn't prefetch and l2arc_noprefetch is set. 2849fa94a07fSbrendan */ 2850e14bb325SJeff Bonwick if (hdr->b_l2hdr != NULL && 28515a98e54bSBrendan Gregg - Sun Microsystems !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && 28525a98e54bSBrendan Gregg - Sun Microsystems !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { 2853fa94a07fSbrendan l2arc_read_callback_t *cb; 2854fa94a07fSbrendan 2855c5904d13Seschrock DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); 2856c5904d13Seschrock ARCSTAT_BUMP(arcstat_l2_hits); 2857c5904d13Seschrock 2858fa94a07fSbrendan cb = kmem_zalloc(sizeof (l2arc_read_callback_t), 2859fa94a07fSbrendan KM_SLEEP); 2860fa94a07fSbrendan cb->l2rcb_buf = buf; 2861fa94a07fSbrendan cb->l2rcb_spa = spa; 2862fa94a07fSbrendan cb->l2rcb_bp = *bp; 2863fa94a07fSbrendan cb->l2rcb_zb = *zb; 28643baa08fcSek cb->l2rcb_flags = zio_flags; 2865fa94a07fSbrendan 2866fa94a07fSbrendan /* 2867e14bb325SJeff Bonwick * l2arc read. The SCL_L2ARC lock will be 2868e14bb325SJeff Bonwick * released by l2arc_read_done(). 2869fa94a07fSbrendan */ 2870fa94a07fSbrendan rzio = zio_read_phys(pio, vd, addr, size, 2871fa94a07fSbrendan buf->b_data, ZIO_CHECKSUM_OFF, 28723baa08fcSek l2arc_read_done, cb, priority, zio_flags | 287349cf58c0SBrendan Gregg - Sun Microsystems ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | 2874e14bb325SJeff Bonwick ZIO_FLAG_DONT_PROPAGATE | 2875e14bb325SJeff Bonwick ZIO_FLAG_DONT_RETRY, B_FALSE); 2876fa94a07fSbrendan DTRACE_PROBE2(l2arc__read, vdev_t *, vd, 2877fa94a07fSbrendan zio_t *, rzio); 28785a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_read_bytes, size); 2879fa94a07fSbrendan 28803a737e0dSbrendan if (*arc_flags & ARC_NOWAIT) { 28813a737e0dSbrendan zio_nowait(rzio); 28823a737e0dSbrendan return (0); 28833a737e0dSbrendan } 2884fa94a07fSbrendan 28853a737e0dSbrendan ASSERT(*arc_flags & ARC_WAIT); 28863a737e0dSbrendan if (zio_wait(rzio) == 0) 28873a737e0dSbrendan return (0); 28883a737e0dSbrendan 28893a737e0dSbrendan /* l2arc read error; goto zio_read() */ 2890fa94a07fSbrendan } else { 2891fa94a07fSbrendan DTRACE_PROBE1(l2arc__miss, 2892fa94a07fSbrendan arc_buf_hdr_t *, hdr); 2893fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_misses); 2894fa94a07fSbrendan if (HDR_L2_WRITING(hdr)) 2895fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_rw_clash); 2896e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, vd); 2897fa94a07fSbrendan } 28985a98e54bSBrendan Gregg - Sun Microsystems } else { 289976a25fafSBill Moore if (vd != NULL) 290076a25fafSBill Moore spa_config_exit(spa, SCL_L2ARC, vd); 29015a98e54bSBrendan Gregg - Sun Microsystems if (l2arc_ndev != 0) { 29025a98e54bSBrendan Gregg - Sun Microsystems DTRACE_PROBE1(l2arc__miss, 29035a98e54bSBrendan Gregg - Sun Microsystems arc_buf_hdr_t *, hdr); 29045a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_BUMP(arcstat_l2_misses); 29055a98e54bSBrendan Gregg - Sun Microsystems } 2906fa94a07fSbrendan } 2907c5904d13Seschrock 2908fa9e4066Sahrens rzio = zio_read(pio, spa, bp, buf->b_data, size, 29093baa08fcSek arc_read_done, buf, priority, zio_flags, zb); 2910fa9e4066Sahrens 291113506d1eSmaybee if (*arc_flags & ARC_WAIT) 2912fa9e4066Sahrens return (zio_wait(rzio)); 2913fa9e4066Sahrens 291413506d1eSmaybee ASSERT(*arc_flags & ARC_NOWAIT); 2915fa9e4066Sahrens zio_nowait(rzio); 2916fa9e4066Sahrens } 2917fa9e4066Sahrens return (0); 2918fa9e4066Sahrens } 2919fa9e4066Sahrens 2920ea8dc4b6Seschrock void 2921ea8dc4b6Seschrock arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private) 2922ea8dc4b6Seschrock { 2923ea8dc4b6Seschrock ASSERT(buf->b_hdr != NULL); 292444cb6abcSbmc ASSERT(buf->b_hdr->b_state != arc_anon); 2925ea8dc4b6Seschrock ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt) || func == NULL); 2926b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 2927b24ab676SJeff Bonwick ASSERT(!HDR_BUF_AVAILABLE(buf->b_hdr)); 2928b24ab676SJeff Bonwick 2929ea8dc4b6Seschrock buf->b_efunc = func; 2930ea8dc4b6Seschrock buf->b_private = private; 2931ea8dc4b6Seschrock } 2932ea8dc4b6Seschrock 2933ea8dc4b6Seschrock /* 2934ea8dc4b6Seschrock * This is used by the DMU to let the ARC know that a buffer is 2935ea8dc4b6Seschrock * being evicted, so the ARC should clean up. If this arc buf 2936ea8dc4b6Seschrock * is not yet in the evicted state, it will be put there. 2937ea8dc4b6Seschrock */ 2938ea8dc4b6Seschrock int 2939ea8dc4b6Seschrock arc_buf_evict(arc_buf_t *buf) 2940ea8dc4b6Seschrock { 294140d7d650Smaybee arc_buf_hdr_t *hdr; 2942ea8dc4b6Seschrock kmutex_t *hash_lock; 2943ea8dc4b6Seschrock arc_buf_t **bufp; 2944ea8dc4b6Seschrock 2945*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 294640d7d650Smaybee hdr = buf->b_hdr; 2947ea8dc4b6Seschrock if (hdr == NULL) { 2948ea8dc4b6Seschrock /* 2949ea8dc4b6Seschrock * We are in arc_do_user_evicts(). 2950ea8dc4b6Seschrock */ 2951ea8dc4b6Seschrock ASSERT(buf->b_data == NULL); 2952*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 2953ea8dc4b6Seschrock return (0); 29546f83844dSMark Maybee } else if (buf->b_data == NULL) { 29556f83844dSMark Maybee arc_buf_t copy = *buf; /* structure assignment */ 29569b23f181Smaybee /* 29576f83844dSMark Maybee * We are on the eviction list; process this buffer now 29586f83844dSMark Maybee * but let arc_do_user_evicts() do the reaping. 29599b23f181Smaybee */ 29606f83844dSMark Maybee buf->b_efunc = NULL; 2961*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 29626f83844dSMark Maybee VERIFY(copy.b_efunc(©) == 0); 29636f83844dSMark Maybee return (1); 29649b23f181Smaybee } 29656f83844dSMark Maybee hash_lock = HDR_LOCK(hdr); 29666f83844dSMark Maybee mutex_enter(hash_lock); 2967*3f9d6ad7SLin Ling hdr = buf->b_hdr; 2968*3f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 29699b23f181Smaybee 29709b23f181Smaybee ASSERT3U(refcount_count(&hdr->b_refcnt), <, hdr->b_datacnt); 297144cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 2972ea8dc4b6Seschrock 2973ea8dc4b6Seschrock /* 2974ea8dc4b6Seschrock * Pull this buffer off of the hdr 2975ea8dc4b6Seschrock */ 2976ea8dc4b6Seschrock bufp = &hdr->b_buf; 2977ea8dc4b6Seschrock while (*bufp != buf) 2978ea8dc4b6Seschrock bufp = &(*bufp)->b_next; 2979ea8dc4b6Seschrock *bufp = buf->b_next; 2980ea8dc4b6Seschrock 2981ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 298244eda4d7Smaybee arc_buf_destroy(buf, FALSE, FALSE); 2983ea8dc4b6Seschrock 2984ea8dc4b6Seschrock if (hdr->b_datacnt == 0) { 2985ea8dc4b6Seschrock arc_state_t *old_state = hdr->b_state; 2986ea8dc4b6Seschrock arc_state_t *evicted_state; 2987ea8dc4b6Seschrock 2988*3f9d6ad7SLin Ling ASSERT(hdr->b_buf == NULL); 2989ea8dc4b6Seschrock ASSERT(refcount_is_zero(&hdr->b_refcnt)); 2990ea8dc4b6Seschrock 2991ea8dc4b6Seschrock evicted_state = 299244cb6abcSbmc (old_state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; 2993ea8dc4b6Seschrock 299444cb6abcSbmc mutex_enter(&old_state->arcs_mtx); 299544cb6abcSbmc mutex_enter(&evicted_state->arcs_mtx); 2996ea8dc4b6Seschrock 2997ea8dc4b6Seschrock arc_change_state(evicted_state, hdr, hash_lock); 2998ea8dc4b6Seschrock ASSERT(HDR_IN_HASH_TABLE(hdr)); 2999fa94a07fSbrendan hdr->b_flags |= ARC_IN_HASH_TABLE; 3000fa94a07fSbrendan hdr->b_flags &= ~ARC_BUF_AVAILABLE; 3001ea8dc4b6Seschrock 300244cb6abcSbmc mutex_exit(&evicted_state->arcs_mtx); 300344cb6abcSbmc mutex_exit(&old_state->arcs_mtx); 3004ea8dc4b6Seschrock } 3005ea8dc4b6Seschrock mutex_exit(hash_lock); 3006*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 3007dd6ef538Smaybee 3008ea8dc4b6Seschrock VERIFY(buf->b_efunc(buf) == 0); 3009ea8dc4b6Seschrock buf->b_efunc = NULL; 3010ea8dc4b6Seschrock buf->b_private = NULL; 3011ea8dc4b6Seschrock buf->b_hdr = NULL; 3012*3f9d6ad7SLin Ling buf->b_next = NULL; 3013ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 3014ea8dc4b6Seschrock return (1); 3015ea8dc4b6Seschrock } 3016ea8dc4b6Seschrock 3017fa9e4066Sahrens /* 3018fa9e4066Sahrens * Release this buffer from the cache. This must be done 3019fa9e4066Sahrens * after a read and prior to modifying the buffer contents. 3020fa9e4066Sahrens * If the buffer has more than one reference, we must make 3021088f3894Sahrens * a new hdr for the buffer. 3022fa9e4066Sahrens */ 3023fa9e4066Sahrens void 3024fa9e4066Sahrens arc_release(arc_buf_t *buf, void *tag) 3025fa9e4066Sahrens { 30266f83844dSMark Maybee arc_buf_hdr_t *hdr; 3027*3f9d6ad7SLin Ling kmutex_t *hash_lock = NULL; 30286f83844dSMark Maybee l2arc_buf_hdr_t *l2hdr; 3029fa94a07fSbrendan uint64_t buf_size; 3030fa9e4066Sahrens 3031*3f9d6ad7SLin Ling /* 3032*3f9d6ad7SLin Ling * It would be nice to assert that if it's DMU metadata (level > 3033*3f9d6ad7SLin Ling * 0 || it's the dnode file), then it must be syncing context. 3034*3f9d6ad7SLin Ling * But we don't know that information at this level. 3035*3f9d6ad7SLin Ling */ 3036*3f9d6ad7SLin Ling 3037*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 30386f83844dSMark Maybee hdr = buf->b_hdr; 30396f83844dSMark Maybee 3040fa9e4066Sahrens /* this buffer is not on any list */ 3041fa9e4066Sahrens ASSERT(refcount_count(&hdr->b_refcnt) > 0); 3042fa9e4066Sahrens 304344cb6abcSbmc if (hdr->b_state == arc_anon) { 3044fa9e4066Sahrens /* this buffer is already released */ 3045ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 30460a95608cSBrendan Gregg - Sun Microsystems } else { 30470a95608cSBrendan Gregg - Sun Microsystems hash_lock = HDR_LOCK(hdr); 30480a95608cSBrendan Gregg - Sun Microsystems mutex_enter(hash_lock); 3049*3f9d6ad7SLin Ling hdr = buf->b_hdr; 3050*3f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 3051fa9e4066Sahrens } 3052fa9e4066Sahrens 30536f83844dSMark Maybee l2hdr = hdr->b_l2hdr; 30546f83844dSMark Maybee if (l2hdr) { 30556f83844dSMark Maybee mutex_enter(&l2arc_buflist_mtx); 30566f83844dSMark Maybee hdr->b_l2hdr = NULL; 30576f83844dSMark Maybee buf_size = hdr->b_size; 30586f83844dSMark Maybee } 30596f83844dSMark Maybee 3060ea8dc4b6Seschrock /* 3061ea8dc4b6Seschrock * Do we have more than one buf? 3062ea8dc4b6Seschrock */ 30636f83844dSMark Maybee if (hdr->b_datacnt > 1) { 3064fa9e4066Sahrens arc_buf_hdr_t *nhdr; 3065fa9e4066Sahrens arc_buf_t **bufp; 3066fa9e4066Sahrens uint64_t blksz = hdr->b_size; 3067ac05c741SMark Maybee uint64_t spa = hdr->b_spa; 3068ad23a2dbSjohansen arc_buf_contents_t type = hdr->b_type; 3069fa94a07fSbrendan uint32_t flags = hdr->b_flags; 3070fa9e4066Sahrens 30716f83844dSMark Maybee ASSERT(hdr->b_buf != buf || buf->b_next != NULL); 3072fa9e4066Sahrens /* 3073*3f9d6ad7SLin Ling * Pull the data off of this hdr and attach it to 3074*3f9d6ad7SLin Ling * a new anonymous hdr. 3075fa9e4066Sahrens */ 3076ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 3077fa9e4066Sahrens bufp = &hdr->b_buf; 3078ea8dc4b6Seschrock while (*bufp != buf) 3079fa9e4066Sahrens bufp = &(*bufp)->b_next; 3080*3f9d6ad7SLin Ling *bufp = buf->b_next; 3081af2c4821Smaybee buf->b_next = NULL; 3082ea8dc4b6Seschrock 308344cb6abcSbmc ASSERT3U(hdr->b_state->arcs_size, >=, hdr->b_size); 