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 /* 225a98e54bSBrendan Gregg - Sun Microsystems * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 23fa9e4066Sahrens * Use is subject to license terms. 24fa9e4066Sahrens */ 25fa9e4066Sahrens 26fa9e4066Sahrens /* 2744cb6abcSbmc * DVA-based Adjustable Replacement Cache 28fa9e4066Sahrens * 29ea8dc4b6Seschrock * While much of the theory of operation used here is 30ea8dc4b6Seschrock * based on the self-tuning, low overhead replacement cache 31fa9e4066Sahrens * presented by Megiddo and Modha at FAST 2003, there are some 32fa9e4066Sahrens * significant differences: 33fa9e4066Sahrens * 34fa9e4066Sahrens * 1. The Megiddo and Modha model assumes any page is evictable. 35fa9e4066Sahrens * Pages in its cache cannot be "locked" into memory. This makes 36fa9e4066Sahrens * the eviction algorithm simple: evict the last page in the list. 37fa9e4066Sahrens * This also make the performance characteristics easy to reason 38fa9e4066Sahrens * about. Our cache is not so simple. At any given moment, some 39fa9e4066Sahrens * subset of the blocks in the cache are un-evictable because we 40fa9e4066Sahrens * have handed out a reference to them. Blocks are only evictable 41fa9e4066Sahrens * when there are no external references active. This makes 42fa9e4066Sahrens * eviction far more problematic: we choose to evict the evictable 43fa9e4066Sahrens * blocks that are the "lowest" in the list. 44fa9e4066Sahrens * 45fa9e4066Sahrens * There are times when it is not possible to evict the requested 46fa9e4066Sahrens * space. In these circumstances we are unable to adjust the cache 47fa9e4066Sahrens * size. To prevent the cache growing unbounded at these times we 48fa94a07fSbrendan * implement a "cache throttle" that slows the flow of new data 49fa94a07fSbrendan * into the cache until we can make space available. 50fa9e4066Sahrens * 51fa9e4066Sahrens * 2. The Megiddo and Modha model assumes a fixed cache size. 52fa9e4066Sahrens * Pages are evicted when the cache is full and there is a cache 53fa9e4066Sahrens * miss. Our model has a variable sized cache. It grows with 54fa94a07fSbrendan * high use, but also tries to react to memory pressure from the 55fa9e4066Sahrens * operating system: decreasing its size when system memory is 56fa9e4066Sahrens * tight. 57fa9e4066Sahrens * 58fa9e4066Sahrens * 3. The Megiddo and Modha model assumes a fixed page size. All 59fa9e4066Sahrens * elements of the cache are therefor exactly the same size. So 60fa9e4066Sahrens * when adjusting the cache size following a cache miss, its simply 61fa9e4066Sahrens * a matter of choosing a single page to evict. In our model, we 62fa9e4066Sahrens * have variable sized cache blocks (rangeing from 512 bytes to 63fa9e4066Sahrens * 128K bytes). We therefor choose a set of blocks to evict to make 64fa9e4066Sahrens * space for a cache miss that approximates as closely as possible 65fa9e4066Sahrens * the space used by the new block. 66fa9e4066Sahrens * 67fa9e4066Sahrens * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" 68fa9e4066Sahrens * by N. Megiddo & D. Modha, FAST 2003 69fa9e4066Sahrens */ 70fa9e4066Sahrens 71fa9e4066Sahrens /* 72fa9e4066Sahrens * The locking model: 73fa9e4066Sahrens * 74fa9e4066Sahrens * A new reference to a cache buffer can be obtained in two 75fa9e4066Sahrens * ways: 1) via a hash table lookup using the DVA as a key, 76fa94a07fSbrendan * or 2) via one of the ARC lists. The arc_read() interface 77fa9e4066Sahrens * uses method 1, while the internal arc algorithms for 78fa9e4066Sahrens * adjusting the cache use method 2. We therefor provide two 79fa9e4066Sahrens * types of locks: 1) the hash table lock array, and 2) the 80fa9e4066Sahrens * arc list locks. 81fa9e4066Sahrens * 82fa9e4066Sahrens * Buffers do not have their own mutexs, rather they rely on the 83fa9e4066Sahrens * hash table mutexs for the bulk of their protection (i.e. most 84fa9e4066Sahrens * fields in the arc_buf_hdr_t are protected by these mutexs). 85fa9e4066Sahrens * 86fa9e4066Sahrens * buf_hash_find() returns the appropriate mutex (held) when it 87fa9e4066Sahrens * locates the requested buffer in the hash table. It returns 88fa9e4066Sahrens * NULL for the mutex if the buffer was not in the table. 89fa9e4066Sahrens * 90fa9e4066Sahrens * buf_hash_remove() expects the appropriate hash mutex to be 91fa9e4066Sahrens * already held before it is invoked. 92fa9e4066Sahrens * 93fa9e4066Sahrens * Each arc state also has a mutex which is used to protect the 94fa9e4066Sahrens * buffer list associated with the state. When attempting to 95fa9e4066Sahrens * obtain a hash table lock while holding an arc list lock you 96fa9e4066Sahrens * must use: mutex_tryenter() to avoid deadlock. Also note that 9744eda4d7Smaybee * the active state mutex must be held before the ghost state mutex. 98fa9e4066Sahrens * 99ea8dc4b6Seschrock * Arc buffers may have an associated eviction callback function. 100ea8dc4b6Seschrock * This function will be invoked prior to removing the buffer (e.g. 101ea8dc4b6Seschrock * in arc_do_user_evicts()). Note however that the data associated 102ea8dc4b6Seschrock * with the buffer may be evicted prior to the callback. The callback 103ea8dc4b6Seschrock * must be made with *no locks held* (to prevent deadlock). Additionally, 104ea8dc4b6Seschrock * the users of callbacks must ensure that their private data is 105ea8dc4b6Seschrock * protected from simultaneous callbacks from arc_buf_evict() 106ea8dc4b6Seschrock * and arc_do_user_evicts(). 107ea8dc4b6Seschrock * 108fa9e4066Sahrens * Note that the majority of the performance stats are manipulated 109fa9e4066Sahrens * with atomic operations. 110fa94a07fSbrendan * 111fa94a07fSbrendan * The L2ARC uses the l2arc_buflist_mtx global mutex for the following: 112fa94a07fSbrendan * 113fa94a07fSbrendan * - L2ARC buflist creation 114fa94a07fSbrendan * - L2ARC buflist eviction 115fa94a07fSbrendan * - L2ARC write completion, which walks L2ARC buflists 116fa94a07fSbrendan * - ARC header destruction, as it removes from L2ARC buflists 117fa94a07fSbrendan * - ARC header release, as it removes from L2ARC buflists 118fa9e4066Sahrens */ 119fa9e4066Sahrens 120fa9e4066Sahrens #include <sys/spa.h> 121fa9e4066Sahrens #include <sys/zio.h> 122fa9e4066Sahrens #include <sys/zfs_context.h> 123fa9e4066Sahrens #include <sys/arc.h> 124fa9e4066Sahrens #include <sys/refcount.h> 125c5904d13Seschrock #include <sys/vdev.h> 126573ca77eSGeorge Wilson #include <sys/vdev_impl.h> 127fa9e4066Sahrens #ifdef _KERNEL 128fa9e4066Sahrens #include <sys/vmsystm.h> 129fa9e4066Sahrens #include <vm/anon.h> 130fa9e4066Sahrens #include <sys/fs/swapnode.h> 131033f9833Sek #include <sys/dnlc.h> 132fa9e4066Sahrens #endif 133fa9e4066Sahrens #include <sys/callb.h> 13444cb6abcSbmc #include <sys/kstat.h> 135*b24ab676SJeff Bonwick #include <zfs_fletcher.h> 136fa9e4066Sahrens 137fa9e4066Sahrens static kmutex_t arc_reclaim_thr_lock; 138fa9e4066Sahrens static kcondvar_t arc_reclaim_thr_cv; /* used to signal reclaim thr */ 139fa9e4066Sahrens static uint8_t arc_thread_exit; 140fa9e4066Sahrens 1411ab7f2deSmaybee extern int zfs_write_limit_shift; 1421ab7f2deSmaybee extern uint64_t zfs_write_limit_max; 14305715f94SMark Maybee extern kmutex_t zfs_write_limit_lock; 1441ab7f2deSmaybee 145033f9833Sek #define ARC_REDUCE_DNLC_PERCENT 3 146033f9833Sek uint_t arc_reduce_dnlc_percent = ARC_REDUCE_DNLC_PERCENT; 147033f9833Sek 148fa9e4066Sahrens typedef enum arc_reclaim_strategy { 149fa9e4066Sahrens ARC_RECLAIM_AGGR, /* Aggressive reclaim strategy */ 150fa9e4066Sahrens ARC_RECLAIM_CONS /* Conservative reclaim strategy */ 151fa9e4066Sahrens } arc_reclaim_strategy_t; 152fa9e4066Sahrens 153fa9e4066Sahrens /* number of seconds before growing cache again */ 154fa9e4066Sahrens static int arc_grow_retry = 60; 155fa9e4066Sahrens 1565a98e54bSBrendan Gregg - Sun Microsystems /* shift of arc_c for calculating both min and max arc_p */ 1575a98e54bSBrendan Gregg - Sun Microsystems static int arc_p_min_shift = 4; 1585a98e54bSBrendan Gregg - Sun Microsystems 1595a98e54bSBrendan Gregg - Sun Microsystems /* log2(fraction of arc to reclaim) */ 1605a98e54bSBrendan Gregg - Sun Microsystems static int arc_shrink_shift = 5; 1615a98e54bSBrendan Gregg - Sun Microsystems 16213506d1eSmaybee /* 163b19a79ecSperrin * minimum lifespan of a prefetch block in clock ticks 164b19a79ecSperrin * (initialized in arc_init()) 16513506d1eSmaybee */ 166b19a79ecSperrin static int arc_min_prefetch_lifespan; 16713506d1eSmaybee 168fa9e4066Sahrens static int arc_dead; 169fa9e4066Sahrens 1703a737e0dSbrendan /* 1713a737e0dSbrendan * The arc has filled available memory and has now warmed up. 1723a737e0dSbrendan */ 1733a737e0dSbrendan static boolean_t arc_warm; 1743a737e0dSbrendan 175a2eea2e1Sahrens /* 176a2eea2e1Sahrens * These tunables are for performance analysis. 177a2eea2e1Sahrens */ 178a2eea2e1Sahrens uint64_t zfs_arc_max; 179a2eea2e1Sahrens uint64_t zfs_arc_min; 1801116048bSek uint64_t zfs_arc_meta_limit = 0; 1815a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_grow_retry = 0; 1825a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_shrink_shift = 0; 1835a98e54bSBrendan Gregg - Sun Microsystems int zfs_arc_p_min_shift = 0; 184a2eea2e1Sahrens 185fa9e4066Sahrens /* 186fa94a07fSbrendan * Note that buffers can be in one of 6 states: 187fa9e4066Sahrens * ARC_anon - anonymous (discussed below) 188ea8dc4b6Seschrock * ARC_mru - recently used, currently cached 189ea8dc4b6Seschrock * ARC_mru_ghost - recentely used, no longer in cache 190ea8dc4b6Seschrock * ARC_mfu - frequently used, currently cached 191ea8dc4b6Seschrock * ARC_mfu_ghost - frequently used, no longer in cache 192fa94a07fSbrendan * ARC_l2c_only - exists in L2ARC but not other states 1930e8c6158Smaybee * When there are no active references to the buffer, they are 1940e8c6158Smaybee * are linked onto a list in one of these arc states. These are 1950e8c6158Smaybee * the only buffers that can be evicted or deleted. Within each 1960e8c6158Smaybee * state there are multiple lists, one for meta-data and one for 1970e8c6158Smaybee * non-meta-data. Meta-data (indirect blocks, blocks of dnodes, 1980e8c6158Smaybee * etc.) is tracked separately so that it can be managed more 199fa94a07fSbrendan * explicitly: favored over data, limited explicitly. 200fa9e4066Sahrens * 201fa9e4066Sahrens * Anonymous buffers are buffers that are not associated with 202fa9e4066Sahrens * a DVA. These are buffers that hold dirty block copies 203fa9e4066Sahrens * before they are written to stable storage. By definition, 204ea8dc4b6Seschrock * they are "ref'd" and are considered part of arc_mru 205fa9e4066Sahrens * that cannot be freed. Generally, they will aquire a DVA 206ea8dc4b6Seschrock * as they are written and migrate onto the arc_mru list. 207fa94a07fSbrendan * 208fa94a07fSbrendan * The ARC_l2c_only state is for buffers that are in the second 209fa94a07fSbrendan * level ARC but no longer in any of the ARC_m* lists. The second 210fa94a07fSbrendan * level ARC itself may also contain buffers that are in any of 211fa94a07fSbrendan * the ARC_m* states - meaning that a buffer can exist in two 212fa94a07fSbrendan * places. The reason for the ARC_l2c_only state is to keep the 213fa94a07fSbrendan * buffer header in the hash table, so that reads that hit the 214fa94a07fSbrendan * second level ARC benefit from these fast lookups. 215fa9e4066Sahrens */ 216fa9e4066Sahrens 217fa9e4066Sahrens typedef struct arc_state { 2180e8c6158Smaybee list_t arcs_list[ARC_BUFC_NUMTYPES]; /* list of evictable buffers */ 2190e8c6158Smaybee uint64_t arcs_lsize[ARC_BUFC_NUMTYPES]; /* amount of evictable data */ 2200e8c6158Smaybee uint64_t arcs_size; /* total amount of data in this state */ 22144cb6abcSbmc kmutex_t arcs_mtx; 222fa9e4066Sahrens } arc_state_t; 223fa9e4066Sahrens 224fa94a07fSbrendan /* The 6 states: */ 225fa9e4066Sahrens static arc_state_t ARC_anon; 226ea8dc4b6Seschrock static arc_state_t ARC_mru; 227ea8dc4b6Seschrock static arc_state_t ARC_mru_ghost; 228ea8dc4b6Seschrock static arc_state_t ARC_mfu; 229ea8dc4b6Seschrock static arc_state_t ARC_mfu_ghost; 230fa94a07fSbrendan static arc_state_t ARC_l2c_only; 231fa9e4066Sahrens 23244cb6abcSbmc typedef struct arc_stats { 23344cb6abcSbmc kstat_named_t arcstat_hits; 23444cb6abcSbmc kstat_named_t arcstat_misses; 23544cb6abcSbmc kstat_named_t arcstat_demand_data_hits; 23644cb6abcSbmc kstat_named_t arcstat_demand_data_misses; 23744cb6abcSbmc kstat_named_t arcstat_demand_metadata_hits; 23844cb6abcSbmc kstat_named_t arcstat_demand_metadata_misses; 23944cb6abcSbmc kstat_named_t arcstat_prefetch_data_hits; 24044cb6abcSbmc kstat_named_t arcstat_prefetch_data_misses; 24144cb6abcSbmc kstat_named_t arcstat_prefetch_metadata_hits; 24244cb6abcSbmc kstat_named_t arcstat_prefetch_metadata_misses; 24344cb6abcSbmc kstat_named_t arcstat_mru_hits; 24444cb6abcSbmc kstat_named_t arcstat_mru_ghost_hits; 24544cb6abcSbmc kstat_named_t arcstat_mfu_hits; 24644cb6abcSbmc kstat_named_t arcstat_mfu_ghost_hits; 24744cb6abcSbmc kstat_named_t arcstat_deleted; 24844cb6abcSbmc kstat_named_t arcstat_recycle_miss; 24944cb6abcSbmc kstat_named_t arcstat_mutex_miss; 25044cb6abcSbmc kstat_named_t arcstat_evict_skip; 2515ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_cached; 2525ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_eligible; 2535ea40c06SBrendan Gregg - Sun Microsystems kstat_named_t arcstat_evict_l2_ineligible; 25444cb6abcSbmc kstat_named_t arcstat_hash_elements; 25544cb6abcSbmc kstat_named_t arcstat_hash_elements_max; 25644cb6abcSbmc kstat_named_t arcstat_hash_collisions; 25744cb6abcSbmc kstat_named_t arcstat_hash_chains; 25844cb6abcSbmc kstat_named_t arcstat_hash_chain_max; 25944cb6abcSbmc kstat_named_t arcstat_p; 26044cb6abcSbmc kstat_named_t arcstat_c; 26144cb6abcSbmc kstat_named_t arcstat_c_min; 26244cb6abcSbmc kstat_named_t arcstat_c_max; 26344cb6abcSbmc kstat_named_t arcstat_size; 264fa94a07fSbrendan kstat_named_t arcstat_hdr_size; 2655a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_data_size; 2665a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_other_size; 267fa94a07fSbrendan kstat_named_t arcstat_l2_hits; 268fa94a07fSbrendan kstat_named_t arcstat_l2_misses; 269fa94a07fSbrendan kstat_named_t arcstat_l2_feeds; 270fa94a07fSbrendan kstat_named_t arcstat_l2_rw_clash; 2715a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_l2_read_bytes; 2725a98e54bSBrendan Gregg - Sun Microsystems kstat_named_t arcstat_l2_write_bytes; 273fa94a07fSbrendan kstat_named_t arcstat_l2_writes_sent; 274fa94a07fSbrendan kstat_named_t arcstat_l2_writes_done; 275fa94a07fSbrendan kstat_named_t arcstat_l2_writes_error; 276fa94a07fSbrendan kstat_named_t arcstat_l2_writes_hdr_miss; 277fa94a07fSbrendan kstat_named_t arcstat_l2_evict_lock_retry; 278fa94a07fSbrendan kstat_named_t arcstat_l2_evict_reading; 279fa94a07fSbrendan kstat_named_t arcstat_l2_free_on_write; 280fa94a07fSbrendan kstat_named_t arcstat_l2_abort_lowmem; 281fa94a07fSbrendan kstat_named_t arcstat_l2_cksum_bad; 282fa94a07fSbrendan kstat_named_t arcstat_l2_io_error; 283fa94a07fSbrendan kstat_named_t arcstat_l2_size; 284fa94a07fSbrendan kstat_named_t arcstat_l2_hdr_size; 2851ab7f2deSmaybee kstat_named_t arcstat_memory_throttle_count; 28644cb6abcSbmc } arc_stats_t; 28744cb6abcSbmc 28844cb6abcSbmc static arc_stats_t arc_stats = { 28944cb6abcSbmc { "hits", KSTAT_DATA_UINT64 }, 29044cb6abcSbmc { "misses", KSTAT_DATA_UINT64 }, 29144cb6abcSbmc { "demand_data_hits", KSTAT_DATA_UINT64 }, 29244cb6abcSbmc { "demand_data_misses", KSTAT_DATA_UINT64 }, 29344cb6abcSbmc { "demand_metadata_hits", KSTAT_DATA_UINT64 }, 29444cb6abcSbmc { "demand_metadata_misses", KSTAT_DATA_UINT64 }, 29544cb6abcSbmc { "prefetch_data_hits", KSTAT_DATA_UINT64 }, 29644cb6abcSbmc { "prefetch_data_misses", KSTAT_DATA_UINT64 }, 29744cb6abcSbmc { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, 29844cb6abcSbmc { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, 29944cb6abcSbmc { "mru_hits", KSTAT_DATA_UINT64 }, 30044cb6abcSbmc { "mru_ghost_hits", KSTAT_DATA_UINT64 }, 30144cb6abcSbmc { "mfu_hits", KSTAT_DATA_UINT64 }, 30244cb6abcSbmc { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, 30344cb6abcSbmc { "deleted", KSTAT_DATA_UINT64 }, 30444cb6abcSbmc { "recycle_miss", KSTAT_DATA_UINT64 }, 30544cb6abcSbmc { "mutex_miss", KSTAT_DATA_UINT64 }, 30644cb6abcSbmc { "evict_skip", KSTAT_DATA_UINT64 }, 3075ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_cached", KSTAT_DATA_UINT64 }, 3085ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_eligible", KSTAT_DATA_UINT64 }, 3095ea40c06SBrendan Gregg - Sun Microsystems { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, 31044cb6abcSbmc { "hash_elements", KSTAT_DATA_UINT64 }, 31144cb6abcSbmc { "hash_elements_max", KSTAT_DATA_UINT64 }, 31244cb6abcSbmc { "hash_collisions", KSTAT_DATA_UINT64 }, 31344cb6abcSbmc { "hash_chains", KSTAT_DATA_UINT64 }, 31444cb6abcSbmc { "hash_chain_max", KSTAT_DATA_UINT64 }, 31544cb6abcSbmc { "p", KSTAT_DATA_UINT64 }, 31644cb6abcSbmc { "c", KSTAT_DATA_UINT64 }, 31744cb6abcSbmc { "c_min", KSTAT_DATA_UINT64 }, 31844cb6abcSbmc { "c_max", KSTAT_DATA_UINT64 }, 319fa94a07fSbrendan { "size", KSTAT_DATA_UINT64 }, 320fa94a07fSbrendan { "hdr_size", KSTAT_DATA_UINT64 }, 3215a98e54bSBrendan Gregg - Sun Microsystems { "data_size", KSTAT_DATA_UINT64 }, 3225a98e54bSBrendan Gregg - Sun Microsystems { "other_size", KSTAT_DATA_UINT64 }, 323fa94a07fSbrendan { "l2_hits", KSTAT_DATA_UINT64 }, 324fa94a07fSbrendan { "l2_misses", KSTAT_DATA_UINT64 }, 325fa94a07fSbrendan { "l2_feeds", KSTAT_DATA_UINT64 }, 326fa94a07fSbrendan { "l2_rw_clash", KSTAT_DATA_UINT64 }, 3275a98e54bSBrendan Gregg - Sun Microsystems { "l2_read_bytes", KSTAT_DATA_UINT64 }, 3285a98e54bSBrendan Gregg - Sun Microsystems { "l2_write_bytes", KSTAT_DATA_UINT64 }, 329fa94a07fSbrendan { "l2_writes_sent", KSTAT_DATA_UINT64 }, 330fa94a07fSbrendan { "l2_writes_done", KSTAT_DATA_UINT64 }, 331fa94a07fSbrendan { "l2_writes_error", KSTAT_DATA_UINT64 }, 332fa94a07fSbrendan { "l2_writes_hdr_miss", KSTAT_DATA_UINT64 }, 333fa94a07fSbrendan { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, 334fa94a07fSbrendan { "l2_evict_reading", KSTAT_DATA_UINT64 }, 335fa94a07fSbrendan { "l2_free_on_write", KSTAT_DATA_UINT64 }, 336fa94a07fSbrendan { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, 337fa94a07fSbrendan { "l2_cksum_bad", KSTAT_DATA_UINT64 }, 338fa94a07fSbrendan { "l2_io_error", KSTAT_DATA_UINT64 }, 339fa94a07fSbrendan { "l2_size", KSTAT_DATA_UINT64 }, 3401ab7f2deSmaybee { "l2_hdr_size", KSTAT_DATA_UINT64 }, 3411ab7f2deSmaybee { "memory_throttle_count", KSTAT_DATA_UINT64 } 34244cb6abcSbmc }; 34344cb6abcSbmc 34444cb6abcSbmc #define ARCSTAT(stat) (arc_stats.stat.value.ui64) 34544cb6abcSbmc 34644cb6abcSbmc #define ARCSTAT_INCR(stat, val) \ 34744cb6abcSbmc atomic_add_64(&arc_stats.stat.value.ui64, (val)); 34844cb6abcSbmc 349*b24ab676SJeff Bonwick #define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1) 35044cb6abcSbmc #define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1) 35144cb6abcSbmc 35244cb6abcSbmc #define ARCSTAT_MAX(stat, val) { \ 35344cb6abcSbmc uint64_t m; \ 35444cb6abcSbmc while ((val) > (m = arc_stats.stat.value.ui64) && \ 35544cb6abcSbmc (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ 35644cb6abcSbmc continue; \ 35744cb6abcSbmc } 35844cb6abcSbmc 35944cb6abcSbmc #define ARCSTAT_MAXSTAT(stat) \ 36044cb6abcSbmc ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64) 36144cb6abcSbmc 36244cb6abcSbmc /* 36344cb6abcSbmc * We define a macro to allow ARC hits/misses to be easily broken down by 36444cb6abcSbmc * two separate conditions, giving a total of four different subtypes for 36544cb6abcSbmc * each of hits and misses (so eight statistics total). 36644cb6abcSbmc */ 36744cb6abcSbmc #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ 36844cb6abcSbmc if (cond1) { \ 36944cb6abcSbmc if (cond2) { \ 37044cb6abcSbmc ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ 37144cb6abcSbmc } else { \ 37244cb6abcSbmc ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ 37344cb6abcSbmc } \ 37444cb6abcSbmc } else { \ 37544cb6abcSbmc if (cond2) { \ 37644cb6abcSbmc ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ 37744cb6abcSbmc } else { \ 37844cb6abcSbmc ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ 37944cb6abcSbmc } \ 38044cb6abcSbmc } 38144cb6abcSbmc 38244cb6abcSbmc kstat_t *arc_ksp; 383*b24ab676SJeff Bonwick static arc_state_t *arc_anon; 38444cb6abcSbmc static arc_state_t *arc_mru; 38544cb6abcSbmc static arc_state_t *arc_mru_ghost; 38644cb6abcSbmc static arc_state_t *arc_mfu; 38744cb6abcSbmc static arc_state_t *arc_mfu_ghost; 388fa94a07fSbrendan static arc_state_t *arc_l2c_only; 38944cb6abcSbmc 39044cb6abcSbmc /* 39144cb6abcSbmc * There are several ARC variables that are critical to export as kstats -- 39244cb6abcSbmc * but we don't want to have to grovel around in the kstat whenever we wish to 39344cb6abcSbmc * manipulate them. For these variables, we therefore define them to be in 39444cb6abcSbmc * terms of the statistic variable. This assures that we are not introducing 39544cb6abcSbmc * the possibility of inconsistency by having shadow copies of the variables, 39644cb6abcSbmc * while still allowing the code to be readable. 39744cb6abcSbmc */ 39844cb6abcSbmc #define arc_size ARCSTAT(arcstat_size) /* actual total arc size */ 39944cb6abcSbmc #define arc_p ARCSTAT(arcstat_p) /* target size of MRU */ 40044cb6abcSbmc #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ 40144cb6abcSbmc #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ 40244cb6abcSbmc #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ 40344cb6abcSbmc 40444cb6abcSbmc static int arc_no_grow; /* Don't try to grow cache size */ 40544cb6abcSbmc static uint64_t arc_tempreserve; 4062fdbea25SAleksandr Guzovskiy static uint64_t arc_loaned_bytes; 4070e8c6158Smaybee static uint64_t arc_meta_used; 4080e8c6158Smaybee static uint64_t arc_meta_limit; 4090e8c6158Smaybee static uint64_t arc_meta_max = 0; 410fa9e4066Sahrens 411fa94a07fSbrendan typedef struct l2arc_buf_hdr l2arc_buf_hdr_t; 412fa94a07fSbrendan 413fa9e4066Sahrens typedef struct arc_callback arc_callback_t; 414fa9e4066Sahrens 415fa9e4066Sahrens struct arc_callback { 416fa9e4066Sahrens void *acb_private; 417c717a561Smaybee arc_done_func_t *acb_done; 418fa9e4066Sahrens arc_buf_t *acb_buf; 419fa9e4066Sahrens zio_t *acb_zio_dummy; 420fa9e4066Sahrens arc_callback_t *acb_next; 421fa9e4066Sahrens }; 422fa9e4066Sahrens 423c717a561Smaybee typedef struct arc_write_callback arc_write_callback_t; 424c717a561Smaybee 425c717a561Smaybee struct arc_write_callback { 426c717a561Smaybee void *awcb_private; 427c717a561Smaybee arc_done_func_t *awcb_ready; 428c717a561Smaybee arc_done_func_t *awcb_done; 429c717a561Smaybee arc_buf_t *awcb_buf; 430c717a561Smaybee }; 431c717a561Smaybee 432fa9e4066Sahrens struct arc_buf_hdr { 433fa9e4066Sahrens /* protected by hash lock */ 434fa9e4066Sahrens dva_t b_dva; 435fa9e4066Sahrens uint64_t b_birth; 436fa9e4066Sahrens uint64_t b_cksum0; 437fa9e4066Sahrens 4386b4acc8bSahrens kmutex_t b_freeze_lock; 4396b4acc8bSahrens zio_cksum_t *b_freeze_cksum; 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)) 548fa9e4066Sahrens #define HDR_LOCK(buf) \ 549fa9e4066Sahrens (BUF_HASH_LOCK(BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->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 667fa9e4066Sahrens static arc_buf_hdr_t * 668ac05c741SMark Maybee buf_hash_find(uint64_t spa, const dva_t *dva, uint64_t birth, kmutex_t **lockp) 669fa9e4066Sahrens { 670fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); 671fa9e4066Sahrens kmutex_t *hash_lock = BUF_HASH_LOCK(idx); 672fa9e4066Sahrens arc_buf_hdr_t *buf; 673fa9e4066Sahrens 674fa9e4066Sahrens mutex_enter(hash_lock); 675fa9e4066Sahrens for (buf = buf_hash_table.ht_table[idx]; buf != NULL; 676fa9e4066Sahrens buf = buf->b_hash_next) { 677fa9e4066Sahrens if (BUF_EQUAL(spa, dva, birth, buf)) { 678fa9e4066Sahrens *lockp = hash_lock; 679fa9e4066Sahrens return (buf); 680fa9e4066Sahrens } 681fa9e4066Sahrens } 682fa9e4066Sahrens mutex_exit(hash_lock); 683fa9e4066Sahrens *lockp = NULL; 684fa9e4066Sahrens return (NULL); 685fa9e4066Sahrens } 686fa9e4066Sahrens 687fa9e4066Sahrens /* 688fa9e4066Sahrens * Insert an entry into the hash table. If there is already an element 689fa9e4066Sahrens * equal to elem in the hash table, then the already existing element 690fa9e4066Sahrens * will be returned and the new element will not be inserted. 691fa9e4066Sahrens * Otherwise returns NULL. 692fa9e4066Sahrens */ 693fa9e4066Sahrens static arc_buf_hdr_t * 694fa9e4066Sahrens buf_hash_insert(arc_buf_hdr_t *buf, kmutex_t **lockp) 695fa9e4066Sahrens { 696fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); 697fa9e4066Sahrens kmutex_t *hash_lock = BUF_HASH_LOCK(idx); 698fa9e4066Sahrens arc_buf_hdr_t *fbuf; 69944cb6abcSbmc uint32_t i; 700fa9e4066Sahrens 701ea8dc4b6Seschrock ASSERT(!HDR_IN_HASH_TABLE(buf)); 702fa9e4066Sahrens *lockp = hash_lock; 703fa9e4066Sahrens mutex_enter(hash_lock); 704fa9e4066Sahrens for (fbuf = buf_hash_table.ht_table[idx], i = 0; fbuf != NULL; 705fa9e4066Sahrens fbuf = fbuf->b_hash_next, i++) { 706fa9e4066Sahrens if (BUF_EQUAL(buf->b_spa, &buf->b_dva, buf->b_birth, fbuf)) 707fa9e4066Sahrens return (fbuf); 708fa9e4066Sahrens } 709fa9e4066Sahrens 710fa9e4066Sahrens buf->b_hash_next = buf_hash_table.ht_table[idx]; 711fa9e4066Sahrens buf_hash_table.ht_table[idx] = buf; 712ea8dc4b6Seschrock buf->b_flags |= ARC_IN_HASH_TABLE; 713fa9e4066Sahrens 714fa9e4066Sahrens /* collect some hash table performance data */ 715fa9e4066Sahrens if (i > 0) { 71644cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_collisions); 717fa9e4066Sahrens if (i == 1) 71844cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_chains); 71944cb6abcSbmc 72044cb6abcSbmc ARCSTAT_MAX(arcstat_hash_chain_max, i); 721fa9e4066Sahrens } 72244cb6abcSbmc 72344cb6abcSbmc ARCSTAT_BUMP(arcstat_hash_elements); 72444cb6abcSbmc ARCSTAT_MAXSTAT(arcstat_hash_elements); 725fa9e4066Sahrens 726fa9e4066Sahrens return (NULL); 727fa9e4066Sahrens } 728fa9e4066Sahrens 729fa9e4066Sahrens static void 730fa9e4066Sahrens buf_hash_remove(arc_buf_hdr_t *buf) 731fa9e4066Sahrens { 732fa9e4066Sahrens arc_buf_hdr_t *fbuf, **bufp; 733fa9e4066Sahrens uint64_t idx = BUF_HASH_INDEX(buf->b_spa, &buf->b_dva, buf->b_birth); 734fa9e4066Sahrens 735fa9e4066Sahrens ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); 736ea8dc4b6Seschrock ASSERT(HDR_IN_HASH_TABLE(buf)); 737fa9e4066Sahrens 738fa9e4066Sahrens bufp = &buf_hash_table.ht_table[idx]; 739fa9e4066Sahrens while ((fbuf = *bufp) != buf) { 740fa9e4066Sahrens ASSERT(fbuf != NULL); 741fa9e4066Sahrens bufp = &fbuf->b_hash_next; 742fa9e4066Sahrens } 743fa9e4066Sahrens *bufp = buf->b_hash_next; 744fa9e4066Sahrens buf->b_hash_next = NULL; 745ea8dc4b6Seschrock buf->b_flags &= ~ARC_IN_HASH_TABLE; 746fa9e4066Sahrens 747fa9e4066Sahrens /* collect some hash table performance data */ 74844cb6abcSbmc ARCSTAT_BUMPDOWN(arcstat_hash_elements); 74944cb6abcSbmc 750fa9e4066Sahrens if (buf_hash_table.ht_table[idx] && 751fa9e4066Sahrens buf_hash_table.ht_table[idx]->b_hash_next == NULL) 75244cb6abcSbmc ARCSTAT_BUMPDOWN(arcstat_hash_chains); 753fa9e4066Sahrens } 754fa9e4066Sahrens 755fa9e4066Sahrens /* 756fa9e4066Sahrens * Global data structures and functions for the buf kmem cache. 