Log message when page cache sleeps for more than 1 second. (#11314)
If the page cache manager can not reserve the requested number of pages, it sleeps based on an exponential-backoff value. Normally, this value is a couple milliseconds. However, in rare cases the sleep duration can grow up to several seconds. This patch logs an error message whenever the sleep period is more than 1 second.
vkalintiris committed
Jul 14, 2021 at 16:52 UTC
4006970974fc4e1187c3ea1e84af9b8c0d57dbf4
1 file changed
+8
-3
database/engine/pagecache.c
+8
-3
@@ -299,10 +299,15 @@ static void pg_cache_reserve_pages(struct rrdengine_instance *ctx, unsigned numb
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destroy_completion(&compl);
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if (unlikely(failures > 1)) {
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- unsigned long slots;
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+ unsigned long slots, usecs_to_sleep;
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/* exponential backoff */
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slots = random() % (2LU << MIN(failures, FAILURES_CEILING));
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- (void)sleep_usec(slots * exp_backoff_slot_usec);
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+ usecs_to_sleep = slots * exp_backoff_slot_usec;
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+
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+ if (usecs_to_sleep >= USEC_PER_SEC)
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+ error("Page cache is full. Sleeping for %llu second(s).", usecs_to_sleep / USEC_PER_SEC);
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+
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+ (void)sleep_usec(usecs_to_sleep);
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}
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uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock);
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}
@@ -1243,4 +1248,4 @@ void free_page_cache(struct rrdengine_instance *ctx)
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bytes_freed += ret_Judy;
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info("Freed %lu bytes of memory from page cache.", bytes_freed);
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-}
\ No newline at end of file
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+}