308444cb6abcSbmc atomic_add_64(&hdr->b_state->arcs_size, -hdr->b_size); 3085ea8dc4b6Seschrock if (refcount_is_zero(&hdr->b_refcnt)) { 30860e8c6158Smaybee uint64_t *size = &hdr->b_state->arcs_lsize[hdr->b_type]; 30870e8c6158Smaybee ASSERT3U(*size, >=, hdr->b_size); 30880e8c6158Smaybee atomic_add_64(size, -hdr->b_size); 3089ea8dc4b6Seschrock } 3090ea8dc4b6Seschrock hdr->b_datacnt -= 1; 3091c717a561Smaybee arc_cksum_verify(buf); 3092ea8dc4b6Seschrock 3093fa9e4066Sahrens mutex_exit(hash_lock); 3094fa9e4066Sahrens 30951ab7f2deSmaybee nhdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 3096fa9e4066Sahrens nhdr->b_size = blksz; 3097fa9e4066Sahrens nhdr->b_spa = spa; 3098ad23a2dbSjohansen nhdr->b_type = type; 3099fa9e4066Sahrens nhdr->b_buf = buf; 310044cb6abcSbmc nhdr->b_state = arc_anon; 3101fa9e4066Sahrens nhdr->b_arc_access = 0; 3102fa94a07fSbrendan nhdr->b_flags = flags & ARC_L2_WRITING; 3103fa94a07fSbrendan nhdr->b_l2hdr = NULL; 3104ea8dc4b6Seschrock nhdr->b_datacnt = 1; 3105c717a561Smaybee nhdr->b_freeze_cksum = NULL; 3106fa9e4066Sahrens (void) refcount_add(&nhdr->b_refcnt, tag); 3107af2c4821Smaybee buf->b_hdr = nhdr; 3108*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 310944cb6abcSbmc atomic_add_64(&arc_anon->arcs_size, blksz); 3110fa9e4066Sahrens } else { 3111*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 3112ea8dc4b6Seschrock ASSERT(refcount_count(&hdr->b_refcnt) == 1); 3113fa9e4066Sahrens ASSERT(!list_link_active(&hdr->b_arc_node)); 3114fa9e4066Sahrens ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 3115*3f9d6ad7SLin Ling if (hdr->b_state != arc_anon) 3116*3f9d6ad7SLin Ling arc_change_state(arc_anon, hdr, hash_lock); 3117fa9e4066Sahrens hdr->b_arc_access = 0; 3118*3f9d6ad7SLin Ling if (hash_lock) 3119*3f9d6ad7SLin Ling mutex_exit(hash_lock); 3120fa94a07fSbrendan 3121*3f9d6ad7SLin Ling buf_discard_identity(hdr); 3122c717a561Smaybee arc_buf_thaw(buf); 3123fa9e4066Sahrens } 3124ea8dc4b6Seschrock buf->b_efunc = NULL; 3125ea8dc4b6Seschrock buf->b_private = NULL; 3126fa94a07fSbrendan 3127fa94a07fSbrendan if (l2hdr) { 3128fa94a07fSbrendan list_remove(l2hdr->b_dev->l2ad_buflist, hdr); 3129fa94a07fSbrendan kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); 3130fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, -buf_size); 3131fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 31326f83844dSMark Maybee } 3133fa9e4066Sahrens } 3134fa9e4066Sahrens 3135*3f9d6ad7SLin Ling /* 3136*3f9d6ad7SLin Ling * Release this buffer. If it does not match the provided BP, fill it 3137*3f9d6ad7SLin Ling * with that block's contents. 3138*3f9d6ad7SLin Ling */ 3139*3f9d6ad7SLin Ling /* ARGSUSED */ 3140*3f9d6ad7SLin Ling int 3141*3f9d6ad7SLin Ling arc_release_bp(arc_buf_t *buf, void *tag, blkptr_t *bp, spa_t *spa, 3142*3f9d6ad7SLin Ling zbookmark_t *zb) 3143*3f9d6ad7SLin Ling { 3144*3f9d6ad7SLin Ling arc_release(buf, tag); 3145*3f9d6ad7SLin Ling return (0); 3146*3f9d6ad7SLin Ling } 3147*3f9d6ad7SLin Ling 3148fa9e4066Sahrens int 3149fa9e4066Sahrens arc_released(arc_buf_t *buf) 3150fa9e4066Sahrens { 31516f83844dSMark Maybee int released; 31526f83844dSMark Maybee 3153*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 31546f83844dSMark Maybee released = (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon); 3155*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 31566f83844dSMark Maybee return (released); 3157ea8dc4b6Seschrock } 3158ea8dc4b6Seschrock 3159ea8dc4b6Seschrock int 3160ea8dc4b6Seschrock arc_has_callback(arc_buf_t *buf) 3161ea8dc4b6Seschrock { 31626f83844dSMark Maybee int callback; 31636f83844dSMark Maybee 3164*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 31656f83844dSMark Maybee callback = (buf->b_efunc != NULL); 3166*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 31676f83844dSMark Maybee return (callback); 3168fa9e4066Sahrens } 3169fa9e4066Sahrens 3170ea8dc4b6Seschrock #ifdef ZFS_DEBUG 3171ea8dc4b6Seschrock int 3172ea8dc4b6Seschrock arc_referenced(arc_buf_t *buf) 3173ea8dc4b6Seschrock { 31746f83844dSMark Maybee int referenced; 31756f83844dSMark Maybee 3176*3f9d6ad7SLin Ling mutex_enter(&buf->b_evict_lock); 31776f83844dSMark Maybee referenced = (refcount_count(&buf->b_hdr->b_refcnt)); 3178*3f9d6ad7SLin Ling mutex_exit(&buf->b_evict_lock); 31796f83844dSMark Maybee return (referenced); 3180ea8dc4b6Seschrock } 3181ea8dc4b6Seschrock #endif 3182ea8dc4b6Seschrock 3183c717a561Smaybee static void 3184c717a561Smaybee arc_write_ready(zio_t *zio) 3185c717a561Smaybee { 3186c717a561Smaybee arc_write_callback_t *callback = zio->io_private; 3187c717a561Smaybee arc_buf_t *buf = callback->awcb_buf; 31880a4e9518Sgw arc_buf_hdr_t *hdr = buf->b_hdr; 3189c717a561Smaybee 3190e14bb325SJeff Bonwick ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt)); 3191e14bb325SJeff Bonwick callback->awcb_ready(zio, buf, callback->awcb_private); 3192e14bb325SJeff Bonwick 31930a4e9518Sgw /* 31940a4e9518Sgw * If the IO is already in progress, then this is a re-write 3195e14bb325SJeff Bonwick * attempt, so we need to thaw and re-compute the cksum. 3196e14bb325SJeff Bonwick * It is the responsibility of the callback to handle the 3197e14bb325SJeff Bonwick * accounting for any re-write attempt. 31980a4e9518Sgw */ 31990a4e9518Sgw if (HDR_IO_IN_PROGRESS(hdr)) { 32000a4e9518Sgw mutex_enter(&hdr->b_freeze_lock); 32010a4e9518Sgw if (hdr->b_freeze_cksum != NULL) { 32020a4e9518Sgw kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 32030a4e9518Sgw hdr->b_freeze_cksum = NULL; 32040a4e9518Sgw } 32050a4e9518Sgw mutex_exit(&hdr->b_freeze_lock); 32060a4e9518Sgw } 3207fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 32080a4e9518Sgw hdr->b_flags |= ARC_IO_IN_PROGRESS; 3209c717a561Smaybee } 3210c717a561Smaybee 3211fa9e4066Sahrens static void 3212fa9e4066Sahrens arc_write_done(zio_t *zio) 3213fa9e4066Sahrens { 3214c717a561Smaybee arc_write_callback_t *callback = zio->io_private; 3215c717a561Smaybee arc_buf_t *buf = callback->awcb_buf; 3216c717a561Smaybee arc_buf_hdr_t *hdr = buf->b_hdr; 3217fa9e4066Sahrens 3218b24ab676SJeff Bonwick ASSERT(hdr->b_acb == NULL); 3219b24ab676SJeff Bonwick 3220b24ab676SJeff Bonwick if (zio->io_error == 0) { 3221b24ab676SJeff Bonwick hdr->b_dva = *BP_IDENTITY(zio->io_bp); 3222b24ab676SJeff Bonwick hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); 3223b24ab676SJeff Bonwick hdr->b_cksum0 = zio->io_bp->blk_cksum.zc_word[0]; 3224b24ab676SJeff Bonwick } else { 3225b24ab676SJeff Bonwick ASSERT(BUF_EMPTY(hdr)); 3226b24ab676SJeff Bonwick } 3227fa9e4066Sahrens 3228ea8dc4b6Seschrock /* 3229ea8dc4b6Seschrock * If the block to be written was all-zero, we may have 3230ea8dc4b6Seschrock * compressed it away. In this case no write was performed 3231*3f9d6ad7SLin Ling * so there will be no dva/birth/checksum. The buffer must 3232*3f9d6ad7SLin Ling * therefore remain anonymous (and uncached). 3233ea8dc4b6Seschrock */ 3234fa9e4066Sahrens if (!BUF_EMPTY(hdr)) { 3235fa9e4066Sahrens arc_buf_hdr_t *exists; 3236fa9e4066Sahrens kmutex_t *hash_lock; 3237fa9e4066Sahrens 3238b24ab676SJeff Bonwick ASSERT(zio->io_error == 0); 3239b24ab676SJeff Bonwick 32406b4acc8bSahrens arc_cksum_verify(buf); 32416b4acc8bSahrens 3242fa9e4066Sahrens exists = buf_hash_insert(hdr, &hash_lock); 3243fa9e4066Sahrens if (exists) { 3244fa9e4066Sahrens /* 3245fa9e4066Sahrens * This can only happen if we overwrite for 3246fa9e4066Sahrens * sync-to-convergence, because we remove 3247fa9e4066Sahrens * buffers from the hash table when we arc_free(). 3248fa9e4066Sahrens */ 3249b24ab676SJeff Bonwick if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { 3250b24ab676SJeff Bonwick if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) 3251b24ab676SJeff Bonwick panic("bad overwrite, hdr=%p exists=%p", 3252b24ab676SJeff Bonwick (void *)hdr, (void *)exists); 3253b24ab676SJeff Bonwick ASSERT(refcount_is_zero(&exists->b_refcnt)); 3254b24ab676SJeff Bonwick arc_change_state(arc_anon, exists, hash_lock); 3255b24ab676SJeff Bonwick mutex_exit(hash_lock); 3256b24ab676SJeff Bonwick arc_hdr_destroy(exists); 3257b24ab676SJeff Bonwick exists = buf_hash_insert(hdr, &hash_lock); 3258b24ab676SJeff Bonwick ASSERT3P(exists, ==, NULL); 3259b24ab676SJeff Bonwick } else { 3260b24ab676SJeff Bonwick /* Dedup */ 3261b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 3262b24ab676SJeff Bonwick ASSERT(hdr->b_state == arc_anon); 3263b24ab676SJeff Bonwick ASSERT(BP_GET_DEDUP(zio->io_bp)); 3264b24ab676SJeff Bonwick ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); 3265ae46e4c7SMatthew Ahrens } 3266fa9e4066Sahrens } 3267ea8dc4b6Seschrock hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 3268088f3894Sahrens /* if it's not anon, we are doing a scrub */ 3269b24ab676SJeff Bonwick if (!exists && hdr->b_state == arc_anon) 3270088f3894Sahrens arc_access(hdr, hash_lock); 327144eda4d7Smaybee mutex_exit(hash_lock); 3272ea8dc4b6Seschrock } else { 3273ea8dc4b6Seschrock hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 3274fa9e4066Sahrens } 3275ea8dc4b6Seschrock 3276b24ab676SJeff Bonwick ASSERT(!refcount_is_zero(&hdr->b_refcnt)); 3277b24ab676SJeff Bonwick callback->awcb_done(zio, buf, callback->awcb_private); 3278fa9e4066Sahrens 3279c717a561Smaybee kmem_free(callback, sizeof (arc_write_callback_t)); 3280fa9e4066Sahrens } 3281fa9e4066Sahrens 3282c717a561Smaybee zio_t * 3283b24ab676SJeff Bonwick arc_write(zio_t *pio, spa_t *spa, uint64_t txg, 3284b24ab676SJeff Bonwick blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp, 3285b24ab676SJeff Bonwick arc_done_func_t *ready, arc_done_func_t *done, void *private, 3286b24ab676SJeff Bonwick int priority, int zio_flags, const zbookmark_t *zb) 3287fa9e4066Sahrens { 3288fa9e4066Sahrens arc_buf_hdr_t *hdr = buf->b_hdr; 3289c717a561Smaybee arc_write_callback_t *callback; 3290e14bb325SJeff Bonwick zio_t *zio; 3291fa9e4066Sahrens 3292e14bb325SJeff Bonwick ASSERT(ready != NULL); 3293b24ab676SJeff Bonwick ASSERT(done != NULL); 3294fa9e4066Sahrens ASSERT(!HDR_IO_ERROR(hdr)); 3295c5c6ffa0Smaybee ASSERT((hdr->b_flags & ARC_IO_IN_PROGRESS) == 0); 3296b24ab676SJeff Bonwick ASSERT(hdr->b_acb == NULL); 32973baa08fcSek if (l2arc) 32983baa08fcSek hdr->b_flags |= ARC_L2CACHE; 3299c717a561Smaybee callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP); 3300c717a561Smaybee callback->awcb_ready = ready; 3301c717a561Smaybee callback->awcb_done = done; 3302c717a561Smaybee callback->awcb_private = private; 3303c717a561Smaybee callback->awcb_buf = buf; 3304088f3894Sahrens 3305b24ab676SJeff Bonwick zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, zp, 3306e14bb325SJeff Bonwick arc_write_ready, arc_write_done, callback, priority, zio_flags, zb); 3307fa9e4066Sahrens 3308c717a561Smaybee return (zio); 3309fa9e4066Sahrens } 3310fa9e4066Sahrens 3311b24ab676SJeff Bonwick void 3312b24ab676SJeff Bonwick arc_free(spa_t *spa, const blkptr_t *bp) 3313fa9e4066Sahrens { 3314fa9e4066Sahrens arc_buf_hdr_t *ab; 3315fa9e4066Sahrens kmutex_t *hash_lock; 3316ac05c741SMark Maybee uint64_t guid = spa_guid(spa); 3317fa9e4066Sahrens 3318fa9e4066Sahrens /* 3319b24ab676SJeff Bonwick * If this buffer is in the cache, release it, so it can be re-used. 3320fa9e4066Sahrens */ 3321b24ab676SJeff Bonwick ab = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), 3322b24ab676SJeff Bonwick &hash_lock); 3323fa9e4066Sahrens if (ab != NULL) { 332444cb6abcSbmc if (ab->b_state != arc_anon) 332544cb6abcSbmc arc_change_state(arc_anon, ab, hash_lock); 332613506d1eSmaybee if (HDR_IO_IN_PROGRESS(ab)) { 332713506d1eSmaybee /* 332813506d1eSmaybee * This should only happen when we prefetch. 