757fa9e4066Sahrens */ 758fa9e4066Sahrens static kmem_cache_t *hdr_cache; 759fa9e4066Sahrens static kmem_cache_t *buf_cache; 760fa9e4066Sahrens 761fa9e4066Sahrens static void 762fa9e4066Sahrens buf_fini(void) 763fa9e4066Sahrens { 764fa9e4066Sahrens int i; 765fa9e4066Sahrens 766fa9e4066Sahrens kmem_free(buf_hash_table.ht_table, 767fa9e4066Sahrens (buf_hash_table.ht_mask + 1) * sizeof (void *)); 768fa9e4066Sahrens for (i = 0; i < BUF_LOCKS; i++) 769fa9e4066Sahrens mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock); 770fa9e4066Sahrens kmem_cache_destroy(hdr_cache); 771fa9e4066Sahrens kmem_cache_destroy(buf_cache); 772fa9e4066Sahrens } 773fa9e4066Sahrens 774fa9e4066Sahrens /* 775fa9e4066Sahrens * Constructor callback - called when the cache is empty 776fa9e4066Sahrens * and a new buf is requested. 777fa9e4066Sahrens */ 778fa9e4066Sahrens /* ARGSUSED */ 779fa9e4066Sahrens static int 780fa9e4066Sahrens hdr_cons(void *vbuf, void *unused, int kmflag) 781fa9e4066Sahrens { 782fa9e4066Sahrens arc_buf_hdr_t *buf = vbuf; 783fa9e4066Sahrens 784fa9e4066Sahrens bzero(buf, sizeof (arc_buf_hdr_t)); 785fa9e4066Sahrens refcount_create(&buf->b_refcnt); 786fa9e4066Sahrens cv_init(&buf->b_cv, NULL, CV_DEFAULT, NULL); 787c25056deSgw mutex_init(&buf->b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); 7885a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); 789fa94a07fSbrendan 790fa9e4066Sahrens return (0); 791fa9e4066Sahrens } 792fa9e4066Sahrens 7936f83844dSMark Maybee /* ARGSUSED */ 7946f83844dSMark Maybee static int 7956f83844dSMark Maybee buf_cons(void *vbuf, void *unused, int kmflag) 7966f83844dSMark Maybee { 7976f83844dSMark Maybee arc_buf_t *buf = vbuf; 7986f83844dSMark Maybee 7996f83844dSMark Maybee bzero(buf, sizeof (arc_buf_t)); 8006f83844dSMark Maybee rw_init(&buf->b_lock, NULL, RW_DEFAULT, NULL); 8015a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); 8025a98e54bSBrendan Gregg - Sun Microsystems 8036f83844dSMark Maybee return (0); 8046f83844dSMark Maybee } 8056f83844dSMark Maybee 806fa9e4066Sahrens /* 807fa9e4066Sahrens * Destructor callback - called when a cached buf is 808fa9e4066Sahrens * no longer required. 809fa9e4066Sahrens */ 810fa9e4066Sahrens /* ARGSUSED */ 811fa9e4066Sahrens static void 812fa9e4066Sahrens hdr_dest(void *vbuf, void *unused) 813fa9e4066Sahrens { 814fa9e4066Sahrens arc_buf_hdr_t *buf = vbuf; 815fa9e4066Sahrens 816*b24ab676SJeff Bonwick ASSERT(BUF_EMPTY(buf)); 817fa9e4066Sahrens refcount_destroy(&buf->b_refcnt); 818fa9e4066Sahrens cv_destroy(&buf->b_cv); 819c25056deSgw mutex_destroy(&buf->b_freeze_lock); 8205a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(sizeof (arc_buf_hdr_t), ARC_SPACE_HDRS); 821fa9e4066Sahrens } 822fa9e4066Sahrens 8236f83844dSMark Maybee /* ARGSUSED */ 8246f83844dSMark Maybee static void 8256f83844dSMark Maybee buf_dest(void *vbuf, void *unused) 8266f83844dSMark Maybee { 8276f83844dSMark Maybee arc_buf_t *buf = vbuf; 8286f83844dSMark Maybee 8296f83844dSMark Maybee rw_destroy(&buf->b_lock); 8305a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); 8316f83844dSMark Maybee } 8326f83844dSMark Maybee 833fa9e4066Sahrens /* 834fa9e4066Sahrens * Reclaim callback -- invoked when memory is low. 835fa9e4066Sahrens */ 836fa9e4066Sahrens /* ARGSUSED */ 837fa9e4066Sahrens static void 838fa9e4066Sahrens hdr_recl(void *unused) 839fa9e4066Sahrens { 840fa9e4066Sahrens dprintf("hdr_recl called\n"); 84149e3519aSmaybee /* 84249e3519aSmaybee * umem calls the reclaim func when we destroy the buf cache, 84349e3519aSmaybee * which is after we do arc_fini(). 84449e3519aSmaybee */ 84549e3519aSmaybee if (!arc_dead) 84649e3519aSmaybee cv_signal(&arc_reclaim_thr_cv); 847fa9e4066Sahrens } 848fa9e4066Sahrens 849fa9e4066Sahrens static void 850fa9e4066Sahrens buf_init(void) 851fa9e4066Sahrens { 852fa9e4066Sahrens uint64_t *ct; 853ea8dc4b6Seschrock uint64_t hsize = 1ULL << 12; 854fa9e4066Sahrens int i, j; 855fa9e4066Sahrens 856fa9e4066Sahrens /* 857fa9e4066Sahrens * The hash table is big enough to fill all of physical memory 858ea8dc4b6Seschrock * with an average 64K block size. The table will take up 859ea8dc4b6Seschrock * totalmem*sizeof(void*)/64K (eg. 128KB/GB with 8-byte pointers). 860fa9e4066Sahrens */ 861ea8dc4b6Seschrock while (hsize * 65536 < physmem * PAGESIZE) 862fa9e4066Sahrens hsize <<= 1; 863ea8dc4b6Seschrock retry: 864fa9e4066Sahrens buf_hash_table.ht_mask = hsize - 1; 865ea8dc4b6Seschrock buf_hash_table.ht_table = 866ea8dc4b6Seschrock kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); 867ea8dc4b6Seschrock if (buf_hash_table.ht_table == NULL) { 868ea8dc4b6Seschrock ASSERT(hsize > (1ULL << 8)); 869ea8dc4b6Seschrock hsize >>= 1; 870ea8dc4b6Seschrock goto retry; 871ea8dc4b6Seschrock } 872fa9e4066Sahrens 873fa9e4066Sahrens hdr_cache = kmem_cache_create("arc_buf_hdr_t", sizeof (arc_buf_hdr_t), 874fa9e4066Sahrens 0, hdr_cons, hdr_dest, hdr_recl, NULL, NULL, 0); 875fa9e4066Sahrens buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), 8766f83844dSMark Maybee 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); 877fa9e4066Sahrens 878fa9e4066Sahrens for (i = 0; i < 256; i++) 879fa9e4066Sahrens for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) 880fa9e4066Sahrens *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); 881fa9e4066Sahrens 882fa9e4066Sahrens for (i = 0; i < BUF_LOCKS; i++) { 883fa9e4066Sahrens mutex_init(&buf_hash_table.ht_locks[i].ht_lock, 884fa9e4066Sahrens NULL, MUTEX_DEFAULT, NULL); 885fa9e4066Sahrens } 886fa9e4066Sahrens } 887fa9e4066Sahrens 888fa9e4066Sahrens #define ARC_MINTIME (hz>>4) /* 62 ms */ 889fa9e4066Sahrens 8906b4acc8bSahrens static void 8916b4acc8bSahrens arc_cksum_verify(arc_buf_t *buf) 8926b4acc8bSahrens { 8936b4acc8bSahrens zio_cksum_t zc; 8946b4acc8bSahrens 895cc60fd72Sahrens if (!(zfs_flags & ZFS_DEBUG_MODIFY)) 8966b4acc8bSahrens return; 8976b4acc8bSahrens 8986b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 8993ccfa83cSahrens if (buf->b_hdr->b_freeze_cksum == NULL || 9003ccfa83cSahrens (buf->b_hdr->b_flags & ARC_IO_ERROR)) { 9016b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9026b4acc8bSahrens return; 9036b4acc8bSahrens } 9046b4acc8bSahrens fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); 9056b4acc8bSahrens if (!ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc)) 9066b4acc8bSahrens panic("buffer modified while frozen!"); 9076b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9086b4acc8bSahrens } 9096b4acc8bSahrens 910fa94a07fSbrendan static int 911fa94a07fSbrendan arc_cksum_equal(arc_buf_t *buf) 912fa94a07fSbrendan { 913fa94a07fSbrendan zio_cksum_t zc; 914fa94a07fSbrendan int equal; 915fa94a07fSbrendan 916fa94a07fSbrendan mutex_enter(&buf->b_hdr->b_freeze_lock); 917fa94a07fSbrendan fletcher_2_native(buf->b_data, buf->b_hdr->b_size, &zc); 918fa94a07fSbrendan equal = ZIO_CHECKSUM_EQUAL(*buf->b_hdr->b_freeze_cksum, zc); 919fa94a07fSbrendan mutex_exit(&buf->b_hdr->b_freeze_lock); 920fa94a07fSbrendan 921fa94a07fSbrendan return (equal); 922fa94a07fSbrendan } 923fa94a07fSbrendan 9246b4acc8bSahrens static void 925fa94a07fSbrendan arc_cksum_compute(arc_buf_t *buf, boolean_t force) 9266b4acc8bSahrens { 927fa94a07fSbrendan if (!force && !(zfs_flags & ZFS_DEBUG_MODIFY)) 9286b4acc8bSahrens return; 9296b4acc8bSahrens 9306b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9316b4acc8bSahrens if (buf->b_hdr->b_freeze_cksum != NULL) { 9326b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9336b4acc8bSahrens return; 9346b4acc8bSahrens } 9356b4acc8bSahrens buf->b_hdr->b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), KM_SLEEP); 9366b4acc8bSahrens fletcher_2_native(buf->b_data, buf->b_hdr->b_size, 9376b4acc8bSahrens buf->b_hdr->b_freeze_cksum); 9386b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9396b4acc8bSahrens } 9406b4acc8bSahrens 9416b4acc8bSahrens void 9426b4acc8bSahrens arc_buf_thaw(arc_buf_t *buf) 9436b4acc8bSahrens { 944fa94a07fSbrendan if (zfs_flags & ZFS_DEBUG_MODIFY) { 945fa94a07fSbrendan if (buf->b_hdr->b_state != arc_anon) 946fa94a07fSbrendan panic("modifying non-anon buffer!"); 947fa94a07fSbrendan if (buf->b_hdr->b_flags & ARC_IO_IN_PROGRESS) 948fa94a07fSbrendan panic("modifying buffer while i/o in progress!"); 949fa94a07fSbrendan arc_cksum_verify(buf); 950fa94a07fSbrendan } 9516b4acc8bSahrens 9526b4acc8bSahrens mutex_enter(&buf->b_hdr->b_freeze_lock); 9536b4acc8bSahrens if (buf->b_hdr->b_freeze_cksum != NULL) { 9546b4acc8bSahrens kmem_free(buf->b_hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 9556b4acc8bSahrens buf->b_hdr->b_freeze_cksum = NULL; 9566b4acc8bSahrens } 9576b4acc8bSahrens mutex_exit(&buf->b_hdr->b_freeze_lock); 9586b4acc8bSahrens } 9596b4acc8bSahrens 9606b4acc8bSahrens void 9616b4acc8bSahrens arc_buf_freeze(arc_buf_t *buf) 9626b4acc8bSahrens { 963cc60fd72Sahrens if (!(zfs_flags & ZFS_DEBUG_MODIFY)) 964cc60fd72Sahrens return; 965cc60fd72Sahrens 9666b4acc8bSahrens ASSERT(buf->b_hdr->b_freeze_cksum != NULL || 96744cb6abcSbmc buf->b_hdr->b_state == arc_anon); 968fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 9696b4acc8bSahrens } 9706b4acc8bSahrens 971fa9e4066Sahrens static void 972fa9e4066Sahrens add_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) 973fa9e4066Sahrens { 974fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 975fa9e4066Sahrens 976fa9e4066Sahrens if ((refcount_add(&ab->b_refcnt, tag) == 1) && 97744cb6abcSbmc (ab->b_state != arc_anon)) { 978c0a81264Sek uint64_t delta = ab->b_size * ab->b_datacnt; 9790e8c6158Smaybee list_t *list = &ab->b_state->arcs_list[ab->b_type]; 9800e8c6158Smaybee uint64_t *size = &ab->b_state->arcs_lsize[ab->b_type]; 981fa9e4066Sahrens 98244cb6abcSbmc ASSERT(!MUTEX_HELD(&ab->b_state->arcs_mtx)); 98344cb6abcSbmc mutex_enter(&ab->b_state->arcs_mtx); 984fa9e4066Sahrens ASSERT(list_link_active(&ab->b_arc_node)); 9850e8c6158Smaybee list_remove(list, ab); 986ea8dc4b6Seschrock if (GHOST_STATE(ab->b_state)) { 987ea8dc4b6Seschrock ASSERT3U(ab->b_datacnt, ==, 0); 988ea8dc4b6Seschrock ASSERT3P(ab->b_buf, ==, NULL); 989ea8dc4b6Seschrock delta = ab->b_size; 990ea8dc4b6Seschrock } 991ea8dc4b6Seschrock ASSERT(delta > 0); 9920e8c6158Smaybee ASSERT3U(*size, >=, delta); 9930e8c6158Smaybee atomic_add_64(size, -delta); 99444cb6abcSbmc mutex_exit(&ab->b_state->arcs_mtx); 995088f3894Sahrens /* remove the prefetch flag if we get a reference */ 99613506d1eSmaybee if (ab->b_flags & ARC_PREFETCH) 99713506d1eSmaybee ab->b_flags &= ~ARC_PREFETCH; 998fa9e4066Sahrens } 999fa9e4066Sahrens } 1000fa9e4066Sahrens 1001fa9e4066Sahrens static int 1002fa9e4066Sahrens remove_reference(arc_buf_hdr_t *ab, kmutex_t *hash_lock, void *tag) 1003fa9e4066Sahrens { 1004fa9e4066Sahrens int cnt; 100544cb6abcSbmc arc_state_t *state = ab->b_state; 1006fa9e4066Sahrens 100744cb6abcSbmc ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); 100844cb6abcSbmc ASSERT(!GHOST_STATE(state)); 1009fa9e4066Sahrens 1010fa9e4066Sahrens if (((cnt = refcount_remove(&ab->b_refcnt, tag)) == 0) && 101144cb6abcSbmc (state != arc_anon)) { 10120e8c6158Smaybee uint64_t *size = &state->arcs_lsize[ab->b_type]; 10130e8c6158Smaybee 101444cb6abcSbmc ASSERT(!MUTEX_HELD(&state->arcs_mtx)); 101544cb6abcSbmc mutex_enter(&state->arcs_mtx); 1016fa9e4066Sahrens ASSERT(!list_link_active(&ab->b_arc_node)); 10170e8c6158Smaybee list_insert_head(&state->arcs_list[ab->b_type], ab); 1018ea8dc4b6Seschrock ASSERT(ab->b_datacnt > 0); 10190e8c6158Smaybee atomic_add_64(size, ab->b_size * ab->b_datacnt); 102044cb6abcSbmc mutex_exit(&state->arcs_mtx); 1021fa9e4066Sahrens } 1022fa9e4066Sahrens return (cnt); 1023fa9e4066Sahrens } 1024fa9e4066Sahrens 1025fa9e4066Sahrens /* 1026fa9e4066Sahrens * Move the supplied buffer to the indicated state. The mutex 1027fa9e4066Sahrens * for the buffer must be held by the caller. 1028fa9e4066Sahrens */ 1029fa9e4066Sahrens static void 1030ea8dc4b6Seschrock arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *ab, kmutex_t *hash_lock) 1031fa9e4066Sahrens { 1032ea8dc4b6Seschrock arc_state_t *old_state = ab->b_state; 1033c0a81264Sek int64_t refcnt = refcount_count(&ab->b_refcnt); 1034c0a81264Sek uint64_t from_delta, to_delta; 1035fa9e4066Sahrens 1036fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 1037ea8dc4b6Seschrock ASSERT(new_state != old_state); 1038ea8dc4b6Seschrock ASSERT(refcnt == 0 || ab->b_datacnt > 0); 1039ea8dc4b6Seschrock ASSERT(ab->b_datacnt == 0 || !GHOST_STATE(new_state)); 1040*b24ab676SJeff Bonwick ASSERT(ab->b_datacnt <= 1 || new_state != arc_anon); 1041*b24ab676SJeff Bonwick ASSERT(ab->b_datacnt <= 1 || old_state != arc_anon); 1042ea8dc4b6Seschrock 1043ea8dc4b6Seschrock from_delta = to_delta = ab->b_datacnt * ab->b_size; 1044fa9e4066Sahrens 1045fa9e4066Sahrens /* 1046fa9e4066Sahrens * If this buffer is evictable, transfer it from the 1047fa9e4066Sahrens * old state list to the new state list. 1048fa9e4066Sahrens */ 1049ea8dc4b6Seschrock if (refcnt == 0) { 105044cb6abcSbmc if (old_state != arc_anon) { 105144cb6abcSbmc int use_mutex = !MUTEX_HELD(&old_state->arcs_mtx); 10520e8c6158Smaybee uint64_t *size = &old_state->arcs_lsize[ab->b_type]; 1053ea8dc4b6Seschrock 1054ea8dc4b6Seschrock if (use_mutex) 105544cb6abcSbmc mutex_enter(&old_state->arcs_mtx); 1056fa9e4066Sahrens 1057fa9e4066Sahrens ASSERT(list_link_active(&ab->b_arc_node)); 10580e8c6158Smaybee list_remove(&old_state->arcs_list[ab->b_type], ab); 1059ea8dc4b6Seschrock 106013506d1eSmaybee /* 106113506d1eSmaybee * If prefetching out of the ghost cache, 106213506d1eSmaybee * we will have a non-null datacnt. 106313506d1eSmaybee */ 106413506d1eSmaybee if (GHOST_STATE(old_state) && ab->b_datacnt == 0) { 106513506d1eSmaybee /* ghost elements have a ghost size */ 1066ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 1067ea8dc4b6Seschrock from_delta = ab->b_size; 1068ea8dc4b6Seschrock } 10690e8c6158Smaybee ASSERT3U(*size, >=, from_delta); 10700e8c6158Smaybee atomic_add_64(size, -from_delta); 1071ea8dc4b6Seschrock 1072ea8dc4b6Seschrock if (use_mutex) 107344cb6abcSbmc mutex_exit(&old_state->arcs_mtx); 1074fa9e4066Sahrens } 107544cb6abcSbmc if (new_state != arc_anon) { 107644cb6abcSbmc int use_mutex = !MUTEX_HELD(&new_state->arcs_mtx); 10770e8c6158Smaybee uint64_t *size = &new_state->arcs_lsize[ab->b_type]; 1078fa9e4066Sahrens 1079ea8dc4b6Seschrock if (use_mutex) 108044cb6abcSbmc mutex_enter(&new_state->arcs_mtx); 1081ea8dc4b6Seschrock 10820e8c6158Smaybee list_insert_head(&new_state->arcs_list[ab->b_type], ab); 1083ea8dc4b6Seschrock 1084ea8dc4b6Seschrock /* ghost elements have a ghost size */ 1085ea8dc4b6Seschrock if (GHOST_STATE(new_state)) { 1086ea8dc4b6Seschrock ASSERT(ab->b_datacnt == 0); 1087ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 1088ea8dc4b6Seschrock to_delta = ab->b_size; 1089ea8dc4b6Seschrock } 10900e8c6158Smaybee atomic_add_64(size, to_delta); 1091ea8dc4b6Seschrock 1092ea8dc4b6Seschrock if (use_mutex) 109344cb6abcSbmc mutex_exit(&new_state->arcs_mtx); 1094fa9e4066Sahrens } 1095fa9e4066Sahrens } 1096fa9e4066Sahrens 1097fa9e4066Sahrens ASSERT(!BUF_EMPTY(ab)); 1098fa94a07fSbrendan if (new_state == arc_anon) { 1099fa9e4066Sahrens buf_hash_remove(ab); 1100fa9e4066Sahrens } 1101fa9e4066Sahrens 1102ea8dc4b6Seschrock /* adjust state sizes */ 1103ea8dc4b6Seschrock if (to_delta) 110444cb6abcSbmc atomic_add_64(&new_state->arcs_size, to_delta); 1105ea8dc4b6Seschrock if (from_delta) { 110644cb6abcSbmc ASSERT3U(old_state->arcs_size, >=, from_delta); 110744cb6abcSbmc atomic_add_64(&old_state->arcs_size, -from_delta); 1108fa9e4066Sahrens } 1109fa9e4066Sahrens ab->b_state = new_state; 1110fa94a07fSbrendan 1111fa94a07fSbrendan /* adjust l2arc hdr stats */ 1112fa94a07fSbrendan if (new_state == arc_l2c_only) 1113fa94a07fSbrendan l2arc_hdr_stat_add(); 1114fa94a07fSbrendan else if (old_state == arc_l2c_only) 1115fa94a07fSbrendan l2arc_hdr_stat_remove(); 1116fa9e4066Sahrens } 1117fa9e4066Sahrens 11180e8c6158Smaybee void 11195a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(uint64_t space, arc_space_type_t type) 11200e8c6158Smaybee { 11215a98e54bSBrendan Gregg - Sun Microsystems ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); 11225a98e54bSBrendan Gregg - Sun Microsystems 11235a98e54bSBrendan Gregg - Sun Microsystems switch (type) { 11245a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_DATA: 11255a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, space); 11265a98e54bSBrendan Gregg - Sun Microsystems break; 11275a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_OTHER: 11285a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_other_size, space); 11295a98e54bSBrendan Gregg - Sun Microsystems break; 11305a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_HDRS: 11315a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_hdr_size, space); 11325a98e54bSBrendan Gregg - Sun Microsystems break; 11335a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_L2HDRS: 11345a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_hdr_size, space); 11355a98e54bSBrendan Gregg - Sun Microsystems break; 11365a98e54bSBrendan Gregg - Sun Microsystems } 11375a98e54bSBrendan Gregg - Sun Microsystems 11380e8c6158Smaybee atomic_add_64(&arc_meta_used, space); 11390e8c6158Smaybee atomic_add_64(&arc_size, space); 11400e8c6158Smaybee } 11410e8c6158Smaybee 11420e8c6158Smaybee void 11435a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(uint64_t space, arc_space_type_t type) 11440e8c6158Smaybee { 11455a98e54bSBrendan Gregg - Sun Microsystems ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); 11465a98e54bSBrendan Gregg - Sun Microsystems 11475a98e54bSBrendan Gregg - Sun Microsystems switch (type) { 11485a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_DATA: 11495a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, -space); 11505a98e54bSBrendan Gregg - Sun Microsystems break; 11515a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_OTHER: 11525a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_other_size, -space); 11535a98e54bSBrendan Gregg - Sun Microsystems break; 11545a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_HDRS: 11555a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_hdr_size, -space); 11565a98e54bSBrendan Gregg - Sun Microsystems break; 11575a98e54bSBrendan Gregg - Sun Microsystems case ARC_SPACE_L2HDRS: 11585a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_hdr_size, -space); 11595a98e54bSBrendan Gregg - Sun Microsystems break; 11605a98e54bSBrendan Gregg - Sun Microsystems } 11615a98e54bSBrendan Gregg - Sun Microsystems 11620e8c6158Smaybee ASSERT(arc_meta_used >= space); 11630e8c6158Smaybee if (arc_meta_max < arc_meta_used) 11640e8c6158Smaybee arc_meta_max = arc_meta_used; 11650e8c6158Smaybee atomic_add_64(&arc_meta_used, -space); 11660e8c6158Smaybee ASSERT(arc_size >= space); 11670e8c6158Smaybee atomic_add_64(&arc_size, -space); 11680e8c6158Smaybee } 11690e8c6158Smaybee 11700e8c6158Smaybee void * 11710e8c6158Smaybee arc_data_buf_alloc(uint64_t size) 11720e8c6158Smaybee { 11730e8c6158Smaybee if (arc_evict_needed(ARC_BUFC_DATA)) 11740e8c6158Smaybee cv_signal(&arc_reclaim_thr_cv); 11750e8c6158Smaybee atomic_add_64(&arc_size, size); 11760e8c6158Smaybee return (zio_data_buf_alloc(size)); 11770e8c6158Smaybee } 11780e8c6158Smaybee 11790e8c6158Smaybee void 11800e8c6158Smaybee arc_data_buf_free(void *buf, uint64_t size) 11810e8c6158Smaybee { 11820e8c6158Smaybee zio_data_buf_free(buf, size); 11830e8c6158Smaybee ASSERT(arc_size >= size); 11840e8c6158Smaybee atomic_add_64(&arc_size, -size); 11850e8c6158Smaybee } 11860e8c6158Smaybee 1187fa9e4066Sahrens arc_buf_t * 1188ad23a2dbSjohansen arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type) 1189fa9e4066Sahrens { 1190fa9e4066Sahrens arc_buf_hdr_t *hdr; 1191fa9e4066Sahrens arc_buf_t *buf; 1192fa9e4066Sahrens 1193fa9e4066Sahrens ASSERT3U(size, >, 0); 11941ab7f2deSmaybee hdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 1195fa9e4066Sahrens ASSERT(BUF_EMPTY(hdr)); 1196fa9e4066Sahrens hdr->b_size = size; 1197ad23a2dbSjohansen hdr->b_type = type; 1198ac05c741SMark Maybee hdr->b_spa = spa_guid(spa); 119944cb6abcSbmc hdr->b_state = arc_anon; 1200fa9e4066Sahrens hdr->b_arc_access = 0; 12011ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 1202fa9e4066Sahrens buf->b_hdr = hdr; 120344eda4d7Smaybee buf->b_data = NULL; 1204ea8dc4b6Seschrock buf->b_efunc = NULL; 1205ea8dc4b6Seschrock buf->b_private = NULL; 1206fa9e4066Sahrens buf->b_next = NULL; 1207fa9e4066Sahrens hdr->b_buf = buf; 120844eda4d7Smaybee arc_get_data_buf(buf); 1209ea8dc4b6Seschrock hdr->b_datacnt = 1; 1210fa9e4066Sahrens hdr->b_flags = 0; 1211fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt)); 1212fa9e4066Sahrens (void) refcount_add(&hdr->b_refcnt, tag); 1213fa9e4066Sahrens 1214fa9e4066Sahrens return (buf); 1215fa9e4066Sahrens } 1216fa9e4066Sahrens 12172fdbea25SAleksandr Guzovskiy static char *arc_onloan_tag = "onloan"; 12182fdbea25SAleksandr Guzovskiy 12192fdbea25SAleksandr Guzovskiy /* 12202fdbea25SAleksandr Guzovskiy * Loan out an anonymous arc buffer. Loaned buffers are not counted as in 12212fdbea25SAleksandr Guzovskiy * flight data by arc_tempreserve_space() until they are "returned". Loaned 12222fdbea25SAleksandr Guzovskiy * buffers must be returned to the arc before they can be used by the DMU or 12232fdbea25SAleksandr Guzovskiy * freed. 12242fdbea25SAleksandr Guzovskiy */ 12252fdbea25SAleksandr Guzovskiy arc_buf_t * 12262fdbea25SAleksandr Guzovskiy arc_loan_buf(spa_t *spa, int size) 12272fdbea25SAleksandr Guzovskiy { 12282fdbea25SAleksandr Guzovskiy arc_buf_t *buf; 12292fdbea25SAleksandr Guzovskiy 12302fdbea25SAleksandr Guzovskiy buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA); 12312fdbea25SAleksandr Guzovskiy 12322fdbea25SAleksandr Guzovskiy atomic_add_64(&arc_loaned_bytes, size); 12332fdbea25SAleksandr Guzovskiy return (buf); 12342fdbea25SAleksandr Guzovskiy } 12352fdbea25SAleksandr Guzovskiy 12362fdbea25SAleksandr Guzovskiy /* 12372fdbea25SAleksandr Guzovskiy * Return a loaned arc buffer to the arc. 12382fdbea25SAleksandr Guzovskiy */ 12392fdbea25SAleksandr Guzovskiy void 12402fdbea25SAleksandr Guzovskiy arc_return_buf(arc_buf_t *buf, void *tag) 12412fdbea25SAleksandr Guzovskiy { 12422fdbea25SAleksandr Guzovskiy arc_buf_hdr_t *hdr = buf->b_hdr; 12432fdbea25SAleksandr Guzovskiy 12442fdbea25SAleksandr Guzovskiy ASSERT(hdr->b_state == arc_anon); 12452fdbea25SAleksandr Guzovskiy ASSERT(buf->b_data != NULL); 12462fdbea25SAleksandr Guzovskiy VERIFY(refcount_remove(&hdr->b_refcnt, arc_onloan_tag) == 0); 12472fdbea25SAleksandr Guzovskiy VERIFY(refcount_add(&hdr->b_refcnt, tag) == 1); 12482fdbea25SAleksandr Guzovskiy 12492fdbea25SAleksandr Guzovskiy atomic_add_64(&arc_loaned_bytes, -hdr->b_size); 12502fdbea25SAleksandr Guzovskiy } 12512fdbea25SAleksandr Guzovskiy 125244eda4d7Smaybee static arc_buf_t * 125344eda4d7Smaybee arc_buf_clone(arc_buf_t *from) 1254ea8dc4b6Seschrock { 125544eda4d7Smaybee arc_buf_t *buf; 125644eda4d7Smaybee arc_buf_hdr_t *hdr = from->b_hdr; 125744eda4d7Smaybee uint64_t size = hdr->b_size; 1258ea8dc4b6Seschrock 1259*b24ab676SJeff Bonwick ASSERT(hdr->b_state != arc_anon); 1260*b24ab676SJeff Bonwick 12611ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 126244eda4d7Smaybee buf->b_hdr = hdr; 126344eda4d7Smaybee buf->b_data = NULL; 126444eda4d7Smaybee buf->b_efunc = NULL; 126544eda4d7Smaybee buf->b_private = NULL; 126644eda4d7Smaybee buf->b_next = hdr->b_buf; 126744eda4d7Smaybee hdr->b_buf = buf; 126844eda4d7Smaybee arc_get_data_buf(buf); 126944eda4d7Smaybee bcopy(from->b_data, buf->b_data, size); 127044eda4d7Smaybee hdr->b_datacnt += 1; 127144eda4d7Smaybee return (buf); 1272ea8dc4b6Seschrock } 1273ea8dc4b6Seschrock 1274ea8dc4b6Seschrock void 1275ea8dc4b6Seschrock arc_buf_add_ref(arc_buf_t *buf, void* tag) 1276ea8dc4b6Seschrock { 127740d7d650Smaybee arc_buf_hdr_t *hdr; 1278ea8dc4b6Seschrock kmutex_t *hash_lock; 1279ea8dc4b6Seschrock 12809b23f181Smaybee /* 12816f83844dSMark Maybee * Check to see if this buffer is evicted. Callers 12826f83844dSMark Maybee * must verify b_data != NULL to know if the add_ref 12836f83844dSMark Maybee * was successful. 12849b23f181Smaybee */ 12856f83844dSMark Maybee rw_enter(&buf->b_lock, RW_READER); 12866f83844dSMark Maybee if (buf->b_data == NULL) { 12876f83844dSMark Maybee rw_exit(&buf->b_lock); 12889b23f181Smaybee return; 128940d7d650Smaybee } 12906f83844dSMark Maybee hdr = buf->b_hdr; 12916f83844dSMark Maybee ASSERT(hdr != NULL); 12929b23f181Smaybee hash_lock = HDR_LOCK(hdr); 12939b23f181Smaybee mutex_enter(hash_lock); 12946f83844dSMark Maybee rw_exit(&buf->b_lock); 1295ea8dc4b6Seschrock 129644cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 1297ea8dc4b6Seschrock add_reference(hdr, hash_lock, tag); 12985a98e54bSBrendan Gregg - Sun Microsystems DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); 129944eda4d7Smaybee arc_access(hdr, hash_lock); 130044eda4d7Smaybee mutex_exit(hash_lock); 130144cb6abcSbmc ARCSTAT_BUMP(arcstat_hits); 130244cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 130344cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 130444cb6abcSbmc data, metadata, hits); 1305ea8dc4b6Seschrock } 1306ea8dc4b6Seschrock 1307fa94a07fSbrendan /* 1308fa94a07fSbrendan * Free the arc data buffer. If it is an l2arc write in progress, 1309fa94a07fSbrendan * the buffer is placed on l2arc_free_on_write to be freed later. 