/*- * Copyright (c) 2014-2016 MongoDB, Inc. * Copyright (c) 2008-2014 WiredTiger, Inc. * All rights reserved. * * See the file LICENSE for redistribution information. */ /* * Tuning constants: I hesitate to call this tuning, but we want to review some * number of pages from each file's in-memory tree for each page we evict. */ #define WT_EVICT_INT_SKEW (1<<20) /* Prefer leaf pages over internal pages by this many increments of the read generation. */ #define WT_EVICT_WALK_BASE 300 /* Pages tracked across file visits */ #define WT_EVICT_WALK_INCR 100 /* Pages added each walk */ /* * WT_EVICT_ENTRY -- * Encapsulation of an eviction candidate. */ struct __wt_evict_entry { WT_BTREE *btree; /* Enclosing btree object */ WT_REF *ref; /* Page to flush/evict */ uint64_t score; /* Relative eviction priority */ }; #define WT_EVICT_QUEUE_MAX 3 /* Two ordinary queues plus urgent */ #define WT_EVICT_URGENT_QUEUE 2 /* Urgent queue index */ /* * WT_EVICT_QUEUE -- * Encapsulation of an eviction candidate queue. */ struct __wt_evict_queue { WT_SPINLOCK evict_lock; /* Eviction LRU queue */ WT_EVICT_ENTRY *evict_queue; /* LRU pages being tracked */ WT_EVICT_ENTRY *evict_current; /* LRU current page to be evicted */ uint32_t evict_candidates; /* LRU list pages to evict */ uint32_t evict_entries; /* LRU entries in the queue */ volatile uint32_t evict_max; /* LRU maximum eviction slot used */ }; /* Cache operations. */ typedef enum __wt_cache_op { WT_SYNC_CHECKPOINT, WT_SYNC_CLOSE, WT_SYNC_DISCARD, WT_SYNC_WRITE_LEAVES } WT_CACHE_OP; /* * WiredTiger cache structure. */ struct __wt_cache { /* * Different threads read/write pages to/from the cache and create pages * in the cache, so we cannot know precisely how much memory is in use * at any specific time. However, even though the values don't have to * be exact, they can't be garbage, we track what comes in and what goes * out and calculate the difference as needed. */ uint64_t bytes_dirty_intl; /* Bytes/pages currently dirty */ uint64_t pages_dirty_intl; uint64_t bytes_dirty_leaf; uint64_t pages_dirty_leaf; uint64_t bytes_evict; /* Bytes/pages discarded by eviction */ volatile uint64_t pages_evict; uint64_t pages_evicted; /* Pages evicted during a pass */ uint64_t bytes_image; /* Bytes of disk images */ uint64_t bytes_inmem; /* Bytes/pages in memory */ uint64_t pages_inmem; uint64_t bytes_internal; /* Bytes of internal pages */ uint64_t bytes_read; /* Bytes read into memory */ uint64_t bytes_written; uint64_t app_waits; /* User threads waited for cache */ uint64_t app_evicts; /* Pages evicted by user threads */ uint64_t server_evicts; /* Pages evicted by server thread */ uint64_t worker_evicts; /* Pages evicted by worker threads */ uint64_t evict_max_page_size; /* Largest page seen at eviction */ #ifdef HAVE_DIAGNOSTIC struct timespec stuck_ts; /* Stuck timestamp */ #endif /* * Read information. */ uint64_t read_gen; /* Current page read generation */ uint64_t read_gen_oldest; /* Oldest read generation the eviction * server saw in its last queue load */ uint64_t evict_pass_gen; /* Number of eviction passes */ /* * Eviction thread information. */ WT_CONDVAR *evict_cond; /* Eviction server condition */ WT_SPINLOCK evict_walk_lock; /* Eviction walk location */ u_int eviction_dirty_target; /* Percent to allow dirty */ u_int eviction_dirty_trigger; /* Percent to trigger dirty eviction */ u_int eviction_trigger; /* Percent to trigger eviction */ u_int eviction_target; /* Percent to end eviction */ u_int eviction_checkpoint_target;/* Percent to reduce dirty to during checkpoint scrubs */ double eviction_scrub_limit; /* Percent of cache to trigger dirty eviction