332913506d1eSmaybee */ 333013506d1eSmaybee ASSERT(ab->b_flags & ARC_PREFETCH); 333113506d1eSmaybee ASSERT3U(ab->b_datacnt, ==, 1); 333213506d1eSmaybee ab->b_flags |= ARC_FREED_IN_READ; 333313506d1eSmaybee if (HDR_IN_HASH_TABLE(ab)) 333413506d1eSmaybee buf_hash_remove(ab); 333513506d1eSmaybee ab->b_arc_access = 0; 3336*3f9d6ad7SLin Ling buf_discard_identity(ab); 333713506d1eSmaybee ab->b_buf->b_efunc = NULL; 333813506d1eSmaybee ab->b_buf->b_private = NULL; 333913506d1eSmaybee mutex_exit(hash_lock); 3340b24ab676SJeff Bonwick } else { 3341b24ab676SJeff Bonwick ASSERT(refcount_is_zero(&ab->b_refcnt)); 3342fa94a07fSbrendan ab->b_flags |= ARC_FREE_IN_PROGRESS; 3343fa9e4066Sahrens mutex_exit(hash_lock); 3344ea8dc4b6Seschrock arc_hdr_destroy(ab); 334544cb6abcSbmc ARCSTAT_BUMP(arcstat_deleted); 3346fa9e4066Sahrens } 3347fa9e4066Sahrens } 3348fa9e4066Sahrens } 3349fa9e4066Sahrens 33501ab7f2deSmaybee static int 33512fdbea25SAleksandr Guzovskiy arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg) 33521ab7f2deSmaybee { 33531ab7f2deSmaybee #ifdef _KERNEL 33541ab7f2deSmaybee uint64_t available_memory = ptob(freemem); 33551ab7f2deSmaybee static uint64_t page_load = 0; 33561ab7f2deSmaybee static uint64_t last_txg = 0; 33571ab7f2deSmaybee 33581ab7f2deSmaybee #if defined(__i386) 33591ab7f2deSmaybee available_memory = 33601ab7f2deSmaybee MIN(available_memory, vmem_size(heap_arena, VMEM_FREE)); 33611ab7f2deSmaybee #endif 33621ab7f2deSmaybee if (available_memory >= zfs_write_limit_max) 33631ab7f2deSmaybee return (0); 33641ab7f2deSmaybee 33651ab7f2deSmaybee if (txg > last_txg) { 33661ab7f2deSmaybee last_txg = txg; 33671ab7f2deSmaybee page_load = 0; 33681ab7f2deSmaybee } 33691ab7f2deSmaybee /* 33701ab7f2deSmaybee * If we are in pageout, we know that memory is already tight, 33711ab7f2deSmaybee * the arc is already going to be evicting, so we just want to 33721ab7f2deSmaybee * continue to let page writes occur as quickly as possible. 33731ab7f2deSmaybee */ 33741ab7f2deSmaybee if (curproc == proc_pageout) { 33751ab7f2deSmaybee if (page_load > MAX(ptob(minfree), available_memory) / 4) 33761ab7f2deSmaybee return (ERESTART); 33771ab7f2deSmaybee /* Note: reserve is inflated, so we deflate */ 33781ab7f2deSmaybee page_load += reserve / 8; 33791ab7f2deSmaybee return (0); 33801ab7f2deSmaybee } else if (page_load > 0 && arc_reclaim_needed()) { 33811ab7f2deSmaybee /* memory is low, delay before restarting */ 33821ab7f2deSmaybee ARCSTAT_INCR(arcstat_memory_throttle_count, 1); 33831ab7f2deSmaybee return (EAGAIN); 33841ab7f2deSmaybee } 33851ab7f2deSmaybee page_load = 0; 33861ab7f2deSmaybee 33871ab7f2deSmaybee if (arc_size > arc_c_min) { 33881ab7f2deSmaybee uint64_t evictable_memory = 33891ab7f2deSmaybee arc_mru->arcs_lsize[ARC_BUFC_DATA] + 33901ab7f2deSmaybee arc_mru->arcs_lsize[ARC_BUFC_METADATA] + 33911ab7f2deSmaybee arc_mfu->arcs_lsize[ARC_BUFC_DATA] + 33921ab7f2deSmaybee arc_mfu->arcs_lsize[ARC_BUFC_METADATA]; 33931ab7f2deSmaybee available_memory += MIN(evictable_memory, arc_size - arc_c_min); 33941ab7f2deSmaybee } 33951ab7f2deSmaybee 33961ab7f2deSmaybee if (inflight_data > available_memory / 4) { 33971ab7f2deSmaybee ARCSTAT_INCR(arcstat_memory_throttle_count, 1); 33981ab7f2deSmaybee return (ERESTART); 33991ab7f2deSmaybee } 34001ab7f2deSmaybee #endif 34011ab7f2deSmaybee return (0); 34021ab7f2deSmaybee } 34031ab7f2deSmaybee 3404fa9e4066Sahrens void 34051ab7f2deSmaybee arc_tempreserve_clear(uint64_t reserve) 3406fa9e4066Sahrens { 34071ab7f2deSmaybee atomic_add_64(&arc_tempreserve, -reserve); 3408fa9e4066Sahrens ASSERT((int64_t)arc_tempreserve >= 0); 3409fa9e4066Sahrens } 3410fa9e4066Sahrens 3411fa9e4066Sahrens int 34121ab7f2deSmaybee arc_tempreserve_space(uint64_t reserve, uint64_t txg) 3413fa9e4066Sahrens { 34141ab7f2deSmaybee int error; 34152fdbea25SAleksandr Guzovskiy uint64_t anon_size; 34161ab7f2deSmaybee 3417fa9e4066Sahrens #ifdef ZFS_DEBUG 3418fa9e4066Sahrens /* 3419fa9e4066Sahrens * Once in a while, fail for no reason. Everything should cope. 3420fa9e4066Sahrens */ 3421fa9e4066Sahrens if (spa_get_random(10000) == 0) { 3422fa9e4066Sahrens dprintf("forcing random failure\n"); 3423fa9e4066Sahrens return (ERESTART); 3424fa9e4066Sahrens } 3425fa9e4066Sahrens #endif 34261ab7f2deSmaybee if (reserve > arc_c/4 && !arc_no_grow) 34271ab7f2deSmaybee arc_c = MIN(arc_c_max, reserve * 4); 34281ab7f2deSmaybee if (reserve > arc_c) 3429112fe045Smaybee return (ENOMEM); 3430112fe045Smaybee 34312fdbea25SAleksandr Guzovskiy /* 34322fdbea25SAleksandr Guzovskiy * Don't count loaned bufs as in flight dirty data to prevent long 34332fdbea25SAleksandr Guzovskiy * network delays from blocking transactions that are ready to be 34342fdbea25SAleksandr Guzovskiy * assigned to a txg. 34352fdbea25SAleksandr Guzovskiy */ 34362fdbea25SAleksandr Guzovskiy anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0); 34372fdbea25SAleksandr Guzovskiy 34381ab7f2deSmaybee /* 34391ab7f2deSmaybee * Writes will, almost always, require additional memory allocations 34401ab7f2deSmaybee * in order to compress/encrypt/etc the data. We therefor need to 34411ab7f2deSmaybee * make sure that there is sufficient available memory for this. 34421ab7f2deSmaybee */ 34432fdbea25SAleksandr Guzovskiy if (error = arc_memory_throttle(reserve, anon_size, txg)) 34441ab7f2deSmaybee return (error); 34451ab7f2deSmaybee 3446fa9e4066Sahrens /* 3447112fe045Smaybee * Throttle writes when the amount of dirty data in the cache 3448112fe045Smaybee * gets too large. We try to keep the cache less than half full 3449112fe045Smaybee * of dirty blocks so that our sync times don't grow too large. 3450112fe045Smaybee * Note: if two requests come in concurrently, we might let them 3451112fe045Smaybee * both succeed, when one of them should fail. Not a huge deal. 3452fa9e4066Sahrens */ 34532fdbea25SAleksandr Guzovskiy 34542fdbea25SAleksandr Guzovskiy if (reserve + arc_tempreserve + anon_size > arc_c / 2 && 34552fdbea25SAleksandr Guzovskiy anon_size > arc_c / 4) { 34560e8c6158Smaybee dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " 34570e8c6158Smaybee "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n", 34580e8c6158Smaybee arc_tempreserve>>10, 34590e8c6158Smaybee arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10, 34600e8c6158Smaybee arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10, 34611ab7f2deSmaybee reserve>>10, arc_c>>10); 3462fa9e4066Sahrens return (ERESTART); 3463fa9e4066Sahrens } 34641ab7f2deSmaybee atomic_add_64(&arc_tempreserve, reserve); 3465fa9e4066Sahrens return (0); 3466fa9e4066Sahrens } 3467fa9e4066Sahrens 3468fa9e4066Sahrens void 3469fa9e4066Sahrens arc_init(void) 3470fa9e4066Sahrens { 3471fa9e4066Sahrens mutex_init(&arc_reclaim_thr_lock, NULL, MUTEX_DEFAULT, NULL); 3472fa9e4066Sahrens cv_init(&arc_reclaim_thr_cv, NULL, CV_DEFAULT, NULL); 3473fa9e4066Sahrens 347413506d1eSmaybee /* Convert seconds to clock ticks */ 3475b19a79ecSperrin arc_min_prefetch_lifespan = 1 * hz; 347613506d1eSmaybee 3477fa9e4066Sahrens /* Start out with 1/8 of all memory */ 347844cb6abcSbmc arc_c = physmem * PAGESIZE / 8; 3479fa9e4066Sahrens 3480fa9e4066Sahrens #ifdef _KERNEL 3481fa9e4066Sahrens /* 3482fa9e4066Sahrens * On architectures where the physical memory can be larger 3483fa9e4066Sahrens * than the addressable space (intel in 32-bit mode), we may 3484fa9e4066Sahrens * need to limit the cache to 1/8 of VM size. 3485fa9e4066Sahrens */ 348644cb6abcSbmc arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8); 3487fa9e4066Sahrens #endif 3488fa9e4066Sahrens 3489112fe045Smaybee /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ 349044cb6abcSbmc arc_c_min = MAX(arc_c / 4, 64<<20); 3491112fe045Smaybee /* set max to 3/4 of all memory, or all but 1GB, whichever is more */ 349244cb6abcSbmc if (arc_c * 8 >= 1<<30) 349344cb6abcSbmc arc_c_max = (arc_c * 8) - (1<<30); 3494fa9e4066Sahrens else 349544cb6abcSbmc arc_c_max = arc_c_min; 349644cb6abcSbmc arc_c_max = MAX(arc_c * 6, arc_c_max); 3497a2eea2e1Sahrens 3498a2eea2e1Sahrens /* 3499a2eea2e1Sahrens * Allow the tunables to override our calculations if they are 3500a2eea2e1Sahrens * reasonable (ie. over 64MB) 3501a2eea2e1Sahrens */ 3502a2eea2e1Sahrens if (zfs_arc_max > 64<<20 && zfs_arc_max < physmem * PAGESIZE) 350344cb6abcSbmc arc_c_max = zfs_arc_max; 350444cb6abcSbmc if (zfs_arc_min > 64<<20 && zfs_arc_min <= arc_c_max) 350544cb6abcSbmc arc_c_min = zfs_arc_min; 3506a2eea2e1Sahrens 350744cb6abcSbmc arc_c = arc_c_max; 350844cb6abcSbmc arc_p = (arc_c >> 1); 3509fa9e4066Sahrens 35100e8c6158Smaybee /* limit meta-data to 1/4 of the arc capacity */ 35110e8c6158Smaybee arc_meta_limit = arc_c_max / 4; 35121116048bSek 35131116048bSek /* Allow the tunable to override if it is reasonable */ 35141116048bSek if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max) 35151116048bSek arc_meta_limit = zfs_arc_meta_limit; 35161116048bSek 35170e8c6158Smaybee if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0) 35180e8c6158Smaybee arc_c_min = arc_meta_limit / 2; 35190e8c6158Smaybee 35205a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_grow_retry > 0) 35215a98e54bSBrendan Gregg - Sun Microsystems arc_grow_retry = zfs_arc_grow_retry; 35225a98e54bSBrendan Gregg - Sun Microsystems 35235a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_shrink_shift > 0) 35245a98e54bSBrendan Gregg - Sun Microsystems arc_shrink_shift = zfs_arc_shrink_shift; 35255a98e54bSBrendan Gregg - Sun Microsystems 35265a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_p_min_shift > 0) 35275a98e54bSBrendan Gregg - Sun Microsystems arc_p_min_shift = zfs_arc_p_min_shift; 35285a98e54bSBrendan Gregg - Sun Microsystems 3529fa9e4066Sahrens /* if kmem_flags are set, lets try to use less memory */ 3530fa9e4066Sahrens if (kmem_debugging()) 353144cb6abcSbmc arc_c = arc_c / 2; 353244cb6abcSbmc if (arc_c < arc_c_min) 353344cb6abcSbmc arc_c = arc_c_min; 353444cb6abcSbmc 353544cb6abcSbmc arc_anon = &ARC_anon; 353644cb6abcSbmc arc_mru = &ARC_mru; 353744cb6abcSbmc arc_mru_ghost = &ARC_mru_ghost; 353844cb6abcSbmc arc_mfu = &ARC_mfu; 353944cb6abcSbmc arc_mfu_ghost = &ARC_mfu_ghost; 3540fa94a07fSbrendan arc_l2c_only = &ARC_l2c_only; 354144cb6abcSbmc arc_size = 0; 354244cb6abcSbmc 354344cb6abcSbmc mutex_init(&arc_anon->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 354444cb6abcSbmc