1310fa94a07fSbrendan */ 1311fa94a07fSbrendan static void 1312fa94a07fSbrendan arc_buf_data_free(arc_buf_hdr_t *hdr, void (*free_func)(void *, size_t), 1313fa94a07fSbrendan void *data, size_t size) 1314fa94a07fSbrendan { 1315fa94a07fSbrendan if (HDR_L2_WRITING(hdr)) { 1316fa94a07fSbrendan l2arc_data_free_t *df; 1317fa94a07fSbrendan df = kmem_alloc(sizeof (l2arc_data_free_t), KM_SLEEP); 1318fa94a07fSbrendan df->l2df_data = data; 1319fa94a07fSbrendan df->l2df_size = size; 1320fa94a07fSbrendan df->l2df_func = free_func; 1321fa94a07fSbrendan mutex_enter(&l2arc_free_on_write_mtx); 1322fa94a07fSbrendan list_insert_head(l2arc_free_on_write, df); 1323fa94a07fSbrendan mutex_exit(&l2arc_free_on_write_mtx); 1324fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_free_on_write); 1325fa94a07fSbrendan } else { 1326fa94a07fSbrendan free_func(data, size); 1327fa94a07fSbrendan } 1328fa94a07fSbrendan } 1329fa94a07fSbrendan 1330ea8dc4b6Seschrock static void 133144eda4d7Smaybee arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all) 1332ea8dc4b6Seschrock { 1333ea8dc4b6Seschrock arc_buf_t **bufp; 1334ea8dc4b6Seschrock 1335ea8dc4b6Seschrock /* free up data associated with the buf */ 1336ea8dc4b6Seschrock if (buf->b_data) { 1337ea8dc4b6Seschrock arc_state_t *state = buf->b_hdr->b_state; 1338ea8dc4b6Seschrock uint64_t size = buf->b_hdr->b_size; 1339ad23a2dbSjohansen arc_buf_contents_t type = buf->b_hdr->b_type; 1340ea8dc4b6Seschrock 13416b4acc8bSahrens arc_cksum_verify(buf); 1342*b24ab676SJeff Bonwick 134344eda4d7Smaybee if (!recycle) { 1344ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 1345fa94a07fSbrendan arc_buf_data_free(buf->b_hdr, zio_buf_free, 1346fa94a07fSbrendan buf->b_data, size); 13475a98e54bSBrendan Gregg - Sun Microsystems arc_space_return(size, ARC_SPACE_DATA); 1348ad23a2dbSjohansen } else { 1349ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 1350fa94a07fSbrendan arc_buf_data_free(buf->b_hdr, 1351fa94a07fSbrendan zio_data_buf_free, buf->b_data, size); 13525a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, -size); 13530e8c6158Smaybee atomic_add_64(&arc_size, -size); 1354ad23a2dbSjohansen } 135544eda4d7Smaybee } 1356ea8dc4b6Seschrock if (list_link_active(&buf->b_hdr->b_arc_node)) { 13570e8c6158Smaybee uint64_t *cnt = &state->arcs_lsize[type]; 13580e8c6158Smaybee 1359ea8dc4b6Seschrock ASSERT(refcount_is_zero(&buf->b_hdr->b_refcnt)); 136044cb6abcSbmc ASSERT(state != arc_anon); 13610e8c6158Smaybee 13620e8c6158Smaybee ASSERT3U(*cnt, >=, size); 13630e8c6158Smaybee atomic_add_64(cnt, -size); 1364ea8dc4b6Seschrock } 136544cb6abcSbmc ASSERT3U(state->arcs_size, >=, size); 136644cb6abcSbmc atomic_add_64(&state->arcs_size, -size); 1367ea8dc4b6Seschrock buf->b_data = NULL; 1368ea8dc4b6Seschrock ASSERT(buf->b_hdr->b_datacnt > 0); 1369ea8dc4b6Seschrock buf->b_hdr->b_datacnt -= 1; 1370ea8dc4b6Seschrock } 1371ea8dc4b6Seschrock 1372ea8dc4b6Seschrock /* only remove the buf if requested */ 1373ea8dc4b6Seschrock if (!all) 1374ea8dc4b6Seschrock return; 1375ea8dc4b6Seschrock 1376ea8dc4b6Seschrock /* remove the buf from the hdr list */ 1377ea8dc4b6Seschrock for (bufp = &buf->b_hdr->b_buf; *bufp != buf; bufp = &(*bufp)->b_next) 1378ea8dc4b6Seschrock continue; 1379ea8dc4b6Seschrock *bufp = buf->b_next; 1380ea8dc4b6Seschrock 1381ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 1382ea8dc4b6Seschrock 1383ea8dc4b6Seschrock /* clean up the buf */ 1384ea8dc4b6Seschrock buf->b_hdr = NULL; 1385ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 1386ea8dc4b6Seschrock } 1387ea8dc4b6Seschrock 1388fa9e4066Sahrens static void 1389ea8dc4b6Seschrock arc_hdr_destroy(arc_buf_hdr_t *hdr) 1390fa9e4066Sahrens { 1391fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt)); 139244cb6abcSbmc ASSERT3P(hdr->b_state, ==, arc_anon); 1393ea8dc4b6Seschrock ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 1394*b24ab676SJeff Bonwick l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr; 1395fa9e4066Sahrens 1396*b24ab676SJeff Bonwick if (l2hdr != NULL) { 1397*b24ab676SJeff Bonwick boolean_t buflist_held = MUTEX_HELD(&l2arc_buflist_mtx); 1398*b24ab676SJeff Bonwick /* 1399*b24ab676SJeff Bonwick * To prevent arc_free() and l2arc_evict() from 1400*b24ab676SJeff Bonwick * attempting to free the same buffer at the same time, 1401*b24ab676SJeff Bonwick * a FREE_IN_PROGRESS flag is given to arc_free() to 1402*b24ab676SJeff Bonwick * give it priority. l2arc_evict() can't destroy this 1403*b24ab676SJeff Bonwick * header while we are waiting on l2arc_buflist_mtx. 1404*b24ab676SJeff Bonwick * 1405*b24ab676SJeff Bonwick * The hdr may be removed from l2ad_buflist before we 1406*b24ab676SJeff Bonwick * grab l2arc_buflist_mtx, so b_l2hdr is rechecked. 1407*b24ab676SJeff Bonwick */ 1408*b24ab676SJeff Bonwick if (!buflist_held) { 1409fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 1410*b24ab676SJeff Bonwick l2hdr = hdr->b_l2hdr; 1411fa94a07fSbrendan } 1412*b24ab676SJeff Bonwick 1413*b24ab676SJeff Bonwick if (l2hdr != NULL) { 1414*b24ab676SJeff Bonwick list_remove(l2hdr->b_dev->l2ad_buflist, hdr); 1415*b24ab676SJeff Bonwick ARCSTAT_INCR(arcstat_l2_size, -hdr->b_size); 1416*b24ab676SJeff Bonwick kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); 1417*b24ab676SJeff Bonwick if (hdr->b_state == arc_l2c_only) 1418*b24ab676SJeff Bonwick l2arc_hdr_stat_remove(); 1419*b24ab676SJeff Bonwick hdr->b_l2hdr = NULL; 1420*b24ab676SJeff Bonwick } 1421*b24ab676SJeff Bonwick 1422*b24ab676SJeff Bonwick if (!buflist_held) 1423*b24ab676SJeff Bonwick mutex_exit(&l2arc_buflist_mtx); 1424fa94a07fSbrendan } 1425fa94a07fSbrendan 1426fa9e4066Sahrens if (!BUF_EMPTY(hdr)) { 1427ea8dc4b6Seschrock ASSERT(!HDR_IN_HASH_TABLE(hdr)); 1428fa9e4066Sahrens bzero(&hdr->b_dva, sizeof (dva_t)); 1429fa9e4066Sahrens hdr->b_birth = 0; 1430fa9e4066Sahrens hdr->b_cksum0 = 0; 1431fa9e4066Sahrens } 1432ea8dc4b6Seschrock while (hdr->b_buf) { 1433fa9e4066Sahrens arc_buf_t *buf = hdr->b_buf; 1434fa9e4066Sahrens 1435ea8dc4b6Seschrock if (buf->b_efunc) { 1436ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 14376f83844dSMark Maybee rw_enter(&buf->b_lock, RW_WRITER); 1438ea8dc4b6Seschrock ASSERT(buf->b_hdr != NULL); 143944eda4d7Smaybee arc_buf_destroy(hdr->b_buf, FALSE, FALSE); 1440ea8dc4b6Seschrock hdr->b_buf = buf->b_next; 144140d7d650Smaybee buf->b_hdr = &arc_eviction_hdr; 1442ea8dc4b6Seschrock buf->b_next = arc_eviction_list; 1443ea8dc4b6Seschrock arc_eviction_list = buf; 14446f83844dSMark Maybee rw_exit(&buf->b_lock); 1445ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1446ea8dc4b6Seschrock } else { 144744eda4d7Smaybee arc_buf_destroy(hdr->b_buf, FALSE, TRUE); 1448ea8dc4b6Seschrock } 1449fa9e4066Sahrens } 14506b4acc8bSahrens if (hdr->b_freeze_cksum != NULL) { 14516b4acc8bSahrens kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 14526b4acc8bSahrens hdr->b_freeze_cksum = NULL; 14536b4acc8bSahrens } 1454ea8dc4b6Seschrock 1455fa9e4066Sahrens ASSERT(!list_link_active(&hdr->b_arc_node)); 1456fa9e4066Sahrens ASSERT3P(hdr->b_hash_next, ==, NULL); 1457fa9e4066Sahrens ASSERT3P(hdr->b_acb, ==, NULL); 1458fa9e4066Sahrens kmem_cache_free(hdr_cache, hdr); 1459fa9e4066Sahrens } 1460fa9e4066Sahrens 1461fa9e4066Sahrens void 1462fa9e4066Sahrens arc_buf_free(arc_buf_t *buf, void *tag) 1463fa9e4066Sahrens { 1464fa9e4066Sahrens arc_buf_hdr_t *hdr = buf->b_hdr; 146544cb6abcSbmc int hashed = hdr->b_state != arc_anon; 1466fa9e4066Sahrens 1467ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 1468ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 1469ea8dc4b6Seschrock 1470ea8dc4b6Seschrock if (hashed) { 1471ea8dc4b6Seschrock kmutex_t *hash_lock = HDR_LOCK(hdr); 1472ea8dc4b6Seschrock 1473ea8dc4b6Seschrock mutex_enter(hash_lock); 1474ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 1475*b24ab676SJeff Bonwick if (hdr->b_datacnt > 1) { 147644eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1477*b24ab676SJeff Bonwick } else { 1478*b24ab676SJeff Bonwick ASSERT(buf == hdr->b_buf); 1479*b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 1480ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 1481*b24ab676SJeff Bonwick } 1482fa9e4066Sahrens mutex_exit(hash_lock); 1483ea8dc4b6Seschrock } else if (HDR_IO_IN_PROGRESS(hdr)) { 1484ea8dc4b6Seschrock int destroy_hdr; 1485ea8dc4b6Seschrock /* 1486ea8dc4b6Seschrock * We are in the middle of an async write. Don't destroy 1487ea8dc4b6Seschrock * this buffer unless the write completes before we finish 1488ea8dc4b6Seschrock * decrementing the reference count. 1489ea8dc4b6Seschrock */ 1490ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1491ea8dc4b6Seschrock (void) remove_reference(hdr, NULL, tag); 1492ea8dc4b6Seschrock ASSERT(refcount_is_zero(&hdr->b_refcnt)); 1493ea8dc4b6Seschrock destroy_hdr = !HDR_IO_IN_PROGRESS(hdr); 1494ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1495ea8dc4b6Seschrock if (destroy_hdr) 1496ea8dc4b6Seschrock arc_hdr_destroy(hdr); 1497ea8dc4b6Seschrock } else { 1498ea8dc4b6Seschrock if (remove_reference(hdr, NULL, tag) > 0) { 1499ea8dc4b6Seschrock ASSERT(HDR_IO_ERROR(hdr)); 150044eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1501ea8dc4b6Seschrock } else { 1502ea8dc4b6Seschrock arc_hdr_destroy(hdr); 1503ea8dc4b6Seschrock } 1504fa9e4066Sahrens } 1505ea8dc4b6Seschrock } 1506fa9e4066Sahrens 1507ea8dc4b6Seschrock int 1508ea8dc4b6Seschrock arc_buf_remove_ref(arc_buf_t *buf, void* tag) 1509ea8dc4b6Seschrock { 1510ea8dc4b6Seschrock arc_buf_hdr_t *hdr = buf->b_hdr; 1511ea8dc4b6Seschrock kmutex_t *hash_lock = HDR_LOCK(hdr); 1512ea8dc4b6Seschrock int no_callback = (buf->b_efunc == NULL); 1513fa9e4066Sahrens 151444cb6abcSbmc if (hdr->b_state == arc_anon) { 1515*b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 1516ea8dc4b6Seschrock arc_buf_free(buf, tag); 1517ea8dc4b6Seschrock return (no_callback); 1518ea8dc4b6Seschrock } 1519ea8dc4b6Seschrock 1520ea8dc4b6Seschrock mutex_enter(hash_lock); 152144cb6abcSbmc ASSERT(hdr->b_state != arc_anon); 1522ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 1523ea8dc4b6Seschrock 1524ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 1525ea8dc4b6Seschrock if (hdr->b_datacnt > 1) { 1526ea8dc4b6Seschrock if (no_callback) 152744eda4d7Smaybee arc_buf_destroy(buf, FALSE, TRUE); 1528ea8dc4b6Seschrock } else if (no_callback) { 1529ea8dc4b6Seschrock ASSERT(hdr->b_buf == buf && buf->b_next == NULL); 1530*b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 1531ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 1532ea8dc4b6Seschrock } 1533ea8dc4b6Seschrock ASSERT(no_callback || hdr->b_datacnt > 1 || 1534ea8dc4b6Seschrock refcount_is_zero(&hdr->b_refcnt)); 1535ea8dc4b6Seschrock mutex_exit(hash_lock); 1536ea8dc4b6Seschrock return (no_callback); 1537fa9e4066Sahrens } 1538fa9e4066Sahrens 1539fa9e4066Sahrens int 1540fa9e4066Sahrens arc_buf_size(arc_buf_t *buf) 1541fa9e4066Sahrens { 1542fa9e4066Sahrens return (buf->b_hdr->b_size); 1543fa9e4066Sahrens } 1544fa9e4066Sahrens 1545fa9e4066Sahrens /* 1546fa9e4066Sahrens * Evict buffers from list until we've removed the specified number of 1547fa9e4066Sahrens * bytes. Move the removed buffers to the appropriate evict state. 154844eda4d7Smaybee * If the recycle flag is set, then attempt to "recycle" a buffer: 154944eda4d7Smaybee * - look for a buffer to evict that is `bytes' long. 155044eda4d7Smaybee * - return the data block from this buffer rather than freeing it. 155144eda4d7Smaybee * This flag is used by callers that are trying to make space for a 155244eda4d7Smaybee * new buffer in a full arc cache. 1553874395d5Smaybee * 1554874395d5Smaybee * This function makes a "best effort". It skips over any buffers 1555874395d5Smaybee * it can't get a hash_lock on, and so may not catch all candidates. 1556874395d5Smaybee * It may also return without evicting as much space as requested. 1557fa9e4066Sahrens */ 155844eda4d7Smaybee static void * 1559ac05c741SMark Maybee arc_evict(arc_state_t *state, uint64_t spa, int64_t bytes, boolean_t recycle, 1560ad23a2dbSjohansen arc_buf_contents_t type) 1561fa9e4066Sahrens { 1562fa9e4066Sahrens arc_state_t *evicted_state; 156344eda4d7Smaybee uint64_t bytes_evicted = 0, skipped = 0, missed = 0; 15643fa51506Smaybee arc_buf_hdr_t *ab, *ab_prev = NULL; 15650e8c6158Smaybee list_t *list = &state->arcs_list[type]; 1566fa9e4066Sahrens kmutex_t *hash_lock; 156744eda4d7Smaybee boolean_t have_lock; 15683fa51506Smaybee void *stolen = NULL; 1569fa9e4066Sahrens 157044cb6abcSbmc ASSERT(state == arc_mru || state == arc_mfu); 1571fa9e4066Sahrens 157244cb6abcSbmc evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; 1573fa9e4066Sahrens 157444cb6abcSbmc mutex_enter(&state->arcs_mtx); 157544cb6abcSbmc mutex_enter(&evicted_state->arcs_mtx); 1576fa9e4066Sahrens 15770e8c6158Smaybee for (ab = list_tail(list); ab; ab = ab_prev) { 15780e8c6158Smaybee ab_prev = list_prev(list, ab); 157913506d1eSmaybee /* prefetch buffers have a minimum lifespan */ 158044eda4d7Smaybee if (HDR_IO_IN_PROGRESS(ab) || 1581874395d5Smaybee (spa && ab->b_spa != spa) || 158244eda4d7Smaybee (ab->b_flags & (ARC_PREFETCH|ARC_INDIRECT) && 158344eda4d7Smaybee lbolt - ab->b_arc_access < arc_min_prefetch_lifespan)) { 158413506d1eSmaybee skipped++; 158513506d1eSmaybee continue; 158613506d1eSmaybee } 15873fa51506Smaybee /* "lookahead" for better eviction candidate */ 15883fa51506Smaybee if (recycle && ab->b_size != bytes && 15893fa51506Smaybee ab_prev && ab_prev->b_size == bytes) 159044eda4d7Smaybee continue; 1591fa9e4066Sahrens hash_lock = HDR_LOCK(ab); 159244eda4d7Smaybee have_lock = MUTEX_HELD(hash_lock); 159344eda4d7Smaybee if (have_lock || mutex_tryenter(hash_lock)) { 1594fa9e4066Sahrens ASSERT3U(refcount_count(&ab->b_refcnt), ==, 0); 1595ea8dc4b6Seschrock ASSERT(ab->b_datacnt > 0); 1596ea8dc4b6Seschrock while (ab->b_buf) { 1597ea8dc4b6Seschrock arc_buf_t *buf = ab->b_buf; 15986f83844dSMark Maybee if (!rw_tryenter(&buf->b_lock, RW_WRITER)) { 15996f83844dSMark Maybee missed += 1; 16006f83844dSMark Maybee break; 16016f83844dSMark Maybee } 160244eda4d7Smaybee if (buf->b_data) { 1603ea8dc4b6Seschrock bytes_evicted += ab->b_size; 1604ad23a2dbSjohansen if (recycle && ab->b_type == type && 1605fa94a07fSbrendan ab->b_size == bytes && 1606fa94a07fSbrendan !HDR_L2_WRITING(ab)) { 16073fa51506Smaybee stolen = buf->b_data; 16083fa51506Smaybee recycle = FALSE; 16093fa51506Smaybee } 161044eda4d7Smaybee } 1611ea8dc4b6Seschrock if (buf->b_efunc) { 1612ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 16133fa51506Smaybee arc_buf_destroy(buf, 16143fa51506Smaybee buf->b_data == stolen, FALSE); 1615ea8dc4b6Seschrock ab->b_buf = buf->b_next; 161640d7d650Smaybee buf->b_hdr = &arc_eviction_hdr; 1617ea8dc4b6Seschrock buf->b_next = arc_eviction_list; 1618ea8dc4b6Seschrock arc_eviction_list = buf; 1619ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 16206f83844dSMark Maybee rw_exit(&buf->b_lock); 1621ea8dc4b6Seschrock } else { 16226f83844dSMark Maybee rw_exit(&buf->b_lock); 16233fa51506Smaybee arc_buf_destroy(buf, 16243fa51506Smaybee buf->b_data == stolen, TRUE); 1625ea8dc4b6Seschrock } 1626ea8dc4b6Seschrock } 16275ea40c06SBrendan Gregg - Sun Microsystems 16285ea40c06SBrendan Gregg - Sun Microsystems if (ab->b_l2hdr) { 16295ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_evict_l2_cached, 16305ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16315ea40c06SBrendan Gregg - Sun Microsystems } else { 16325ea40c06SBrendan Gregg - Sun Microsystems if (l2arc_write_eligible(ab->b_spa, ab)) { 16335ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_evict_l2_eligible, 16345ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16355ea40c06SBrendan Gregg - Sun Microsystems } else { 16365ea40c06SBrendan Gregg - Sun Microsystems ARCSTAT_INCR( 16375ea40c06SBrendan Gregg - Sun Microsystems arcstat_evict_l2_ineligible, 16385ea40c06SBrendan Gregg - Sun Microsystems ab->b_size); 16395ea40c06SBrendan Gregg - Sun Microsystems } 16405ea40c06SBrendan Gregg - Sun Microsystems } 16415ea40c06SBrendan Gregg - Sun Microsystems 16426f83844dSMark Maybee if (ab->b_datacnt == 0) { 16436f83844dSMark Maybee arc_change_state(evicted_state, ab, hash_lock); 16446f83844dSMark Maybee ASSERT(HDR_IN_HASH_TABLE(ab)); 16456f83844dSMark Maybee ab->b_flags |= ARC_IN_HASH_TABLE; 16466f83844dSMark Maybee ab->b_flags &= ~ARC_BUF_AVAILABLE; 16476f83844dSMark Maybee DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, ab); 16486f83844dSMark Maybee } 164944eda4d7Smaybee if (!have_lock) 165044eda4d7Smaybee mutex_exit(hash_lock); 1651ea8dc4b6Seschrock if (bytes >= 0 && bytes_evicted >= bytes) 1652fa9e4066Sahrens break; 1653fa9e4066Sahrens } else { 165444eda4d7Smaybee missed += 1; 1655fa9e4066Sahrens } 1656fa9e4066Sahrens } 165744cb6abcSbmc 165844cb6abcSbmc mutex_exit(&evicted_state->arcs_mtx); 165944cb6abcSbmc mutex_exit(&state->arcs_mtx); 1660fa9e4066Sahrens 1661fa9e4066Sahrens if (bytes_evicted < bytes) 1662fa9e4066Sahrens dprintf("only evicted %lld bytes from %x", 1663fa9e4066Sahrens (longlong_t)bytes_evicted, state); 1664fa9e4066Sahrens 166544eda4d7Smaybee if (skipped) 166644cb6abcSbmc ARCSTAT_INCR(arcstat_evict_skip, skipped); 166744cb6abcSbmc 166844eda4d7Smaybee if (missed) 166944cb6abcSbmc ARCSTAT_INCR(arcstat_mutex_miss, missed); 1670f4d2e9e6Smaybee 1671f4d2e9e6Smaybee /* 1672f4d2e9e6Smaybee * We have just evicted some date into the ghost state, make 1673f4d2e9e6Smaybee * sure we also adjust the ghost state size if necessary. 1674f4d2e9e6Smaybee */ 1675f4d2e9e6Smaybee if (arc_no_grow && 1676f4d2e9e6Smaybee arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size > arc_c) { 1677f4d2e9e6Smaybee int64_t mru_over = arc_anon->arcs_size + arc_mru->arcs_size + 1678f4d2e9e6Smaybee arc_mru_ghost->arcs_size - arc_c; 1679f4d2e9e6Smaybee 1680f4d2e9e6Smaybee if (mru_over > 0 && arc_mru_ghost->arcs_lsize[type] > 0) { 1681f4d2e9e6Smaybee int64_t todelete = 1682f4d2e9e6Smaybee MIN(arc_mru_ghost->arcs_lsize[type], mru_over); 1683874395d5Smaybee arc_evict_ghost(arc_mru_ghost, NULL, todelete); 1684f4d2e9e6Smaybee } else if (arc_mfu_ghost->arcs_lsize[type] > 0) { 1685f4d2e9e6Smaybee int64_t todelete = MIN(arc_mfu_ghost->arcs_lsize[type], 1686f4d2e9e6Smaybee arc_mru_ghost->arcs_size + 1687f4d2e9e6Smaybee arc_mfu_ghost->arcs_size - arc_c); 1688874395d5Smaybee arc_evict_ghost(arc_mfu_ghost, NULL, todelete); 1689f4d2e9e6Smaybee } 1690f4d2e9e6Smaybee } 169144cb6abcSbmc 16923fa51506Smaybee return (stolen); 1693fa9e4066Sahrens } 1694fa9e4066Sahrens 1695fa9e4066Sahrens /* 1696fa9e4066Sahrens * Remove buffers from list until we've removed the specified number of 1697fa9e4066Sahrens * bytes. Destroy the buffers that are removed. 1698fa9e4066Sahrens */ 1699fa9e4066Sahrens static void 1700ac05c741SMark Maybee arc_evict_ghost(arc_state_t *state, uint64_t spa, int64_t bytes) 1701fa9e4066Sahrens { 1702fa9e4066Sahrens arc_buf_hdr_t *ab, *ab_prev; 17030e8c6158Smaybee list_t *list = &state->arcs_list[ARC_BUFC_DATA]; 1704fa9e4066Sahrens kmutex_t *hash_lock; 1705ea8dc4b6Seschrock uint64_t bytes_deleted = 0; 1706c0a81264Sek uint64_t bufs_skipped = 0; 1707fa9e4066Sahrens 1708ea8dc4b6Seschrock ASSERT(GHOST_STATE(state)); 1709fa9e4066Sahrens top: 171044cb6abcSbmc mutex_enter(&state->arcs_mtx); 17110e8c6158Smaybee for (ab = list_tail(list); ab; ab = ab_prev) { 17120e8c6158Smaybee ab_prev = list_prev(list, ab); 1713874395d5Smaybee if (spa && ab->b_spa != spa) 1714874395d5Smaybee continue; 1715fa9e4066Sahrens hash_lock = HDR_LOCK(ab); 1716fa9e4066Sahrens if (mutex_tryenter(hash_lock)) { 171713506d1eSmaybee ASSERT(!HDR_IO_IN_PROGRESS(ab)); 1718ea8dc4b6Seschrock ASSERT(ab->b_buf == NULL); 171944cb6abcSbmc ARCSTAT_BUMP(arcstat_deleted); 1720fa9e4066Sahrens bytes_deleted += ab->b_size; 1721fa94a07fSbrendan 1722fa94a07fSbrendan if (ab->b_l2hdr != NULL) { 1723fa94a07fSbrendan /* 1724fa94a07fSbrendan * This buffer is cached on the 2nd Level ARC; 1725fa94a07fSbrendan * don't destroy the header. 1726fa94a07fSbrendan */ 1727fa94a07fSbrendan arc_change_state(arc_l2c_only, ab, hash_lock); 1728fa94a07fSbrendan mutex_exit(hash_lock); 1729fa94a07fSbrendan } else { 1730fa94a07fSbrendan arc_change_state(arc_anon, ab, hash_lock); 1731fa94a07fSbrendan mutex_exit(hash_lock); 1732fa94a07fSbrendan arc_hdr_destroy(ab); 1733fa94a07fSbrendan } 1734fa94a07fSbrendan 1735ea8dc4b6Seschrock DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, ab); 1736fa9e4066Sahrens if (bytes >= 0 && bytes_deleted >= bytes) 1737fa9e4066Sahrens break; 1738fa9e4066Sahrens } else { 1739fa9e4066Sahrens if (bytes < 0) { 174044cb6abcSbmc mutex_exit(&state->arcs_mtx); 1741fa9e4066Sahrens mutex_enter(hash_lock); 1742fa9e4066Sahrens mutex_exit(hash_lock); 1743fa9e4066Sahrens goto top; 1744fa9e4066Sahrens } 1745fa9e4066Sahrens bufs_skipped += 1; 1746fa9e4066Sahrens } 1747fa9e4066Sahrens } 174844cb6abcSbmc mutex_exit(&state->arcs_mtx); 1749fa9e4066Sahrens 17500e8c6158Smaybee if (list == &state->arcs_list[ARC_BUFC_DATA] && 17510e8c6158Smaybee (bytes < 0 || bytes_deleted < bytes)) { 17520e8c6158Smaybee list = &state->arcs_list[ARC_BUFC_METADATA]; 17530e8c6158Smaybee goto top; 17540e8c6158Smaybee } 17550e8c6158Smaybee 1756fa9e4066Sahrens if (bufs_skipped) { 175744cb6abcSbmc ARCSTAT_INCR(arcstat_mutex_miss, bufs_skipped); 1758fa9e4066Sahrens ASSERT(bytes >= 0); 1759fa9e4066Sahrens } 1760fa9e4066Sahrens 1761fa9e4066Sahrens if (bytes_deleted < bytes) 1762fa9e4066Sahrens dprintf("only deleted %lld bytes from %p", 1763fa9e4066Sahrens (longlong_t)bytes_deleted, state); 1764fa9e4066Sahrens } 1765fa9e4066Sahrens 1766fa9e4066Sahrens static void 1767fa9e4066Sahrens arc_adjust(void) 1768fa9e4066Sahrens { 17695a98e54bSBrendan Gregg - Sun Microsystems int64_t adjustment, delta; 1770fa9e4066Sahrens 17715a98e54bSBrendan Gregg - Sun Microsystems /* 17725a98e54bSBrendan Gregg - Sun Microsystems * Adjust MRU size 17735a98e54bSBrendan Gregg - Sun Microsystems */ 17745a98e54bSBrendan Gregg - Sun Microsystems 17755a98e54bSBrendan Gregg - Sun Microsystems adjustment = MIN(arc_size - arc_c, 17765a98e54bSBrendan Gregg - Sun Microsystems arc_anon->arcs_size + arc_mru->arcs_size + arc_meta_used - arc_p); 1777fa9e4066Sahrens 17785a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_DATA] > 0) { 17795a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_DATA], adjustment); 17805a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mru, NULL, delta, FALSE, ARC_BUFC_DATA); 17815a98e54bSBrendan Gregg - Sun Microsystems adjustment -= delta; 17820e8c6158Smaybee } 17830e8c6158Smaybee 17845a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru->arcs_lsize[ARC_BUFC_METADATA] > 0) { 17855a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru->arcs_lsize[ARC_BUFC_METADATA], adjustment); 17865a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mru, NULL, delta, FALSE, 1787874395d5Smaybee ARC_BUFC_METADATA); 1788fa9e4066Sahrens } 1789fa9e4066Sahrens 17905a98e54bSBrendan Gregg - Sun Microsystems /* 17915a98e54bSBrendan Gregg - Sun Microsystems * Adjust MFU size 17925a98e54bSBrendan Gregg - Sun Microsystems */ 1793fa9e4066Sahrens 17945a98e54bSBrendan Gregg - Sun Microsystems adjustment = arc_size - arc_c; 17955a98e54bSBrendan Gregg - Sun Microsystems 17965a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_DATA] > 0) { 17975a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(adjustment, arc_mfu->arcs_lsize[ARC_BUFC_DATA]); 17985a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mfu, NULL, delta, FALSE, ARC_BUFC_DATA); 17995a98e54bSBrendan Gregg - Sun Microsystems adjustment -= delta; 1800fa9e4066Sahrens } 1801fa9e4066Sahrens 18025a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu->arcs_lsize[ARC_BUFC_METADATA] > 0) { 18035a98e54bSBrendan Gregg - Sun Microsystems int64_t delta = MIN(adjustment, 18045a98e54bSBrendan Gregg - Sun Microsystems arc_mfu->arcs_lsize[ARC_BUFC_METADATA]); 18055a98e54bSBrendan Gregg - Sun Microsystems (void) arc_evict(arc_mfu, NULL, delta, FALSE, 18065a98e54bSBrendan Gregg - Sun Microsystems ARC_BUFC_METADATA); 18075a98e54bSBrendan Gregg - Sun Microsystems } 1808fa9e4066Sahrens 18095a98e54bSBrendan Gregg - Sun Microsystems /* 18105a98e54bSBrendan Gregg - Sun Microsystems * Adjust ghost lists 18115a98e54bSBrendan Gregg - Sun Microsystems */ 1812fa9e4066Sahrens 18135a98e54bSBrendan Gregg - Sun Microsystems adjustment = arc_mru->arcs_size + arc_mru_ghost->arcs_size - arc_c; 1814fa9e4066Sahrens 18155a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mru_ghost->arcs_size > 0) { 18165a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mru_ghost->arcs_size, adjustment); 18175a98e54bSBrendan Gregg - Sun Microsystems arc_evict_ghost(arc_mru_ghost, NULL, delta); 18185a98e54bSBrendan Gregg - Sun Microsystems } 18190e8c6158Smaybee 18205a98e54bSBrendan Gregg - Sun Microsystems adjustment = 18215a98e54bSBrendan Gregg - Sun Microsystems arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size - arc_c; 18225a98e54bSBrendan Gregg - Sun Microsystems 18235a98e54bSBrendan Gregg - Sun Microsystems if (adjustment > 0 && arc_mfu_ghost->arcs_size > 0) { 18245a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(arc_mfu_ghost->arcs_size, adjustment); 18255a98e54bSBrendan Gregg - Sun Microsystems arc_evict_ghost(arc_mfu_ghost, NULL, delta); 1826fa9e4066Sahrens } 1827fa9e4066Sahrens } 1828fa9e4066Sahrens 1829ea8dc4b6Seschrock static void 1830ea8dc4b6Seschrock arc_do_user_evicts(void) 1831ea8dc4b6Seschrock { 1832ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1833ea8dc4b6Seschrock while (arc_eviction_list != NULL) { 1834ea8dc4b6Seschrock arc_buf_t *buf = arc_eviction_list; 1835ea8dc4b6Seschrock arc_eviction_list = buf->b_next; 18366f83844dSMark Maybee rw_enter(&buf->b_lock, RW_WRITER); 1837ea8dc4b6Seschrock buf->b_hdr = NULL; 18386f83844dSMark Maybee rw_exit(&buf->b_lock); 1839ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1840ea8dc4b6Seschrock 1841dd6ef538Smaybee if (buf->b_efunc != NULL) 1842dd6ef538Smaybee VERIFY(buf->b_efunc(buf) == 0); 1843ea8dc4b6Seschrock 1844ea8dc4b6Seschrock buf->b_efunc = NULL; 1845ea8dc4b6Seschrock buf->b_private = NULL; 1846ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 1847ea8dc4b6Seschrock mutex_enter(&arc_eviction_mtx); 1848ea8dc4b6Seschrock } 1849ea8dc4b6Seschrock mutex_exit(&arc_eviction_mtx); 1850ea8dc4b6Seschrock } 1851ea8dc4b6Seschrock 1852fa9e4066Sahrens /* 1853874395d5Smaybee * Flush all *evictable* data from the cache for the given spa. 1854fa9e4066Sahrens * NOTE: this will not touch "active" (i.e. referenced) data. 1855fa9e4066Sahrens */ 1856fa9e4066Sahrens void 1857874395d5Smaybee arc_flush(spa_t *spa) 1858fa9e4066Sahrens { 1859ac05c741SMark Maybee uint64_t guid = 0; 1860ac05c741SMark Maybee 1861ac05c741SMark Maybee if (spa) 1862ac05c741SMark Maybee guid = spa_guid(spa); 1863ac05c741SMark Maybee 1864874395d5Smaybee while (list_head(&arc_mru->arcs_list[ARC_BUFC_DATA])) { 1865ac05c741SMark Maybee (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_DATA); 1866874395d5Smaybee if (spa) 1867874395d5Smaybee break; 1868874395d5Smaybee } 1869874395d5Smaybee while (list_head(&arc_mru->arcs_list[ARC_BUFC_METADATA])) { 1870ac05c741SMark Maybee (void) arc_evict(arc_mru, guid, -1, FALSE, ARC_BUFC_METADATA); 1871874395d5Smaybee if (spa) 1872874395d5Smaybee break; 1873874395d5Smaybee } 1874874395d5Smaybee while (list_head(&arc_mfu->arcs_list[ARC_BUFC_DATA])) { 1875ac05c741SMark Maybee (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_DATA); 1876874395d5Smaybee if (spa) 1877874395d5Smaybee break; 1878874395d5Smaybee } 1879874395d5Smaybee while (list_head(&arc_mfu->arcs_list[ARC_BUFC_METADATA])) { 1880ac05c741SMark Maybee (void) arc_evict(arc_mfu, guid, -1, FALSE, ARC_BUFC_METADATA); 1881874395d5Smaybee if (spa) 1882874395d5Smaybee break; 1883874395d5Smaybee } 1884874395d5Smaybee 1885ac05c741SMark Maybee arc_evict_ghost(arc_mru_ghost, guid, -1); 1886ac05c741SMark Maybee arc_evict_ghost(arc_mfu_ghost, guid, -1); 1887ea8dc4b6Seschrock 1888ea8dc4b6Seschrock mutex_enter(&arc_reclaim_thr_lock); 1889ea8dc4b6Seschrock arc_do_user_evicts(); 1890ea8dc4b6Seschrock mutex_exit(&arc_reclaim_thr_lock); 1891874395d5Smaybee ASSERT(spa || arc_eviction_list == NULL); 1892fa9e4066Sahrens } 1893fa9e4066Sahrens 1894fa9e4066Sahrens void 189549e3519aSmaybee arc_shrink(void) 1896fa9e4066Sahrens { 189744cb6abcSbmc if (arc_c > arc_c_min) { 189849e3519aSmaybee uint64_t to_free; 1899fa9e4066Sahrens 19003cff2f43Sstans #ifdef _KERNEL 190144cb6abcSbmc to_free = MAX(arc_c >> arc_shrink_shift, ptob(needfree)); 19023cff2f43Sstans #else 190344cb6abcSbmc to_free = arc_c >> arc_shrink_shift; 19043cff2f43Sstans #endif 190544cb6abcSbmc if (arc_c > arc_c_min + to_free) 190644cb6abcSbmc atomic_add_64(&arc_c, -to_free); 190749e3519aSmaybee else 190844cb6abcSbmc arc_c = arc_c_min; 190944cb6abcSbmc 191044cb6abcSbmc atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift)); 191144cb6abcSbmc if (arc_c > arc_size) 191244cb6abcSbmc arc_c = MAX(arc_size, arc_c_min); 191344cb6abcSbmc if (arc_p > arc_c) 191444cb6abcSbmc arc_p = (arc_c >> 1); 191544cb6abcSbmc ASSERT(arc_c >= arc_c_min); 191644cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 191749e3519aSmaybee } 1918fa9e4066Sahrens 191944cb6abcSbmc if (arc_size > arc_c) 192049e3519aSmaybee arc_adjust(); 1921fa9e4066Sahrens } 1922fa9e4066Sahrens 1923fa9e4066Sahrens static int 1924fa9e4066Sahrens arc_reclaim_needed(void) 1925fa9e4066Sahrens { 1926fa9e4066Sahrens uint64_t extra; 1927fa9e4066Sahrens 1928fa9e4066Sahrens #ifdef _KERNEL 19293cff2f43Sstans 19303cff2f43Sstans if (needfree) 19313cff2f43Sstans return (1); 19323cff2f43Sstans 1933fa9e4066Sahrens /* 1934fa9e4066Sahrens * take 'desfree' extra pages, so we reclaim sooner, rather than later 1935fa9e4066Sahrens */ 1936fa9e4066Sahrens extra = desfree; 1937fa9e4066Sahrens 1938fa9e4066Sahrens /* 1939fa9e4066Sahrens * check that we're out of range of the pageout scanner. It starts to 1940fa9e4066Sahrens * schedule paging if freemem is less than lotsfree and needfree. 