during checkpoint scrubs */ u_int overhead_pct; /* Cache percent adjustment */ /* * Pass interrupt counter. */ volatile uint32_t pass_intr; /* Interrupt eviction pass. */ /* * LRU eviction list information. */ WT_SPINLOCK evict_pass_lock; /* Eviction pass lock */ WT_SESSION_IMPL *walk_session; /* Eviction pass session */ WT_DATA_HANDLE *evict_file_next;/* LRU next file to search */ WT_SPINLOCK evict_queue_lock; /* Eviction current queue lock */ WT_EVICT_QUEUE evict_queues[WT_EVICT_QUEUE_MAX]; WT_EVICT_QUEUE *evict_current_queue; /* LRU current queue in use */ WT_EVICT_QUEUE *evict_fill_queue; /* LRU next queue to fill. This is usually the same as the "other" queue but under heavy load the eviction server will start filling the current queue before it switches. */ WT_EVICT_QUEUE *evict_other_queue; /* LRU queue not in use */ WT_EVICT_QUEUE *evict_urgent_queue; /* LRU urgent queue */ uint32_t evict_slots; /* LRU list eviction slots */ #define WT_EVICT_SCORE_BUMP 10 #define WT_EVICT_SCORE_CUTOFF 10 #define WT_EVICT_SCORE_MAX 100 uint32_t evict_aggressive_score;/* Score of how aggressive eviction should be about selecting eviction candidates. If eviction is struggling to make progress, this score rises (up to a maximum of 100), at which point the cache is "stuck" and transaction will be rolled back. */ uint32_t evict_empty_score; /* Score of how often LRU queues are empty on refill. This score varies between 0 (if the queue hasn't been empty for a long time) and 100 (if the queue has been empty the last 10 times we filled up. */ /* * Cache pool information. */ uint64_t cp_pass_pressure; /* Calculated pressure from this pass */ uint64_t cp_quota; /* Maximum size for this cache */ uint64_t cp_reserved; /* Base size for this cache */ WT_SESSION_IMPL *cp_session; /* May be used for cache management */ uint32_t cp_skip_count; /* Post change stabilization */ wt_thread_t cp_tid; /* Thread ID for cache pool manager */ /* State seen at the last pass of the shared cache manager */ uint64_t cp_saved_app_evicts; /* User eviction count at last review */ uint64_t cp_saved_app_waits; /* User wait count at last review */ uint64_t cp_saved_read; /* Read count at last review */ /* * Flags. */ #define WT_CACHE_EVICT_CLEAN 0x001 /* Evict clean pages */ #define WT_CACHE_EVICT_CLEAN_HARD 0x002 /* Clean % blocking app threads */ #define WT_CACHE_EVICT_DIRTY 0x004 /* Evict dirty pages */ #define WT_CACHE_EVICT_DIRTY_HARD 0x008 /* Dirty % blocking app threads */ #define WT_CACHE_EVICT_SCRUB 0x010 /* Scrub dirty pages */ #define WT_CACHE_EVICT_URGENT 0x020 /* Pages are in the urgent queue */ #define WT_CACHE_EVICT_ALL (WT_CACHE_EVICT_CLEAN | WT_CACHE_EVICT_DIRTY) #define WT_CACHE_EVICT_MASK 0x0FF #define WT_CACHE_POOL_MANAGER 0x100 /* The active cache pool manager */ #define WT_CACHE_POOL_RUN 0x200 /* Cache pool thread running */ uint32_t flags; }; #define WT_WITH_PASS_LOCK(session, ret, op) do { \ WT_ASSERT(session, !F_ISSET(session, WT_SESSION_LOCKED_PASS)); \ WT_WITH_LOCK(session, ret, \ &cache->evict_pass_lock, WT_SESSION_LOCKED_PASS, op); \ } while (0) /* * WT_CACHE_POOL -- * A structure that represents a shared cache. */ struct __wt_cache_pool { WT_SPINLOCK cache_pool_lock; WT_CONDVAR *cache_pool_cond; const char *name; uint64_t size; uint64_t chunk; uint64_t quota; uint64_t currently_used; uint32_t refs; /* Reference count for structure. */ /* Locked: List of connections participating in the cache pool. */ TAILQ_HEAD(__wt_cache_pool_qh, __wt_connection_impl) cache_pool_qh; uint8_t pool_managed; /* Cache pool has a manager thread */ #define WT_CACHE_POOL_ACTIVE 0x01 /* Cache pool is active */ uint8_t flags; };