mutex_init(&arc_mru->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 354544cb6abcSbmc mutex_init(&arc_mru_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 354644cb6abcSbmc mutex_init(&arc_mfu->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 354744cb6abcSbmc mutex_init(&arc_mfu_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 3548fa94a07fSbrendan mutex_init(&arc_l2c_only->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 354944cb6abcSbmc 35500e8c6158Smaybee list_create(&arc_mru->arcs_list[ARC_BUFC_METADATA], 35510e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35520e8c6158Smaybee list_create(&arc_mru->arcs_list[ARC_BUFC_DATA], 35530e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35540e8c6158Smaybee list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA], 35550e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35560e8c6158Smaybee list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA], 35570e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35580e8c6158Smaybee list_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA], 35590e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35600e8c6158Smaybee list_create(&arc_mfu->arcs_list[ARC_BUFC_DATA], 35610e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35620e8c6158Smaybee list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA], 35630e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 35640e8c6158Smaybee list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA], 35650e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3566fa94a07fSbrendan list_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA], 3567fa94a07fSbrendan sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3568fa94a07fSbrendan list_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA], 3569fa94a07fSbrendan sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3570fa9e4066Sahrens 3571fa9e4066Sahrens buf_init(); 3572fa9e4066Sahrens 3573fa9e4066Sahrens arc_thread_exit = 0; 3574ea8dc4b6Seschrock arc_eviction_list = NULL; 3575ea8dc4b6Seschrock mutex_init(&arc_eviction_mtx, NULL, MUTEX_DEFAULT, NULL); 357640d7d650Smaybee bzero(&arc_eviction_hdr, sizeof (arc_buf_hdr_t)); 3577fa9e4066Sahrens 357844cb6abcSbmc arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, 357944cb6abcSbmc sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); 358044cb6abcSbmc 358144cb6abcSbmc if (arc_ksp != NULL) { 358244cb6abcSbmc arc_ksp->ks_data = &arc_stats; 358344cb6abcSbmc kstat_install(arc_ksp); 358444cb6abcSbmc } 358544cb6abcSbmc 3586fa9e4066Sahrens (void) thread_create(NULL, 0, arc_reclaim_thread, NULL, 0, &p0, 3587fa9e4066Sahrens TS_RUN, minclsyspri); 358849e3519aSmaybee 358949e3519aSmaybee arc_dead = FALSE; 35903a737e0dSbrendan arc_warm = B_FALSE; 35911ab7f2deSmaybee 35921ab7f2deSmaybee if (zfs_write_limit_max == 0) 359305715f94SMark Maybee zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift; 35941ab7f2deSmaybee else 35951ab7f2deSmaybee zfs_write_limit_shift = 0; 359605715f94SMark Maybee mutex_init(&zfs_write_limit_lock, NULL, MUTEX_DEFAULT, NULL); 3597fa9e4066Sahrens } 3598fa9e4066Sahrens 3599fa9e4066Sahrens void 3600fa9e4066Sahrens arc_fini(void) 3601fa9e4066Sahrens { 3602fa9e4066Sahrens mutex_enter(&arc_reclaim_thr_lock); 3603fa9e4066Sahrens arc_thread_exit = 1; 3604fa9e4066Sahrens while (arc_thread_exit != 0) 3605fa9e4066Sahrens cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock); 3606fa9e4066Sahrens mutex_exit(&arc_reclaim_thr_lock); 3607fa9e4066Sahrens 3608874395d5Smaybee arc_flush(NULL); 3609fa9e4066Sahrens 3610fa9e4066Sahrens arc_dead = TRUE; 3611fa9e4066Sahrens 361244cb6abcSbmc if (arc_ksp != NULL) { 361344cb6abcSbmc kstat_delete(arc_ksp); 361444cb6abcSbmc arc_ksp = NULL; 361544cb6abcSbmc } 361644cb6abcSbmc 3617ea8dc4b6Seschrock mutex_destroy(&arc_eviction_mtx); 3618fa9e4066Sahrens mutex_destroy(&arc_reclaim_thr_lock); 3619fa9e4066Sahrens cv_destroy(&arc_reclaim_thr_cv); 3620fa9e4066Sahrens 36210e8c6158Smaybee list_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]); 36220e8c6158Smaybee list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); 36230e8c6158Smaybee list_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]); 36240e8c6158Smaybee list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); 36250e8c6158Smaybee list_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]); 36260e8c6158Smaybee list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); 36270e8c6158Smaybee list_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]); 36280e8c6158Smaybee list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); 3629fa9e4066Sahrens 363044cb6abcSbmc mutex_destroy(&arc_anon->arcs_mtx); 363144cb6abcSbmc mutex_destroy(&arc_mru->arcs_mtx); 363244cb6abcSbmc mutex_destroy(&arc_mru_ghost->arcs_mtx); 363344cb6abcSbmc mutex_destroy(&arc_mfu->arcs_mtx); 363444cb6abcSbmc mutex_destroy(&arc_mfu_ghost->arcs_mtx); 3635b5e70f97SRicardo M. Correia mutex_destroy(&arc_l2c_only->arcs_mtx); 36365ad82045Snd 363705715f94SMark Maybee mutex_destroy(&zfs_write_limit_lock); 363805715f94SMark Maybee 3639fa9e4066Sahrens buf_fini(); 36402fdbea25SAleksandr Guzovskiy 36412fdbea25SAleksandr Guzovskiy ASSERT(arc_loaned_bytes == 0); 3642fa9e4066Sahrens } 3643fa94a07fSbrendan 3644fa94a07fSbrendan /* 3645fa94a07fSbrendan * Level 2 ARC 3646fa94a07fSbrendan * 3647fa94a07fSbrendan * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. 3648fa94a07fSbrendan * It uses dedicated storage devices to hold cached data, which are populated 3649fa94a07fSbrendan * using large infrequent writes. The main role of this cache is to boost 3650fa94a07fSbrendan * the performance of random read workloads. The intended L2ARC devices 3651fa94a07fSbrendan * include short-stroked disks, solid state disks, and other media with 3652fa94a07fSbrendan * substantially faster read latency than disk. 3653fa94a07fSbrendan * 3654fa94a07fSbrendan * +-----------------------+ 3655fa94a07fSbrendan * | ARC | 3656fa94a07fSbrendan * +-----------------------+ 3657fa94a07fSbrendan * | ^ ^ 3658fa94a07fSbrendan * | | | 3659fa94a07fSbrendan * l2arc_feed_thread() arc_read() 3660fa94a07fSbrendan * | | | 3661fa94a07fSbrendan * | l2arc read | 3662fa94a07fSbrendan * V | | 3663fa94a07fSbrendan * +---------------+ | 3664fa94a07fSbrendan * | L2ARC | | 3665fa94a07fSbrendan * +---------------+ | 3666fa94a07fSbrendan * | ^ | 3667fa94a07fSbrendan * l2arc_write() | | 3668fa94a07fSbrendan * | | | 3669fa94a07fSbrendan * V | | 3670fa94a07fSbrendan * +-------+ +-------+ 3671fa94a07fSbrendan * | vdev | | vdev | 3672fa94a07fSbrendan * | cache | | cache | 3673fa94a07fSbrendan * +-------+ +-------+ 3674fa94a07fSbrendan * +=========+ .-----. 3675fa94a07fSbrendan * : L2ARC : |-_____-| 3676fa94a07fSbrendan * : devices : | Disks | 3677fa94a07fSbrendan * +=========+ `-_____-' 3678fa94a07fSbrendan * 3679fa94a07fSbrendan * Read requests are satisfied from the following sources, in order: 3680fa94a07fSbrendan * 3681fa94a07fSbrendan * 1) ARC 3682fa94a07fSbrendan * 2) vdev cache of L2ARC devices 3683fa94a07fSbrendan * 3) L2ARC devices 3684fa94a07fSbrendan * 4) vdev cache of disks 3685fa94a07fSbrendan * 5) disks 3686fa94a07fSbrendan * 3687fa94a07fSbrendan * Some L2ARC device types exhibit extremely slow write performance. 3688fa94a07fSbrendan * To accommodate for this there are some significant differences between 3689fa94a07fSbrendan * the L2ARC and traditional cache design: 3690fa94a07fSbrendan * 3691fa94a07fSbrendan * 1. There is no eviction path from the ARC to the L2ARC. Evictions from 3692fa94a07fSbrendan * the ARC behave as usual, freeing buffers and placing headers on ghost 3693fa94a07fSbrendan * lists. The ARC does not send buffers to the L2ARC during eviction as 3694fa94a07fSbrendan * this would add inflated write latencies for all ARC memory pressure. 3695fa94a07fSbrendan * 3696fa94a07fSbrendan * 2. The L2ARC attempts to cache data from the ARC before it is evicted. 3697fa94a07fSbrendan * It does this by periodically scanning buffers from the eviction-end of 3698fa94a07fSbrendan * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are 3699fa94a07fSbrendan * not already there. It scans until a headroom of buffers is satisfied, 3700fa94a07fSbrendan * which itself is a buffer for ARC eviction. The thread that does this is 3701fa94a07fSbrendan * l2arc_feed_thread(), illustrated below; example sizes are included to 3702fa94a07fSbrendan * provide a better sense of ratio than this diagram: 3703fa94a07fSbrendan * 3704fa94a07fSbrendan * head --> tail 3705fa94a07fSbrendan * +---------------------+----------+ 3706fa94a07fSbrendan * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC 3707fa94a07fSbrendan * +---------------------+----------+ | o L2ARC eligible 3708fa94a07fSbrendan * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer 3709fa94a07fSbrendan * +---------------------+----------+ | 3710fa94a07fSbrendan * 15.9 Gbytes ^ 32 Mbytes | 3711fa94a07fSbrendan * headroom | 3712fa94a07fSbrendan * l2arc_feed_thread() 3713fa94a07fSbrendan * | 3714fa94a07fSbrendan * l2arc write hand <--[oooo]--' 3715fa94a07fSbrendan * | 8 Mbyte 3716fa94a07fSbrendan * | write max 3717fa94a07fSbrendan * V 3718fa94a07fSbrendan * +==============================+ 3719fa94a07fSbrendan * L2ARC dev |####|#|###|###| |####| ... | 3720fa94a07fSbrendan * +==============================+ 3721fa94a07fSbrendan * 32 Gbytes 3722fa94a07fSbrendan * 3723fa94a07fSbrendan * 3. If an ARC buffer is copied to the L2ARC but then hit instead of 3724fa94a07fSbrendan * evicted, then the L2ARC has cached a buffer much sooner than it probably 3725fa94a07fSbrendan * needed to, potentially wasting L2ARC device bandwidth and storage. It is 3726fa94a07fSbrendan * safe to say that this is an uncommon case, since buffers at the end of 3727fa94a07fSbrendan * the ARC lists have moved there due to inactivity. 3728fa94a07fSbrendan * 3729fa94a07fSbrendan * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, 3730fa94a07fSbrendan * then the L2ARC simply misses copying some buffers. This serves as a 3731fa94a07fSbrendan * pressure valve to prevent heavy read workloads from both stalling the ARC 3732fa94a07fSbrendan * with waits and clogging the L2ARC with writes. This also helps prevent 3733fa94a07fSbrendan * the potential for the L2ARC to churn if it attempts to cache content too 3734fa94a07fSbrendan * quickly, such as during backups of the entire pool. 3735fa94a07fSbrendan * 37363a737e0dSbrendan * 5. After system boot and before the ARC has filled main memory, there are 37373a737e0dSbrendan * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru 37383a737e0dSbrendan * lists can remain mostly static. Instead of searching from tail of these 37393a737e0dSbrendan * lists as pictured, the l2arc_feed_thread() will search from the list heads 37403a737e0dSbrendan * for eligible buffers, greatly increasing its chance of finding them. 37413a737e0dSbrendan * 37423a737e0dSbrendan * The L2ARC device write speed is also boosted during this time so that 37433a737e0dSbrendan * the L2ARC warms up faster. Since there have been no ARC evictions yet, 37443a737e0dSbrendan * there are no L2ARC reads, and no fear of degrading read performance 37453a737e0dSbrendan * through increased writes. 