1941fa9e4066Sahrens * lotsfree is the high-water mark for pageout, and needfree is the 1942fa9e4066Sahrens * number of needed free pages. We add extra pages here to make sure 1943fa9e4066Sahrens * the scanner doesn't start up while we're freeing memory. 1944fa9e4066Sahrens */ 1945fa9e4066Sahrens if (freemem < lotsfree + needfree + extra) 1946fa9e4066Sahrens return (1); 1947fa9e4066Sahrens 1948fa9e4066Sahrens /* 1949fa9e4066Sahrens * check to make sure that swapfs has enough space so that anon 1950fa94a07fSbrendan * reservations can still succeed. anon_resvmem() checks that the 1951fa9e4066Sahrens * availrmem is greater than swapfs_minfree, and the number of reserved 1952fa9e4066Sahrens * swap pages. We also add a bit of extra here just to prevent 1953fa9e4066Sahrens * circumstances from getting really dire. 1954fa9e4066Sahrens */ 1955fa9e4066Sahrens if (availrmem < swapfs_minfree + swapfs_reserve + extra) 1956fa9e4066Sahrens return (1); 1957fa9e4066Sahrens 19585dc8af33Smaybee #if defined(__i386) 1959fa9e4066Sahrens /* 1960fa9e4066Sahrens * If we're on an i386 platform, it's possible that we'll exhaust the 1961fa9e4066Sahrens * kernel heap space before we ever run out of available physical 1962fa9e4066Sahrens * memory. Most checks of the size of the heap_area compare against 1963fa9e4066Sahrens * tune.t_minarmem, which is the minimum available real memory that we 1964fa9e4066Sahrens * can have in the system. However, this is generally fixed at 25 pages 1965fa9e4066Sahrens * which is so low that it's useless. In this comparison, we seek to 1966fa9e4066Sahrens * calculate the total heap-size, and reclaim if more than 3/4ths of the 1967fa94a07fSbrendan * heap is allocated. (Or, in the calculation, if less than 1/4th is 1968fa9e4066Sahrens * free) 1969fa9e4066Sahrens */ 1970fa9e4066Sahrens if (btop(vmem_size(heap_arena, VMEM_FREE)) < 1971fa9e4066Sahrens (btop(vmem_size(heap_arena, VMEM_FREE | VMEM_ALLOC)) >> 2)) 1972fa9e4066Sahrens return (1); 1973fa9e4066Sahrens #endif 1974fa9e4066Sahrens 1975fa9e4066Sahrens #else 1976fa9e4066Sahrens if (spa_get_random(100) == 0) 1977fa9e4066Sahrens return (1); 1978fa9e4066Sahrens #endif 1979fa9e4066Sahrens return (0); 1980fa9e4066Sahrens } 1981fa9e4066Sahrens 1982fa9e4066Sahrens static void 1983fa9e4066Sahrens arc_kmem_reap_now(arc_reclaim_strategy_t strat) 1984fa9e4066Sahrens { 1985fa9e4066Sahrens size_t i; 1986fa9e4066Sahrens kmem_cache_t *prev_cache = NULL; 1987ad23a2dbSjohansen kmem_cache_t *prev_data_cache = NULL; 1988fa9e4066Sahrens extern kmem_cache_t *zio_buf_cache[]; 1989ad23a2dbSjohansen extern kmem_cache_t *zio_data_buf_cache[]; 1990fa9e4066Sahrens 1991033f9833Sek #ifdef _KERNEL 19920e8c6158Smaybee if (arc_meta_used >= arc_meta_limit) { 19930e8c6158Smaybee /* 19940e8c6158Smaybee * We are exceeding our meta-data cache limit. 19950e8c6158Smaybee * Purge some DNLC entries to release holds on meta-data. 19960e8c6158Smaybee */ 19970e8c6158Smaybee dnlc_reduce_cache((void *)(uintptr_t)arc_reduce_dnlc_percent); 19980e8c6158Smaybee } 19995dc8af33Smaybee #if defined(__i386) 20005dc8af33Smaybee /* 20015dc8af33Smaybee * Reclaim unused memory from all kmem caches. 20025dc8af33Smaybee */ 20035dc8af33Smaybee kmem_reap(); 20045dc8af33Smaybee #endif 2005033f9833Sek #endif 2006033f9833Sek 2007fa9e4066Sahrens /* 2008fa94a07fSbrendan * An aggressive reclamation will shrink the cache size as well as 2009ea8dc4b6Seschrock * reap free buffers from the arc kmem caches. 2010fa9e4066Sahrens */ 2011fa9e4066Sahrens if (strat == ARC_RECLAIM_AGGR) 201249e3519aSmaybee arc_shrink(); 2013fa9e4066Sahrens 2014fa9e4066Sahrens for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { 2015fa9e4066Sahrens if (zio_buf_cache[i] != prev_cache) { 2016fa9e4066Sahrens prev_cache = zio_buf_cache[i]; 2017fa9e4066Sahrens kmem_cache_reap_now(zio_buf_cache[i]); 2018fa9e4066Sahrens } 2019ad23a2dbSjohansen if (zio_data_buf_cache[i] != prev_data_cache) { 2020ad23a2dbSjohansen prev_data_cache = zio_data_buf_cache[i]; 2021ad23a2dbSjohansen kmem_cache_reap_now(zio_data_buf_cache[i]); 2022ad23a2dbSjohansen } 2023fa9e4066Sahrens } 2024ea8dc4b6Seschrock kmem_cache_reap_now(buf_cache); 2025ea8dc4b6Seschrock kmem_cache_reap_now(hdr_cache); 2026fa9e4066Sahrens } 2027fa9e4066Sahrens 2028fa9e4066Sahrens static void 2029fa9e4066Sahrens arc_reclaim_thread(void) 2030fa9e4066Sahrens { 2031fa9e4066Sahrens clock_t growtime = 0; 2032fa9e4066Sahrens arc_reclaim_strategy_t last_reclaim = ARC_RECLAIM_CONS; 2033fa9e4066Sahrens callb_cpr_t cpr; 2034fa9e4066Sahrens 2035fa9e4066Sahrens CALLB_CPR_INIT(&cpr, &arc_reclaim_thr_lock, callb_generic_cpr, FTAG); 2036fa9e4066Sahrens 2037fa9e4066Sahrens mutex_enter(&arc_reclaim_thr_lock); 2038fa9e4066Sahrens while (arc_thread_exit == 0) { 2039fa9e4066Sahrens if (arc_reclaim_needed()) { 2040fa9e4066Sahrens 204144cb6abcSbmc if (arc_no_grow) { 2042fa9e4066Sahrens if (last_reclaim == ARC_RECLAIM_CONS) { 2043fa9e4066Sahrens last_reclaim = ARC_RECLAIM_AGGR; 2044fa9e4066Sahrens } else { 2045fa9e4066Sahrens last_reclaim = ARC_RECLAIM_CONS; 2046fa9e4066Sahrens } 2047fa9e4066Sahrens } else { 204844cb6abcSbmc arc_no_grow = TRUE; 2049fa9e4066Sahrens last_reclaim = ARC_RECLAIM_AGGR; 2050fa9e4066Sahrens membar_producer(); 2051fa9e4066Sahrens } 2052fa9e4066Sahrens 2053fa9e4066Sahrens /* reset the growth delay for every reclaim */ 2054fa9e4066Sahrens growtime = lbolt + (arc_grow_retry * hz); 2055fa9e4066Sahrens 2056fa9e4066Sahrens arc_kmem_reap_now(last_reclaim); 20573a737e0dSbrendan arc_warm = B_TRUE; 2058fa9e4066Sahrens 20590e8c6158Smaybee } else if (arc_no_grow && lbolt >= growtime) { 206044cb6abcSbmc arc_no_grow = FALSE; 2061fa9e4066Sahrens } 2062fa9e4066Sahrens 206344cb6abcSbmc if (2 * arc_c < arc_size + 206444cb6abcSbmc arc_mru_ghost->arcs_size + arc_mfu_ghost->arcs_size) 2065641fbdaeSmaybee arc_adjust(); 2066641fbdaeSmaybee 2067ea8dc4b6Seschrock if (arc_eviction_list != NULL) 2068ea8dc4b6Seschrock arc_do_user_evicts(); 2069ea8dc4b6Seschrock 2070fa9e4066Sahrens /* block until needed, or one second, whichever is shorter */ 2071fa9e4066Sahrens CALLB_CPR_SAFE_BEGIN(&cpr); 2072fa9e4066Sahrens (void) cv_timedwait(&arc_reclaim_thr_cv, 2073fa9e4066Sahrens &arc_reclaim_thr_lock, (lbolt + hz)); 2074fa9e4066Sahrens CALLB_CPR_SAFE_END(&cpr, &arc_reclaim_thr_lock); 2075fa9e4066Sahrens } 2076fa9e4066Sahrens 2077fa9e4066Sahrens arc_thread_exit = 0; 2078fa9e4066Sahrens cv_broadcast(&arc_reclaim_thr_cv); 2079fa9e4066Sahrens CALLB_CPR_EXIT(&cpr); /* drops arc_reclaim_thr_lock */ 2080fa9e4066Sahrens thread_exit(); 2081fa9e4066Sahrens } 2082fa9e4066Sahrens 2083ea8dc4b6Seschrock /* 2084ea8dc4b6Seschrock * Adapt arc info given the number of bytes we are trying to add and 2085ea8dc4b6Seschrock * the state that we are comming from. This function is only called 2086ea8dc4b6Seschrock * when we are adding new content to the cache. 2087ea8dc4b6Seschrock */ 2088fa9e4066Sahrens static void 2089ea8dc4b6Seschrock arc_adapt(int bytes, arc_state_t *state) 2090fa9e4066Sahrens { 2091ea8dc4b6Seschrock int mult; 20925a98e54bSBrendan Gregg - Sun Microsystems uint64_t arc_p_min = (arc_c >> arc_p_min_shift); 2093ea8dc4b6Seschrock 2094fa94a07fSbrendan if (state == arc_l2c_only) 2095fa94a07fSbrendan return; 2096fa94a07fSbrendan 2097ea8dc4b6Seschrock ASSERT(bytes > 0); 2098fa9e4066Sahrens /* 2099ea8dc4b6Seschrock * Adapt the target size of the MRU list: 2100ea8dc4b6Seschrock * - if we just hit in the MRU ghost list, then increase 2101ea8dc4b6Seschrock * the target size of the MRU list. 2102ea8dc4b6Seschrock * - if we just hit in the MFU ghost list, then increase 2103ea8dc4b6Seschrock * the target size of the MFU list by decreasing the 2104ea8dc4b6Seschrock * target size of the MRU list. 2105fa9e4066Sahrens */ 210644cb6abcSbmc if (state == arc_mru_ghost) { 210744cb6abcSbmc mult = ((arc_mru_ghost->arcs_size >= arc_mfu_ghost->arcs_size) ? 210844cb6abcSbmc 1 : (arc_mfu_ghost->arcs_size/arc_mru_ghost->arcs_size)); 2109ea8dc4b6Seschrock 21105a98e54bSBrendan Gregg - Sun Microsystems arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); 211144cb6abcSbmc } else if (state == arc_mfu_ghost) { 21125a98e54bSBrendan Gregg - Sun Microsystems uint64_t delta; 21135a98e54bSBrendan Gregg - Sun Microsystems 211444cb6abcSbmc mult = ((arc_mfu_ghost->arcs_size >= arc_mru_ghost->arcs_size) ? 211544cb6abcSbmc 1 : (arc_mru_ghost->arcs_size/arc_mfu_ghost->arcs_size)); 2116ea8dc4b6Seschrock 21175a98e54bSBrendan Gregg - Sun Microsystems delta = MIN(bytes * mult, arc_p); 21185a98e54bSBrendan Gregg - Sun Microsystems arc_p = MAX(arc_p_min, arc_p - delta); 2119ea8dc4b6Seschrock } 212044cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 2121fa9e4066Sahrens 2122fa9e4066Sahrens if (arc_reclaim_needed()) { 2123fa9e4066Sahrens cv_signal(&arc_reclaim_thr_cv); 2124fa9e4066Sahrens return; 2125fa9e4066Sahrens } 2126fa9e4066Sahrens 212744cb6abcSbmc if (arc_no_grow) 2128fa9e4066Sahrens return; 2129fa9e4066Sahrens 213044cb6abcSbmc if (arc_c >= arc_c_max) 2131ea8dc4b6Seschrock return; 2132ea8dc4b6Seschrock 2133fa9e4066Sahrens /* 2134ea8dc4b6Seschrock * If we're within (2 * maxblocksize) bytes of the target 2135ea8dc4b6Seschrock * cache size, increment the target cache size 2136fa9e4066Sahrens */ 213744cb6abcSbmc if (arc_size > arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) { 213844cb6abcSbmc atomic_add_64(&arc_c, (int64_t)bytes); 213944cb6abcSbmc if (arc_c > arc_c_max) 214044cb6abcSbmc arc_c = arc_c_max; 214144cb6abcSbmc else if (state == arc_anon) 214244cb6abcSbmc atomic_add_64(&arc_p, (int64_t)bytes); 214344cb6abcSbmc if (arc_p > arc_c) 214444cb6abcSbmc arc_p = arc_c; 2145fa9e4066Sahrens } 214644cb6abcSbmc ASSERT((int64_t)arc_p >= 0); 2147fa9e4066Sahrens } 2148fa9e4066Sahrens 2149fa9e4066Sahrens /* 2150ea8dc4b6Seschrock * Check if the cache has reached its limits and eviction is required 2151ea8dc4b6Seschrock * prior to insert. 2152fa9e4066Sahrens */ 2153fa9e4066Sahrens static int 21540e8c6158Smaybee arc_evict_needed(arc_buf_contents_t type) 2155fa9e4066Sahrens { 21560e8c6158Smaybee if (type == ARC_BUFC_METADATA && arc_meta_used >= arc_meta_limit) 21570e8c6158Smaybee return (1); 21580e8c6158Smaybee 21590e8c6158Smaybee #ifdef _KERNEL 21600e8c6158Smaybee /* 21610e8c6158Smaybee * If zio data pages are being allocated out of a separate heap segment, 21620e8c6158Smaybee * then enforce that the size of available vmem for this area remains 21630e8c6158Smaybee * above about 1/32nd free. 21640e8c6158Smaybee */ 21650e8c6158Smaybee if (type == ARC_BUFC_DATA && zio_arena != NULL && 21660e8c6158Smaybee vmem_size(zio_arena, VMEM_FREE) < 21670e8c6158Smaybee (vmem_size(zio_arena, VMEM_ALLOC) >> 5)) 21680e8c6158Smaybee return (1); 21690e8c6158Smaybee #endif 21700e8c6158Smaybee 2171fa9e4066Sahrens if (arc_reclaim_needed()) 2172fa9e4066Sahrens return (1); 2173fa9e4066Sahrens 217444cb6abcSbmc return (arc_size > arc_c); 2175fa9e4066Sahrens } 2176fa9e4066Sahrens 2177fa9e4066Sahrens /* 217844eda4d7Smaybee * The buffer, supplied as the first argument, needs a data block. 217944eda4d7Smaybee * So, if we are at cache max, determine which cache should be victimized. 218044eda4d7Smaybee * We have the following cases: 2181fa9e4066Sahrens * 218244cb6abcSbmc * 1. Insert for MRU, p > sizeof(arc_anon + arc_mru) -> 2183fa9e4066Sahrens * In this situation if we're out of space, but the resident size of the MFU is 2184fa9e4066Sahrens * under the limit, victimize the MFU cache to satisfy this insertion request. 2185fa9e4066Sahrens * 218644cb6abcSbmc * 2. Insert for MRU, p <= sizeof(arc_anon + arc_mru) -> 2187fa9e4066Sahrens * Here, we've used up all of the available space for the MRU, so we need to 2188fa9e4066Sahrens * evict from our own cache instead. Evict from the set of resident MRU 2189fa9e4066Sahrens * entries. 2190fa9e4066Sahrens * 219144cb6abcSbmc * 3. Insert for MFU (c - p) > sizeof(arc_mfu) -> 2192fa9e4066Sahrens * c minus p represents the MFU space in the cache, since p is the size of the 2193fa9e4066Sahrens * cache that is dedicated to the MRU. In this situation there's still space on 2194fa9e4066Sahrens * the MFU side, so the MRU side needs to be victimized. 2195fa9e4066Sahrens * 219644cb6abcSbmc * 4. Insert for MFU (c - p) < sizeof(arc_mfu) -> 2197fa9e4066Sahrens * MFU's resident set is consuming more space than it has been allotted. In 2198fa9e4066Sahrens * this situation, we must victimize our own cache, the MFU, for this insertion. 2199fa9e4066Sahrens */ 2200fa9e4066Sahrens static void 220144eda4d7Smaybee arc_get_data_buf(arc_buf_t *buf) 2202fa9e4066Sahrens { 2203ad23a2dbSjohansen arc_state_t *state = buf->b_hdr->b_state; 2204ad23a2dbSjohansen uint64_t size = buf->b_hdr->b_size; 2205ad23a2dbSjohansen arc_buf_contents_t type = buf->b_hdr->b_type; 2206fa9e4066Sahrens 220744eda4d7Smaybee arc_adapt(size, state); 2208fa9e4066Sahrens 220944eda4d7Smaybee /* 221044eda4d7Smaybee * We have not yet reached cache maximum size, 221144eda4d7Smaybee * just allocate a new buffer. 221244eda4d7Smaybee */ 22130e8c6158Smaybee if (!arc_evict_needed(type)) { 2214ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 2215ad23a2dbSjohansen buf->b_data = zio_buf_alloc(size); 22165a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(size, ARC_SPACE_DATA); 2217ad23a2dbSjohansen } else { 2218ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 2219ad23a2dbSjohansen buf->b_data = zio_data_buf_alloc(size); 22205a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, size); 22210e8c6158Smaybee atomic_add_64(&arc_size, size); 2222ad23a2dbSjohansen } 222344eda4d7Smaybee goto out; 222444eda4d7Smaybee } 222544eda4d7Smaybee 222644eda4d7Smaybee /* 222744eda4d7Smaybee * If we are prefetching from the mfu ghost list, this buffer 222844eda4d7Smaybee * will end up on the mru list; so steal space from there. 222944eda4d7Smaybee */ 223044cb6abcSbmc if (state == arc_mfu_ghost) 223144cb6abcSbmc state = buf->b_hdr->b_flags & ARC_PREFETCH ? arc_mru : arc_mfu; 223244cb6abcSbmc else if (state == arc_mru_ghost) 223344cb6abcSbmc state = arc_mru; 223444cb6abcSbmc 223544cb6abcSbmc if (state == arc_mru || state == arc_anon) { 223644cb6abcSbmc uint64_t mru_used = arc_anon->arcs_size + arc_mru->arcs_size; 22375a98e54bSBrendan Gregg - Sun Microsystems state = (arc_mfu->arcs_lsize[type] >= size && 22380e8c6158Smaybee arc_p > mru_used) ? arc_mfu : arc_mru; 2239fa9e4066Sahrens } else { 224044eda4d7Smaybee /* MFU cases */ 224144cb6abcSbmc uint64_t mfu_space = arc_c - arc_p; 22425a98e54bSBrendan Gregg - Sun Microsystems state = (arc_mru->arcs_lsize[type] >= size && 22430e8c6158Smaybee mfu_space > arc_mfu->arcs_size) ? arc_mru : arc_mfu; 224444eda4d7Smaybee } 2245874395d5Smaybee if ((buf->b_data = arc_evict(state, NULL, size, TRUE, type)) == NULL) { 2246ad23a2dbSjohansen if (type == ARC_BUFC_METADATA) { 2247ad23a2dbSjohansen buf->b_data = zio_buf_alloc(size); 22485a98e54bSBrendan Gregg - Sun Microsystems arc_space_consume(size, ARC_SPACE_DATA); 2249ad23a2dbSjohansen } else { 2250ad23a2dbSjohansen ASSERT(type == ARC_BUFC_DATA); 2251ad23a2dbSjohansen buf->b_data = zio_data_buf_alloc(size); 22525a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_data_size, size); 22530e8c6158Smaybee atomic_add_64(&arc_size, size); 2254ad23a2dbSjohansen } 225544cb6abcSbmc ARCSTAT_BUMP(arcstat_recycle_miss); 225644eda4d7Smaybee } 225744eda4d7Smaybee ASSERT(buf->b_data != NULL); 225844eda4d7Smaybee out: 225944eda4d7Smaybee /* 226044eda4d7Smaybee * Update the state size. Note that ghost states have a 226144eda4d7Smaybee * "ghost size" and so don't need to be updated. 226244eda4d7Smaybee */ 226344eda4d7Smaybee if (!GHOST_STATE(buf->b_hdr->b_state)) { 226444eda4d7Smaybee arc_buf_hdr_t *hdr = buf->b_hdr; 226544eda4d7Smaybee 226644cb6abcSbmc atomic_add_64(&hdr->b_state->arcs_size, size); 226744eda4d7Smaybee if (list_link_active(&hdr->b_arc_node)) { 226844eda4d7Smaybee ASSERT(refcount_is_zero(&hdr->b_refcnt)); 22690e8c6158Smaybee atomic_add_64(&hdr->b_state->arcs_lsize[type], size); 2270fa9e4066Sahrens } 2271641fbdaeSmaybee /* 2272641fbdaeSmaybee * If we are growing the cache, and we are adding anonymous 227344cb6abcSbmc * data, and we have outgrown arc_p, update arc_p 2274641fbdaeSmaybee */ 227544cb6abcSbmc if (arc_size < arc_c && hdr->b_state == arc_anon && 227644cb6abcSbmc arc_anon->arcs_size + arc_mru->arcs_size > arc_p) 227744cb6abcSbmc arc_p = MIN(arc_c, arc_p + size); 2278fa9e4066Sahrens } 2279fa9e4066Sahrens } 2280fa9e4066Sahrens 2281fa9e4066Sahrens /* 2282fa9e4066Sahrens * This routine is called whenever a buffer is accessed. 2283ea8dc4b6Seschrock * NOTE: the hash lock is dropped in this function. 2284fa9e4066Sahrens */ 2285fa9e4066Sahrens static void 228644eda4d7Smaybee arc_access(arc_buf_hdr_t *buf, kmutex_t *hash_lock) 2287fa9e4066Sahrens { 2288fa9e4066Sahrens ASSERT(MUTEX_HELD(hash_lock)); 2289fa9e4066Sahrens 229044cb6abcSbmc if (buf->b_state == arc_anon) { 2291fa9e4066Sahrens /* 2292fa9e4066Sahrens * This buffer is not in the cache, and does not 2293fa9e4066Sahrens * appear in our "ghost" list. Add the new buffer 2294fa9e4066Sahrens * to the MRU state. 2295fa9e4066Sahrens */ 2296fa9e4066Sahrens 2297fa9e4066Sahrens ASSERT(buf->b_arc_access == 0); 2298fa9e4066Sahrens buf->b_arc_access = lbolt; 2299ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); 230044cb6abcSbmc arc_change_state(arc_mru, buf, hash_lock); 2301fa9e4066Sahrens 230244cb6abcSbmc } else if (buf->b_state == arc_mru) { 2303fa9e4066Sahrens /* 230413506d1eSmaybee * If this buffer is here because of a prefetch, then either: 230513506d1eSmaybee * - clear the flag if this is a "referencing" read 230613506d1eSmaybee * (any subsequent access will bump this into the MFU state). 230713506d1eSmaybee * or 230813506d1eSmaybee * - move the buffer to the head of the list if this is 230913506d1eSmaybee * another prefetch (to make it less likely to be evicted). 2310fa9e4066Sahrens */ 2311fa9e4066Sahrens if ((buf->b_flags & ARC_PREFETCH) != 0) { 231213506d1eSmaybee if (refcount_count(&buf->b_refcnt) == 0) { 231313506d1eSmaybee ASSERT(list_link_active(&buf->b_arc_node)); 231413506d1eSmaybee } else { 231513506d1eSmaybee buf->b_flags &= ~ARC_PREFETCH; 231644cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_hits); 231713506d1eSmaybee } 231813506d1eSmaybee buf->b_arc_access = lbolt; 2319fa9e4066Sahrens return; 2320fa9e4066Sahrens } 2321fa9e4066Sahrens 2322fa9e4066Sahrens /* 2323fa9e4066Sahrens * This buffer has been "accessed" only once so far, 2324fa9e4066Sahrens * but it is still in the cache. Move it to the MFU 2325fa9e4066Sahrens * state. 2326fa9e4066Sahrens */ 2327fa9e4066Sahrens if (lbolt > buf->b_arc_access + ARC_MINTIME) { 2328fa9e4066Sahrens /* 2329fa9e4066Sahrens * More than 125ms have passed since we 2330fa9e4066Sahrens * instantiated this buffer. Move it to the 2331fa9e4066Sahrens * most frequently used state. 2332fa9e4066Sahrens */ 2333fa9e4066Sahrens buf->b_arc_access = lbolt; 2334ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 233544cb6abcSbmc arc_change_state(arc_mfu, buf, hash_lock); 2336fa9e4066Sahrens } 233744cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_hits); 233844cb6abcSbmc } else if (buf->b_state == arc_mru_ghost) { 2339fa9e4066Sahrens arc_state_t *new_state; 2340fa9e4066Sahrens /* 2341fa9e4066Sahrens * This buffer has been "accessed" recently, but 2342fa9e4066Sahrens * was evicted from the cache. Move it to the 2343fa9e4066Sahrens * MFU state. 2344fa9e4066Sahrens */ 2345fa9e4066Sahrens 2346fa9e4066Sahrens if (buf->b_flags & ARC_PREFETCH) { 234744cb6abcSbmc new_state = arc_mru; 234813506d1eSmaybee if (refcount_count(&buf->b_refcnt) > 0) 234913506d1eSmaybee buf->b_flags &= ~ARC_PREFETCH; 2350ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, buf); 2351fa9e4066Sahrens } else { 235244cb6abcSbmc new_state = arc_mfu; 2353ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 2354fa9e4066Sahrens } 2355fa9e4066Sahrens 2356fa9e4066Sahrens buf->b_arc_access = lbolt; 2357fa9e4066Sahrens arc_change_state(new_state, buf, hash_lock); 2358fa9e4066Sahrens 235944cb6abcSbmc ARCSTAT_BUMP(arcstat_mru_ghost_hits); 236044cb6abcSbmc } else if (buf->b_state == arc_mfu) { 2361fa9e4066Sahrens /* 2362fa9e4066Sahrens * This buffer has been accessed more than once and is 2363fa9e4066Sahrens * still in the cache. Keep it in the MFU state. 2364fa9e4066Sahrens * 236513506d1eSmaybee * NOTE: an add_reference() that occurred when we did 236613506d1eSmaybee * the arc_read() will have kicked this off the list. 236713506d1eSmaybee * If it was a prefetch, we will explicitly move it to 236813506d1eSmaybee * the head of the list now. 2369fa9e4066Sahrens */ 237013506d1eSmaybee if ((buf->b_flags & ARC_PREFETCH) != 0) { 237113506d1eSmaybee ASSERT(refcount_count(&buf->b_refcnt) == 0); 237213506d1eSmaybee ASSERT(list_link_active(&buf->b_arc_node)); 237313506d1eSmaybee } 237444cb6abcSbmc ARCSTAT_BUMP(arcstat_mfu_hits); 237513506d1eSmaybee buf->b_arc_access = lbolt; 237644cb6abcSbmc } else if (buf->b_state == arc_mfu_ghost) { 237744cb6abcSbmc arc_state_t *new_state = arc_mfu; 2378fa9e4066Sahrens /* 2379fa9e4066Sahrens * This buffer has been accessed more than once but has 2380fa9e4066Sahrens * been evicted from the cache. Move it back to the 2381fa9e4066Sahrens * MFU state. 2382fa9e4066Sahrens */ 2383fa9e4066Sahrens 238413506d1eSmaybee if (buf->b_flags & ARC_PREFETCH) { 238513506d1eSmaybee /* 238613506d1eSmaybee * This is a prefetch access... 238713506d1eSmaybee * move this block back to the MRU state. 