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authorDaniel Baumann <daniel.baumann@progress-linux.org>2021-03-31 12:58:11 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2021-03-31 12:58:11 +0000
commitf99c4526d94d3e04124c5c48ab4a3da6ca53a458 (patch)
treea2ed8860030cc49f492b09b3222d593c65619800 /database/engine/pagecache.c
parentAdding upstream version 1.29.3. (diff)
downloadnetdata-f99c4526d94d3e04124c5c48ab4a3da6ca53a458.tar.xz
netdata-f99c4526d94d3e04124c5c48ab4a3da6ca53a458.zip
Adding upstream version 1.30.0.upstream/1.30.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'database/engine/pagecache.c')
-rw-r--r--database/engine/pagecache.c68
1 files changed, 68 insertions, 0 deletions
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.