37463a737e0dSbrendan * 37473a737e0dSbrendan * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that 3748fa94a07fSbrendan * the vdev queue can aggregate them into larger and fewer writes. Each 3749fa94a07fSbrendan * device is written to in a rotor fashion, sweeping writes through 3750fa94a07fSbrendan * available space then repeating. 3751fa94a07fSbrendan * 37523a737e0dSbrendan * 7. The L2ARC does not store dirty content. It never needs to flush 3753fa94a07fSbrendan * write buffers back to disk based storage. 3754fa94a07fSbrendan * 37553a737e0dSbrendan * 8. If an ARC buffer is written (and dirtied) which also exists in the 3756fa94a07fSbrendan * L2ARC, the now stale L2ARC buffer is immediately dropped. 3757fa94a07fSbrendan * 3758fa94a07fSbrendan * The performance of the L2ARC can be tweaked by a number of tunables, which 3759fa94a07fSbrendan * may be necessary for different workloads: 3760fa94a07fSbrendan * 3761fa94a07fSbrendan * l2arc_write_max max write bytes per interval 37623a737e0dSbrendan * l2arc_write_boost extra write bytes during device warmup 3763fa94a07fSbrendan * l2arc_noprefetch skip caching prefetched buffers 3764fa94a07fSbrendan * l2arc_headroom number of max device writes to precache 3765fa94a07fSbrendan * l2arc_feed_secs seconds between L2ARC writing 3766fa94a07fSbrendan * 3767fa94a07fSbrendan * Tunables may be removed or added as future performance improvements are 3768fa94a07fSbrendan * integrated, and also may become zpool properties. 37695a98e54bSBrendan Gregg - Sun Microsystems * 37705a98e54bSBrendan Gregg - Sun Microsystems * There are three key functions that control how the L2ARC warms up: 37715a98e54bSBrendan Gregg - Sun Microsystems * 37725a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_eligible() check if a buffer is eligible to cache 37735a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_size() calculate how much to write 37745a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_interval() calculate sleep delay between writes 37755a98e54bSBrendan Gregg - Sun Microsystems * 37765a98e54bSBrendan Gregg - Sun Microsystems * These three functions determine what to write, how much, and how quickly 37775a98e54bSBrendan Gregg - Sun Microsystems * to send writes. 3778fa94a07fSbrendan */ 3779fa94a07fSbrendan 37805a98e54bSBrendan Gregg - Sun Microsystems static boolean_t 3781ac05c741SMark Maybee l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab) 37825a98e54bSBrendan Gregg - Sun Microsystems { 37835a98e54bSBrendan Gregg - Sun Microsystems /* 37845a98e54bSBrendan Gregg - Sun Microsystems * A buffer is *not* eligible for the L2ARC if it: 37855a98e54bSBrendan Gregg - Sun Microsystems * 1. belongs to a different spa. 37865ea40c06SBrendan Gregg - Sun Microsystems * 2. is already cached on the L2ARC. 37875ea40c06SBrendan Gregg - Sun Microsystems * 3. has an I/O in progress (it may be an incomplete read). 37885ea40c06SBrendan Gregg - Sun Microsystems * 4. is flagged not eligible (zfs property). 37895a98e54bSBrendan Gregg - Sun Microsystems */ 37905ea40c06SBrendan Gregg - Sun Microsystems if (ab->b_spa != spa_guid || ab->b_l2hdr != NULL || 37915a98e54bSBrendan Gregg - Sun Microsystems HDR_IO_IN_PROGRESS(ab) || !HDR_L2CACHE(ab)) 37925a98e54bSBrendan Gregg - Sun Microsystems return (B_FALSE); 37935a98e54bSBrendan Gregg - Sun Microsystems 37945a98e54bSBrendan Gregg - Sun Microsystems return (B_TRUE); 37955a98e54bSBrendan Gregg - Sun Microsystems } 37965a98e54bSBrendan Gregg - Sun Microsystems 37975a98e54bSBrendan Gregg - Sun Microsystems static uint64_t 37985a98e54bSBrendan Gregg - Sun Microsystems l2arc_write_size(l2arc_dev_t *dev) 37995a98e54bSBrendan Gregg - Sun Microsystems { 38005a98e54bSBrendan Gregg - Sun Microsystems uint64_t size; 38015a98e54bSBrendan Gregg - Sun Microsystems 38025a98e54bSBrendan Gregg - Sun Microsystems size = dev->l2ad_write; 38035a98e54bSBrendan Gregg - Sun Microsystems 38045a98e54bSBrendan Gregg - Sun Microsystems if (arc_warm == B_FALSE) 38055a98e54bSBrendan Gregg - Sun Microsystems size += dev->l2ad_boost; 38065a98e54bSBrendan Gregg - Sun Microsystems 38075a98e54bSBrendan Gregg - Sun Microsystems return (size); 38085a98e54bSBrendan Gregg - Sun Microsystems 38095a98e54bSBrendan Gregg - Sun Microsystems } 38105a98e54bSBrendan Gregg - Sun Microsystems 38115a98e54bSBrendan Gregg - Sun Microsystems static clock_t 38125a98e54bSBrendan Gregg - Sun Microsystems l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) 38135a98e54bSBrendan Gregg - Sun Microsystems { 3814d3d50737SRafael Vanoni clock_t interval, next, now; 38155a98e54bSBrendan Gregg - Sun Microsystems 38165a98e54bSBrendan Gregg - Sun Microsystems /* 38175a98e54bSBrendan Gregg - Sun Microsystems * If the ARC lists are busy, increase our write rate; if the 38185a98e54bSBrendan Gregg - Sun Microsystems * lists are stale, idle back. This is achieved by checking 38195a98e54bSBrendan Gregg - Sun Microsystems * how much we previously wrote - if it was more than half of 38205a98e54bSBrendan Gregg - Sun Microsystems * what we wanted, schedule the next write much sooner. 38215a98e54bSBrendan Gregg - Sun Microsystems */ 38225a98e54bSBrendan Gregg - Sun Microsystems if (l2arc_feed_again && wrote > (wanted / 2)) 38235a98e54bSBrendan Gregg - Sun Microsystems interval = (hz * l2arc_feed_min_ms) / 1000; 38245a98e54bSBrendan Gregg - Sun Microsystems else 38255a98e54bSBrendan Gregg - Sun Microsystems interval = hz * l2arc_feed_secs; 38265a98e54bSBrendan Gregg - Sun Microsystems 3827d3d50737SRafael Vanoni now = ddi_get_lbolt(); 3828d3d50737SRafael Vanoni next = MAX(now, MIN(now + interval, began + interval)); 38295a98e54bSBrendan Gregg - Sun Microsystems 38305a98e54bSBrendan Gregg - Sun Microsystems return (next); 38315a98e54bSBrendan Gregg - Sun Microsystems } 38325a98e54bSBrendan Gregg - Sun Microsystems 3833fa94a07fSbrendan static void 3834fa94a07fSbrendan l2arc_hdr_stat_add(void) 3835fa94a07fSbrendan { 3836e6c728e1Sbrendan ARCSTAT_INCR(arcstat_l2_hdr_size, HDR_SIZE + L2HDR_SIZE); 3837e6c728e1Sbrendan ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE); 3838fa94a07fSbrendan } 3839fa94a07fSbrendan 3840fa94a07fSbrendan static void 3841fa94a07fSbrendan l2arc_hdr_stat_remove(void) 3842fa94a07fSbrendan { 3843e6c728e1Sbrendan ARCSTAT_INCR(arcstat_l2_hdr_size, -(HDR_SIZE + L2HDR_SIZE)); 3844e6c728e1Sbrendan ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE); 3845fa94a07fSbrendan } 3846fa94a07fSbrendan 3847fa94a07fSbrendan /* 3848fa94a07fSbrendan * Cycle through L2ARC devices. This is how L2ARC load balances. 38493a737e0dSbrendan * If a device is returned, this also returns holding the spa config lock. 3850fa94a07fSbrendan */ 3851fa94a07fSbrendan static l2arc_dev_t * 3852fa94a07fSbrendan l2arc_dev_get_next(void) 3853fa94a07fSbrendan { 38543a737e0dSbrendan l2arc_dev_t *first, *next = NULL; 38553a737e0dSbrendan 38563a737e0dSbrendan /* 38573a737e0dSbrendan * Lock out the removal of spas (spa_namespace_lock), then removal 38583a737e0dSbrendan * of cache devices (l2arc_dev_mtx). Once a device has been selected, 38593a737e0dSbrendan * both locks will be dropped and a spa config lock held instead. 38603a737e0dSbrendan */ 38613a737e0dSbrendan mutex_enter(&spa_namespace_lock); 38623a737e0dSbrendan mutex_enter(&l2arc_dev_mtx); 3863fa94a07fSbrendan 3864c5904d13Seschrock /* if there are no vdevs, there is nothing to do */ 3865c5904d13Seschrock if (l2arc_ndev == 0) 38663a737e0dSbrendan goto out; 3867c5904d13Seschrock 3868c5904d13Seschrock first = NULL; 3869c5904d13Seschrock next = l2arc_dev_last; 3870c5904d13Seschrock do { 3871c5904d13Seschrock /* loop around the list looking for a non-faulted vdev */ 3872c5904d13Seschrock if (next == NULL) { 3873fa94a07fSbrendan next = list_head(l2arc_dev_list); 3874c5904d13Seschrock } else { 3875c5904d13Seschrock next = list_next(l2arc_dev_list, next); 3876c5904d13Seschrock if (next == NULL) 3877c5904d13Seschrock next = list_head(l2arc_dev_list); 3878c5904d13Seschrock } 3879c5904d13Seschrock 3880c5904d13Seschrock /* if we have come back to the start, bail out */ 3881c5904d13Seschrock if (first == NULL) 3882c5904d13Seschrock first = next; 3883c5904d13Seschrock else if (next == first) 3884c5904d13Seschrock break; 3885c5904d13Seschrock 3886c5904d13Seschrock } while (vdev_is_dead(next->l2ad_vdev)); 3887c5904d13Seschrock 3888c5904d13Seschrock /* if we were unable to find any usable vdevs, return NULL */ 3889c5904d13Seschrock if (vdev_is_dead(next->l2ad_vdev)) 38903a737e0dSbrendan next = NULL; 3891fa94a07fSbrendan 3892fa94a07fSbrendan l2arc_dev_last = next; 3893fa94a07fSbrendan 38943a737e0dSbrendan out: 38953a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 38963a737e0dSbrendan 38973a737e0dSbrendan /* 38983a737e0dSbrendan * Grab the config lock to prevent the 'next' device from being 38993a737e0dSbrendan * removed while we are writing to it. 39003a737e0dSbrendan */ 39013a737e0dSbrendan if (next != NULL) 3902e14bb325SJeff Bonwick spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); 39033a737e0dSbrendan mutex_exit(&spa_namespace_lock); 39043a737e0dSbrendan 3905fa94a07fSbrendan return (next); 3906fa94a07fSbrendan } 3907fa94a07fSbrendan 39083a737e0dSbrendan /* 39093a737e0dSbrendan * Free buffers that were tagged for destruction. 39103a737e0dSbrendan */ 39113a737e0dSbrendan static void 39123a737e0dSbrendan l2arc_do_free_on_write() 39133a737e0dSbrendan { 39143a737e0dSbrendan list_t *buflist; 39153a737e0dSbrendan l2arc_data_free_t *df, *df_prev; 39163a737e0dSbrendan 39173a737e0dSbrendan mutex_enter(&l2arc_free_on_write_mtx); 39183a737e0dSbrendan buflist = l2arc_free_on_write; 39193a737e0dSbrendan 39203a737e0dSbrendan for (df = list_tail(buflist); df; df = df_prev) { 39213a737e0dSbrendan df_prev = list_prev(buflist, df); 39223a737e0dSbrendan ASSERT(df->l2df_data != NULL); 39233a737e0dSbrendan ASSERT(df->l2df_func != NULL); 39243a737e0dSbrendan df->l2df_func(df->l2df_data, df->l2df_size); 39253a737e0dSbrendan list_remove(buflist, df); 39263a737e0dSbrendan kmem_free(df, sizeof (l2arc_data_free_t)); 39273a737e0dSbrendan } 39283a737e0dSbrendan 39293a737e0dSbrendan mutex_exit(&l2arc_free_on_write_mtx); 39303a737e0dSbrendan } 39313a737e0dSbrendan 3932fa94a07fSbrendan /* 3933fa94a07fSbrendan * A write to a cache device has completed. Update all headers to allow 3934fa94a07fSbrendan * reads from these buffers to begin. 