238813506d1eSmaybee */ 238913506d1eSmaybee ASSERT3U(refcount_count(&buf->b_refcnt), ==, 0); 239044cb6abcSbmc new_state = arc_mru; 239113506d1eSmaybee } 239213506d1eSmaybee 2393fa9e4066Sahrens buf->b_arc_access = lbolt; 2394ea8dc4b6Seschrock DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 239513506d1eSmaybee arc_change_state(new_state, buf, hash_lock); 2396fa9e4066Sahrens 239744cb6abcSbmc ARCSTAT_BUMP(arcstat_mfu_ghost_hits); 2398fa94a07fSbrendan } else if (buf->b_state == arc_l2c_only) { 2399fa94a07fSbrendan /* 2400fa94a07fSbrendan * This buffer is on the 2nd Level ARC. 2401fa94a07fSbrendan */ 2402fa94a07fSbrendan 2403fa94a07fSbrendan buf->b_arc_access = lbolt; 2404fa94a07fSbrendan DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, buf); 2405fa94a07fSbrendan arc_change_state(arc_mfu, buf, hash_lock); 2406fa9e4066Sahrens } else { 2407fa9e4066Sahrens ASSERT(!"invalid arc state"); 2408fa9e4066Sahrens } 2409fa9e4066Sahrens } 2410fa9e4066Sahrens 2411fa9e4066Sahrens /* a generic arc_done_func_t which you can use */ 2412fa9e4066Sahrens /* ARGSUSED */ 2413fa9e4066Sahrens void 2414fa9e4066Sahrens arc_bcopy_func(zio_t *zio, arc_buf_t *buf, void *arg) 2415fa9e4066Sahrens { 2416fa9e4066Sahrens bcopy(buf->b_data, arg, buf->b_hdr->b_size); 2417ea8dc4b6Seschrock VERIFY(arc_buf_remove_ref(buf, arg) == 1); 2418fa9e4066Sahrens } 2419fa9e4066Sahrens 24200e8c6158Smaybee /* a generic arc_done_func_t */ 2421fa9e4066Sahrens void 2422fa9e4066Sahrens arc_getbuf_func(zio_t *zio, arc_buf_t *buf, void *arg) 2423fa9e4066Sahrens { 2424fa9e4066Sahrens arc_buf_t **bufp = arg; 2425fa9e4066Sahrens if (zio && zio->io_error) { 2426ea8dc4b6Seschrock VERIFY(arc_buf_remove_ref(buf, arg) == 1); 2427fa9e4066Sahrens *bufp = NULL; 2428fa9e4066Sahrens } else { 2429fa9e4066Sahrens *bufp = buf; 2430fa9e4066Sahrens } 2431fa9e4066Sahrens } 2432fa9e4066Sahrens 2433fa9e4066Sahrens static void 2434fa9e4066Sahrens arc_read_done(zio_t *zio) 2435fa9e4066Sahrens { 2436bbf4a8dfSmaybee arc_buf_hdr_t *hdr, *found; 2437fa9e4066Sahrens arc_buf_t *buf; 2438fa9e4066Sahrens arc_buf_t *abuf; /* buffer we're assigning to callback */ 2439fa9e4066Sahrens kmutex_t *hash_lock; 2440fa9e4066Sahrens arc_callback_t *callback_list, *acb; 2441fa9e4066Sahrens int freeable = FALSE; 2442fa9e4066Sahrens 2443fa9e4066Sahrens buf = zio->io_private; 2444fa9e4066Sahrens hdr = buf->b_hdr; 2445fa9e4066Sahrens 2446bbf4a8dfSmaybee /* 2447bbf4a8dfSmaybee * The hdr was inserted into hash-table and removed from lists 2448bbf4a8dfSmaybee * prior to starting I/O. We should find this header, since 2449bbf4a8dfSmaybee * it's in the hash table, and it should be legit since it's 2450bbf4a8dfSmaybee * not possible to evict it during the I/O. The only possible 2451bbf4a8dfSmaybee * reason for it not to be found is if we were freed during the 2452bbf4a8dfSmaybee * read. 2453bbf4a8dfSmaybee */ 2454ac05c741SMark Maybee found = buf_hash_find(hdr->b_spa, &hdr->b_dva, hdr->b_birth, 24556b4acc8bSahrens &hash_lock); 2456fa9e4066Sahrens 2457bbf4a8dfSmaybee ASSERT((found == NULL && HDR_FREED_IN_READ(hdr) && hash_lock == NULL) || 2458fa94a07fSbrendan (found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || 2459fa94a07fSbrendan (found == hdr && HDR_L2_READING(hdr))); 2460fa94a07fSbrendan 24613a737e0dSbrendan hdr->b_flags &= ~ARC_L2_EVICTED; 2462fa94a07fSbrendan if (l2arc_noprefetch && (hdr->b_flags & ARC_PREFETCH)) 24633baa08fcSek hdr->b_flags &= ~ARC_L2CACHE; 2464fa9e4066Sahrens 2465fa9e4066Sahrens /* byteswap if necessary */ 2466fa9e4066Sahrens callback_list = hdr->b_acb; 2467fa9e4066Sahrens ASSERT(callback_list != NULL); 24688e0f0d3dSWilliam Gorrell if (BP_SHOULD_BYTESWAP(zio->io_bp) && zio->io_error == 0) { 2469088f3894Sahrens arc_byteswap_func_t *func = BP_GET_LEVEL(zio->io_bp) > 0 ? 2470088f3894Sahrens byteswap_uint64_array : 2471088f3894Sahrens dmu_ot[BP_GET_TYPE(zio->io_bp)].ot_byteswap; 2472088f3894Sahrens func(buf->b_data, hdr->b_size); 2473088f3894Sahrens } 2474fa9e4066Sahrens 2475fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 24766b4acc8bSahrens 2477*b24ab676SJeff Bonwick if (hash_lock && zio->io_error == 0 && hdr->b_state == arc_anon) { 2478*b24ab676SJeff Bonwick /* 2479*b24ab676SJeff Bonwick * Only call arc_access on anonymous buffers. This is because 2480*b24ab676SJeff Bonwick * if we've issued an I/O for an evicted buffer, we've already 2481*b24ab676SJeff Bonwick * called arc_access (to prevent any simultaneous readers from 2482*b24ab676SJeff Bonwick * getting confused). 2483*b24ab676SJeff Bonwick */ 2484*b24ab676SJeff Bonwick arc_access(hdr, hash_lock); 2485*b24ab676SJeff Bonwick } 2486*b24ab676SJeff Bonwick 2487fa9e4066Sahrens /* create copies of the data buffer for the callers */ 2488fa9e4066Sahrens abuf = buf; 2489fa9e4066Sahrens for (acb = callback_list; acb; acb = acb->acb_next) { 2490fa9e4066Sahrens if (acb->acb_done) { 249144eda4d7Smaybee if (abuf == NULL) 249244eda4d7Smaybee abuf = arc_buf_clone(buf); 2493fa9e4066Sahrens acb->acb_buf = abuf; 2494fa9e4066Sahrens abuf = NULL; 2495fa9e4066Sahrens } 2496fa9e4066Sahrens } 2497fa9e4066Sahrens hdr->b_acb = NULL; 2498fa9e4066Sahrens hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 2499ea8dc4b6Seschrock ASSERT(!HDR_BUF_AVAILABLE(hdr)); 2500*b24ab676SJeff Bonwick if (abuf == buf) { 2501*b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 2502*b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 2503ea8dc4b6Seschrock hdr->b_flags |= ARC_BUF_AVAILABLE; 2504*b24ab676SJeff Bonwick } 2505fa9e4066Sahrens 2506fa9e4066Sahrens ASSERT(refcount_is_zero(&hdr->b_refcnt) || callback_list != NULL); 2507fa9e4066Sahrens 2508fa9e4066Sahrens if (zio->io_error != 0) { 2509fa9e4066Sahrens hdr->b_flags |= ARC_IO_ERROR; 251044cb6abcSbmc if (hdr->b_state != arc_anon) 251144cb6abcSbmc arc_change_state(arc_anon, hdr, hash_lock); 2512ea8dc4b6Seschrock if (HDR_IN_HASH_TABLE(hdr)) 2513ea8dc4b6Seschrock buf_hash_remove(hdr); 2514fa9e4066Sahrens freeable = refcount_is_zero(&hdr->b_refcnt); 2515fa9e4066Sahrens } 2516fa9e4066Sahrens 2517ea8dc4b6Seschrock /* 251813506d1eSmaybee * Broadcast before we drop the hash_lock to avoid the possibility 251913506d1eSmaybee * that the hdr (and hence the cv) might be freed before we get to 252013506d1eSmaybee * the cv_broadcast(). 2521ea8dc4b6Seschrock */ 2522ea8dc4b6Seschrock cv_broadcast(&hdr->b_cv); 2523ea8dc4b6Seschrock 2524bbf4a8dfSmaybee if (hash_lock) { 252544eda4d7Smaybee mutex_exit(hash_lock); 2526fa9e4066Sahrens } else { 2527fa9e4066Sahrens /* 2528fa9e4066Sahrens * This block was freed while we waited for the read to 2529fa9e4066Sahrens * complete. It has been removed from the hash table and 2530fa9e4066Sahrens * moved to the anonymous state (so that it won't show up 2531fa9e4066Sahrens * in the cache). 2532fa9e4066Sahrens */ 253344cb6abcSbmc ASSERT3P(hdr->b_state, ==, arc_anon); 2534fa9e4066Sahrens freeable = refcount_is_zero(&hdr->b_refcnt); 2535fa9e4066Sahrens } 2536fa9e4066Sahrens 2537fa9e4066Sahrens /* execute each callback and free its structure */ 2538fa9e4066Sahrens while ((acb = callback_list) != NULL) { 2539fa9e4066Sahrens if (acb->acb_done) 2540fa9e4066Sahrens acb->acb_done(zio, acb->acb_buf, acb->acb_private); 2541fa9e4066Sahrens 2542fa9e4066Sahrens if (acb->acb_zio_dummy != NULL) { 2543fa9e4066Sahrens acb->acb_zio_dummy->io_error = zio->io_error; 2544fa9e4066Sahrens zio_nowait(acb->acb_zio_dummy); 2545fa9e4066Sahrens } 2546fa9e4066Sahrens 2547fa9e4066Sahrens callback_list = acb->acb_next; 2548fa9e4066Sahrens kmem_free(acb, sizeof (arc_callback_t)); 2549fa9e4066Sahrens } 2550fa9e4066Sahrens 2551fa9e4066Sahrens if (freeable) 2552ea8dc4b6Seschrock arc_hdr_destroy(hdr); 2553fa9e4066Sahrens } 2554fa9e4066Sahrens 2555fa9e4066Sahrens /* 2556fa9e4066Sahrens * "Read" the block block at the specified DVA (in bp) via the 2557fa9e4066Sahrens * cache. If the block is found in the cache, invoke the provided 2558fa9e4066Sahrens * callback immediately and return. Note that the `zio' parameter 2559fa9e4066Sahrens * in the callback will be NULL in this case, since no IO was 2560fa9e4066Sahrens * required. If the block is not in the cache pass the read request 2561fa9e4066Sahrens * on to the spa with a substitute callback function, so that the 2562fa9e4066Sahrens * requested block will be added to the cache. 2563fa9e4066Sahrens * 2564fa9e4066Sahrens * If a read request arrives for a block that has a read in-progress, 2565fa9e4066Sahrens * either wait for the in-progress read to complete (and return the 2566fa9e4066Sahrens * results); or, if this is a read with a "done" func, add a record 2567fa9e4066Sahrens * to the read to invoke the "done" func when the read completes, 2568fa9e4066Sahrens * and return; or just return. 2569fa9e4066Sahrens * 2570fa9e4066Sahrens * arc_read_done() will invoke all the requested "done" functions 2571fa9e4066Sahrens * for readers of this block. 2572088f3894Sahrens * 2573088f3894Sahrens * Normal callers should use arc_read and pass the arc buffer and offset 2574088f3894Sahrens * for the bp. But if you know you don't need locking, you can use 25758ad10dceSSuhasini Peddada * arc_read_bp. 2576fa9e4066Sahrens */ 2577fa9e4066Sahrens int 2578*b24ab676SJeff Bonwick arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_buf_t *pbuf, 25793baa08fcSek arc_done_func_t *done, void *private, int priority, int zio_flags, 2580088f3894Sahrens uint32_t *arc_flags, const zbookmark_t *zb) 2581088f3894Sahrens { 2582088f3894Sahrens int err; 2583088f3894Sahrens 2584088f3894Sahrens ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt)); 2585088f3894Sahrens ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size); 25866f83844dSMark Maybee rw_enter(&pbuf->b_lock, RW_READER); 2587088f3894Sahrens 2588088f3894Sahrens err = arc_read_nolock(pio, spa, bp, done, private, priority, 25893baa08fcSek zio_flags, arc_flags, zb); 25906f83844dSMark Maybee rw_exit(&pbuf->b_lock); 259114843421SMatthew Ahrens 2592088f3894Sahrens return (err); 2593088f3894Sahrens } 2594088f3894Sahrens 2595088f3894Sahrens int 2596*b24ab676SJeff Bonwick arc_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bp, 25973baa08fcSek arc_done_func_t *done, void *private, int priority, int zio_flags, 2598088f3894Sahrens uint32_t *arc_flags, const zbookmark_t *zb) 2599fa9e4066Sahrens { 2600fa9e4066Sahrens arc_buf_hdr_t *hdr; 2601fa9e4066Sahrens arc_buf_t *buf; 2602fa9e4066Sahrens kmutex_t *hash_lock; 2603fa94a07fSbrendan zio_t *rzio; 2604ac05c741SMark Maybee uint64_t guid = spa_guid(spa); 2605fa9e4066Sahrens 2606fa9e4066Sahrens top: 2607*b24ab676SJeff Bonwick hdr = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), 2608*b24ab676SJeff Bonwick &hash_lock); 2609ea8dc4b6Seschrock if (hdr && hdr->b_datacnt > 0) { 2610fa9e4066Sahrens 261113506d1eSmaybee *arc_flags |= ARC_CACHED; 261213506d1eSmaybee 2613fa9e4066Sahrens if (HDR_IO_IN_PROGRESS(hdr)) { 261413506d1eSmaybee 261513506d1eSmaybee if (*arc_flags & ARC_WAIT) { 261613506d1eSmaybee cv_wait(&hdr->b_cv, hash_lock); 261713506d1eSmaybee mutex_exit(hash_lock); 261813506d1eSmaybee goto top; 261913506d1eSmaybee } 262013506d1eSmaybee ASSERT(*arc_flags & ARC_NOWAIT); 262113506d1eSmaybee 262213506d1eSmaybee if (done) { 2623fa9e4066Sahrens arc_callback_t *acb = NULL; 2624fa9e4066Sahrens 2625fa9e4066Sahrens acb = kmem_zalloc(sizeof (arc_callback_t), 2626fa9e4066Sahrens KM_SLEEP); 2627fa9e4066Sahrens acb->acb_done = done; 2628fa9e4066Sahrens acb->acb_private = private; 2629fa9e4066Sahrens if (pio != NULL) 2630fa9e4066Sahrens acb->acb_zio_dummy = zio_null(pio, 2631a3f829aeSBill Moore spa, NULL, NULL, NULL, zio_flags); 2632fa9e4066Sahrens 2633fa9e4066Sahrens ASSERT(acb->acb_done != NULL); 2634fa9e4066Sahrens acb->acb_next = hdr->b_acb; 2635fa9e4066Sahrens hdr->b_acb = acb; 2636fa9e4066Sahrens add_reference(hdr, hash_lock, private); 2637fa9e4066Sahrens mutex_exit(hash_lock); 2638fa9e4066Sahrens return (0); 2639fa9e4066Sahrens } 2640fa9e4066Sahrens mutex_exit(hash_lock); 2641fa9e4066Sahrens return (0); 2642fa9e4066Sahrens } 2643fa9e4066Sahrens 264444cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 2645fa9e4066Sahrens 2646ea8dc4b6Seschrock if (done) { 264744eda4d7Smaybee add_reference(hdr, hash_lock, private); 2648ea8dc4b6Seschrock /* 2649ea8dc4b6Seschrock * If this block is already in use, create a new 2650ea8dc4b6Seschrock * copy of the data so that we will be guaranteed 2651ea8dc4b6Seschrock * that arc_release() will always succeed. 2652ea8dc4b6Seschrock */ 2653fa9e4066Sahrens buf = hdr->b_buf; 2654ea8dc4b6Seschrock ASSERT(buf); 2655ea8dc4b6Seschrock ASSERT(buf->b_data); 265644eda4d7Smaybee if (HDR_BUF_AVAILABLE(hdr)) { 2657ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 2658ea8dc4b6Seschrock hdr->b_flags &= ~ARC_BUF_AVAILABLE; 265944eda4d7Smaybee } else { 266044eda4d7Smaybee buf = arc_buf_clone(buf); 2661ea8dc4b6Seschrock } 2662*b24ab676SJeff Bonwick 266313506d1eSmaybee } else if (*arc_flags & ARC_PREFETCH && 266413506d1eSmaybee refcount_count(&hdr->b_refcnt) == 0) { 266513506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 2666fa9e4066Sahrens } 2667fa9e4066Sahrens DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); 266844eda4d7Smaybee arc_access(hdr, hash_lock); 26693baa08fcSek if (*arc_flags & ARC_L2CACHE) 26703baa08fcSek hdr->b_flags |= ARC_L2CACHE; 267144eda4d7Smaybee mutex_exit(hash_lock); 267244cb6abcSbmc ARCSTAT_BUMP(arcstat_hits); 267344cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 267444cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 267544cb6abcSbmc data, metadata, hits); 267644cb6abcSbmc 2677fa9e4066Sahrens if (done) 2678fa9e4066Sahrens done(NULL, buf, private); 2679fa9e4066Sahrens } else { 2680fa9e4066Sahrens uint64_t size = BP_GET_LSIZE(bp); 2681fa9e4066Sahrens arc_callback_t *acb; 26823a737e0dSbrendan vdev_t *vd = NULL; 2683f9d8334fSGeorge Wilson uint64_t addr; 26845a98e54bSBrendan Gregg - Sun Microsystems boolean_t devw = B_FALSE; 2685fa9e4066Sahrens 2686fa9e4066Sahrens if (hdr == NULL) { 2687fa9e4066Sahrens /* this block is not in the cache */ 2688fa9e4066Sahrens arc_buf_hdr_t *exists; 2689ad23a2dbSjohansen arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); 2690ad23a2dbSjohansen buf = arc_buf_alloc(spa, size, private, type); 2691fa9e4066Sahrens hdr = buf->b_hdr; 2692fa9e4066Sahrens hdr->b_dva = *BP_IDENTITY(bp); 2693*b24ab676SJeff Bonwick hdr->b_birth = BP_PHYSICAL_BIRTH(bp); 2694fa9e4066Sahrens hdr->b_cksum0 = bp->blk_cksum.zc_word[0]; 2695fa9e4066Sahrens exists = buf_hash_insert(hdr, &hash_lock); 2696fa9e4066Sahrens if (exists) { 2697fa9e4066Sahrens /* somebody beat us to the hash insert */ 2698fa9e4066Sahrens mutex_exit(hash_lock); 2699fa9e4066Sahrens bzero(&hdr->b_dva, sizeof (dva_t)); 2700fa9e4066Sahrens hdr->b_birth = 0; 2701fa9e4066Sahrens hdr->b_cksum0 = 0; 2702ea8dc4b6Seschrock (void) arc_buf_remove_ref(buf, private); 2703fa9e4066Sahrens goto top; /* restart the IO request */ 2704fa9e4066Sahrens } 270513506d1eSmaybee /* if this is a prefetch, we don't have a reference */ 270613506d1eSmaybee if (*arc_flags & ARC_PREFETCH) { 270713506d1eSmaybee (void) remove_reference(hdr, hash_lock, 270813506d1eSmaybee private); 270913506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 271013506d1eSmaybee } 27113baa08fcSek if (*arc_flags & ARC_L2CACHE) 27123baa08fcSek hdr->b_flags |= ARC_L2CACHE; 271313506d1eSmaybee if (BP_GET_LEVEL(bp) > 0) 271413506d1eSmaybee hdr->b_flags |= ARC_INDIRECT; 2715fa9e4066Sahrens } else { 2716fa9e4066Sahrens /* this block is in the ghost cache */ 2717ea8dc4b6Seschrock ASSERT(GHOST_STATE(hdr->b_state)); 2718ea8dc4b6Seschrock ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 271913506d1eSmaybee ASSERT3U(refcount_count(&hdr->b_refcnt), ==, 0); 2720ea8dc4b6Seschrock ASSERT(hdr->b_buf == NULL); 272113506d1eSmaybee 272213506d1eSmaybee /* if this is a prefetch, we don't have a reference */ 272313506d1eSmaybee if (*arc_flags & ARC_PREFETCH) 272413506d1eSmaybee hdr->b_flags |= ARC_PREFETCH; 272513506d1eSmaybee else 272613506d1eSmaybee add_reference(hdr, hash_lock, private); 27273baa08fcSek if (*arc_flags & ARC_L2CACHE) 27283baa08fcSek hdr->b_flags |= ARC_L2CACHE; 27291ab7f2deSmaybee buf = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); 2730fa9e4066Sahrens buf->b_hdr = hdr; 273144eda4d7Smaybee buf->b_data = NULL; 2732ea8dc4b6Seschrock buf->b_efunc = NULL; 2733ea8dc4b6Seschrock buf->b_private = NULL; 2734fa9e4066Sahrens buf->b_next = NULL; 2735fa9e4066Sahrens hdr->b_buf = buf; 273644eda4d7Smaybee arc_get_data_buf(buf); 2737ea8dc4b6Seschrock ASSERT(hdr->b_datacnt == 0); 2738ea8dc4b6Seschrock hdr->b_datacnt = 1; 2739fa9e4066Sahrens } 2740fa9e4066Sahrens 2741fa9e4066Sahrens acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP); 2742fa9e4066Sahrens acb->acb_done = done; 2743fa9e4066Sahrens acb->acb_private = private; 2744fa9e4066Sahrens 2745fa9e4066Sahrens ASSERT(hdr->b_acb == NULL); 2746fa9e4066Sahrens hdr->b_acb = acb; 2747fa9e4066Sahrens hdr->b_flags |= ARC_IO_IN_PROGRESS; 2748fa9e4066Sahrens 2749fa9e4066Sahrens /* 2750fa9e4066Sahrens * If the buffer has been evicted, migrate it to a present state 2751fa9e4066Sahrens * before issuing the I/O. Once we drop the hash-table lock, 2752fa9e4066Sahrens * the header will be marked as I/O in progress and have an 2753fa9e4066Sahrens * attached buffer. At this point, anybody who finds this 2754fa9e4066Sahrens * buffer ought to notice that it's legit but has a pending I/O. 2755fa9e4066Sahrens */ 2756fa9e4066Sahrens 2757ea8dc4b6Seschrock if (GHOST_STATE(hdr->b_state)) 275844eda4d7Smaybee arc_access(hdr, hash_lock); 2759fa9e4066Sahrens 2760e14bb325SJeff Bonwick if (HDR_L2CACHE(hdr) && hdr->b_l2hdr != NULL && 2761e14bb325SJeff Bonwick (vd = hdr->b_l2hdr->b_dev->l2ad_vdev) != NULL) { 27625a98e54bSBrendan Gregg - Sun Microsystems devw = hdr->b_l2hdr->b_dev->l2ad_writing; 27633a737e0dSbrendan addr = hdr->b_l2hdr->b_daddr; 2764e14bb325SJeff Bonwick /* 2765e14bb325SJeff Bonwick * Lock out device removal. 2766e14bb325SJeff Bonwick */ 2767e14bb325SJeff Bonwick if (vdev_is_dead(vd) || 2768e14bb325SJeff Bonwick !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) 2769e14bb325SJeff Bonwick vd = NULL; 27703a737e0dSbrendan } 27713a737e0dSbrendan 27723a737e0dSbrendan mutex_exit(hash_lock); 27733a737e0dSbrendan 2774fa9e4066Sahrens ASSERT3U(hdr->b_size, ==, size); 27755c28183bSBrendan Gregg - Sun Microsystems DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, 27765c28183bSBrendan Gregg - Sun Microsystems uint64_t, size, zbookmark_t *, zb); 277744cb6abcSbmc ARCSTAT_BUMP(arcstat_misses); 277844cb6abcSbmc ARCSTAT_CONDSTAT(!(hdr->b_flags & ARC_PREFETCH), 277944cb6abcSbmc demand, prefetch, hdr->b_type != ARC_BUFC_METADATA, 278044cb6abcSbmc data, metadata, misses); 2781ea8dc4b6Seschrock 27825a98e54bSBrendan Gregg - Sun Microsystems if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) { 2783fa94a07fSbrendan /* 2784fa94a07fSbrendan * Read from the L2ARC if the following are true: 27853a737e0dSbrendan * 1. The L2ARC vdev was previously cached. 27863a737e0dSbrendan * 2. This buffer still has L2ARC metadata. 27873a737e0dSbrendan * 3. This buffer isn't currently writing to the L2ARC. 27883a737e0dSbrendan * 4. The L2ARC entry wasn't evicted, which may 27893a737e0dSbrendan * also have invalidated the vdev. 27905a98e54bSBrendan Gregg - Sun Microsystems * 5. This isn't prefetch and l2arc_noprefetch is set. 2791fa94a07fSbrendan */ 2792e14bb325SJeff Bonwick if (hdr->b_l2hdr != NULL && 27935a98e54bSBrendan Gregg - Sun Microsystems !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && 27945a98e54bSBrendan Gregg - Sun Microsystems !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { 2795fa94a07fSbrendan l2arc_read_callback_t *cb; 2796fa94a07fSbrendan 2797c5904d13Seschrock DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); 2798c5904d13Seschrock ARCSTAT_BUMP(arcstat_l2_hits); 2799c5904d13Seschrock 2800fa94a07fSbrendan cb = kmem_zalloc(sizeof (l2arc_read_callback_t), 2801fa94a07fSbrendan KM_SLEEP); 2802fa94a07fSbrendan cb->l2rcb_buf = buf; 2803fa94a07fSbrendan cb->l2rcb_spa = spa; 2804fa94a07fSbrendan cb->l2rcb_bp = *bp; 2805fa94a07fSbrendan cb->l2rcb_zb = *zb; 28063baa08fcSek cb->l2rcb_flags = zio_flags; 2807fa94a07fSbrendan 2808fa94a07fSbrendan /* 2809e14bb325SJeff Bonwick * l2arc read. The SCL_L2ARC lock will be 2810e14bb325SJeff Bonwick * released by l2arc_read_done(). 2811fa94a07fSbrendan */ 2812fa94a07fSbrendan rzio = zio_read_phys(pio, vd, addr, size, 2813fa94a07fSbrendan buf->b_data, ZIO_CHECKSUM_OFF, 28143baa08fcSek l2arc_read_done, cb, priority, zio_flags | 281549cf58c0SBrendan Gregg - Sun Microsystems ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | 2816e14bb325SJeff Bonwick ZIO_FLAG_DONT_PROPAGATE | 2817e14bb325SJeff Bonwick ZIO_FLAG_DONT_RETRY, B_FALSE); 2818fa94a07fSbrendan DTRACE_PROBE2(l2arc__read, vdev_t *, vd, 2819fa94a07fSbrendan zio_t *, rzio); 28205a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_read_bytes, size); 2821fa94a07fSbrendan 28223a737e0dSbrendan if (*arc_flags & ARC_NOWAIT) { 28233a737e0dSbrendan zio_nowait(rzio); 28243a737e0dSbrendan return (0); 28253a737e0dSbrendan } 2826fa94a07fSbrendan 28273a737e0dSbrendan ASSERT(*arc_flags & ARC_WAIT); 28283a737e0dSbrendan if (zio_wait(rzio) == 0) 28293a737e0dSbrendan return (0); 28303a737e0dSbrendan 28313a737e0dSbrendan /* l2arc read error; goto zio_read() */ 2832fa94a07fSbrendan } else { 2833fa94a07fSbrendan DTRACE_PROBE1(l2arc__miss, 2834fa94a07fSbrendan arc_buf_hdr_t *, hdr); 2835fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_misses); 2836fa94a07fSbrendan if (HDR_L2_WRITING(hdr)) 2837fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_rw_clash); 2838e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, vd); 2839fa94a07fSbrendan } 28405a98e54bSBrendan Gregg - Sun Microsystems } else { 284176a25fafSBill Moore if (vd != NULL) 284276a25fafSBill Moore spa_config_exit(spa, SCL_L2ARC, vd); 28435a98e54bSBrendan Gregg - Sun Microsystems if (l2arc_ndev != 0) { 28445a98e54bSBrendan Gregg - Sun Microsystems DTRACE_PROBE1(l2arc__miss, 28455a98e54bSBrendan Gregg - Sun Microsystems arc_buf_hdr_t *, hdr); 28465a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_BUMP(arcstat_l2_misses); 28475a98e54bSBrendan Gregg - Sun Microsystems } 2848fa94a07fSbrendan } 2849c5904d13Seschrock 2850fa9e4066Sahrens rzio = zio_read(pio, spa, bp, buf->b_data, size, 28513baa08fcSek arc_read_done, buf, priority, zio_flags, zb); 2852fa9e4066Sahrens 285313506d1eSmaybee if (*arc_flags & ARC_WAIT) 2854fa9e4066Sahrens return (zio_wait(rzio)); 2855fa9e4066Sahrens 285613506d1eSmaybee ASSERT(*arc_flags & ARC_NOWAIT); 2857fa9e4066Sahrens zio_nowait(rzio); 2858fa9e4066Sahrens } 2859fa9e4066Sahrens return (0); 2860fa9e4066Sahrens } 2861fa9e4066Sahrens 2862ea8dc4b6Seschrock void 2863ea8dc4b6Seschrock arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private) 2864ea8dc4b6Seschrock { 2865ea8dc4b6Seschrock ASSERT(buf->b_hdr != NULL); 286644cb6abcSbmc ASSERT(buf->b_hdr->b_state != arc_anon); 2867ea8dc4b6Seschrock ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt) || func == NULL); 2868*b24ab676SJeff Bonwick ASSERT(buf->b_efunc == NULL); 2869*b24ab676SJeff Bonwick ASSERT(!HDR_BUF_AVAILABLE(buf->b_hdr)); 2870*b24ab676SJeff Bonwick 2871ea8dc4b6Seschrock buf->b_efunc = func; 2872ea8dc4b6Seschrock buf->b_private = private; 2873ea8dc4b6Seschrock } 2874ea8dc4b6Seschrock 2875ea8dc4b6Seschrock /* 2876ea8dc4b6Seschrock * This is used by the DMU to let the ARC know that a buffer is 2877ea8dc4b6Seschrock * being evicted, so the ARC should clean up. If this arc buf 2878ea8dc4b6Seschrock * is not yet in the evicted state, it will be put there. 2879ea8dc4b6Seschrock */ 2880ea8dc4b6Seschrock int 2881ea8dc4b6Seschrock arc_buf_evict(arc_buf_t *buf) 2882ea8dc4b6Seschrock { 288340d7d650Smaybee arc_buf_hdr_t *hdr; 2884ea8dc4b6Seschrock kmutex_t *hash_lock; 2885ea8dc4b6Seschrock arc_buf_t **bufp; 2886ea8dc4b6Seschrock 28876f83844dSMark Maybee rw_enter(&buf->b_lock, RW_WRITER); 288840d7d650Smaybee hdr = buf->b_hdr; 2889ea8dc4b6Seschrock if (hdr == NULL) { 2890ea8dc4b6Seschrock /* 2891ea8dc4b6Seschrock * We are in arc_do_user_evicts(). 2892ea8dc4b6Seschrock */ 2893ea8dc4b6Seschrock ASSERT(buf->b_data == NULL); 28946f83844dSMark Maybee rw_exit(&buf->b_lock); 2895ea8dc4b6Seschrock return (0); 28966f83844dSMark Maybee } else if (buf->b_data == NULL) { 28976f83844dSMark Maybee arc_buf_t copy = *buf; /* structure assignment */ 28989b23f181Smaybee /* 28996f83844dSMark Maybee * We are on the eviction list; process this buffer now 29006f83844dSMark Maybee * but let arc_do_user_evicts() do the reaping. 29019b23f181Smaybee */ 29026f83844dSMark Maybee buf->b_efunc = NULL; 29036f83844dSMark Maybee rw_exit(&buf->b_lock); 29046f83844dSMark Maybee VERIFY(copy.b_efunc(©) == 0); 29056f83844dSMark Maybee return (1); 29069b23f181Smaybee } 29076f83844dSMark Maybee hash_lock = HDR_LOCK(hdr); 29086f83844dSMark Maybee mutex_enter(hash_lock); 29099b23f181Smaybee 29109b23f181Smaybee ASSERT(buf->b_hdr == hdr); 29119b23f181Smaybee ASSERT3U(refcount_count(&hdr->b_refcnt), <, hdr->b_datacnt); 291244cb6abcSbmc ASSERT(hdr->b_state == arc_mru || hdr->b_state == arc_mfu); 2913ea8dc4b6Seschrock 2914ea8dc4b6Seschrock /* 2915ea8dc4b6Seschrock * Pull this buffer off of the hdr 2916ea8dc4b6Seschrock */ 2917ea8dc4b6Seschrock bufp = &hdr->b_buf; 2918ea8dc4b6Seschrock while (*bufp != buf) 2919ea8dc4b6Seschrock bufp = &(*bufp)->b_next; 2920ea8dc4b6Seschrock *bufp = buf->b_next; 2921ea8dc4b6Seschrock 2922ea8dc4b6Seschrock ASSERT(buf->b_data != NULL); 292344eda4d7Smaybee arc_buf_destroy(buf, FALSE, FALSE); 2924ea8dc4b6Seschrock 2925ea8dc4b6Seschrock if (hdr->b_datacnt == 0) { 2926ea8dc4b6Seschrock arc_state_t *old_state = hdr->b_state; 2927ea8dc4b6Seschrock arc_state_t *evicted_state; 2928ea8dc4b6Seschrock 2929ea8dc4b6Seschrock ASSERT(refcount_is_zero(&hdr->b_refcnt)); 2930ea8dc4b6Seschrock 2931ea8dc4b6Seschrock evicted_state = 293244cb6abcSbmc (old_state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; 2933ea8dc4b6Seschrock 293444cb6abcSbmc mutex_enter(&old_state->arcs_mtx); 293544cb6abcSbmc mutex_enter(&evicted_state->arcs_mtx); 2936ea8dc4b6Seschrock 2937ea8dc4b6Seschrock arc_change_state(evicted_state, hdr, hash_lock); 2938ea8dc4b6Seschrock ASSERT(HDR_IN_HASH_TABLE(hdr)); 2939fa94a07fSbrendan hdr->b_flags |= ARC_IN_HASH_TABLE; 2940fa94a07fSbrendan hdr->b_flags &= ~ARC_BUF_AVAILABLE; 2941ea8dc4b6Seschrock 294244cb6abcSbmc mutex_exit(&evicted_state->arcs_mtx); 294344cb6abcSbmc mutex_exit(&old_state->arcs_mtx); 2944ea8dc4b6Seschrock } 2945ea8dc4b6Seschrock mutex_exit(hash_lock); 29466f83844dSMark Maybee rw_exit(&buf->b_lock); 2947dd6ef538Smaybee 2948ea8dc4b6Seschrock VERIFY(buf->b_efunc(buf) == 0); 2949ea8dc4b6Seschrock buf->b_efunc = NULL; 2950ea8dc4b6Seschrock buf->b_private = NULL; 2951ea8dc4b6Seschrock buf->b_hdr = NULL; 2952ea8dc4b6Seschrock kmem_cache_free(buf_cache, buf); 2953ea8dc4b6Seschrock return (1); 2954ea8dc4b6Seschrock } 2955ea8dc4b6Seschrock 2956fa9e4066Sahrens /* 2957fa9e4066Sahrens * Release this buffer from the cache. This must be done 2958fa9e4066Sahrens * after a read and prior to modifying the buffer contents. 2959fa9e4066Sahrens * If the buffer has more than one reference, we must make 2960088f3894Sahrens * a new hdr for the buffer. 