diff options
Diffstat (limited to 'src/conn/conn_cache_pool.c')
| -rw-r--r-- | src/conn/conn_cache_pool.c | 64 |
1 files changed, 47 insertions, 17 deletions
diff --git a/src/conn/conn_cache_pool.c b/src/conn/conn_cache_pool.c index 79c2fc23da5..ed078991581 100644 --- a/src/conn/conn_cache_pool.c +++ b/src/conn/conn_cache_pool.c @@ -32,7 +32,7 @@ */ #define WT_CACHE_POOL_APP_EVICT_MULTIPLIER 3 #define WT_CACHE_POOL_APP_WAIT_MULTIPLIER 6 -#define WT_CACHE_POOL_READ_MULTIPLIER 1 +#define WT_CACHE_POOL_READ_MULTIPLIER 1 static void __cache_pool_adjust( WT_SESSION_IMPL *, uint64_t, uint64_t, bool, bool *); @@ -104,8 +104,8 @@ __wt_cache_pool_config(WT_SESSION_IMPL *session, const char **cfg) TAILQ_INIT(&cp->cache_pool_qh); WT_ERR(__wt_spin_init( session, &cp->cache_pool_lock, "cache shared pool")); - WT_ERR(__wt_cond_alloc(session, - "cache pool server", false, &cp->cache_pool_cond)); + WT_ERR(__wt_cond_alloc( + session, "cache pool server", &cp->cache_pool_cond)); __wt_process.cache_pool = cp; __wt_verbose(session, @@ -418,8 +418,9 @@ static void __cache_pool_balance(WT_SESSION_IMPL *session, bool forward) { WT_CACHE_POOL *cp; - bool adjusted; uint64_t bump_threshold, highest; + int i; + bool adjusted; cp = __wt_process.cache_pool; adjusted = false; @@ -438,11 +439,17 @@ __cache_pool_balance(WT_SESSION_IMPL *session, bool forward) /* * Actively attempt to: - * - Reduce the amount allocated, if we are over the budget + * - Reduce the amount allocated, if we are over the budget. * - Increase the amount used if there is capacity and any pressure. + * Don't keep trying indefinitely, if we aren't succeeding in reducing + * the cache in use re-assessing the participants' states is necessary. + * We are also holding a lock across this process, which can slow + * participant shutdown if we spend a long time balancing. */ - while (F_ISSET(cp, WT_CACHE_POOL_ACTIVE) && - F_ISSET(S2C(session)->cache, WT_CACHE_POOL_RUN)) { + for (i = 0; + i < 2 * WT_CACHE_POOL_BUMP_THRESHOLD && + F_ISSET(cp, WT_CACHE_POOL_ACTIVE) && + F_ISSET(S2C(session)->cache, WT_CACHE_POOL_RUN); i++) { __cache_pool_adjust( session, highest, bump_threshold, forward, &adjusted); /* @@ -565,7 +572,7 @@ __cache_pool_adjust(WT_SESSION_IMPL *session, WT_CONNECTION_IMPL *entry; uint64_t adjustment, highest_percentile, pressure, reserved, smallest; u_int pct_full; - bool busy, pool_full, grow; + bool busy, decrease_ok, grow, pool_full; *adjustedp = false; cp = __wt_process.cache_pool; @@ -612,6 +619,34 @@ __cache_pool_adjust(WT_SESSION_IMPL *session, continue; /* + * The bump threshold decreases as we try longer to balance + * the pool. Adjust how aggressively we free space from + * participants depending on how long we have been trying. + */ + decrease_ok = false; + /* + * Any participant is a candidate if we have been trying + * for long enough. + */ + if (bump_threshold == 0) + decrease_ok = true; + /* + * Participants that aren't doing application eviction and + * are showing a reasonable amount of usage are excluded + * even if we have been trying for a while. + */ + else if (bump_threshold < WT_CACHE_POOL_BUMP_THRESHOLD / 3 && + (!busy && highest > 1)) + decrease_ok = true; + /* + * Any participant that is proportionally less busy is a + * candidate from the first attempt. + */ + else if (highest > 1 && + pressure < WT_CACHE_POOL_REDUCE_THRESHOLD) + decrease_ok = true; + + /* * If the entry is currently allocated less than the reserved * size, increase its allocation. This should only happen if: * - it's the first time we've seen this member, or @@ -624,17 +659,12 @@ __cache_pool_adjust(WT_SESSION_IMPL *session, * Conditions for reducing the amount of resources for an * entry: * - the pool is full, - * - application threads are not busy doing eviction already, * - this entry has more than the minimum amount of space in * use, - * - the read pressure in this entry is below the threshold, - * other entries need more cache, the entry has more than - * the minimum space and there is no available space in the - * pool. + * - it was determined that this slot is a good candidate */ - } else if (pool_full && !busy && - entry->cache_size > reserved && - pressure < WT_CACHE_POOL_REDUCE_THRESHOLD && highest > 1) { + } else if (pool_full && + entry->cache_size > reserved && decrease_ok) { grow = false; /* * Don't drop the size down too much - or it can @@ -733,7 +763,7 @@ __wt_cache_pool_server(void *arg) F_ISSET(cache, WT_CACHE_POOL_RUN)) { if (cp->currently_used <= cp->size) __wt_cond_wait( - session, cp->cache_pool_cond, WT_MILLION); + session, cp->cache_pool_cond, WT_MILLION, NULL); /* * Re-check pool run flag - since we want to avoid getting the |