3935fa94a07fSbrendan */ 3936fa94a07fSbrendan static void 3937fa94a07fSbrendan l2arc_write_done(zio_t *zio) 3938fa94a07fSbrendan { 3939fa94a07fSbrendan l2arc_write_callback_t *cb; 3940fa94a07fSbrendan l2arc_dev_t *dev; 3941fa94a07fSbrendan list_t *buflist; 3942fa94a07fSbrendan arc_buf_hdr_t *head, *ab, *ab_prev; 39433a737e0dSbrendan l2arc_buf_hdr_t *abl2; 3944fa94a07fSbrendan kmutex_t *hash_lock; 3945fa94a07fSbrendan 3946fa94a07fSbrendan cb = zio->io_private; 3947fa94a07fSbrendan ASSERT(cb != NULL); 3948fa94a07fSbrendan dev = cb->l2wcb_dev; 3949fa94a07fSbrendan ASSERT(dev != NULL); 3950fa94a07fSbrendan head = cb->l2wcb_head; 3951fa94a07fSbrendan ASSERT(head != NULL); 3952fa94a07fSbrendan buflist = dev->l2ad_buflist; 3953fa94a07fSbrendan ASSERT(buflist != NULL); 3954fa94a07fSbrendan DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, 3955fa94a07fSbrendan l2arc_write_callback_t *, cb); 3956fa94a07fSbrendan 3957fa94a07fSbrendan if (zio->io_error != 0) 3958fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_error); 3959fa94a07fSbrendan 3960fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 3961fa94a07fSbrendan 3962fa94a07fSbrendan /* 3963fa94a07fSbrendan * All writes completed, or an error was hit. 3964fa94a07fSbrendan */ 3965fa94a07fSbrendan for (ab = list_prev(buflist, head); ab; ab = ab_prev) { 3966fa94a07fSbrendan ab_prev = list_prev(buflist, ab); 3967fa94a07fSbrendan 3968fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 3969fa94a07fSbrendan if (!mutex_tryenter(hash_lock)) { 3970fa94a07fSbrendan /* 3971fa94a07fSbrendan * This buffer misses out. It may be in a stage 3972fa94a07fSbrendan * of eviction. Its ARC_L2_WRITING flag will be 3973fa94a07fSbrendan * left set, denying reads to this buffer. 3974fa94a07fSbrendan */ 3975fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_hdr_miss); 3976fa94a07fSbrendan continue; 3977fa94a07fSbrendan } 3978fa94a07fSbrendan 3979fa94a07fSbrendan if (zio->io_error != 0) { 3980fa94a07fSbrendan /* 39813a737e0dSbrendan * Error - drop L2ARC entry. 3982fa94a07fSbrendan */ 39833a737e0dSbrendan list_remove(buflist, ab); 39843a737e0dSbrendan abl2 = ab->b_l2hdr; 3985fa94a07fSbrendan ab->b_l2hdr = NULL; 39863a737e0dSbrendan kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); 39873a737e0dSbrendan ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); 3988fa94a07fSbrendan } 3989fa94a07fSbrendan 3990fa94a07fSbrendan /* 3991fa94a07fSbrendan * Allow ARC to begin reads to this L2ARC entry. 3992fa94a07fSbrendan */ 3993fa94a07fSbrendan ab->b_flags &= ~ARC_L2_WRITING; 3994fa94a07fSbrendan 3995fa94a07fSbrendan mutex_exit(hash_lock); 3996fa94a07fSbrendan } 3997fa94a07fSbrendan 3998fa94a07fSbrendan atomic_inc_64(&l2arc_writes_done); 3999fa94a07fSbrendan list_remove(buflist, head); 4000fa94a07fSbrendan kmem_cache_free(hdr_cache, head); 4001fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4002fa94a07fSbrendan 40033a737e0dSbrendan l2arc_do_free_on_write(); 4004fa94a07fSbrendan 4005fa94a07fSbrendan kmem_free(cb, sizeof (l2arc_write_callback_t)); 4006fa94a07fSbrendan } 4007fa94a07fSbrendan 4008fa94a07fSbrendan /* 4009fa94a07fSbrendan * A read to a cache device completed. Validate buffer contents before 4010fa94a07fSbrendan * handing over to the regular ARC routines. 4011fa94a07fSbrendan */ 4012fa94a07fSbrendan static void 4013fa94a07fSbrendan l2arc_read_done(zio_t *zio) 4014fa94a07fSbrendan { 4015fa94a07fSbrendan l2arc_read_callback_t *cb; 4016fa94a07fSbrendan arc_buf_hdr_t *hdr; 4017fa94a07fSbrendan arc_buf_t *buf; 4018fa94a07fSbrendan kmutex_t *hash_lock; 40193a737e0dSbrendan int equal; 4020fa94a07fSbrendan 4021e14bb325SJeff Bonwick ASSERT(zio->io_vd != NULL); 4022e14bb325SJeff Bonwick ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); 4023e14bb325SJeff Bonwick 4024e14bb325SJeff Bonwick spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); 4025e14bb325SJeff Bonwick 4026fa94a07fSbrendan cb = zio->io_private; 4027fa94a07fSbrendan ASSERT(cb != NULL); 4028fa94a07fSbrendan buf = cb->l2rcb_buf; 4029fa94a07fSbrendan ASSERT(buf != NULL); 4030fa94a07fSbrendan 4031*3f9d6ad7SLin Ling hash_lock = HDR_LOCK(buf->b_hdr); 4032fa94a07fSbrendan mutex_enter(hash_lock); 4033*3f9d6ad7SLin Ling hdr = buf->b_hdr; 4034*3f9d6ad7SLin Ling ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); 4035fa94a07fSbrendan 4036fa94a07fSbrendan /* 4037fa94a07fSbrendan * Check this survived the L2ARC journey. 4038fa94a07fSbrendan */ 4039fa94a07fSbrendan equal = arc_cksum_equal(buf); 4040fa94a07fSbrendan if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) { 4041fa94a07fSbrendan mutex_exit(hash_lock); 4042fa94a07fSbrendan zio->io_private = buf; 4043e14bb325SJeff Bonwick zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ 4044e14bb325SJeff Bonwick zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ 4045fa94a07fSbrendan arc_read_done(zio); 4046fa94a07fSbrendan } else { 4047fa94a07fSbrendan mutex_exit(hash_lock); 4048fa94a07fSbrendan /* 4049fa94a07fSbrendan * Buffer didn't survive caching. Increment stats and 4050fa94a07fSbrendan * reissue to the original storage device. 4051fa94a07fSbrendan */ 40523a737e0dSbrendan if (zio->io_error != 0) { 4053fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_io_error); 40543a737e0dSbrendan } else { 40553a737e0dSbrendan zio->io_error = EIO; 40563a737e0dSbrendan } 4057fa94a07fSbrendan if (!equal) 4058fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_cksum_bad); 4059fa94a07fSbrendan 4060e14bb325SJeff Bonwick /* 4061e14bb325SJeff Bonwick * If there's no waiter, issue an async i/o to the primary 4062e14bb325SJeff Bonwick * storage now. If there *is* a waiter, the caller must 4063e14bb325SJeff Bonwick * issue the i/o in a context where it's OK to block. 4064e14bb325SJeff Bonwick */ 4065a3f829aeSBill Moore if (zio->io_waiter == NULL) { 4066a3f829aeSBill Moore zio_t *pio = zio_unique_parent(zio); 4067a3f829aeSBill Moore 4068a3f829aeSBill Moore ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); 4069a3f829aeSBill Moore 4070a3f829aeSBill Moore zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp, 4071e14bb325SJeff Bonwick buf->b_data, zio->io_size, arc_read_done, buf, 4072e14bb325SJeff Bonwick zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb)); 4073a3f829aeSBill Moore } 4074fa94a07fSbrendan } 4075fa94a07fSbrendan 4076fa94a07fSbrendan kmem_free(cb, sizeof (l2arc_read_callback_t)); 4077fa94a07fSbrendan } 4078fa94a07fSbrendan 4079fa94a07fSbrendan /* 4080fa94a07fSbrendan * This is the list priority from which the L2ARC will search for pages to 4081fa94a07fSbrendan * cache. This is used within loops (0..3) to cycle through lists in the 4082fa94a07fSbrendan * desired order. This order can have a significant effect on cache 4083fa94a07fSbrendan * performance. 4084fa94a07fSbrendan * 4085fa94a07fSbrendan * Currently the metadata lists are hit first, MFU then MRU, followed by 4086fa94a07fSbrendan * the data lists. This function returns a locked list, and also returns 4087fa94a07fSbrendan * the lock pointer. 4088fa94a07fSbrendan */ 4089fa94a07fSbrendan static list_t * 4090fa94a07fSbrendan l2arc_list_locked(int list_num, kmutex_t **lock) 4091fa94a07fSbrendan { 4092fa94a07fSbrendan list_t *list; 4093fa94a07fSbrendan 4094fa94a07fSbrendan ASSERT(list_num >= 0 && list_num <= 3); 4095fa94a07fSbrendan 4096fa94a07fSbrendan switch (list_num) { 4097fa94a07fSbrendan case 0: 4098fa94a07fSbrendan list = &arc_mfu->arcs_list[ARC_BUFC_METADATA]; 4099fa94a07fSbrendan *lock = &arc_mfu->arcs_mtx; 4100fa94a07fSbrendan break; 4101fa94a07fSbrendan case 1: 4102fa94a07fSbrendan list = &arc_mru->arcs_list[ARC_BUFC_METADATA]; 4103fa94a07fSbrendan *lock = &arc_mru->arcs_mtx; 4104fa94a07fSbrendan break; 4105fa94a07fSbrendan case 2: 4106fa94a07fSbrendan list = &arc_mfu->arcs_list[ARC_BUFC_DATA]; 4107fa94a07fSbrendan *lock = &arc_mfu->arcs_mtx; 4108fa94a07fSbrendan break; 4109fa94a07fSbrendan case 3: 4110fa94a07fSbrendan list = &arc_mru->arcs_list[ARC_BUFC_DATA]; 4111fa94a07fSbrendan *lock = &arc_mru->arcs_mtx; 4112fa94a07fSbrendan break; 4113fa94a07fSbrendan } 4114fa94a07fSbrendan 4115fa94a07fSbrendan ASSERT(!(MUTEX_HELD(*lock))); 4116fa94a07fSbrendan mutex_enter(*lock); 4117fa94a07fSbrendan return (list); 4118fa94a07fSbrendan } 4119fa94a07fSbrendan 4120fa94a07fSbrendan /* 4121fa94a07fSbrendan * Evict buffers from the device write hand to the distance specified in 4122fa94a07fSbrendan * bytes. This distance may span populated buffers, it may span nothing. 4123fa94a07fSbrendan * This is clearing a region on the L2ARC device ready for writing. 4124fa94a07fSbrendan * If the 'all' boolean is set, every buffer is evicted. 4125fa94a07fSbrendan */ 4126fa94a07fSbrendan static void 4127fa94a07fSbrendan l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) 4128fa94a07fSbrendan { 4129fa94a07fSbrendan list_t *buflist; 4130fa94a07fSbrendan l2arc_buf_hdr_t *abl2; 4131fa94a07fSbrendan arc_buf_hdr_t *ab, *ab_prev; 4132fa94a07fSbrendan kmutex_t *hash_lock; 4133fa94a07fSbrendan uint64_t taddr; 4134fa94a07fSbrendan 4135fa94a07fSbrendan buflist = dev->l2ad_buflist; 4136fa94a07fSbrendan 4137fa94a07fSbrendan if (buflist == NULL) 4138fa94a07fSbrendan return; 4139fa94a07fSbrendan 4140fa94a07fSbrendan if (!all && dev->l2ad_first) { 4141fa94a07fSbrendan /* 4142fa94a07fSbrendan * This is the first sweep through the device. There is 4143fa94a07fSbrendan * nothing to evict. 4144fa94a07fSbrendan */ 4145fa94a07fSbrendan return; 4146fa94a07fSbrendan } 4147fa94a07fSbrendan 41483a737e0dSbrendan if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) { 4149fa94a07fSbrendan /* 4150fa94a07fSbrendan * When nearing the end of the device, evict to the end 4151fa94a07fSbrendan * before the device write hand jumps to the start. 4152fa94a07fSbrendan */ 4153fa94a07fSbrendan taddr = dev->l2ad_end; 4154fa94a07fSbrendan } else { 4155fa94a07fSbrendan taddr = dev->l2ad_hand + distance; 4156fa94a07fSbrendan } 4157fa94a07fSbrendan DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, 4158fa94a07fSbrendan uint64_t, taddr, boolean_t, all); 4159fa94a07fSbrendan 4160fa94a07fSbrendan top: 4161fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 4162fa94a07fSbrendan for (ab = list_tail(buflist); ab; ab = ab_prev) { 4163fa94a07fSbrendan ab_prev = list_prev(buflist, ab); 4164fa94a07fSbrendan 4165fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 4166fa94a07fSbrendan if (!mutex_tryenter(hash_lock)) { 4167fa94a07fSbrendan /* 4168fa94a07fSbrendan * Missed the hash lock. Retry. 4169fa94a07fSbrendan */ 4170fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); 4171fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4172fa94a07fSbrendan mutex_enter(hash_lock); 4173fa94a07fSbrendan mutex_exit(hash_lock); 4174fa94a07fSbrendan goto top; 4175fa94a07fSbrendan } 4176fa94a07fSbrendan 4177fa94a07fSbrendan if (HDR_L2_WRITE_HEAD(ab)) { 4178fa94a07fSbrendan /* 4179fa94a07fSbrendan * We hit a write head node. Leave it for 4180fa94a07fSbrendan * l2arc_write_done(). 4181fa94a07fSbrendan */ 4182fa94a07fSbrendan list_remove(buflist, ab); 4183fa94a07fSbrendan mutex_exit(hash_lock); 4184fa94a07fSbrendan continue; 4185fa94a07fSbrendan } 4186fa94a07fSbrendan 4187fa94a07fSbrendan if (!all && ab->b_l2hdr != NULL && 4188fa94a07fSbrendan (ab->b_l2hdr->b_daddr > taddr || 4189fa94a07fSbrendan ab->b_l2hdr->b_daddr < dev->l2ad_hand)) { 4190fa94a07fSbrendan /* 4191fa94a07fSbrendan * We've evicted to the target address, 4192fa94a07fSbrendan * or the end of the device. 