2961fa9e4066Sahrens */ 2962fa9e4066Sahrens void 2963fa9e4066Sahrens arc_release(arc_buf_t *buf, void *tag) 2964fa9e4066Sahrens { 29656f83844dSMark Maybee arc_buf_hdr_t *hdr; 29666f83844dSMark Maybee kmutex_t *hash_lock; 29676f83844dSMark Maybee l2arc_buf_hdr_t *l2hdr; 2968fa94a07fSbrendan uint64_t buf_size; 29690a95608cSBrendan Gregg - Sun Microsystems boolean_t released = B_FALSE; 2970fa9e4066Sahrens 29716f83844dSMark Maybee rw_enter(&buf->b_lock, RW_WRITER); 29726f83844dSMark Maybee hdr = buf->b_hdr; 29736f83844dSMark Maybee 2974fa9e4066Sahrens /* this buffer is not on any list */ 2975fa9e4066Sahrens ASSERT(refcount_count(&hdr->b_refcnt) > 0); 2976fa9e4066Sahrens 297744cb6abcSbmc if (hdr->b_state == arc_anon) { 2978fa9e4066Sahrens /* this buffer is already released */ 2979fa9e4066Sahrens ASSERT3U(refcount_count(&hdr->b_refcnt), ==, 1); 2980fa9e4066Sahrens ASSERT(BUF_EMPTY(hdr)); 2981ea8dc4b6Seschrock ASSERT(buf->b_efunc == NULL); 29826b4acc8bSahrens arc_buf_thaw(buf); 29836f83844dSMark Maybee rw_exit(&buf->b_lock); 29840a95608cSBrendan Gregg - Sun Microsystems released = B_TRUE; 29850a95608cSBrendan Gregg - Sun Microsystems } else { 29860a95608cSBrendan Gregg - Sun Microsystems hash_lock = HDR_LOCK(hdr); 29870a95608cSBrendan Gregg - Sun Microsystems mutex_enter(hash_lock); 2988fa9e4066Sahrens } 2989fa9e4066Sahrens 29906f83844dSMark Maybee l2hdr = hdr->b_l2hdr; 29916f83844dSMark Maybee if (l2hdr) { 29926f83844dSMark Maybee mutex_enter(&l2arc_buflist_mtx); 29936f83844dSMark Maybee hdr->b_l2hdr = NULL; 29946f83844dSMark Maybee buf_size = hdr->b_size; 29956f83844dSMark Maybee } 29966f83844dSMark Maybee 29970a95608cSBrendan Gregg - Sun Microsystems if (released) 29980a95608cSBrendan Gregg - Sun Microsystems goto out; 29990a95608cSBrendan Gregg - Sun Microsystems 3000ea8dc4b6Seschrock /* 3001ea8dc4b6Seschrock * Do we have more than one buf? 3002ea8dc4b6Seschrock */ 30036f83844dSMark Maybee if (hdr->b_datacnt > 1) { 3004fa9e4066Sahrens arc_buf_hdr_t *nhdr; 3005fa9e4066Sahrens arc_buf_t **bufp; 3006fa9e4066Sahrens uint64_t blksz = hdr->b_size; 3007ac05c741SMark Maybee uint64_t spa = hdr->b_spa; 3008ad23a2dbSjohansen arc_buf_contents_t type = hdr->b_type; 3009fa94a07fSbrendan uint32_t flags = hdr->b_flags; 3010fa9e4066Sahrens 30116f83844dSMark Maybee ASSERT(hdr->b_buf != buf || buf->b_next != NULL); 3012fa9e4066Sahrens /* 3013fa9e4066Sahrens * Pull the data off of this buf and attach it to 3014fa9e4066Sahrens * a new anonymous buf. 3015fa9e4066Sahrens */ 3016ea8dc4b6Seschrock (void) remove_reference(hdr, hash_lock, tag); 3017fa9e4066Sahrens bufp = &hdr->b_buf; 3018ea8dc4b6Seschrock while (*bufp != buf) 3019fa9e4066Sahrens bufp = &(*bufp)->b_next; 3020fa9e4066Sahrens *bufp = (*bufp)->b_next; 3021af2c4821Smaybee buf->b_next = NULL; 3022ea8dc4b6Seschrock 302344cb6abcSbmc ASSERT3U(hdr->b_state->arcs_size, >=, hdr->b_size); 302444cb6abcSbmc atomic_add_64(&hdr->b_state->arcs_size, -hdr->b_size); 3025ea8dc4b6Seschrock if (refcount_is_zero(&hdr->b_refcnt)) { 30260e8c6158Smaybee uint64_t *size = &hdr->b_state->arcs_lsize[hdr->b_type]; 30270e8c6158Smaybee ASSERT3U(*size, >=, hdr->b_size); 30280e8c6158Smaybee atomic_add_64(size, -hdr->b_size); 3029ea8dc4b6Seschrock } 3030ea8dc4b6Seschrock hdr->b_datacnt -= 1; 3031c717a561Smaybee arc_cksum_verify(buf); 3032ea8dc4b6Seschrock 3033fa9e4066Sahrens mutex_exit(hash_lock); 3034fa9e4066Sahrens 30351ab7f2deSmaybee nhdr = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 3036fa9e4066Sahrens nhdr->b_size = blksz; 3037fa9e4066Sahrens nhdr->b_spa = spa; 3038ad23a2dbSjohansen nhdr->b_type = type; 3039fa9e4066Sahrens nhdr->b_buf = buf; 304044cb6abcSbmc nhdr->b_state = arc_anon; 3041fa9e4066Sahrens nhdr->b_arc_access = 0; 3042fa94a07fSbrendan nhdr->b_flags = flags & ARC_L2_WRITING; 3043fa94a07fSbrendan nhdr->b_l2hdr = NULL; 3044ea8dc4b6Seschrock nhdr->b_datacnt = 1; 3045c717a561Smaybee nhdr->b_freeze_cksum = NULL; 3046fa9e4066Sahrens (void) refcount_add(&nhdr->b_refcnt, tag); 3047af2c4821Smaybee buf->b_hdr = nhdr; 30486f83844dSMark Maybee rw_exit(&buf->b_lock); 304944cb6abcSbmc atomic_add_64(&arc_anon->arcs_size, blksz); 3050fa9e4066Sahrens } else { 30516f83844dSMark Maybee rw_exit(&buf->b_lock); 3052ea8dc4b6Seschrock ASSERT(refcount_count(&hdr->b_refcnt) == 1); 3053fa9e4066Sahrens ASSERT(!list_link_active(&hdr->b_arc_node)); 3054fa9e4066Sahrens ASSERT(!HDR_IO_IN_PROGRESS(hdr)); 305544cb6abcSbmc arc_change_state(arc_anon, hdr, hash_lock); 3056fa9e4066Sahrens hdr->b_arc_access = 0; 3057fa9e4066Sahrens mutex_exit(hash_lock); 3058fa94a07fSbrendan 3059fa9e4066Sahrens bzero(&hdr->b_dva, sizeof (dva_t)); 3060fa9e4066Sahrens hdr->b_birth = 0; 3061fa9e4066Sahrens hdr->b_cksum0 = 0; 3062c717a561Smaybee arc_buf_thaw(buf); 3063fa9e4066Sahrens } 3064ea8dc4b6Seschrock buf->b_efunc = NULL; 3065ea8dc4b6Seschrock buf->b_private = NULL; 3066fa94a07fSbrendan 30670a95608cSBrendan Gregg - Sun Microsystems out: 3068fa94a07fSbrendan if (l2hdr) { 3069fa94a07fSbrendan list_remove(l2hdr->b_dev->l2ad_buflist, hdr); 3070fa94a07fSbrendan kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t)); 3071fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, -buf_size); 3072fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 30736f83844dSMark Maybee } 3074fa9e4066Sahrens } 3075fa9e4066Sahrens 3076fa9e4066Sahrens int 3077fa9e4066Sahrens arc_released(arc_buf_t *buf) 3078fa9e4066Sahrens { 30796f83844dSMark Maybee int released; 30806f83844dSMark Maybee 30816f83844dSMark Maybee rw_enter(&buf->b_lock, RW_READER); 30826f83844dSMark Maybee released = (buf->b_data != NULL && buf->b_hdr->b_state == arc_anon); 30836f83844dSMark Maybee rw_exit(&buf->b_lock); 30846f83844dSMark Maybee return (released); 3085ea8dc4b6Seschrock } 3086ea8dc4b6Seschrock 3087ea8dc4b6Seschrock int 3088ea8dc4b6Seschrock arc_has_callback(arc_buf_t *buf) 3089ea8dc4b6Seschrock { 30906f83844dSMark Maybee int callback; 30916f83844dSMark Maybee 30926f83844dSMark Maybee rw_enter(&buf->b_lock, RW_READER); 30936f83844dSMark Maybee callback = (buf->b_efunc != NULL); 30946f83844dSMark Maybee rw_exit(&buf->b_lock); 30956f83844dSMark Maybee return (callback); 3096fa9e4066Sahrens } 3097fa9e4066Sahrens 3098ea8dc4b6Seschrock #ifdef ZFS_DEBUG 3099ea8dc4b6Seschrock int 3100ea8dc4b6Seschrock arc_referenced(arc_buf_t *buf) 3101ea8dc4b6Seschrock { 31026f83844dSMark Maybee int referenced; 31036f83844dSMark Maybee 31046f83844dSMark Maybee rw_enter(&buf->b_lock, RW_READER); 31056f83844dSMark Maybee referenced = (refcount_count(&buf->b_hdr->b_refcnt)); 31066f83844dSMark Maybee rw_exit(&buf->b_lock); 31076f83844dSMark Maybee return (referenced); 3108ea8dc4b6Seschrock } 3109ea8dc4b6Seschrock #endif 3110ea8dc4b6Seschrock 3111c717a561Smaybee static void 3112c717a561Smaybee arc_write_ready(zio_t *zio) 3113c717a561Smaybee { 3114c717a561Smaybee arc_write_callback_t *callback = zio->io_private; 3115c717a561Smaybee arc_buf_t *buf = callback->awcb_buf; 31160a4e9518Sgw arc_buf_hdr_t *hdr = buf->b_hdr; 3117c717a561Smaybee 3118e14bb325SJeff Bonwick ASSERT(!refcount_is_zero(&buf->b_hdr->b_refcnt)); 3119e14bb325SJeff Bonwick callback->awcb_ready(zio, buf, callback->awcb_private); 3120e14bb325SJeff Bonwick 31210a4e9518Sgw /* 31220a4e9518Sgw * If the IO is already in progress, then this is a re-write 3123e14bb325SJeff Bonwick * attempt, so we need to thaw and re-compute the cksum. 3124e14bb325SJeff Bonwick * It is the responsibility of the callback to handle the 3125e14bb325SJeff Bonwick * accounting for any re-write attempt. 31260a4e9518Sgw */ 31270a4e9518Sgw if (HDR_IO_IN_PROGRESS(hdr)) { 31280a4e9518Sgw mutex_enter(&hdr->b_freeze_lock); 31290a4e9518Sgw if (hdr->b_freeze_cksum != NULL) { 31300a4e9518Sgw kmem_free(hdr->b_freeze_cksum, sizeof (zio_cksum_t)); 31310a4e9518Sgw hdr->b_freeze_cksum = NULL; 31320a4e9518Sgw } 31330a4e9518Sgw mutex_exit(&hdr->b_freeze_lock); 31340a4e9518Sgw } 3135fa94a07fSbrendan arc_cksum_compute(buf, B_FALSE); 31360a4e9518Sgw hdr->b_flags |= ARC_IO_IN_PROGRESS; 3137c717a561Smaybee } 3138c717a561Smaybee 3139fa9e4066Sahrens static void 3140fa9e4066Sahrens arc_write_done(zio_t *zio) 3141fa9e4066Sahrens { 3142c717a561Smaybee arc_write_callback_t *callback = zio->io_private; 3143c717a561Smaybee arc_buf_t *buf = callback->awcb_buf; 3144c717a561Smaybee arc_buf_hdr_t *hdr = buf->b_hdr; 3145fa9e4066Sahrens 3146*b24ab676SJeff Bonwick ASSERT(hdr->b_acb == NULL); 3147*b24ab676SJeff Bonwick 3148*b24ab676SJeff Bonwick if (zio->io_error == 0) { 3149*b24ab676SJeff Bonwick hdr->b_dva = *BP_IDENTITY(zio->io_bp); 3150*b24ab676SJeff Bonwick hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); 3151*b24ab676SJeff Bonwick hdr->b_cksum0 = zio->io_bp->blk_cksum.zc_word[0]; 3152*b24ab676SJeff Bonwick } else { 3153*b24ab676SJeff Bonwick ASSERT(BUF_EMPTY(hdr)); 3154*b24ab676SJeff Bonwick } 3155fa9e4066Sahrens 3156ea8dc4b6Seschrock /* 3157ea8dc4b6Seschrock * If the block to be written was all-zero, we may have 3158ea8dc4b6Seschrock * compressed it away. In this case no write was performed 3159ea8dc4b6Seschrock * so there will be no dva/birth-date/checksum. The buffer 3160ea8dc4b6Seschrock * must therefor remain anonymous (and uncached). 3161ea8dc4b6Seschrock */ 3162fa9e4066Sahrens if (!BUF_EMPTY(hdr)) { 3163fa9e4066Sahrens arc_buf_hdr_t *exists; 3164fa9e4066Sahrens kmutex_t *hash_lock; 3165fa9e4066Sahrens 3166*b24ab676SJeff Bonwick ASSERT(zio->io_error == 0); 3167*b24ab676SJeff Bonwick 31686b4acc8bSahrens arc_cksum_verify(buf); 31696b4acc8bSahrens 3170fa9e4066Sahrens exists = buf_hash_insert(hdr, &hash_lock); 3171fa9e4066Sahrens if (exists) { 3172fa9e4066Sahrens /* 3173fa9e4066Sahrens * This can only happen if we overwrite for 3174fa9e4066Sahrens * sync-to-convergence, because we remove 3175fa9e4066Sahrens * buffers from the hash table when we arc_free(). 3176fa9e4066Sahrens */ 3177*b24ab676SJeff Bonwick if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { 3178*b24ab676SJeff Bonwick if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) 3179*b24ab676SJeff Bonwick panic("bad overwrite, hdr=%p exists=%p", 3180*b24ab676SJeff Bonwick (void *)hdr, (void *)exists); 3181*b24ab676SJeff Bonwick ASSERT(refcount_is_zero(&exists->b_refcnt)); 3182*b24ab676SJeff Bonwick arc_change_state(arc_anon, exists, hash_lock); 3183*b24ab676SJeff Bonwick mutex_exit(hash_lock); 3184*b24ab676SJeff Bonwick arc_hdr_destroy(exists); 3185*b24ab676SJeff Bonwick exists = buf_hash_insert(hdr, &hash_lock); 3186*b24ab676SJeff Bonwick ASSERT3P(exists, ==, NULL); 3187*b24ab676SJeff Bonwick } else { 3188*b24ab676SJeff Bonwick /* Dedup */ 3189*b24ab676SJeff Bonwick ASSERT(hdr->b_datacnt == 1); 3190*b24ab676SJeff Bonwick ASSERT(hdr->b_state == arc_anon); 3191*b24ab676SJeff Bonwick ASSERT(BP_GET_DEDUP(zio->io_bp)); 3192*b24ab676SJeff Bonwick ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); 3193ae46e4c7SMatthew Ahrens } 3194fa9e4066Sahrens } 3195ea8dc4b6Seschrock hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 3196088f3894Sahrens /* if it's not anon, we are doing a scrub */ 3197*b24ab676SJeff Bonwick if (!exists && hdr->b_state == arc_anon) 3198088f3894Sahrens arc_access(hdr, hash_lock); 319944eda4d7Smaybee mutex_exit(hash_lock); 3200ea8dc4b6Seschrock } else { 3201ea8dc4b6Seschrock hdr->b_flags &= ~ARC_IO_IN_PROGRESS; 3202fa9e4066Sahrens } 3203ea8dc4b6Seschrock 3204*b24ab676SJeff Bonwick ASSERT(!refcount_is_zero(&hdr->b_refcnt)); 3205*b24ab676SJeff Bonwick callback->awcb_done(zio, buf, callback->awcb_private); 3206fa9e4066Sahrens 3207c717a561Smaybee kmem_free(callback, sizeof (arc_write_callback_t)); 3208fa9e4066Sahrens } 3209fa9e4066Sahrens 3210c717a561Smaybee zio_t * 3211*b24ab676SJeff Bonwick arc_write(zio_t *pio, spa_t *spa, uint64_t txg, 3212*b24ab676SJeff Bonwick blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp, 3213*b24ab676SJeff Bonwick arc_done_func_t *ready, arc_done_func_t *done, void *private, 3214*b24ab676SJeff Bonwick int priority, int zio_flags, const zbookmark_t *zb) 3215fa9e4066Sahrens { 3216fa9e4066Sahrens arc_buf_hdr_t *hdr = buf->b_hdr; 3217c717a561Smaybee arc_write_callback_t *callback; 3218e14bb325SJeff Bonwick zio_t *zio; 3219fa9e4066Sahrens 3220e14bb325SJeff Bonwick ASSERT(ready != NULL); 3221*b24ab676SJeff Bonwick ASSERT(done != NULL); 3222fa9e4066Sahrens ASSERT(!HDR_IO_ERROR(hdr)); 3223c5c6ffa0Smaybee ASSERT((hdr->b_flags & ARC_IO_IN_PROGRESS) == 0); 3224*b24ab676SJeff Bonwick ASSERT(hdr->b_acb == NULL); 32253baa08fcSek if (l2arc) 32263baa08fcSek hdr->b_flags |= ARC_L2CACHE; 3227c717a561Smaybee callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP); 3228c717a561Smaybee callback->awcb_ready = ready; 3229c717a561Smaybee callback->awcb_done = done; 3230c717a561Smaybee callback->awcb_private = private; 3231c717a561Smaybee callback->awcb_buf = buf; 3232088f3894Sahrens 3233*b24ab676SJeff Bonwick zio = zio_write(pio, spa, txg, bp, buf->b_data, hdr->b_size, zp, 3234e14bb325SJeff Bonwick arc_write_ready, arc_write_done, callback, priority, zio_flags, zb); 3235fa9e4066Sahrens 3236c717a561Smaybee return (zio); 3237fa9e4066Sahrens } 3238fa9e4066Sahrens 3239*b24ab676SJeff Bonwick void 3240*b24ab676SJeff Bonwick arc_free(spa_t *spa, const blkptr_t *bp) 3241fa9e4066Sahrens { 3242fa9e4066Sahrens arc_buf_hdr_t *ab; 3243fa9e4066Sahrens kmutex_t *hash_lock; 3244ac05c741SMark Maybee uint64_t guid = spa_guid(spa); 3245fa9e4066Sahrens 3246fa9e4066Sahrens /* 3247*b24ab676SJeff Bonwick * If this buffer is in the cache, release it, so it can be re-used. 3248fa9e4066Sahrens */ 3249*b24ab676SJeff Bonwick ab = buf_hash_find(guid, BP_IDENTITY(bp), BP_PHYSICAL_BIRTH(bp), 3250*b24ab676SJeff Bonwick &hash_lock); 3251fa9e4066Sahrens if (ab != NULL) { 325244cb6abcSbmc if (ab->b_state != arc_anon) 325344cb6abcSbmc arc_change_state(arc_anon, ab, hash_lock); 325413506d1eSmaybee if (HDR_IO_IN_PROGRESS(ab)) { 325513506d1eSmaybee /* 325613506d1eSmaybee * This should only happen when we prefetch. 325713506d1eSmaybee */ 325813506d1eSmaybee ASSERT(ab->b_flags & ARC_PREFETCH); 325913506d1eSmaybee ASSERT3U(ab->b_datacnt, ==, 1); 326013506d1eSmaybee ab->b_flags |= ARC_FREED_IN_READ; 326113506d1eSmaybee if (HDR_IN_HASH_TABLE(ab)) 326213506d1eSmaybee buf_hash_remove(ab); 326313506d1eSmaybee ab->b_arc_access = 0; 326413506d1eSmaybee bzero(&ab->b_dva, sizeof (dva_t)); 326513506d1eSmaybee ab->b_birth = 0; 326613506d1eSmaybee ab->b_cksum0 = 0; 326713506d1eSmaybee ab->b_buf->b_efunc = NULL; 326813506d1eSmaybee ab->b_buf->b_private = NULL; 326913506d1eSmaybee mutex_exit(hash_lock); 3270*b24ab676SJeff Bonwick } else { 3271*b24ab676SJeff Bonwick ASSERT(refcount_is_zero(&ab->b_refcnt)); 3272fa94a07fSbrendan ab->b_flags |= ARC_FREE_IN_PROGRESS; 3273fa9e4066Sahrens mutex_exit(hash_lock); 3274ea8dc4b6Seschrock arc_hdr_destroy(ab); 327544cb6abcSbmc ARCSTAT_BUMP(arcstat_deleted); 3276fa9e4066Sahrens } 3277fa9e4066Sahrens } 3278fa9e4066Sahrens } 3279fa9e4066Sahrens 32801ab7f2deSmaybee static int 32812fdbea25SAleksandr Guzovskiy arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg) 32821ab7f2deSmaybee { 32831ab7f2deSmaybee #ifdef _KERNEL 32841ab7f2deSmaybee uint64_t available_memory = ptob(freemem); 32851ab7f2deSmaybee static uint64_t page_load = 0; 32861ab7f2deSmaybee static uint64_t last_txg = 0; 32871ab7f2deSmaybee 32881ab7f2deSmaybee #if defined(__i386) 32891ab7f2deSmaybee available_memory = 32901ab7f2deSmaybee MIN(available_memory, vmem_size(heap_arena, VMEM_FREE)); 32911ab7f2deSmaybee #endif 32921ab7f2deSmaybee if (available_memory >= zfs_write_limit_max) 32931ab7f2deSmaybee return (0); 32941ab7f2deSmaybee 32951ab7f2deSmaybee if (txg > last_txg) { 32961ab7f2deSmaybee last_txg = txg; 32971ab7f2deSmaybee page_load = 0; 32981ab7f2deSmaybee } 32991ab7f2deSmaybee /* 33001ab7f2deSmaybee * If we are in pageout, we know that memory is already tight, 33011ab7f2deSmaybee * the arc is already going to be evicting, so we just want to 33021ab7f2deSmaybee * continue to let page writes occur as quickly as possible. 33031ab7f2deSmaybee */ 33041ab7f2deSmaybee if (curproc == proc_pageout) { 33051ab7f2deSmaybee if (page_load > MAX(ptob(minfree), available_memory) / 4) 33061ab7f2deSmaybee return (ERESTART); 33071ab7f2deSmaybee /* Note: reserve is inflated, so we deflate */ 33081ab7f2deSmaybee page_load += reserve / 8; 33091ab7f2deSmaybee return (0); 33101ab7f2deSmaybee } else if (page_load > 0 && arc_reclaim_needed()) { 33111ab7f2deSmaybee /* memory is low, delay before restarting */ 33121ab7f2deSmaybee ARCSTAT_INCR(arcstat_memory_throttle_count, 1); 33131ab7f2deSmaybee return (EAGAIN); 33141ab7f2deSmaybee } 33151ab7f2deSmaybee page_load = 0; 33161ab7f2deSmaybee 33171ab7f2deSmaybee if (arc_size > arc_c_min) { 33181ab7f2deSmaybee uint64_t evictable_memory = 33191ab7f2deSmaybee arc_mru->arcs_lsize[ARC_BUFC_DATA] + 33201ab7f2deSmaybee arc_mru->arcs_lsize[ARC_BUFC_METADATA] + 33211ab7f2deSmaybee arc_mfu->arcs_lsize[ARC_BUFC_DATA] + 33221ab7f2deSmaybee arc_mfu->arcs_lsize[ARC_BUFC_METADATA]; 33231ab7f2deSmaybee available_memory += MIN(evictable_memory, arc_size - arc_c_min); 33241ab7f2deSmaybee } 33251ab7f2deSmaybee 33261ab7f2deSmaybee if (inflight_data > available_memory / 4) { 33271ab7f2deSmaybee ARCSTAT_INCR(arcstat_memory_throttle_count, 1); 33281ab7f2deSmaybee return (ERESTART); 33291ab7f2deSmaybee } 33301ab7f2deSmaybee #endif 33311ab7f2deSmaybee return (0); 33321ab7f2deSmaybee } 33331ab7f2deSmaybee 3334fa9e4066Sahrens void 33351ab7f2deSmaybee arc_tempreserve_clear(uint64_t reserve) 3336fa9e4066Sahrens { 33371ab7f2deSmaybee atomic_add_64(&arc_tempreserve, -reserve); 3338fa9e4066Sahrens ASSERT((int64_t)arc_tempreserve >= 0); 3339fa9e4066Sahrens } 3340fa9e4066Sahrens 3341fa9e4066Sahrens int 33421ab7f2deSmaybee arc_tempreserve_space(uint64_t reserve, uint64_t txg) 3343fa9e4066Sahrens { 33441ab7f2deSmaybee int error; 33452fdbea25SAleksandr Guzovskiy uint64_t anon_size; 33461ab7f2deSmaybee 3347fa9e4066Sahrens #ifdef ZFS_DEBUG 3348fa9e4066Sahrens /* 3349fa9e4066Sahrens * Once in a while, fail for no reason. Everything should cope. 3350fa9e4066Sahrens */ 3351fa9e4066Sahrens if (spa_get_random(10000) == 0) { 3352fa9e4066Sahrens dprintf("forcing random failure\n"); 3353fa9e4066Sahrens return (ERESTART); 3354fa9e4066Sahrens } 3355fa9e4066Sahrens #endif 33561ab7f2deSmaybee if (reserve > arc_c/4 && !arc_no_grow) 33571ab7f2deSmaybee arc_c = MIN(arc_c_max, reserve * 4); 33581ab7f2deSmaybee if (reserve > arc_c) 3359112fe045Smaybee return (ENOMEM); 3360112fe045Smaybee 33612fdbea25SAleksandr Guzovskiy /* 33622fdbea25SAleksandr Guzovskiy * Don't count loaned bufs as in flight dirty data to prevent long 33632fdbea25SAleksandr Guzovskiy * network delays from blocking transactions that are ready to be 33642fdbea25SAleksandr Guzovskiy * assigned to a txg. 33652fdbea25SAleksandr Guzovskiy */ 33662fdbea25SAleksandr Guzovskiy anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0); 33672fdbea25SAleksandr Guzovskiy 33681ab7f2deSmaybee /* 33691ab7f2deSmaybee * Writes will, almost always, require additional memory allocations 33701ab7f2deSmaybee * in order to compress/encrypt/etc the data. We therefor need to 33711ab7f2deSmaybee * make sure that there is sufficient available memory for this. 33721ab7f2deSmaybee */ 33732fdbea25SAleksandr Guzovskiy if (error = arc_memory_throttle(reserve, anon_size, txg)) 33741ab7f2deSmaybee return (error); 33751ab7f2deSmaybee 3376fa9e4066Sahrens /* 3377112fe045Smaybee * Throttle writes when the amount of dirty data in the cache 3378112fe045Smaybee * gets too large. We try to keep the cache less than half full 3379112fe045Smaybee * of dirty blocks so that our sync times don't grow too large. 3380112fe045Smaybee * Note: if two requests come in concurrently, we might let them 3381112fe045Smaybee * both succeed, when one of them should fail. Not a huge deal. 3382fa9e4066Sahrens */ 33832fdbea25SAleksandr Guzovskiy 33842fdbea25SAleksandr Guzovskiy if (reserve + arc_tempreserve + anon_size > arc_c / 2 && 33852fdbea25SAleksandr Guzovskiy anon_size > arc_c / 4) { 33860e8c6158Smaybee dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " 33870e8c6158Smaybee "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n", 33880e8c6158Smaybee arc_tempreserve>>10, 33890e8c6158Smaybee arc_anon->arcs_lsize[ARC_BUFC_METADATA]>>10, 33900e8c6158Smaybee arc_anon->arcs_lsize[ARC_BUFC_DATA]>>10, 33911ab7f2deSmaybee reserve>>10, arc_c>>10); 3392fa9e4066Sahrens return (ERESTART); 3393fa9e4066Sahrens } 33941ab7f2deSmaybee atomic_add_64(&arc_tempreserve, reserve); 3395fa9e4066Sahrens return (0); 3396fa9e4066Sahrens } 3397fa9e4066Sahrens 3398fa9e4066Sahrens void 3399fa9e4066Sahrens arc_init(void) 3400fa9e4066Sahrens { 3401fa9e4066Sahrens mutex_init(&arc_reclaim_thr_lock, NULL, MUTEX_DEFAULT, NULL); 3402fa9e4066Sahrens cv_init(&arc_reclaim_thr_cv, NULL, CV_DEFAULT, NULL); 3403fa9e4066Sahrens 340413506d1eSmaybee /* Convert seconds to clock ticks */ 3405b19a79ecSperrin arc_min_prefetch_lifespan = 1 * hz; 340613506d1eSmaybee 3407fa9e4066Sahrens /* Start out with 1/8 of all memory */ 340844cb6abcSbmc arc_c = physmem * PAGESIZE / 8; 3409fa9e4066Sahrens 3410fa9e4066Sahrens #ifdef _KERNEL 3411fa9e4066Sahrens /* 3412fa9e4066Sahrens * On architectures where the physical memory can be larger 3413fa9e4066Sahrens * than the addressable space (intel in 32-bit mode), we may 3414fa9e4066Sahrens * need to limit the cache to 1/8 of VM size. 3415fa9e4066Sahrens */ 341644cb6abcSbmc arc_c = MIN(arc_c, vmem_size(heap_arena, VMEM_ALLOC | VMEM_FREE) / 8); 3417fa9e4066Sahrens #endif 3418fa9e4066Sahrens 3419112fe045Smaybee /* set min cache to 1/32 of all memory, or 64MB, whichever is more */ 342044cb6abcSbmc arc_c_min = MAX(arc_c / 4, 64<<20); 3421112fe045Smaybee /* set max to 3/4 of all memory, or all but 1GB, whichever is more */ 342244cb6abcSbmc if (arc_c * 8 >= 1<<30) 342344cb6abcSbmc arc_c_max = (arc_c * 8) - (1<<30); 3424fa9e4066Sahrens else 342544cb6abcSbmc arc_c_max = arc_c_min; 342644cb6abcSbmc arc_c_max = MAX(arc_c * 6, arc_c_max); 3427a2eea2e1Sahrens 3428a2eea2e1Sahrens /* 3429a2eea2e1Sahrens * Allow the tunables to override our calculations if they are 3430a2eea2e1Sahrens * reasonable (ie. over 64MB) 3431a2eea2e1Sahrens */ 3432a2eea2e1Sahrens if (zfs_arc_max > 64<<20 && zfs_arc_max < physmem * PAGESIZE) 343344cb6abcSbmc arc_c_max = zfs_arc_max; 343444cb6abcSbmc if (zfs_arc_min > 64<<20 && zfs_arc_min <= arc_c_max) 343544cb6abcSbmc arc_c_min = zfs_arc_min; 3436a2eea2e1Sahrens 343744cb6abcSbmc arc_c = arc_c_max; 343844cb6abcSbmc arc_p = (arc_c >> 1); 3439fa9e4066Sahrens 34400e8c6158Smaybee /* limit meta-data to 1/4 of the arc capacity */ 34410e8c6158Smaybee arc_meta_limit = arc_c_max / 4; 34421116048bSek 34431116048bSek /* Allow the tunable to override if it is reasonable */ 34441116048bSek if (zfs_arc_meta_limit > 0 && zfs_arc_meta_limit <= arc_c_max) 34451116048bSek arc_meta_limit = zfs_arc_meta_limit; 34461116048bSek 34470e8c6158Smaybee if (arc_c_min < arc_meta_limit / 2 && zfs_arc_min == 0) 34480e8c6158Smaybee arc_c_min = arc_meta_limit / 2; 34490e8c6158Smaybee 34505a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_grow_retry > 0) 34515a98e54bSBrendan Gregg - Sun Microsystems arc_grow_retry = zfs_arc_grow_retry; 34525a98e54bSBrendan Gregg - Sun Microsystems 34535a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_shrink_shift > 0) 34545a98e54bSBrendan Gregg - Sun Microsystems arc_shrink_shift = zfs_arc_shrink_shift; 34555a98e54bSBrendan Gregg - Sun Microsystems 34565a98e54bSBrendan Gregg - Sun Microsystems if (zfs_arc_p_min_shift > 0) 34575a98e54bSBrendan Gregg - Sun Microsystems arc_p_min_shift = zfs_arc_p_min_shift; 34585a98e54bSBrendan Gregg - Sun Microsystems 3459fa9e4066Sahrens /* if kmem_flags are set, lets try to use less memory */ 3460fa9e4066Sahrens if (kmem_debugging()) 346144cb6abcSbmc arc_c = arc_c / 2; 346244cb6abcSbmc if (arc_c < arc_c_min) 346344cb6abcSbmc arc_c = arc_c_min; 346444cb6abcSbmc 346544cb6abcSbmc arc_anon = &ARC_anon; 346644cb6abcSbmc arc_mru = &ARC_mru; 346744cb6abcSbmc arc_mru_ghost = &ARC_mru_ghost; 346844cb6abcSbmc arc_mfu = &ARC_mfu; 346944cb6abcSbmc arc_mfu_ghost = &ARC_mfu_ghost; 3470fa94a07fSbrendan arc_l2c_only = &ARC_l2c_only; 347144cb6abcSbmc arc_size = 0; 347244cb6abcSbmc 347344cb6abcSbmc mutex_init(&arc_anon->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 347444cb6abcSbmc mutex_init(&arc_mru->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 347544cb6abcSbmc mutex_init(&arc_mru_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 347644cb6abcSbmc mutex_init(&arc_mfu->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 347744cb6abcSbmc mutex_init(&arc_mfu_ghost->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 3478fa94a07fSbrendan mutex_init(&arc_l2c_only->arcs_mtx, NULL, MUTEX_DEFAULT, NULL); 347944cb6abcSbmc 34800e8c6158Smaybee list_create(&arc_mru->arcs_list[ARC_BUFC_METADATA], 34810e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 34820e8c6158Smaybee list_create(&arc_mru->arcs_list[ARC_BUFC_DATA], 34830e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 34840e8c6158Smaybee list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA], 34850e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 34860e8c6158Smaybee list_create(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA], 34870e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 34880e8c6158Smaybee list_create(&arc_mfu->arcs_list[ARC_BUFC_METADATA], 34890e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 34900e8c6158Smaybee list_create(&arc_mfu->arcs_list[ARC_BUFC_DATA], 34910e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 34920e8c6158Smaybee list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA], 34930e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 34940e8c6158Smaybee list_create(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA], 34950e8c6158Smaybee sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3496fa94a07fSbrendan list_create(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA], 3497fa94a07fSbrendan sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3498fa94a07fSbrendan list_create(&arc_l2c_only->arcs_list[ARC_BUFC_DATA], 3499fa94a07fSbrendan sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_arc_node)); 3500fa9e4066Sahrens 3501fa9e4066Sahrens buf_init(); 3502fa9e4066Sahrens 3503fa9e4066Sahrens arc_thread_exit = 0; 3504ea8dc4b6Seschrock arc_eviction_list = NULL; 3505ea8dc4b6Seschrock mutex_init(&arc_eviction_mtx, NULL, MUTEX_DEFAULT, NULL); 350640d7d650Smaybee bzero(&arc_eviction_hdr, sizeof (arc_buf_hdr_t)); 3507fa9e4066Sahrens 350844cb6abcSbmc arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, 350944cb6abcSbmc sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); 351044cb6abcSbmc 351144cb6abcSbmc if (arc_ksp != NULL) { 351244cb6abcSbmc arc_ksp->ks_data = &arc_stats; 351344cb6abcSbmc kstat_install(arc_ksp); 351444cb6abcSbmc } 351544cb6abcSbmc 3516fa9e4066Sahrens (void) thread_create(NULL, 0, arc_reclaim_thread, NULL, 0, &p0, 3517fa9e4066Sahrens TS_RUN, minclsyspri); 351849e3519aSmaybee 351949e3519aSmaybee arc_dead = FALSE; 35203a737e0dSbrendan arc_warm = B_FALSE; 35211ab7f2deSmaybee 35221ab7f2deSmaybee if (zfs_write_limit_max == 0) 352305715f94SMark Maybee zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift; 35241ab7f2deSmaybee else 35251ab7f2deSmaybee zfs_write_limit_shift = 0; 352605715f94SMark Maybee mutex_init(&zfs_write_limit_lock, NULL, MUTEX_DEFAULT, NULL); 3527fa9e4066Sahrens } 3528fa9e4066Sahrens 3529fa9e4066Sahrens void 3530fa9e4066Sahrens arc_fini(void) 3531fa9e4066Sahrens { 3532fa9e4066Sahrens mutex_enter(&arc_reclaim_thr_lock); 3533fa9e4066Sahrens arc_thread_exit = 1; 3534fa9e4066Sahrens while (arc_thread_exit != 0) 3535fa9e4066Sahrens cv_wait(&arc_reclaim_thr_cv, &arc_reclaim_thr_lock); 3536fa9e4066Sahrens mutex_exit(&arc_reclaim_thr_lock); 3537fa9e4066Sahrens 3538874395d5Smaybee arc_flush(NULL); 3539fa9e4066Sahrens 3540fa9e4066Sahrens arc_dead = TRUE; 3541fa9e4066Sahrens 354244cb6abcSbmc if (arc_ksp != NULL) { 354344cb6abcSbmc kstat_delete(arc_ksp); 354444cb6abcSbmc arc_ksp = NULL; 354544cb6abcSbmc } 354644cb6abcSbmc 3547ea8dc4b6Seschrock mutex_destroy(&arc_eviction_mtx); 3548fa9e4066Sahrens mutex_destroy(&arc_reclaim_thr_lock); 3549fa9e4066Sahrens cv_destroy(&arc_reclaim_thr_cv); 3550fa9e4066Sahrens 35510e8c6158Smaybee list_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]); 35520e8c6158Smaybee list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); 35530e8c6158Smaybee list_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]); 35540e8c6158Smaybee list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); 35550e8c6158Smaybee list_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]); 35560e8c6158Smaybee list_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); 35570e8c6158Smaybee list_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]); 35580e8c6158Smaybee list_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); 3559fa9e4066Sahrens 356044cb6abcSbmc mutex_destroy(&arc_anon->arcs_mtx); 356144cb6abcSbmc mutex_destroy(&arc_mru->arcs_mtx); 356244cb6abcSbmc mutex_destroy(&arc_mru_ghost->arcs_mtx); 356344cb6abcSbmc mutex_destroy(&arc_mfu->arcs_mtx); 356444cb6abcSbmc mutex_destroy(&arc_mfu_ghost->arcs_mtx); 3565b5e70f97SRicardo M. Correia mutex_destroy(&arc_l2c_only->arcs_mtx); 35665ad82045Snd 356705715f94SMark Maybee mutex_destroy(&zfs_write_limit_lock); 356805715f94SMark Maybee 3569fa9e4066Sahrens buf_fini(); 35702fdbea25SAleksandr Guzovskiy 35712fdbea25SAleksandr Guzovskiy ASSERT(arc_loaned_bytes == 0); 3572fa9e4066Sahrens } 3573fa94a07fSbrendan 3574fa94a07fSbrendan /* 3575fa94a07fSbrendan * Level 2 ARC 3576fa94a07fSbrendan * 3577fa94a07fSbrendan * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. 