project-base/server-skynet-source-3rd-jemalloc
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Over purge by 1 extent always.

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When purging, large allocations are usually the ones that cross the npages_limit
threshold, simply because they are "large".  This means we often leave the large
extent around for a while, which has the downsides of: 1) high RSS and 2) more
chance of them getting fragmented.  Given that they are not likely to be reused
very soon (LRU), let's over purge by 1 extent (which is often large and not
reused frequently).
This commit is contained in:
Qi Wang 2017-12-08 12:13:50 -08:00 committed by Qi Wang
parent f70785de91
commit 740bdd68b1
3 changed files with 5 additions and 8 deletions
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3
include/jemalloc/internal/extent_externs.h
View File

@ -38,8 +38,7 @@ extent_t *extents_alloc(tsdn_t *tsdn, arena_t *arena,
void extents_dalloc(tsdn_t *tsdn, arena_t *arena, void extents_dalloc(tsdn_t *tsdn, arena_t *arena,
extent_hooks_t **r_extent_hooks, extents_t *extents, extent_t *extent); extent_hooks_t **r_extent_hooks, extents_t *extents, extent_t *extent);
extent_t *extents_evict(tsdn_t *tsdn, arena_t *arena, extent_t *extents_evict(tsdn_t *tsdn, arena_t *arena,
extent_hooks_t **r_extent_hooks, extents_t *extents, size_t npages_min, extent_hooks_t **r_extent_hooks, extents_t *extents, size_t npages_min);
size_t npages_max);
void extents_prefork(tsdn_t *tsdn, extents_t *extents); void extents_prefork(tsdn_t *tsdn, extents_t *extents);
void extents_postfork_parent(tsdn_t *tsdn, extents_t *extents); void extents_postfork_parent(tsdn_t *tsdn, extents_t *extents);
void extents_postfork_child(tsdn_t *tsdn, extents_t *extents); void extents_postfork_child(tsdn_t *tsdn, extents_t *extents);

4
src/arena.c
View File

@ -912,7 +912,7 @@ arena_stash_decayed(tsdn_t *tsdn, arena_t *arena,
extent_t *extent; extent_t *extent;
while (nstashed < npages_decay_max && while (nstashed < npages_decay_max &&
(extent = extents_evict(tsdn, arena, r_extent_hooks, extents, (extent = extents_evict(tsdn, arena, r_extent_hooks, extents,
npages_limit, npages_decay_max - nstashed)) != NULL) { npages_limit)) != NULL) {
extent_list_append(decay_extents, extent); extent_list_append(decay_extents, extent);
nstashed += extent_size_get(extent) >> LG_PAGE; nstashed += extent_size_get(extent) >> LG_PAGE;
} }
@ -1226,7 +1226,7 @@ arena_destroy_retained(tsdn_t *tsdn, arena_t *arena) {
extent_hooks_t *extent_hooks = extent_hooks_get(arena); extent_hooks_t *extent_hooks = extent_hooks_get(arena);
extent_t *extent; extent_t *extent;
while ((extent = extents_evict(tsdn, arena, &extent_hooks, while ((extent = extents_evict(tsdn, arena, &extent_hooks,
&arena->extents_retained, 0, SIZE_MAX)) != NULL) { &arena->extents_retained, 0)) != NULL) {
extent_destroy_wrapper(tsdn, arena, &extent_hooks, extent); extent_destroy_wrapper(tsdn, arena, &extent_hooks, extent);
} }
} }

6
src/extent.c
View File

@ -481,7 +481,7 @@ extents_dalloc(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
extent_t * extent_t *
extents_evict(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks, extents_evict(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
extents_t *extents, size_t npages_min, size_t npages_max) { extents_t *extents, size_t npages_min) {
rtree_ctx_t rtree_ctx_fallback; rtree_ctx_t rtree_ctx_fallback;
rtree_ctx_t *rtree_ctx = tsdn_rtree_ctx(tsdn, &rtree_ctx_fallback); rtree_ctx_t *rtree_ctx = tsdn_rtree_ctx(tsdn, &rtree_ctx_fallback);
@ -499,11 +499,9 @@ extents_evict(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
goto label_return; goto label_return;
} }
/* Check the eviction limit. */ /* Check the eviction limit. */
size_t npages = extent_size_get(extent) >> LG_PAGE;
size_t extents_npages = atomic_load_zu(&extents->npages, size_t extents_npages = atomic_load_zu(&extents->npages,
ATOMIC_RELAXED); ATOMIC_RELAXED);
if (extents_npages - npages < npages_min || if (extents_npages <= npages_min) {
npages > npages_max) {
extent = NULL; extent = NULL;
goto label_return; goto label_return;
} }