4193fa94a07fSbrendan */ 4194fa94a07fSbrendan mutex_exit(hash_lock); 4195fa94a07fSbrendan break; 4196fa94a07fSbrendan } 4197fa94a07fSbrendan 4198fa94a07fSbrendan if (HDR_FREE_IN_PROGRESS(ab)) { 4199fa94a07fSbrendan /* 4200fa94a07fSbrendan * Already on the path to destruction. 4201fa94a07fSbrendan */ 4202fa94a07fSbrendan mutex_exit(hash_lock); 4203fa94a07fSbrendan continue; 4204fa94a07fSbrendan } 4205fa94a07fSbrendan 4206fa94a07fSbrendan if (ab->b_state == arc_l2c_only) { 4207fa94a07fSbrendan ASSERT(!HDR_L2_READING(ab)); 4208fa94a07fSbrendan /* 4209fa94a07fSbrendan * This doesn't exist in the ARC. Destroy. 4210fa94a07fSbrendan * arc_hdr_destroy() will call list_remove() 4211fa94a07fSbrendan * and decrement arcstat_l2_size. 4212fa94a07fSbrendan */ 4213fa94a07fSbrendan arc_change_state(arc_anon, ab, hash_lock); 4214fa94a07fSbrendan arc_hdr_destroy(ab); 4215fa94a07fSbrendan } else { 42163a737e0dSbrendan /* 42173a737e0dSbrendan * Invalidate issued or about to be issued 42183a737e0dSbrendan * reads, since we may be about to write 42193a737e0dSbrendan * over this location. 42203a737e0dSbrendan */ 42213a737e0dSbrendan if (HDR_L2_READING(ab)) { 42223a737e0dSbrendan ARCSTAT_BUMP(arcstat_l2_evict_reading); 42233a737e0dSbrendan ab->b_flags |= ARC_L2_EVICTED; 42243a737e0dSbrendan } 42253a737e0dSbrendan 4226fa94a07fSbrendan /* 4227fa94a07fSbrendan * Tell ARC this no longer exists in L2ARC. 4228fa94a07fSbrendan */ 4229fa94a07fSbrendan if (ab->b_l2hdr != NULL) { 4230fa94a07fSbrendan abl2 = ab->b_l2hdr; 4231fa94a07fSbrendan ab->b_l2hdr = NULL; 4232fa94a07fSbrendan kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); 4233fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); 4234fa94a07fSbrendan } 4235fa94a07fSbrendan list_remove(buflist, ab); 4236fa94a07fSbrendan 4237fa94a07fSbrendan /* 4238fa94a07fSbrendan * This may have been leftover after a 4239fa94a07fSbrendan * failed write. 4240fa94a07fSbrendan */ 4241fa94a07fSbrendan ab->b_flags &= ~ARC_L2_WRITING; 4242fa94a07fSbrendan } 4243fa94a07fSbrendan mutex_exit(hash_lock); 4244fa94a07fSbrendan } 4245fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4246fa94a07fSbrendan 4247b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, -(taddr - dev->l2ad_evict), 0, 0); 4248fa94a07fSbrendan dev->l2ad_evict = taddr; 4249fa94a07fSbrendan } 4250fa94a07fSbrendan 4251fa94a07fSbrendan /* 4252fa94a07fSbrendan * Find and write ARC buffers to the L2ARC device. 4253fa94a07fSbrendan * 4254fa94a07fSbrendan * An ARC_L2_WRITING flag is set so that the L2ARC buffers are not valid 4255fa94a07fSbrendan * for reading until they have completed writing. 4256fa94a07fSbrendan */ 42575a98e54bSBrendan Gregg - Sun Microsystems static uint64_t 42583a737e0dSbrendan l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) 4259fa94a07fSbrendan { 4260fa94a07fSbrendan arc_buf_hdr_t *ab, *ab_prev, *head; 4261fa94a07fSbrendan l2arc_buf_hdr_t *hdrl2; 4262fa94a07fSbrendan list_t *list; 42633a737e0dSbrendan uint64_t passed_sz, write_sz, buf_sz, headroom; 4264fa94a07fSbrendan void *buf_data; 4265fa94a07fSbrendan kmutex_t *hash_lock, *list_lock; 4266fa94a07fSbrendan boolean_t have_lock, full; 4267fa94a07fSbrendan l2arc_write_callback_t *cb; 4268fa94a07fSbrendan zio_t *pio, *wzio; 4269ac05c741SMark Maybee uint64_t guid = spa_guid(spa); 4270fa94a07fSbrendan 4271fa94a07fSbrendan ASSERT(dev->l2ad_vdev != NULL); 4272fa94a07fSbrendan 4273fa94a07fSbrendan pio = NULL; 4274fa94a07fSbrendan write_sz = 0; 4275fa94a07fSbrendan full = B_FALSE; 42761ab7f2deSmaybee head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 4277fa94a07fSbrendan head->b_flags |= ARC_L2_WRITE_HEAD; 4278fa94a07fSbrendan 4279fa94a07fSbrendan /* 4280fa94a07fSbrendan * Copy buffers for L2ARC writing. 4281fa94a07fSbrendan */ 4282fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 4283fa94a07fSbrendan for (int try = 0; try <= 3; try++) { 4284fa94a07fSbrendan list = l2arc_list_locked(try, &list_lock); 4285fa94a07fSbrendan passed_sz = 0; 4286fa94a07fSbrendan 42873a737e0dSbrendan /* 42883a737e0dSbrendan * L2ARC fast warmup. 42893a737e0dSbrendan * 42903a737e0dSbrendan * Until the ARC is warm and starts to evict, read from the 42913a737e0dSbrendan * head of the ARC lists rather than the tail. 42923a737e0dSbrendan */ 42933a737e0dSbrendan headroom = target_sz * l2arc_headroom; 42943a737e0dSbrendan if (arc_warm == B_FALSE) 42953a737e0dSbrendan ab = list_head(list); 42963a737e0dSbrendan else 42973a737e0dSbrendan ab = list_tail(list); 42983a737e0dSbrendan 42993a737e0dSbrendan for (; ab; ab = ab_prev) { 43003a737e0dSbrendan if (arc_warm == B_FALSE) 43013a737e0dSbrendan ab_prev = list_next(list, ab); 43023a737e0dSbrendan else 43033a737e0dSbrendan ab_prev = list_prev(list, ab); 4304fa94a07fSbrendan 4305fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 4306fa94a07fSbrendan have_lock = MUTEX_HELD(hash_lock); 4307fa94a07fSbrendan if (!have_lock && !mutex_tryenter(hash_lock)) { 4308fa94a07fSbrendan /* 4309fa94a07fSbrendan * Skip this buffer rather than waiting. 4310fa94a07fSbrendan */ 4311fa94a07fSbrendan continue; 4312fa94a07fSbrendan } 4313fa94a07fSbrendan 4314fa94a07fSbrendan passed_sz += ab->b_size; 4315fa94a07fSbrendan if (passed_sz > headroom) { 4316fa94a07fSbrendan /* 4317fa94a07fSbrendan * Searched too far. 4318fa94a07fSbrendan */ 4319fa94a07fSbrendan mutex_exit(hash_lock); 4320fa94a07fSbrendan break; 4321fa94a07fSbrendan } 4322fa94a07fSbrendan 4323ac05c741SMark Maybee if (!l2arc_write_eligible(guid, ab)) { 4324fa94a07fSbrendan mutex_exit(hash_lock); 4325fa94a07fSbrendan continue; 4326fa94a07fSbrendan } 4327fa94a07fSbrendan 4328fa94a07fSbrendan if ((write_sz + ab->b_size) > target_sz) { 4329fa94a07fSbrendan full = B_TRUE; 4330fa94a07fSbrendan mutex_exit(hash_lock); 4331fa94a07fSbrendan break; 4332fa94a07fSbrendan } 4333fa94a07fSbrendan 4334fa94a07fSbrendan if (pio == NULL) { 4335fa94a07fSbrendan /* 4336fa94a07fSbrendan * Insert a dummy header on the buflist so 4337fa94a07fSbrendan * l2arc_write_done() can find where the 4338fa94a07fSbrendan * write buffers begin without searching. 4339fa94a07fSbrendan */ 4340fa94a07fSbrendan list_insert_head(dev->l2ad_buflist, head); 4341fa94a07fSbrendan 4342fa94a07fSbrendan cb = kmem_alloc( 4343fa94a07fSbrendan sizeof (l2arc_write_callback_t), KM_SLEEP); 4344fa94a07fSbrendan cb->l2wcb_dev = dev; 4345fa94a07fSbrendan cb->l2wcb_head = head; 4346fa94a07fSbrendan pio = zio_root(spa, l2arc_write_done, cb, 4347fa94a07fSbrendan ZIO_FLAG_CANFAIL); 4348fa94a07fSbrendan } 4349fa94a07fSbrendan 4350fa94a07fSbrendan /* 4351fa94a07fSbrendan * Create and add a new L2ARC header. 4352fa94a07fSbrendan */ 4353fa94a07fSbrendan hdrl2 = kmem_zalloc(sizeof (l2arc_buf_hdr_t), KM_SLEEP); 4354fa94a07fSbrendan hdrl2->b_dev = dev; 4355fa94a07fSbrendan hdrl2->b_daddr = dev->l2ad_hand; 4356fa94a07fSbrendan 4357fa94a07fSbrendan ab->b_flags |= ARC_L2_WRITING; 4358fa94a07fSbrendan ab->b_l2hdr = hdrl2; 4359fa94a07fSbrendan list_insert_head(dev->l2ad_buflist, ab); 4360fa94a07fSbrendan buf_data = ab->b_buf->b_data; 4361fa94a07fSbrendan buf_sz = ab->b_size; 4362fa94a07fSbrendan 4363fa94a07fSbrendan /* 4364fa94a07fSbrendan * Compute and store the buffer cksum before 4365fa94a07fSbrendan * writing. On debug the cksum is verified first. 4366fa94a07fSbrendan */ 4367fa94a07fSbrendan arc_cksum_verify(ab->b_buf); 4368fa94a07fSbrendan arc_cksum_compute(ab->b_buf, B_TRUE); 4369fa94a07fSbrendan 4370fa94a07fSbrendan mutex_exit(hash_lock); 4371fa94a07fSbrendan 4372fa94a07fSbrendan wzio = zio_write_phys(pio, dev->l2ad_vdev, 4373fa94a07fSbrendan dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF, 4374fa94a07fSbrendan NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, 4375fa94a07fSbrendan ZIO_FLAG_CANFAIL, B_FALSE); 4376fa94a07fSbrendan 4377fa94a07fSbrendan DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, 4378fa94a07fSbrendan zio_t *, wzio); 4379fa94a07fSbrendan (void) zio_nowait(wzio); 4380fa94a07fSbrendan 4381e14bb325SJeff Bonwick /* 4382e14bb325SJeff Bonwick * Keep the clock hand suitably device-aligned. 4383e14bb325SJeff Bonwick */ 4384e14bb325SJeff Bonwick buf_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); 4385e14bb325SJeff Bonwick 4386fa94a07fSbrendan write_sz += buf_sz; 4387fa94a07fSbrendan dev->l2ad_hand += buf_sz; 4388fa94a07fSbrendan } 4389fa94a07fSbrendan 4390fa94a07fSbrendan mutex_exit(list_lock); 4391fa94a07fSbrendan 4392fa94a07fSbrendan if (full == B_TRUE) 4393fa94a07fSbrendan break; 4394fa94a07fSbrendan } 4395fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4396fa94a07fSbrendan 4397fa94a07fSbrendan if (pio == NULL) { 4398fa94a07fSbrendan ASSERT3U(write_sz, ==, 0); 4399fa94a07fSbrendan kmem_cache_free(hdr_cache, head); 44005a98e54bSBrendan Gregg - Sun Microsystems return (0); 4401fa94a07fSbrendan } 4402fa94a07fSbrendan 4403fa94a07fSbrendan ASSERT3U(write_sz, <=, target_sz); 4404fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_sent); 44055a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_write_bytes, write_sz); 4406fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, write_sz); 4407b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, write_sz, 0, 0); 4408fa94a07fSbrendan 4409fa94a07fSbrendan /* 4410fa94a07fSbrendan * Bump device hand to the device start if it is approaching the end. 4411fa94a07fSbrendan * l2arc_evict() will already have evicted ahead for this case. 4412fa94a07fSbrendan */ 44133a737e0dSbrendan if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) { 4414b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, 4415b24ab676SJeff Bonwick dev->l2ad_end - dev->l2ad_hand, 0, 0); 4416fa94a07fSbrendan dev->l2ad_hand = dev->l2ad_start; 4417fa94a07fSbrendan dev->l2ad_evict = dev->l2ad_start; 4418fa94a07fSbrendan dev->l2ad_first = B_FALSE; 4419fa94a07fSbrendan } 4420fa94a07fSbrendan 44215a98e54bSBrendan Gregg - Sun Microsystems dev->l2ad_writing = B_TRUE; 4422fa94a07fSbrendan (void) zio_wait(pio); 44235a98e54bSBrendan Gregg - Sun Microsystems dev->l2ad_writing = B_FALSE; 44245a98e54bSBrendan Gregg - Sun Microsystems 44255a98e54bSBrendan Gregg - Sun Microsystems return (write_sz); 4426fa94a07fSbrendan } 4427fa94a07fSbrendan 4428fa94a07fSbrendan /* 4429fa94a07fSbrendan * This thread feeds the L2ARC at regular intervals. This is the beating 4430fa94a07fSbrendan * heart of the L2ARC. 4431fa94a07fSbrendan */ 4432fa94a07fSbrendan static void 4433fa94a07fSbrendan l2arc_feed_thread(void) 4434fa94a07fSbrendan { 4435fa94a07fSbrendan callb_cpr_t cpr; 4436fa94a07fSbrendan l2arc_dev_t *dev; 4437fa94a07fSbrendan spa_t *spa; 44385a98e54bSBrendan Gregg - Sun Microsystems uint64_t size, wrote; 4439d3d50737SRafael Vanoni clock_t begin, next = ddi_get_lbolt(); 4440fa94a07fSbrendan 4441fa94a07fSbrendan CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); 4442fa94a07fSbrendan 4443fa94a07fSbrendan mutex_enter(&l2arc_feed_thr_lock); 4444fa94a07fSbrendan 4445fa94a07fSbrendan while (l2arc_thread_exit == 0) { 4446fa94a07fSbrendan CALLB_CPR_SAFE_BEGIN(&cpr); 4447fa94a07fSbrendan (void) cv_timedwait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock, 44485a98e54bSBrendan Gregg - Sun Microsystems next); 4449fa94a07fSbrendan CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); 4450d3d50737SRafael Vanoni next = ddi_get_lbolt() + hz; 4451fa94a07fSbrendan 44523a737e0dSbrendan /* 44533a737e0dSbrendan * Quick check for L2ARC devices. 