From f99c4526d94d3e04124c5c48ab4a3da6ca53a458 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 31 Mar 2021 14:58:11 +0200 Subject: Adding upstream version 1.30.0. Signed-off-by: Daniel Baumann --- database/engine/pagecache.c | 68 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) (limited to 'database/engine/pagecache.c') diff --git a/database/engine/pagecache.c b/database/engine/pagecache.c index a18207100..d7698de01 100644 --- a/database/engine/pagecache.c +++ b/database/engine/pagecache.c @@ -699,6 +699,74 @@ void pg_cache_get_filtered_info_prev(struct rrdengine_instance *ctx, struct pg_c } uv_rwlock_rdunlock(&page_index->lock); } + +/** + * Searches for an unallocated page without triggering disk I/O. Attempts to reserve the page and get a reference. + * @param ctx DB context + * @param id lookup by UUID + * @param start_time exact starting time in usec + * @param ret_page_indexp Sets the page index pointer (*ret_page_indexp) for the given UUID. + * @return the page descriptor or NULL on failure. It can fail if: + * 1. The page is already allocated to the page cache. + * 2. It did not succeed to get a reference. + * 3. It did not succeed to reserve a spot in the page cache. + */ +struct rrdeng_page_descr *pg_cache_lookup_unpopulated_and_lock(struct rrdengine_instance *ctx, uuid_t *id, + usec_t start_time) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct rrdeng_page_descr *descr = NULL; + struct page_cache_descr *pg_cache_descr = NULL; + unsigned long flags; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index = NULL; + Word_t Index; + + uv_rwlock_rdlock(&pg_cache->metrics_index.lock); + PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, id, sizeof(uuid_t)); + if (likely(NULL != PValue)) { + page_index = *PValue; + } + uv_rwlock_rdunlock(&pg_cache->metrics_index.lock); + + if ((NULL == PValue) || !pg_cache_try_reserve_pages(ctx, 1)) { + /* Failed to find page or failed to reserve a spot in the cache */ + return NULL; + } + + uv_rwlock_rdlock(&page_index->lock); + Index = (Word_t)(start_time / USEC_PER_SEC); + PValue = JudyLGet(page_index->JudyL_array, Index, PJE0); + if (likely(NULL != PValue)) { + descr = *PValue; + } + if (NULL == PValue || 0 == descr->page_length) { + /* Failed to find non-empty page */ + uv_rwlock_rdunlock(&page_index->lock); + + pg_cache_release_pages(ctx, 1); + return NULL; + } + + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_descr = descr->pg_cache_descr; + flags = pg_cache_descr->flags; + uv_rwlock_rdunlock(&page_index->lock); + + if ((flags & RRD_PAGE_POPULATED) || !pg_cache_try_get_unsafe(descr, 1)) { + /* Failed to get reference or page is already populated */ + rrdeng_page_descr_mutex_unlock(ctx, descr); + + pg_cache_release_pages(ctx, 1); + return NULL; + } + /* success */ + rrdeng_page_descr_mutex_unlock(ctx, descr); + rrd_stat_atomic_add(&ctx->stats.pg_cache_misses, 1); + + return descr; +} + /** * Searches for pages in a time range and triggers disk I/O if necessary and possible. * Does not get a reference. -- cgit v1.2.3