3578fa94a07fSbrendan * It uses dedicated storage devices to hold cached data, which are populated 3579fa94a07fSbrendan * using large infrequent writes. The main role of this cache is to boost 3580fa94a07fSbrendan * the performance of random read workloads. The intended L2ARC devices 3581fa94a07fSbrendan * include short-stroked disks, solid state disks, and other media with 3582fa94a07fSbrendan * substantially faster read latency than disk. 3583fa94a07fSbrendan * 3584fa94a07fSbrendan * +-----------------------+ 3585fa94a07fSbrendan * | ARC | 3586fa94a07fSbrendan * +-----------------------+ 3587fa94a07fSbrendan * | ^ ^ 3588fa94a07fSbrendan * | | | 3589fa94a07fSbrendan * l2arc_feed_thread() arc_read() 3590fa94a07fSbrendan * | | | 3591fa94a07fSbrendan * | l2arc read | 3592fa94a07fSbrendan * V | | 3593fa94a07fSbrendan * +---------------+ | 3594fa94a07fSbrendan * | L2ARC | | 3595fa94a07fSbrendan * +---------------+ | 3596fa94a07fSbrendan * | ^ | 3597fa94a07fSbrendan * l2arc_write() | | 3598fa94a07fSbrendan * | | | 3599fa94a07fSbrendan * V | | 3600fa94a07fSbrendan * +-------+ +-------+ 3601fa94a07fSbrendan * | vdev | | vdev | 3602fa94a07fSbrendan * | cache | | cache | 3603fa94a07fSbrendan * +-------+ +-------+ 3604fa94a07fSbrendan * +=========+ .-----. 3605fa94a07fSbrendan * : L2ARC : |-_____-| 3606fa94a07fSbrendan * : devices : | Disks | 3607fa94a07fSbrendan * +=========+ `-_____-' 3608fa94a07fSbrendan * 3609fa94a07fSbrendan * Read requests are satisfied from the following sources, in order: 3610fa94a07fSbrendan * 3611fa94a07fSbrendan * 1) ARC 3612fa94a07fSbrendan * 2) vdev cache of L2ARC devices 3613fa94a07fSbrendan * 3) L2ARC devices 3614fa94a07fSbrendan * 4) vdev cache of disks 3615fa94a07fSbrendan * 5) disks 3616fa94a07fSbrendan * 3617fa94a07fSbrendan * Some L2ARC device types exhibit extremely slow write performance. 3618fa94a07fSbrendan * To accommodate for this there are some significant differences between 3619fa94a07fSbrendan * the L2ARC and traditional cache design: 3620fa94a07fSbrendan * 3621fa94a07fSbrendan * 1. There is no eviction path from the ARC to the L2ARC. Evictions from 3622fa94a07fSbrendan * the ARC behave as usual, freeing buffers and placing headers on ghost 3623fa94a07fSbrendan * lists. The ARC does not send buffers to the L2ARC during eviction as 3624fa94a07fSbrendan * this would add inflated write latencies for all ARC memory pressure. 3625fa94a07fSbrendan * 3626fa94a07fSbrendan * 2. The L2ARC attempts to cache data from the ARC before it is evicted. 3627fa94a07fSbrendan * It does this by periodically scanning buffers from the eviction-end of 3628fa94a07fSbrendan * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are 3629fa94a07fSbrendan * not already there. It scans until a headroom of buffers is satisfied, 3630fa94a07fSbrendan * which itself is a buffer for ARC eviction. The thread that does this is 3631fa94a07fSbrendan * l2arc_feed_thread(), illustrated below; example sizes are included to 3632fa94a07fSbrendan * provide a better sense of ratio than this diagram: 3633fa94a07fSbrendan * 3634fa94a07fSbrendan * head --> tail 3635fa94a07fSbrendan * +---------------------+----------+ 3636fa94a07fSbrendan * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC 3637fa94a07fSbrendan * +---------------------+----------+ | o L2ARC eligible 3638fa94a07fSbrendan * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer 3639fa94a07fSbrendan * +---------------------+----------+ | 3640fa94a07fSbrendan * 15.9 Gbytes ^ 32 Mbytes | 3641fa94a07fSbrendan * headroom | 3642fa94a07fSbrendan * l2arc_feed_thread() 3643fa94a07fSbrendan * | 3644fa94a07fSbrendan * l2arc write hand <--[oooo]--' 3645fa94a07fSbrendan * | 8 Mbyte 3646fa94a07fSbrendan * | write max 3647fa94a07fSbrendan * V 3648fa94a07fSbrendan * +==============================+ 3649fa94a07fSbrendan * L2ARC dev |####|#|###|###| |####| ... | 3650fa94a07fSbrendan * +==============================+ 3651fa94a07fSbrendan * 32 Gbytes 3652fa94a07fSbrendan * 3653fa94a07fSbrendan * 3. If an ARC buffer is copied to the L2ARC but then hit instead of 3654fa94a07fSbrendan * evicted, then the L2ARC has cached a buffer much sooner than it probably 3655fa94a07fSbrendan * needed to, potentially wasting L2ARC device bandwidth and storage. It is 3656fa94a07fSbrendan * safe to say that this is an uncommon case, since buffers at the end of 3657fa94a07fSbrendan * the ARC lists have moved there due to inactivity. 3658fa94a07fSbrendan * 3659fa94a07fSbrendan * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, 3660fa94a07fSbrendan * then the L2ARC simply misses copying some buffers. This serves as a 3661fa94a07fSbrendan * pressure valve to prevent heavy read workloads from both stalling the ARC 3662fa94a07fSbrendan * with waits and clogging the L2ARC with writes. This also helps prevent 3663fa94a07fSbrendan * the potential for the L2ARC to churn if it attempts to cache content too 3664fa94a07fSbrendan * quickly, such as during backups of the entire pool. 3665fa94a07fSbrendan * 36663a737e0dSbrendan * 5. After system boot and before the ARC has filled main memory, there are 36673a737e0dSbrendan * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru 36683a737e0dSbrendan * lists can remain mostly static. Instead of searching from tail of these 36693a737e0dSbrendan * lists as pictured, the l2arc_feed_thread() will search from the list heads 36703a737e0dSbrendan * for eligible buffers, greatly increasing its chance of finding them. 36713a737e0dSbrendan * 36723a737e0dSbrendan * The L2ARC device write speed is also boosted during this time so that 36733a737e0dSbrendan * the L2ARC warms up faster. Since there have been no ARC evictions yet, 36743a737e0dSbrendan * there are no L2ARC reads, and no fear of degrading read performance 36753a737e0dSbrendan * through increased writes. 36763a737e0dSbrendan * 36773a737e0dSbrendan * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that 3678fa94a07fSbrendan * the vdev queue can aggregate them into larger and fewer writes. Each 3679fa94a07fSbrendan * device is written to in a rotor fashion, sweeping writes through 3680fa94a07fSbrendan * available space then repeating. 3681fa94a07fSbrendan * 36823a737e0dSbrendan * 7. The L2ARC does not store dirty content. It never needs to flush 3683fa94a07fSbrendan * write buffers back to disk based storage. 3684fa94a07fSbrendan * 36853a737e0dSbrendan * 8. If an ARC buffer is written (and dirtied) which also exists in the 3686fa94a07fSbrendan * L2ARC, the now stale L2ARC buffer is immediately dropped. 3687fa94a07fSbrendan * 3688fa94a07fSbrendan * The performance of the L2ARC can be tweaked by a number of tunables, which 3689fa94a07fSbrendan * may be necessary for different workloads: 3690fa94a07fSbrendan * 3691fa94a07fSbrendan * l2arc_write_max max write bytes per interval 36923a737e0dSbrendan * l2arc_write_boost extra write bytes during device warmup 3693fa94a07fSbrendan * l2arc_noprefetch skip caching prefetched buffers 3694fa94a07fSbrendan * l2arc_headroom number of max device writes to precache 3695fa94a07fSbrendan * l2arc_feed_secs seconds between L2ARC writing 3696fa94a07fSbrendan * 3697fa94a07fSbrendan * Tunables may be removed or added as future performance improvements are 3698fa94a07fSbrendan * integrated, and also may become zpool properties. 36995a98e54bSBrendan Gregg - Sun Microsystems * 37005a98e54bSBrendan Gregg - Sun Microsystems * There are three key functions that control how the L2ARC warms up: 37015a98e54bSBrendan Gregg - Sun Microsystems * 37025a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_eligible() check if a buffer is eligible to cache 37035a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_size() calculate how much to write 37045a98e54bSBrendan Gregg - Sun Microsystems * l2arc_write_interval() calculate sleep delay between writes 37055a98e54bSBrendan Gregg - Sun Microsystems * 37065a98e54bSBrendan Gregg - Sun Microsystems * These three functions determine what to write, how much, and how quickly 37075a98e54bSBrendan Gregg - Sun Microsystems * to send writes. 3708fa94a07fSbrendan */ 3709fa94a07fSbrendan 37105a98e54bSBrendan Gregg - Sun Microsystems static boolean_t 3711ac05c741SMark Maybee l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *ab) 37125a98e54bSBrendan Gregg - Sun Microsystems { 37135a98e54bSBrendan Gregg - Sun Microsystems /* 37145a98e54bSBrendan Gregg - Sun Microsystems * A buffer is *not* eligible for the L2ARC if it: 37155a98e54bSBrendan Gregg - Sun Microsystems * 1. belongs to a different spa. 37165ea40c06SBrendan Gregg - Sun Microsystems * 2. is already cached on the L2ARC. 37175ea40c06SBrendan Gregg - Sun Microsystems * 3. has an I/O in progress (it may be an incomplete read). 37185ea40c06SBrendan Gregg - Sun Microsystems * 4. is flagged not eligible (zfs property). 37195a98e54bSBrendan Gregg - Sun Microsystems */ 37205ea40c06SBrendan Gregg - Sun Microsystems if (ab->b_spa != spa_guid || ab->b_l2hdr != NULL || 37215a98e54bSBrendan Gregg - Sun Microsystems HDR_IO_IN_PROGRESS(ab) || !HDR_L2CACHE(ab)) 37225a98e54bSBrendan Gregg - Sun Microsystems return (B_FALSE); 37235a98e54bSBrendan Gregg - Sun Microsystems 37245a98e54bSBrendan Gregg - Sun Microsystems return (B_TRUE); 37255a98e54bSBrendan Gregg - Sun Microsystems } 37265a98e54bSBrendan Gregg - Sun Microsystems 37275a98e54bSBrendan Gregg - Sun Microsystems static uint64_t 37285a98e54bSBrendan Gregg - Sun Microsystems l2arc_write_size(l2arc_dev_t *dev) 37295a98e54bSBrendan Gregg - Sun Microsystems { 37305a98e54bSBrendan Gregg - Sun Microsystems uint64_t size; 37315a98e54bSBrendan Gregg - Sun Microsystems 37325a98e54bSBrendan Gregg - Sun Microsystems size = dev->l2ad_write; 37335a98e54bSBrendan Gregg - Sun Microsystems 37345a98e54bSBrendan Gregg - Sun Microsystems if (arc_warm == B_FALSE) 37355a98e54bSBrendan Gregg - Sun Microsystems size += dev->l2ad_boost; 37365a98e54bSBrendan Gregg - Sun Microsystems 37375a98e54bSBrendan Gregg - Sun Microsystems return (size); 37385a98e54bSBrendan Gregg - Sun Microsystems 37395a98e54bSBrendan Gregg - Sun Microsystems } 37405a98e54bSBrendan Gregg - Sun Microsystems 37415a98e54bSBrendan Gregg - Sun Microsystems static clock_t 37425a98e54bSBrendan Gregg - Sun Microsystems l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) 37435a98e54bSBrendan Gregg - Sun Microsystems { 37445a98e54bSBrendan Gregg - Sun Microsystems clock_t interval, next; 37455a98e54bSBrendan Gregg - Sun Microsystems 37465a98e54bSBrendan Gregg - Sun Microsystems /* 37475a98e54bSBrendan Gregg - Sun Microsystems * If the ARC lists are busy, increase our write rate; if the 37485a98e54bSBrendan Gregg - Sun Microsystems * lists are stale, idle back. This is achieved by checking 37495a98e54bSBrendan Gregg - Sun Microsystems * how much we previously wrote - if it was more than half of 37505a98e54bSBrendan Gregg - Sun Microsystems * what we wanted, schedule the next write much sooner. 37515a98e54bSBrendan Gregg - Sun Microsystems */ 37525a98e54bSBrendan Gregg - Sun Microsystems if (l2arc_feed_again && wrote > (wanted / 2)) 37535a98e54bSBrendan Gregg - Sun Microsystems interval = (hz * l2arc_feed_min_ms) / 1000; 37545a98e54bSBrendan Gregg - Sun Microsystems else 37555a98e54bSBrendan Gregg - Sun Microsystems interval = hz * l2arc_feed_secs; 37565a98e54bSBrendan Gregg - Sun Microsystems 37575a98e54bSBrendan Gregg - Sun Microsystems next = MAX(lbolt, MIN(lbolt + interval, began + interval)); 37585a98e54bSBrendan Gregg - Sun Microsystems 37595a98e54bSBrendan Gregg - Sun Microsystems return (next); 37605a98e54bSBrendan Gregg - Sun Microsystems } 37615a98e54bSBrendan Gregg - Sun Microsystems 3762fa94a07fSbrendan static void 3763fa94a07fSbrendan l2arc_hdr_stat_add(void) 3764fa94a07fSbrendan { 3765e6c728e1Sbrendan ARCSTAT_INCR(arcstat_l2_hdr_size, HDR_SIZE + L2HDR_SIZE); 3766e6c728e1Sbrendan ARCSTAT_INCR(arcstat_hdr_size, -HDR_SIZE); 3767fa94a07fSbrendan } 3768fa94a07fSbrendan 3769fa94a07fSbrendan static void 3770fa94a07fSbrendan l2arc_hdr_stat_remove(void) 3771fa94a07fSbrendan { 3772e6c728e1Sbrendan ARCSTAT_INCR(arcstat_l2_hdr_size, -(HDR_SIZE + L2HDR_SIZE)); 3773e6c728e1Sbrendan ARCSTAT_INCR(arcstat_hdr_size, HDR_SIZE); 3774fa94a07fSbrendan } 3775fa94a07fSbrendan 3776fa94a07fSbrendan /* 3777fa94a07fSbrendan * Cycle through L2ARC devices. This is how L2ARC load balances. 37783a737e0dSbrendan * If a device is returned, this also returns holding the spa config lock. 3779fa94a07fSbrendan */ 3780fa94a07fSbrendan static l2arc_dev_t * 3781fa94a07fSbrendan l2arc_dev_get_next(void) 3782fa94a07fSbrendan { 37833a737e0dSbrendan l2arc_dev_t *first, *next = NULL; 37843a737e0dSbrendan 37853a737e0dSbrendan /* 37863a737e0dSbrendan * Lock out the removal of spas (spa_namespace_lock), then removal 37873a737e0dSbrendan * of cache devices (l2arc_dev_mtx). Once a device has been selected, 37883a737e0dSbrendan * both locks will be dropped and a spa config lock held instead. 37893a737e0dSbrendan */ 37903a737e0dSbrendan mutex_enter(&spa_namespace_lock); 37913a737e0dSbrendan mutex_enter(&l2arc_dev_mtx); 3792fa94a07fSbrendan 3793c5904d13Seschrock /* if there are no vdevs, there is nothing to do */ 3794c5904d13Seschrock if (l2arc_ndev == 0) 37953a737e0dSbrendan goto out; 3796c5904d13Seschrock 3797c5904d13Seschrock first = NULL; 3798c5904d13Seschrock next = l2arc_dev_last; 3799c5904d13Seschrock do { 3800c5904d13Seschrock /* loop around the list looking for a non-faulted vdev */ 3801c5904d13Seschrock if (next == NULL) { 3802fa94a07fSbrendan next = list_head(l2arc_dev_list); 3803c5904d13Seschrock } else { 3804c5904d13Seschrock next = list_next(l2arc_dev_list, next); 3805c5904d13Seschrock if (next == NULL) 3806c5904d13Seschrock next = list_head(l2arc_dev_list); 3807c5904d13Seschrock } 3808c5904d13Seschrock 3809c5904d13Seschrock /* if we have come back to the start, bail out */ 3810c5904d13Seschrock if (first == NULL) 3811c5904d13Seschrock first = next; 3812c5904d13Seschrock else if (next == first) 3813c5904d13Seschrock break; 3814c5904d13Seschrock 3815c5904d13Seschrock } while (vdev_is_dead(next->l2ad_vdev)); 3816c5904d13Seschrock 3817c5904d13Seschrock /* if we were unable to find any usable vdevs, return NULL */ 3818c5904d13Seschrock if (vdev_is_dead(next->l2ad_vdev)) 38193a737e0dSbrendan next = NULL; 3820fa94a07fSbrendan 3821fa94a07fSbrendan l2arc_dev_last = next; 3822fa94a07fSbrendan 38233a737e0dSbrendan out: 38243a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 38253a737e0dSbrendan 38263a737e0dSbrendan /* 38273a737e0dSbrendan * Grab the config lock to prevent the 'next' device from being 38283a737e0dSbrendan * removed while we are writing to it. 38293a737e0dSbrendan */ 38303a737e0dSbrendan if (next != NULL) 3831e14bb325SJeff Bonwick spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); 38323a737e0dSbrendan mutex_exit(&spa_namespace_lock); 38333a737e0dSbrendan 3834fa94a07fSbrendan return (next); 3835fa94a07fSbrendan } 3836fa94a07fSbrendan 38373a737e0dSbrendan /* 38383a737e0dSbrendan * Free buffers that were tagged for destruction. 38393a737e0dSbrendan */ 38403a737e0dSbrendan static void 38413a737e0dSbrendan l2arc_do_free_on_write() 38423a737e0dSbrendan { 38433a737e0dSbrendan list_t *buflist; 38443a737e0dSbrendan l2arc_data_free_t *df, *df_prev; 38453a737e0dSbrendan 38463a737e0dSbrendan mutex_enter(&l2arc_free_on_write_mtx); 38473a737e0dSbrendan buflist = l2arc_free_on_write; 38483a737e0dSbrendan 38493a737e0dSbrendan for (df = list_tail(buflist); df; df = df_prev) { 38503a737e0dSbrendan df_prev = list_prev(buflist, df); 38513a737e0dSbrendan ASSERT(df->l2df_data != NULL); 38523a737e0dSbrendan ASSERT(df->l2df_func != NULL); 38533a737e0dSbrendan df->l2df_func(df->l2df_data, df->l2df_size); 38543a737e0dSbrendan list_remove(buflist, df); 38553a737e0dSbrendan kmem_free(df, sizeof (l2arc_data_free_t)); 38563a737e0dSbrendan } 38573a737e0dSbrendan 38583a737e0dSbrendan mutex_exit(&l2arc_free_on_write_mtx); 38593a737e0dSbrendan } 38603a737e0dSbrendan 3861fa94a07fSbrendan /* 3862fa94a07fSbrendan * A write to a cache device has completed. Update all headers to allow 3863fa94a07fSbrendan * reads from these buffers to begin. 3864fa94a07fSbrendan */ 3865fa94a07fSbrendan static void 3866fa94a07fSbrendan l2arc_write_done(zio_t *zio) 3867fa94a07fSbrendan { 3868fa94a07fSbrendan l2arc_write_callback_t *cb; 3869fa94a07fSbrendan l2arc_dev_t *dev; 3870fa94a07fSbrendan list_t *buflist; 3871fa94a07fSbrendan arc_buf_hdr_t *head, *ab, *ab_prev; 38723a737e0dSbrendan l2arc_buf_hdr_t *abl2; 3873fa94a07fSbrendan kmutex_t *hash_lock; 3874fa94a07fSbrendan 3875fa94a07fSbrendan cb = zio->io_private; 3876fa94a07fSbrendan ASSERT(cb != NULL); 3877fa94a07fSbrendan dev = cb->l2wcb_dev; 3878fa94a07fSbrendan ASSERT(dev != NULL); 3879fa94a07fSbrendan head = cb->l2wcb_head; 3880fa94a07fSbrendan ASSERT(head != NULL); 3881fa94a07fSbrendan buflist = dev->l2ad_buflist; 3882fa94a07fSbrendan ASSERT(buflist != NULL); 3883fa94a07fSbrendan DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, 3884fa94a07fSbrendan l2arc_write_callback_t *, cb); 3885fa94a07fSbrendan 3886fa94a07fSbrendan if (zio->io_error != 0) 3887fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_error); 3888fa94a07fSbrendan 3889fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 3890fa94a07fSbrendan 3891fa94a07fSbrendan /* 3892fa94a07fSbrendan * All writes completed, or an error was hit. 3893fa94a07fSbrendan */ 3894fa94a07fSbrendan for (ab = list_prev(buflist, head); ab; ab = ab_prev) { 3895fa94a07fSbrendan ab_prev = list_prev(buflist, ab); 3896fa94a07fSbrendan 3897fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 3898fa94a07fSbrendan if (!mutex_tryenter(hash_lock)) { 3899fa94a07fSbrendan /* 3900fa94a07fSbrendan * This buffer misses out. It may be in a stage 3901fa94a07fSbrendan * of eviction. Its ARC_L2_WRITING flag will be 3902fa94a07fSbrendan * left set, denying reads to this buffer. 3903fa94a07fSbrendan */ 3904fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_hdr_miss); 3905fa94a07fSbrendan continue; 3906fa94a07fSbrendan } 3907fa94a07fSbrendan 3908fa94a07fSbrendan if (zio->io_error != 0) { 3909fa94a07fSbrendan /* 39103a737e0dSbrendan * Error - drop L2ARC entry. 3911fa94a07fSbrendan */ 39123a737e0dSbrendan list_remove(buflist, ab); 39133a737e0dSbrendan abl2 = ab->b_l2hdr; 3914fa94a07fSbrendan ab->b_l2hdr = NULL; 39153a737e0dSbrendan kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); 39163a737e0dSbrendan ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); 3917fa94a07fSbrendan } 3918fa94a07fSbrendan 3919fa94a07fSbrendan /* 3920fa94a07fSbrendan * Allow ARC to begin reads to this L2ARC entry. 3921fa94a07fSbrendan */ 3922fa94a07fSbrendan ab->b_flags &= ~ARC_L2_WRITING; 3923fa94a07fSbrendan 3924fa94a07fSbrendan mutex_exit(hash_lock); 3925fa94a07fSbrendan } 3926fa94a07fSbrendan 3927fa94a07fSbrendan atomic_inc_64(&l2arc_writes_done); 3928fa94a07fSbrendan list_remove(buflist, head); 3929fa94a07fSbrendan kmem_cache_free(hdr_cache, head); 3930fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 3931fa94a07fSbrendan 39323a737e0dSbrendan l2arc_do_free_on_write(); 3933fa94a07fSbrendan 3934fa94a07fSbrendan kmem_free(cb, sizeof (l2arc_write_callback_t)); 3935fa94a07fSbrendan } 3936fa94a07fSbrendan 3937fa94a07fSbrendan /* 3938fa94a07fSbrendan * A read to a cache device completed. Validate buffer contents before 3939fa94a07fSbrendan * handing over to the regular ARC routines. 3940fa94a07fSbrendan */ 3941fa94a07fSbrendan static void 3942fa94a07fSbrendan l2arc_read_done(zio_t *zio) 3943fa94a07fSbrendan { 3944fa94a07fSbrendan l2arc_read_callback_t *cb; 3945fa94a07fSbrendan arc_buf_hdr_t *hdr; 3946fa94a07fSbrendan arc_buf_t *buf; 3947fa94a07fSbrendan kmutex_t *hash_lock; 39483a737e0dSbrendan int equal; 3949fa94a07fSbrendan 3950e14bb325SJeff Bonwick ASSERT(zio->io_vd != NULL); 3951e14bb325SJeff Bonwick ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); 3952e14bb325SJeff Bonwick 3953e14bb325SJeff Bonwick spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); 3954e14bb325SJeff Bonwick 3955fa94a07fSbrendan cb = zio->io_private; 3956fa94a07fSbrendan ASSERT(cb != NULL); 3957fa94a07fSbrendan buf = cb->l2rcb_buf; 3958fa94a07fSbrendan ASSERT(buf != NULL); 3959fa94a07fSbrendan hdr = buf->b_hdr; 3960fa94a07fSbrendan ASSERT(hdr != NULL); 3961fa94a07fSbrendan 3962fa94a07fSbrendan hash_lock = HDR_LOCK(hdr); 3963fa94a07fSbrendan mutex_enter(hash_lock); 3964fa94a07fSbrendan 3965fa94a07fSbrendan /* 3966fa94a07fSbrendan * Check this survived the L2ARC journey. 3967fa94a07fSbrendan */ 3968fa94a07fSbrendan equal = arc_cksum_equal(buf); 3969fa94a07fSbrendan if (equal && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) { 3970fa94a07fSbrendan mutex_exit(hash_lock); 3971fa94a07fSbrendan zio->io_private = buf; 3972e14bb325SJeff Bonwick zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ 3973e14bb325SJeff Bonwick zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ 3974fa94a07fSbrendan arc_read_done(zio); 3975fa94a07fSbrendan } else { 3976fa94a07fSbrendan mutex_exit(hash_lock); 3977fa94a07fSbrendan /* 3978fa94a07fSbrendan * Buffer didn't survive caching. Increment stats and 3979fa94a07fSbrendan * reissue to the original storage device. 3980fa94a07fSbrendan */ 39813a737e0dSbrendan if (zio->io_error != 0) { 3982fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_io_error); 39833a737e0dSbrendan } else { 39843a737e0dSbrendan zio->io_error = EIO; 39853a737e0dSbrendan } 3986fa94a07fSbrendan if (!equal) 3987fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_cksum_bad); 3988fa94a07fSbrendan 3989e14bb325SJeff Bonwick /* 3990e14bb325SJeff Bonwick * If there's no waiter, issue an async i/o to the primary 3991e14bb325SJeff Bonwick * storage now. If there *is* a waiter, the caller must 3992e14bb325SJeff Bonwick * issue the i/o in a context where it's OK to block. 3993e14bb325SJeff Bonwick */ 3994a3f829aeSBill Moore if (zio->io_waiter == NULL) { 3995a3f829aeSBill Moore zio_t *pio = zio_unique_parent(zio); 3996a3f829aeSBill Moore 3997a3f829aeSBill Moore ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); 3998a3f829aeSBill Moore 3999a3f829aeSBill Moore zio_nowait(zio_read(pio, cb->l2rcb_spa, &cb->l2rcb_bp, 4000e14bb325SJeff Bonwick buf->b_data, zio->io_size, arc_read_done, buf, 4001e14bb325SJeff Bonwick zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb)); 4002a3f829aeSBill Moore } 4003fa94a07fSbrendan } 4004fa94a07fSbrendan 4005fa94a07fSbrendan kmem_free(cb, sizeof (l2arc_read_callback_t)); 4006fa94a07fSbrendan } 4007fa94a07fSbrendan 4008fa94a07fSbrendan /* 4009fa94a07fSbrendan * This is the list priority from which the L2ARC will search for pages to 4010fa94a07fSbrendan * cache. This is used within loops (0..3) to cycle through lists in the 4011fa94a07fSbrendan * desired order. This order can have a significant effect on cache 4012fa94a07fSbrendan * performance. 