44543a737e0dSbrendan */ 4455c5904d13Seschrock mutex_enter(&l2arc_dev_mtx); 44563a737e0dSbrendan if (l2arc_ndev == 0) { 44573a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 44583a737e0dSbrendan continue; 44593a737e0dSbrendan } 44603a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 4461d3d50737SRafael Vanoni begin = ddi_get_lbolt(); 4462c5904d13Seschrock 4463fa94a07fSbrendan /* 4464c5904d13Seschrock * This selects the next l2arc device to write to, and in 4465c5904d13Seschrock * doing so the next spa to feed from: dev->l2ad_spa. This 44663a737e0dSbrendan * will return NULL if there are now no l2arc devices or if 44673a737e0dSbrendan * they are all faulted. 44683a737e0dSbrendan * 44693a737e0dSbrendan * If a device is returned, its spa's config lock is also 44703a737e0dSbrendan * held to prevent device removal. l2arc_dev_get_next() 44713a737e0dSbrendan * will grab and release l2arc_dev_mtx. 4472fa94a07fSbrendan */ 44733a737e0dSbrendan if ((dev = l2arc_dev_get_next()) == NULL) 4474fa94a07fSbrendan continue; 44753a737e0dSbrendan 44763a737e0dSbrendan spa = dev->l2ad_spa; 44773a737e0dSbrendan ASSERT(spa != NULL); 4478fa94a07fSbrendan 4479fa94a07fSbrendan /* 4480fa94a07fSbrendan * Avoid contributing to memory pressure. 4481fa94a07fSbrendan */ 4482fa94a07fSbrendan if (arc_reclaim_needed()) { 4483fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_abort_lowmem); 4484e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, dev); 4485fa94a07fSbrendan continue; 4486fa94a07fSbrendan } 4487fa94a07fSbrendan 4488fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_feeds); 4489fa94a07fSbrendan 44905a98e54bSBrendan Gregg - Sun Microsystems size = l2arc_write_size(dev); 44913a737e0dSbrendan 4492fa94a07fSbrendan /* 4493fa94a07fSbrendan * Evict L2ARC buffers that will be overwritten. 4494fa94a07fSbrendan */ 44953a737e0dSbrendan l2arc_evict(dev, size, B_FALSE); 4496fa94a07fSbrendan 4497fa94a07fSbrendan /* 4498fa94a07fSbrendan * Write ARC buffers. 4499fa94a07fSbrendan */ 45005a98e54bSBrendan Gregg - Sun Microsystems wrote = l2arc_write_buffers(spa, dev, size); 45015a98e54bSBrendan Gregg - Sun Microsystems 45025a98e54bSBrendan Gregg - Sun Microsystems /* 45035a98e54bSBrendan Gregg - Sun Microsystems * Calculate interval between writes. 45045a98e54bSBrendan Gregg - Sun Microsystems */ 45055a98e54bSBrendan Gregg - Sun Microsystems next = l2arc_write_interval(begin, size, wrote); 4506e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, dev); 4507fa94a07fSbrendan } 4508fa94a07fSbrendan 4509fa94a07fSbrendan l2arc_thread_exit = 0; 4510fa94a07fSbrendan cv_broadcast(&l2arc_feed_thr_cv); 4511fa94a07fSbrendan CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ 4512fa94a07fSbrendan thread_exit(); 4513fa94a07fSbrendan } 4514fa94a07fSbrendan 4515c5904d13Seschrock boolean_t 4516c5904d13Seschrock l2arc_vdev_present(vdev_t *vd) 4517c5904d13Seschrock { 4518c5904d13Seschrock l2arc_dev_t *dev; 4519c5904d13Seschrock 4520c5904d13Seschrock mutex_enter(&l2arc_dev_mtx); 4521c5904d13Seschrock for (dev = list_head(l2arc_dev_list); dev != NULL; 4522c5904d13Seschrock dev = list_next(l2arc_dev_list, dev)) { 4523c5904d13Seschrock if (dev->l2ad_vdev == vd) 4524c5904d13Seschrock break; 4525c5904d13Seschrock } 4526c5904d13Seschrock mutex_exit(&l2arc_dev_mtx); 4527c5904d13Seschrock 4528c5904d13Seschrock return (dev != NULL); 4529c5904d13Seschrock } 4530c5904d13Seschrock 4531fa94a07fSbrendan /* 4532fa94a07fSbrendan * Add a vdev for use by the L2ARC. By this point the spa has already 4533fa94a07fSbrendan * validated the vdev and opened it. 4534fa94a07fSbrendan */ 4535fa94a07fSbrendan void 4536573ca77eSGeorge Wilson l2arc_add_vdev(spa_t *spa, vdev_t *vd) 4537fa94a07fSbrendan { 4538fa94a07fSbrendan l2arc_dev_t *adddev; 4539fa94a07fSbrendan 4540c5904d13Seschrock ASSERT(!l2arc_vdev_present(vd)); 4541c5904d13Seschrock 4542fa94a07fSbrendan /* 4543fa94a07fSbrendan * Create a new l2arc device entry. 4544fa94a07fSbrendan */ 4545fa94a07fSbrendan adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); 4546fa94a07fSbrendan adddev->l2ad_spa = spa; 4547fa94a07fSbrendan adddev->l2ad_vdev = vd; 4548fa94a07fSbrendan adddev->l2ad_write = l2arc_write_max; 45493a737e0dSbrendan adddev->l2ad_boost = l2arc_write_boost; 4550573ca77eSGeorge Wilson adddev->l2ad_start = VDEV_LABEL_START_SIZE; 4551573ca77eSGeorge Wilson adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); 4552fa94a07fSbrendan adddev->l2ad_hand = adddev->l2ad_start; 4553fa94a07fSbrendan adddev->l2ad_evict = adddev->l2ad_start; 4554fa94a07fSbrendan adddev->l2ad_first = B_TRUE; 45555a98e54bSBrendan Gregg - Sun Microsystems adddev->l2ad_writing = B_FALSE; 4556fa94a07fSbrendan ASSERT3U(adddev->l2ad_write, >, 0); 4557fa94a07fSbrendan 4558fa94a07fSbrendan /* 4559fa94a07fSbrendan * This is a list of all ARC buffers that are still valid on the 4560fa94a07fSbrendan * device. 4561fa94a07fSbrendan */ 4562fa94a07fSbrendan adddev->l2ad_buflist = kmem_zalloc(sizeof (list_t), KM_SLEEP); 4563fa94a07fSbrendan list_create(adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), 4564fa94a07fSbrendan offsetof(arc_buf_hdr_t, b_l2node)); 4565fa94a07fSbrendan 4566b24ab676SJeff Bonwick vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); 4567fa94a07fSbrendan 4568fa94a07fSbrendan /* 4569fa94a07fSbrendan * Add device to global list 4570fa94a07fSbrendan */ 4571fa94a07fSbrendan mutex_enter(&l2arc_dev_mtx); 4572fa94a07fSbrendan list_insert_head(l2arc_dev_list, adddev); 4573fa94a07fSbrendan atomic_inc_64(&l2arc_ndev); 4574fa94a07fSbrendan mutex_exit(&l2arc_dev_mtx); 4575fa94a07fSbrendan } 4576fa94a07fSbrendan 4577fa94a07fSbrendan /* 4578fa94a07fSbrendan * Remove a vdev from the L2ARC. 4579fa94a07fSbrendan */ 4580fa94a07fSbrendan void 4581fa94a07fSbrendan l2arc_remove_vdev(vdev_t *vd) 4582fa94a07fSbrendan { 4583fa94a07fSbrendan l2arc_dev_t *dev, *nextdev, *remdev = NULL; 4584fa94a07fSbrendan 4585fa94a07fSbrendan /* 4586fa94a07fSbrendan * Find the device by vdev 4587fa94a07fSbrendan */ 4588fa94a07fSbrendan mutex_enter(&l2arc_dev_mtx); 4589fa94a07fSbrendan for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) { 4590fa94a07fSbrendan nextdev = list_next(l2arc_dev_list, dev); 4591fa94a07fSbrendan if (vd == dev->l2ad_vdev) { 4592fa94a07fSbrendan remdev = dev; 4593fa94a07fSbrendan break; 4594fa94a07fSbrendan } 4595fa94a07fSbrendan } 4596fa94a07fSbrendan ASSERT(remdev != NULL); 4597fa94a07fSbrendan 4598fa94a07fSbrendan /* 4599fa94a07fSbrendan * Remove device from global list 4600fa94a07fSbrendan */ 4601fa94a07fSbrendan list_remove(l2arc_dev_list, remdev); 4602fa94a07fSbrendan l2arc_dev_last = NULL; /* may have been invalidated */ 46033a737e0dSbrendan atomic_dec_64(&l2arc_ndev); 46043a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 4605fa94a07fSbrendan 4606fa94a07fSbrendan /* 4607fa94a07fSbrendan * Clear all buflists and ARC references. L2ARC device flush. 4608fa94a07fSbrendan */ 4609fa94a07fSbrendan l2arc_evict(remdev, 0, B_TRUE); 4610fa94a07fSbrendan list_destroy(remdev->l2ad_buflist); 4611fa94a07fSbrendan kmem_free(remdev->l2ad_buflist, sizeof (list_t)); 4612fa94a07fSbrendan kmem_free(remdev, sizeof (l2arc_dev_t)); 4613fa94a07fSbrendan } 4614fa94a07fSbrendan 4615fa94a07fSbrendan void 4616e14bb325SJeff Bonwick l2arc_init(void) 4617fa94a07fSbrendan { 4618fa94a07fSbrendan l2arc_thread_exit = 0; 4619fa94a07fSbrendan l2arc_ndev = 0; 4620fa94a07fSbrendan l2arc_writes_sent = 0; 4621fa94a07fSbrendan l2arc_writes_done = 0; 4622fa94a07fSbrendan 4623fa94a07fSbrendan mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); 4624fa94a07fSbrendan cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); 4625fa94a07fSbrendan mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); 4626fa94a07fSbrendan mutex_init(&l2arc_buflist_mtx, NULL, MUTEX_DEFAULT, NULL); 4627fa94a07fSbrendan mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); 4628fa94a07fSbrendan 4629fa94a07fSbrendan l2arc_dev_list = &L2ARC_dev_list; 4630fa94a07fSbrendan l2arc_free_on_write = &L2ARC_free_on_write; 4631fa94a07fSbrendan list_create(l2arc_dev_list, sizeof (l2arc_dev_t), 4632fa94a07fSbrendan offsetof(l2arc_dev_t, l2ad_node)); 4633fa94a07fSbrendan list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), 4634fa94a07fSbrendan offsetof(l2arc_data_free_t, l2df_list_node)); 4635fa94a07fSbrendan } 4636fa94a07fSbrendan 4637fa94a07fSbrendan void 4638e14bb325SJeff Bonwick l2arc_fini(void) 4639fa94a07fSbrendan { 46403a737e0dSbrendan /* 46413a737e0dSbrendan * This is called from dmu_fini(), which is called from spa_fini(); 46423a737e0dSbrendan * Because of this, we can assume that all l2arc devices have 46433a737e0dSbrendan * already been removed when the pools themselves were removed. 46443a737e0dSbrendan */ 46453a737e0dSbrendan 46463a737e0dSbrendan l2arc_do_free_on_write(); 46473a737e0dSbrendan 4648fa94a07fSbrendan mutex_destroy(&l2arc_feed_thr_lock); 4649fa94a07fSbrendan cv_destroy(&l2arc_feed_thr_cv); 4650fa94a07fSbrendan mutex_destroy(&l2arc_dev_mtx); 4651fa94a07fSbrendan mutex_destroy(&l2arc_buflist_mtx); 4652fa94a07fSbrendan mutex_destroy(&l2arc_free_on_write_mtx); 4653fa94a07fSbrendan 4654fa94a07fSbrendan list_destroy(l2arc_dev_list); 4655fa94a07fSbrendan list_destroy(l2arc_free_on_write); 4656fa94a07fSbrendan } 4657e14bb325SJeff Bonwick 4658e14bb325SJeff Bonwick void 4659e14bb325SJeff Bonwick l2arc_start(void) 4660e14bb325SJeff Bonwick { 46618ad4d6ddSJeff Bonwick if (!(spa_mode_global & FWRITE)) 4662e14bb325SJeff Bonwick return; 4663e14bb325SJeff Bonwick 4664e14bb325SJeff Bonwick (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, 4665e14bb325SJeff Bonwick TS_RUN, minclsyspri); 4666e14bb325SJeff Bonwick } 4667e14bb325SJeff Bonwick 4668e14bb325SJeff Bonwick void 4669e14bb325SJeff Bonwick l2arc_stop(void) 4670e14bb325SJeff Bonwick { 46718ad4d6ddSJeff Bonwick if (!(spa_mode_global & FWRITE)) 4672e14bb325SJeff Bonwick return; 4673e14bb325SJeff Bonwick 4674e14bb325SJeff Bonwick mutex_enter(&l2arc_feed_thr_lock); 4675e14bb325SJeff Bonwick cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ 4676e14bb325SJeff Bonwick l2arc_thread_exit = 1; 4677e14bb325SJeff Bonwick while (l2arc_thread_exit != 0) 4678e14bb325SJeff Bonwick cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); 4679e14bb325SJeff Bonwick mutex_exit(&l2arc_feed_thr_lock); 4680e14bb325SJeff Bonwick } 4681