project-base/server-skynet-source-3rd-jemalloc
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Improve interval-based profile dump triggering.

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When an allocation is large enough to trigger multiple dumps, use
modular math rather than subtraction to reset the interval counter.
Prior to this change, it was possible for a single allocation to cause
many subsequent allocations to all trigger profile dumps.

When updating usable size for a sampled object, try to cancel out
the difference between LARGE_MINCLASS and usable size from the interval
counter.
This commit is contained in:
Jason Evans 2016-05-28 17:29:03 -07:00
parent ed2c2427a7
commit d28e5a6696
2 changed files with 15 additions and 1 deletions
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2
include/jemalloc/internal/arena.h
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@ -984,7 +984,7 @@ arena_prof_accum_impl(arena_t *arena, uint64_t accumbytes)
arena->prof_accumbytes += accumbytes; arena->prof_accumbytes += accumbytes;
if (arena->prof_accumbytes >= prof_interval) { if (arena->prof_accumbytes >= prof_interval) {
arena->prof_accumbytes -= prof_interval; arena->prof_accumbytes %= prof_interval;
return (true); return (true);
} }
return (false); return (false);

14
src/arena.c
View File

@ -2258,6 +2258,7 @@ void
arena_prof_promote(tsdn_t *tsdn, extent_t *extent, const void *ptr, arena_prof_promote(tsdn_t *tsdn, extent_t *extent, const void *ptr,
size_t usize) size_t usize)
{ {
arena_t *arena = extent_arena_get(extent);
cassert(config_prof); cassert(config_prof);
assert(ptr != NULL); assert(ptr != NULL);
@ -2266,6 +2267,19 @@ arena_prof_promote(tsdn_t *tsdn, extent_t *extent, const void *ptr,
extent_usize_set(extent, usize); extent_usize_set(extent, usize);
/*
* Cancel out as much of the excessive prof_accumbytes increase as
* possible without underflowing. Interval-triggered dumps occur
* slightly more often than intended as a result of incomplete
* canceling.
*/
malloc_mutex_lock(tsdn, &arena->lock);
if (arena->prof_accumbytes >= LARGE_MINCLASS - usize)
arena->prof_accumbytes -= LARGE_MINCLASS - usize;
else
arena->prof_accumbytes = 0;
malloc_mutex_unlock(tsdn, &arena->lock);
assert(isalloc(tsdn, extent, ptr) == usize); assert(isalloc(tsdn, extent, ptr) == usize);
} }