4013fa94a07fSbrendan * 4014fa94a07fSbrendan * Currently the metadata lists are hit first, MFU then MRU, followed by 4015fa94a07fSbrendan * the data lists. This function returns a locked list, and also returns 4016fa94a07fSbrendan * the lock pointer. 4017fa94a07fSbrendan */ 4018fa94a07fSbrendan static list_t * 4019fa94a07fSbrendan l2arc_list_locked(int list_num, kmutex_t **lock) 4020fa94a07fSbrendan { 4021fa94a07fSbrendan list_t *list; 4022fa94a07fSbrendan 4023fa94a07fSbrendan ASSERT(list_num >= 0 && list_num <= 3); 4024fa94a07fSbrendan 4025fa94a07fSbrendan switch (list_num) { 4026fa94a07fSbrendan case 0: 4027fa94a07fSbrendan list = &arc_mfu->arcs_list[ARC_BUFC_METADATA]; 4028fa94a07fSbrendan *lock = &arc_mfu->arcs_mtx; 4029fa94a07fSbrendan break; 4030fa94a07fSbrendan case 1: 4031fa94a07fSbrendan list = &arc_mru->arcs_list[ARC_BUFC_METADATA]; 4032fa94a07fSbrendan *lock = &arc_mru->arcs_mtx; 4033fa94a07fSbrendan break; 4034fa94a07fSbrendan case 2: 4035fa94a07fSbrendan list = &arc_mfu->arcs_list[ARC_BUFC_DATA]; 4036fa94a07fSbrendan *lock = &arc_mfu->arcs_mtx; 4037fa94a07fSbrendan break; 4038fa94a07fSbrendan case 3: 4039fa94a07fSbrendan list = &arc_mru->arcs_list[ARC_BUFC_DATA]; 4040fa94a07fSbrendan *lock = &arc_mru->arcs_mtx; 4041fa94a07fSbrendan break; 4042fa94a07fSbrendan } 4043fa94a07fSbrendan 4044fa94a07fSbrendan ASSERT(!(MUTEX_HELD(*lock))); 4045fa94a07fSbrendan mutex_enter(*lock); 4046fa94a07fSbrendan return (list); 4047fa94a07fSbrendan } 4048fa94a07fSbrendan 4049fa94a07fSbrendan /* 4050fa94a07fSbrendan * Evict buffers from the device write hand to the distance specified in 4051fa94a07fSbrendan * bytes. This distance may span populated buffers, it may span nothing. 4052fa94a07fSbrendan * This is clearing a region on the L2ARC device ready for writing. 4053fa94a07fSbrendan * If the 'all' boolean is set, every buffer is evicted. 4054fa94a07fSbrendan */ 4055fa94a07fSbrendan static void 4056fa94a07fSbrendan l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) 4057fa94a07fSbrendan { 4058fa94a07fSbrendan list_t *buflist; 4059fa94a07fSbrendan l2arc_buf_hdr_t *abl2; 4060fa94a07fSbrendan arc_buf_hdr_t *ab, *ab_prev; 4061fa94a07fSbrendan kmutex_t *hash_lock; 4062fa94a07fSbrendan uint64_t taddr; 4063fa94a07fSbrendan 4064fa94a07fSbrendan buflist = dev->l2ad_buflist; 4065fa94a07fSbrendan 4066fa94a07fSbrendan if (buflist == NULL) 4067fa94a07fSbrendan return; 4068fa94a07fSbrendan 4069fa94a07fSbrendan if (!all && dev->l2ad_first) { 4070fa94a07fSbrendan /* 4071fa94a07fSbrendan * This is the first sweep through the device. There is 4072fa94a07fSbrendan * nothing to evict. 4073fa94a07fSbrendan */ 4074fa94a07fSbrendan return; 4075fa94a07fSbrendan } 4076fa94a07fSbrendan 40773a737e0dSbrendan if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) { 4078fa94a07fSbrendan /* 4079fa94a07fSbrendan * When nearing the end of the device, evict to the end 4080fa94a07fSbrendan * before the device write hand jumps to the start. 4081fa94a07fSbrendan */ 4082fa94a07fSbrendan taddr = dev->l2ad_end; 4083fa94a07fSbrendan } else { 4084fa94a07fSbrendan taddr = dev->l2ad_hand + distance; 4085fa94a07fSbrendan } 4086fa94a07fSbrendan DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, 4087fa94a07fSbrendan uint64_t, taddr, boolean_t, all); 4088fa94a07fSbrendan 4089fa94a07fSbrendan top: 4090fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 4091fa94a07fSbrendan for (ab = list_tail(buflist); ab; ab = ab_prev) { 4092fa94a07fSbrendan ab_prev = list_prev(buflist, ab); 4093fa94a07fSbrendan 4094fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 4095fa94a07fSbrendan if (!mutex_tryenter(hash_lock)) { 4096fa94a07fSbrendan /* 4097fa94a07fSbrendan * Missed the hash lock. Retry. 4098fa94a07fSbrendan */ 4099fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); 4100fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4101fa94a07fSbrendan mutex_enter(hash_lock); 4102fa94a07fSbrendan mutex_exit(hash_lock); 4103fa94a07fSbrendan goto top; 4104fa94a07fSbrendan } 4105fa94a07fSbrendan 4106fa94a07fSbrendan if (HDR_L2_WRITE_HEAD(ab)) { 4107fa94a07fSbrendan /* 4108fa94a07fSbrendan * We hit a write head node. Leave it for 4109fa94a07fSbrendan * l2arc_write_done(). 4110fa94a07fSbrendan */ 4111fa94a07fSbrendan list_remove(buflist, ab); 4112fa94a07fSbrendan mutex_exit(hash_lock); 4113fa94a07fSbrendan continue; 4114fa94a07fSbrendan } 4115fa94a07fSbrendan 4116fa94a07fSbrendan if (!all && ab->b_l2hdr != NULL && 4117fa94a07fSbrendan (ab->b_l2hdr->b_daddr > taddr || 4118fa94a07fSbrendan ab->b_l2hdr->b_daddr < dev->l2ad_hand)) { 4119fa94a07fSbrendan /* 4120fa94a07fSbrendan * We've evicted to the target address, 4121fa94a07fSbrendan * or the end of the device. 4122fa94a07fSbrendan */ 4123fa94a07fSbrendan mutex_exit(hash_lock); 4124fa94a07fSbrendan break; 4125fa94a07fSbrendan } 4126fa94a07fSbrendan 4127fa94a07fSbrendan if (HDR_FREE_IN_PROGRESS(ab)) { 4128fa94a07fSbrendan /* 4129fa94a07fSbrendan * Already on the path to destruction. 4130fa94a07fSbrendan */ 4131fa94a07fSbrendan mutex_exit(hash_lock); 4132fa94a07fSbrendan continue; 4133fa94a07fSbrendan } 4134fa94a07fSbrendan 4135fa94a07fSbrendan if (ab->b_state == arc_l2c_only) { 4136fa94a07fSbrendan ASSERT(!HDR_L2_READING(ab)); 4137fa94a07fSbrendan /* 4138fa94a07fSbrendan * This doesn't exist in the ARC. Destroy. 4139fa94a07fSbrendan * arc_hdr_destroy() will call list_remove() 4140fa94a07fSbrendan * and decrement arcstat_l2_size. 4141fa94a07fSbrendan */ 4142fa94a07fSbrendan arc_change_state(arc_anon, ab, hash_lock); 4143fa94a07fSbrendan arc_hdr_destroy(ab); 4144fa94a07fSbrendan } else { 41453a737e0dSbrendan /* 41463a737e0dSbrendan * Invalidate issued or about to be issued 41473a737e0dSbrendan * reads, since we may be about to write 41483a737e0dSbrendan * over this location. 41493a737e0dSbrendan */ 41503a737e0dSbrendan if (HDR_L2_READING(ab)) { 41513a737e0dSbrendan ARCSTAT_BUMP(arcstat_l2_evict_reading); 41523a737e0dSbrendan ab->b_flags |= ARC_L2_EVICTED; 41533a737e0dSbrendan } 41543a737e0dSbrendan 4155fa94a07fSbrendan /* 4156fa94a07fSbrendan * Tell ARC this no longer exists in L2ARC. 4157fa94a07fSbrendan */ 4158fa94a07fSbrendan if (ab->b_l2hdr != NULL) { 4159fa94a07fSbrendan abl2 = ab->b_l2hdr; 4160fa94a07fSbrendan ab->b_l2hdr = NULL; 4161fa94a07fSbrendan kmem_free(abl2, sizeof (l2arc_buf_hdr_t)); 4162fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, -ab->b_size); 4163fa94a07fSbrendan } 4164fa94a07fSbrendan list_remove(buflist, ab); 4165fa94a07fSbrendan 4166fa94a07fSbrendan /* 4167fa94a07fSbrendan * This may have been leftover after a 4168fa94a07fSbrendan * failed write. 4169fa94a07fSbrendan */ 4170fa94a07fSbrendan ab->b_flags &= ~ARC_L2_WRITING; 4171fa94a07fSbrendan } 4172fa94a07fSbrendan mutex_exit(hash_lock); 4173fa94a07fSbrendan } 4174fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4175fa94a07fSbrendan 4176*b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, -(taddr - dev->l2ad_evict), 0, 0); 4177fa94a07fSbrendan dev->l2ad_evict = taddr; 4178fa94a07fSbrendan } 4179fa94a07fSbrendan 4180fa94a07fSbrendan /* 4181fa94a07fSbrendan * Find and write ARC buffers to the L2ARC device. 4182fa94a07fSbrendan * 4183fa94a07fSbrendan * An ARC_L2_WRITING flag is set so that the L2ARC buffers are not valid 4184fa94a07fSbrendan * for reading until they have completed writing. 4185fa94a07fSbrendan */ 41865a98e54bSBrendan Gregg - Sun Microsystems static uint64_t 41873a737e0dSbrendan l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) 4188fa94a07fSbrendan { 4189fa94a07fSbrendan arc_buf_hdr_t *ab, *ab_prev, *head; 4190fa94a07fSbrendan l2arc_buf_hdr_t *hdrl2; 4191fa94a07fSbrendan list_t *list; 41923a737e0dSbrendan uint64_t passed_sz, write_sz, buf_sz, headroom; 4193fa94a07fSbrendan void *buf_data; 4194fa94a07fSbrendan kmutex_t *hash_lock, *list_lock; 4195fa94a07fSbrendan boolean_t have_lock, full; 4196fa94a07fSbrendan l2arc_write_callback_t *cb; 4197fa94a07fSbrendan zio_t *pio, *wzio; 4198ac05c741SMark Maybee uint64_t guid = spa_guid(spa); 4199fa94a07fSbrendan 4200fa94a07fSbrendan ASSERT(dev->l2ad_vdev != NULL); 4201fa94a07fSbrendan 4202fa94a07fSbrendan pio = NULL; 4203fa94a07fSbrendan write_sz = 0; 4204fa94a07fSbrendan full = B_FALSE; 42051ab7f2deSmaybee head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); 4206fa94a07fSbrendan head->b_flags |= ARC_L2_WRITE_HEAD; 4207fa94a07fSbrendan 4208fa94a07fSbrendan /* 4209fa94a07fSbrendan * Copy buffers for L2ARC writing. 4210fa94a07fSbrendan */ 4211fa94a07fSbrendan mutex_enter(&l2arc_buflist_mtx); 4212fa94a07fSbrendan for (int try = 0; try <= 3; try++) { 4213fa94a07fSbrendan list = l2arc_list_locked(try, &list_lock); 4214fa94a07fSbrendan passed_sz = 0; 4215fa94a07fSbrendan 42163a737e0dSbrendan /* 42173a737e0dSbrendan * L2ARC fast warmup. 42183a737e0dSbrendan * 42193a737e0dSbrendan * Until the ARC is warm and starts to evict, read from the 42203a737e0dSbrendan * head of the ARC lists rather than the tail. 42213a737e0dSbrendan */ 42223a737e0dSbrendan headroom = target_sz * l2arc_headroom; 42233a737e0dSbrendan if (arc_warm == B_FALSE) 42243a737e0dSbrendan ab = list_head(list); 42253a737e0dSbrendan else 42263a737e0dSbrendan ab = list_tail(list); 42273a737e0dSbrendan 42283a737e0dSbrendan for (; ab; ab = ab_prev) { 42293a737e0dSbrendan if (arc_warm == B_FALSE) 42303a737e0dSbrendan ab_prev = list_next(list, ab); 42313a737e0dSbrendan else 42323a737e0dSbrendan ab_prev = list_prev(list, ab); 4233fa94a07fSbrendan 4234fa94a07fSbrendan hash_lock = HDR_LOCK(ab); 4235fa94a07fSbrendan have_lock = MUTEX_HELD(hash_lock); 4236fa94a07fSbrendan if (!have_lock && !mutex_tryenter(hash_lock)) { 4237fa94a07fSbrendan /* 4238fa94a07fSbrendan * Skip this buffer rather than waiting. 4239fa94a07fSbrendan */ 4240fa94a07fSbrendan continue; 4241fa94a07fSbrendan } 4242fa94a07fSbrendan 4243fa94a07fSbrendan passed_sz += ab->b_size; 4244fa94a07fSbrendan if (passed_sz > headroom) { 4245fa94a07fSbrendan /* 4246fa94a07fSbrendan * Searched too far. 4247fa94a07fSbrendan */ 4248fa94a07fSbrendan mutex_exit(hash_lock); 4249fa94a07fSbrendan break; 4250fa94a07fSbrendan } 4251fa94a07fSbrendan 4252ac05c741SMark Maybee if (!l2arc_write_eligible(guid, ab)) { 4253fa94a07fSbrendan mutex_exit(hash_lock); 4254fa94a07fSbrendan continue; 4255fa94a07fSbrendan } 4256fa94a07fSbrendan 4257fa94a07fSbrendan if ((write_sz + ab->b_size) > target_sz) { 4258fa94a07fSbrendan full = B_TRUE; 4259fa94a07fSbrendan mutex_exit(hash_lock); 4260fa94a07fSbrendan break; 4261fa94a07fSbrendan } 4262fa94a07fSbrendan 4263fa94a07fSbrendan if (pio == NULL) { 4264fa94a07fSbrendan /* 4265fa94a07fSbrendan * Insert a dummy header on the buflist so 4266fa94a07fSbrendan * l2arc_write_done() can find where the 4267fa94a07fSbrendan * write buffers begin without searching. 4268fa94a07fSbrendan */ 4269fa94a07fSbrendan list_insert_head(dev->l2ad_buflist, head); 4270fa94a07fSbrendan 4271fa94a07fSbrendan cb = kmem_alloc( 4272fa94a07fSbrendan sizeof (l2arc_write_callback_t), KM_SLEEP); 4273fa94a07fSbrendan cb->l2wcb_dev = dev; 4274fa94a07fSbrendan cb->l2wcb_head = head; 4275fa94a07fSbrendan pio = zio_root(spa, l2arc_write_done, cb, 4276fa94a07fSbrendan ZIO_FLAG_CANFAIL); 4277fa94a07fSbrendan } 4278fa94a07fSbrendan 4279fa94a07fSbrendan /* 4280fa94a07fSbrendan * Create and add a new L2ARC header. 4281fa94a07fSbrendan */ 4282fa94a07fSbrendan hdrl2 = kmem_zalloc(sizeof (l2arc_buf_hdr_t), KM_SLEEP); 4283fa94a07fSbrendan hdrl2->b_dev = dev; 4284fa94a07fSbrendan hdrl2->b_daddr = dev->l2ad_hand; 4285fa94a07fSbrendan 4286fa94a07fSbrendan ab->b_flags |= ARC_L2_WRITING; 4287fa94a07fSbrendan ab->b_l2hdr = hdrl2; 4288fa94a07fSbrendan list_insert_head(dev->l2ad_buflist, ab); 4289fa94a07fSbrendan buf_data = ab->b_buf->b_data; 4290fa94a07fSbrendan buf_sz = ab->b_size; 4291fa94a07fSbrendan 4292fa94a07fSbrendan /* 4293fa94a07fSbrendan * Compute and store the buffer cksum before 4294fa94a07fSbrendan * writing. On debug the cksum is verified first. 4295fa94a07fSbrendan */ 4296fa94a07fSbrendan arc_cksum_verify(ab->b_buf); 4297fa94a07fSbrendan arc_cksum_compute(ab->b_buf, B_TRUE); 4298fa94a07fSbrendan 4299fa94a07fSbrendan mutex_exit(hash_lock); 4300fa94a07fSbrendan 4301fa94a07fSbrendan wzio = zio_write_phys(pio, dev->l2ad_vdev, 4302fa94a07fSbrendan dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF, 4303fa94a07fSbrendan NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, 4304fa94a07fSbrendan ZIO_FLAG_CANFAIL, B_FALSE); 4305fa94a07fSbrendan 4306fa94a07fSbrendan DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, 4307fa94a07fSbrendan zio_t *, wzio); 4308fa94a07fSbrendan (void) zio_nowait(wzio); 4309fa94a07fSbrendan 4310e14bb325SJeff Bonwick /* 4311e14bb325SJeff Bonwick * Keep the clock hand suitably device-aligned. 4312e14bb325SJeff Bonwick */ 4313e14bb325SJeff Bonwick buf_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); 4314e14bb325SJeff Bonwick 4315fa94a07fSbrendan write_sz += buf_sz; 4316fa94a07fSbrendan dev->l2ad_hand += buf_sz; 4317fa94a07fSbrendan } 4318fa94a07fSbrendan 4319fa94a07fSbrendan mutex_exit(list_lock); 4320fa94a07fSbrendan 4321fa94a07fSbrendan if (full == B_TRUE) 4322fa94a07fSbrendan break; 4323fa94a07fSbrendan } 4324fa94a07fSbrendan mutex_exit(&l2arc_buflist_mtx); 4325fa94a07fSbrendan 4326fa94a07fSbrendan if (pio == NULL) { 4327fa94a07fSbrendan ASSERT3U(write_sz, ==, 0); 4328fa94a07fSbrendan kmem_cache_free(hdr_cache, head); 43295a98e54bSBrendan Gregg - Sun Microsystems return (0); 4330fa94a07fSbrendan } 4331fa94a07fSbrendan 4332fa94a07fSbrendan ASSERT3U(write_sz, <=, target_sz); 4333fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_writes_sent); 43345a98e54bSBrendan Gregg - Sun Microsystems ARCSTAT_INCR(arcstat_l2_write_bytes, write_sz); 4335fa94a07fSbrendan ARCSTAT_INCR(arcstat_l2_size, write_sz); 4336*b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, write_sz, 0, 0); 4337fa94a07fSbrendan 4338fa94a07fSbrendan /* 4339fa94a07fSbrendan * Bump device hand to the device start if it is approaching the end. 4340fa94a07fSbrendan * l2arc_evict() will already have evicted ahead for this case. 4341fa94a07fSbrendan */ 43423a737e0dSbrendan if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) { 4343*b24ab676SJeff Bonwick vdev_space_update(dev->l2ad_vdev, 4344*b24ab676SJeff Bonwick dev->l2ad_end - dev->l2ad_hand, 0, 0); 4345fa94a07fSbrendan dev->l2ad_hand = dev->l2ad_start; 4346fa94a07fSbrendan dev->l2ad_evict = dev->l2ad_start; 4347fa94a07fSbrendan dev->l2ad_first = B_FALSE; 4348fa94a07fSbrendan } 4349fa94a07fSbrendan 43505a98e54bSBrendan Gregg - Sun Microsystems dev->l2ad_writing = B_TRUE; 4351fa94a07fSbrendan (void) zio_wait(pio); 43525a98e54bSBrendan Gregg - Sun Microsystems dev->l2ad_writing = B_FALSE; 43535a98e54bSBrendan Gregg - Sun Microsystems 43545a98e54bSBrendan Gregg - Sun Microsystems return (write_sz); 4355fa94a07fSbrendan } 4356fa94a07fSbrendan 4357fa94a07fSbrendan /* 4358fa94a07fSbrendan * This thread feeds the L2ARC at regular intervals. This is the beating 4359fa94a07fSbrendan * heart of the L2ARC. 4360fa94a07fSbrendan */ 4361fa94a07fSbrendan static void 4362fa94a07fSbrendan l2arc_feed_thread(void) 4363fa94a07fSbrendan { 4364fa94a07fSbrendan callb_cpr_t cpr; 4365fa94a07fSbrendan l2arc_dev_t *dev; 4366fa94a07fSbrendan spa_t *spa; 43675a98e54bSBrendan Gregg - Sun Microsystems uint64_t size, wrote; 43685a98e54bSBrendan Gregg - Sun Microsystems clock_t begin, next = lbolt; 4369fa94a07fSbrendan 4370fa94a07fSbrendan CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); 4371fa94a07fSbrendan 4372fa94a07fSbrendan mutex_enter(&l2arc_feed_thr_lock); 4373fa94a07fSbrendan 4374fa94a07fSbrendan while (l2arc_thread_exit == 0) { 4375fa94a07fSbrendan CALLB_CPR_SAFE_BEGIN(&cpr); 4376fa94a07fSbrendan (void) cv_timedwait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock, 43775a98e54bSBrendan Gregg - Sun Microsystems next); 4378fa94a07fSbrendan CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); 43795a98e54bSBrendan Gregg - Sun Microsystems next = lbolt + hz; 4380fa94a07fSbrendan 43813a737e0dSbrendan /* 43823a737e0dSbrendan * Quick check for L2ARC devices. 43833a737e0dSbrendan */ 4384c5904d13Seschrock mutex_enter(&l2arc_dev_mtx); 43853a737e0dSbrendan if (l2arc_ndev == 0) { 43863a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 43873a737e0dSbrendan continue; 43883a737e0dSbrendan } 43893a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 43905a98e54bSBrendan Gregg - Sun Microsystems begin = lbolt; 4391c5904d13Seschrock 4392fa94a07fSbrendan /* 4393c5904d13Seschrock * This selects the next l2arc device to write to, and in 4394c5904d13Seschrock * doing so the next spa to feed from: dev->l2ad_spa. This 43953a737e0dSbrendan * will return NULL if there are now no l2arc devices or if 43963a737e0dSbrendan * they are all faulted. 43973a737e0dSbrendan * 43983a737e0dSbrendan * If a device is returned, its spa's config lock is also 43993a737e0dSbrendan * held to prevent device removal. l2arc_dev_get_next() 44003a737e0dSbrendan * will grab and release l2arc_dev_mtx. 4401fa94a07fSbrendan */ 44023a737e0dSbrendan if ((dev = l2arc_dev_get_next()) == NULL) 4403fa94a07fSbrendan continue; 44043a737e0dSbrendan 44053a737e0dSbrendan spa = dev->l2ad_spa; 44063a737e0dSbrendan ASSERT(spa != NULL); 4407fa94a07fSbrendan 4408fa94a07fSbrendan /* 4409fa94a07fSbrendan * Avoid contributing to memory pressure. 4410fa94a07fSbrendan */ 4411fa94a07fSbrendan if (arc_reclaim_needed()) { 4412fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_abort_lowmem); 4413e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, dev); 4414fa94a07fSbrendan continue; 4415fa94a07fSbrendan } 4416fa94a07fSbrendan 4417fa94a07fSbrendan ARCSTAT_BUMP(arcstat_l2_feeds); 4418fa94a07fSbrendan 44195a98e54bSBrendan Gregg - Sun Microsystems size = l2arc_write_size(dev); 44203a737e0dSbrendan 4421fa94a07fSbrendan /* 4422fa94a07fSbrendan * Evict L2ARC buffers that will be overwritten. 4423fa94a07fSbrendan */ 44243a737e0dSbrendan l2arc_evict(dev, size, B_FALSE); 4425fa94a07fSbrendan 4426fa94a07fSbrendan /* 4427fa94a07fSbrendan * Write ARC buffers. 4428fa94a07fSbrendan */ 44295a98e54bSBrendan Gregg - Sun Microsystems wrote = l2arc_write_buffers(spa, dev, size); 44305a98e54bSBrendan Gregg - Sun Microsystems 44315a98e54bSBrendan Gregg - Sun Microsystems /* 44325a98e54bSBrendan Gregg - Sun Microsystems * Calculate interval between writes. 44335a98e54bSBrendan Gregg - Sun Microsystems */ 44345a98e54bSBrendan Gregg - Sun Microsystems next = l2arc_write_interval(begin, size, wrote); 4435e14bb325SJeff Bonwick spa_config_exit(spa, SCL_L2ARC, dev); 4436fa94a07fSbrendan } 4437fa94a07fSbrendan 4438fa94a07fSbrendan l2arc_thread_exit = 0; 4439fa94a07fSbrendan cv_broadcast(&l2arc_feed_thr_cv); 4440fa94a07fSbrendan CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ 4441fa94a07fSbrendan thread_exit(); 4442fa94a07fSbrendan } 4443fa94a07fSbrendan 4444c5904d13Seschrock boolean_t 4445c5904d13Seschrock l2arc_vdev_present(vdev_t *vd) 4446c5904d13Seschrock { 4447c5904d13Seschrock l2arc_dev_t *dev; 4448c5904d13Seschrock 4449c5904d13Seschrock mutex_enter(&l2arc_dev_mtx); 4450c5904d13Seschrock for (dev = list_head(l2arc_dev_list); dev != NULL; 4451c5904d13Seschrock dev = list_next(l2arc_dev_list, dev)) { 4452c5904d13Seschrock if (dev->l2ad_vdev == vd) 4453c5904d13Seschrock break; 4454c5904d13Seschrock } 4455c5904d13Seschrock mutex_exit(&l2arc_dev_mtx); 4456c5904d13Seschrock 4457c5904d13Seschrock return (dev != NULL); 4458c5904d13Seschrock } 4459c5904d13Seschrock 4460fa94a07fSbrendan /* 4461fa94a07fSbrendan * Add a vdev for use by the L2ARC. By this point the spa has already 4462fa94a07fSbrendan * validated the vdev and opened it. 4463fa94a07fSbrendan */ 4464fa94a07fSbrendan void 4465573ca77eSGeorge Wilson l2arc_add_vdev(spa_t *spa, vdev_t *vd) 4466fa94a07fSbrendan { 4467fa94a07fSbrendan l2arc_dev_t *adddev; 4468fa94a07fSbrendan 4469c5904d13Seschrock ASSERT(!l2arc_vdev_present(vd)); 4470c5904d13Seschrock 4471fa94a07fSbrendan /* 4472fa94a07fSbrendan * Create a new l2arc device entry. 4473fa94a07fSbrendan */ 4474fa94a07fSbrendan adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); 4475fa94a07fSbrendan adddev->l2ad_spa = spa; 4476fa94a07fSbrendan adddev->l2ad_vdev = vd; 4477fa94a07fSbrendan adddev->l2ad_write = l2arc_write_max; 44783a737e0dSbrendan adddev->l2ad_boost = l2arc_write_boost; 4479573ca77eSGeorge Wilson adddev->l2ad_start = VDEV_LABEL_START_SIZE; 4480573ca77eSGeorge Wilson adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); 4481fa94a07fSbrendan adddev->l2ad_hand = adddev->l2ad_start; 4482fa94a07fSbrendan adddev->l2ad_evict = adddev->l2ad_start; 4483fa94a07fSbrendan adddev->l2ad_first = B_TRUE; 44845a98e54bSBrendan Gregg - Sun Microsystems adddev->l2ad_writing = B_FALSE; 4485fa94a07fSbrendan ASSERT3U(adddev->l2ad_write, >, 0); 4486fa94a07fSbrendan 4487fa94a07fSbrendan /* 4488fa94a07fSbrendan * This is a list of all ARC buffers that are still valid on the 4489fa94a07fSbrendan * device. 4490fa94a07fSbrendan */ 4491fa94a07fSbrendan adddev->l2ad_buflist = kmem_zalloc(sizeof (list_t), KM_SLEEP); 4492fa94a07fSbrendan list_create(adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), 4493fa94a07fSbrendan offsetof(arc_buf_hdr_t, b_l2node)); 4494fa94a07fSbrendan 4495*b24ab676SJeff Bonwick vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); 4496fa94a07fSbrendan 4497fa94a07fSbrendan /* 4498fa94a07fSbrendan * Add device to global list 4499fa94a07fSbrendan */ 4500fa94a07fSbrendan mutex_enter(&l2arc_dev_mtx); 4501fa94a07fSbrendan list_insert_head(l2arc_dev_list, adddev); 4502fa94a07fSbrendan atomic_inc_64(&l2arc_ndev); 4503fa94a07fSbrendan mutex_exit(&l2arc_dev_mtx); 4504fa94a07fSbrendan } 4505fa94a07fSbrendan 4506fa94a07fSbrendan /* 4507fa94a07fSbrendan * Remove a vdev from the L2ARC. 4508fa94a07fSbrendan */ 4509fa94a07fSbrendan void 4510fa94a07fSbrendan l2arc_remove_vdev(vdev_t *vd) 4511fa94a07fSbrendan { 4512fa94a07fSbrendan l2arc_dev_t *dev, *nextdev, *remdev = NULL; 4513fa94a07fSbrendan 4514fa94a07fSbrendan /* 4515fa94a07fSbrendan * Find the device by vdev 4516fa94a07fSbrendan */ 4517fa94a07fSbrendan mutex_enter(&l2arc_dev_mtx); 4518fa94a07fSbrendan for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) { 4519fa94a07fSbrendan nextdev = list_next(l2arc_dev_list, dev); 4520fa94a07fSbrendan if (vd == dev->l2ad_vdev) { 4521fa94a07fSbrendan remdev = dev; 4522fa94a07fSbrendan break; 4523fa94a07fSbrendan } 4524fa94a07fSbrendan } 4525fa94a07fSbrendan ASSERT(remdev != NULL); 4526fa94a07fSbrendan 4527fa94a07fSbrendan /* 4528fa94a07fSbrendan * Remove device from global list 4529fa94a07fSbrendan */ 4530fa94a07fSbrendan list_remove(l2arc_dev_list, remdev); 4531fa94a07fSbrendan l2arc_dev_last = NULL; /* may have been invalidated */ 45323a737e0dSbrendan atomic_dec_64(&l2arc_ndev); 45333a737e0dSbrendan mutex_exit(&l2arc_dev_mtx); 4534fa94a07fSbrendan 4535fa94a07fSbrendan /* 4536fa94a07fSbrendan * Clear all buflists and ARC references. L2ARC device flush. 4537fa94a07fSbrendan */ 4538fa94a07fSbrendan l2arc_evict(remdev, 0, B_TRUE); 4539fa94a07fSbrendan list_destroy(remdev->l2ad_buflist); 4540fa94a07fSbrendan kmem_free(remdev->l2ad_buflist, sizeof (list_t)); 4541fa94a07fSbrendan kmem_free(remdev, sizeof (l2arc_dev_t)); 4542fa94a07fSbrendan } 4543fa94a07fSbrendan 4544fa94a07fSbrendan void 4545e14bb325SJeff Bonwick l2arc_init(void) 4546fa94a07fSbrendan { 4547fa94a07fSbrendan l2arc_thread_exit = 0; 4548fa94a07fSbrendan l2arc_ndev = 0; 4549fa94a07fSbrendan l2arc_writes_sent = 0; 4550fa94a07fSbrendan l2arc_writes_done = 0; 4551fa94a07fSbrendan 4552fa94a07fSbrendan mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); 4553fa94a07fSbrendan cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); 4554fa94a07fSbrendan mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); 4555fa94a07fSbrendan mutex_init(&l2arc_buflist_mtx, NULL, MUTEX_DEFAULT, NULL); 4556fa94a07fSbrendan mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); 4557fa94a07fSbrendan 4558fa94a07fSbrendan l2arc_dev_list = &L2ARC_dev_list; 4559fa94a07fSbrendan l2arc_free_on_write = &L2ARC_free_on_write; 4560fa94a07fSbrendan list_create(l2arc_dev_list, sizeof (l2arc_dev_t), 4561fa94a07fSbrendan offsetof(l2arc_dev_t, l2ad_node)); 4562fa94a07fSbrendan list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), 4563fa94a07fSbrendan offsetof(l2arc_data_free_t, l2df_list_node)); 4564fa94a07fSbrendan } 4565fa94a07fSbrendan 4566fa94a07fSbrendan void 4567e14bb325SJeff Bonwick l2arc_fini(void) 4568fa94a07fSbrendan { 45693a737e0dSbrendan /* 45703a737e0dSbrendan * This is called from dmu_fini(), which is called from spa_fini(); 45713a737e0dSbrendan * Because of this, we can assume that all l2arc devices have 45723a737e0dSbrendan * already been removed when the pools themselves were removed. 45733a737e0dSbrendan */ 45743a737e0dSbrendan 45753a737e0dSbrendan l2arc_do_free_on_write(); 45763a737e0dSbrendan 4577fa94a07fSbrendan mutex_destroy(&l2arc_feed_thr_lock); 4578fa94a07fSbrendan cv_destroy(&l2arc_feed_thr_cv); 4579fa94a07fSbrendan mutex_destroy(&l2arc_dev_mtx); 4580fa94a07fSbrendan mutex_destroy(&l2arc_buflist_mtx); 4581fa94a07fSbrendan mutex_destroy(&l2arc_free_on_write_mtx); 4582fa94a07fSbrendan 4583fa94a07fSbrendan list_destroy(l2arc_dev_list); 4584fa94a07fSbrendan list_destroy(l2arc_free_on_write); 4585fa94a07fSbrendan } 4586e14bb325SJeff Bonwick 4587e14bb325SJeff Bonwick void 4588e14bb325SJeff Bonwick l2arc_start(void) 4589e14bb325SJeff Bonwick { 45908ad4d6ddSJeff Bonwick if (!(spa_mode_global & FWRITE)) 4591e14bb325SJeff Bonwick return; 4592e14bb325SJeff Bonwick 4593e14bb325SJeff Bonwick (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, 4594e14bb325SJeff Bonwick TS_RUN, minclsyspri); 4595e14bb325SJeff Bonwick } 4596e14bb325SJeff Bonwick 4597e14bb325SJeff Bonwick void 4598e14bb325SJeff Bonwick l2arc_stop(void) 4599e14bb325SJeff Bonwick { 46008ad4d6ddSJeff Bonwick if (!(spa_mode_global & FWRITE)) 4601e14bb325SJeff Bonwick return; 4602e14bb325SJeff Bonwick 4603e14bb325SJeff Bonwick mutex_enter(&l2arc_feed_thr_lock); 4604e14bb325SJeff Bonwick cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ 4605e14bb325SJeff Bonwick l2arc_thread_exit = 1; 4606e14bb325SJeff Bonwick while (l2arc_thread_exit != 0) 4607e14bb325SJeff Bonwick cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); 4608e14bb325SJeff Bonwick mutex_exit(&l2arc_feed_thr_lock); 4609e14bb325SJeff Bonwick } 4610