Eagerly purge oversized merged extents.

This change improves memory usage slightly, at virtually no CPU cost.
This commit is contained in:
Qi Wang 2019-03-12 15:02:41 -07:00 committed by Qi Wang
parent f6c30cbafa
commit fb56766ca9
3 changed files with 36 additions and 3 deletions

View File

@ -135,6 +135,26 @@ arena_decay_tick(tsdn_t *tsdn, arena_t *arena) {
arena_decay_ticks(tsdn, arena, 1); arena_decay_ticks(tsdn, arena, 1);
} }
/* Purge a single extent to retained / unmapped directly. */
JEMALLOC_ALWAYS_INLINE void
arena_decay_extent(tsdn_t *tsdn,arena_t *arena, extent_hooks_t **r_extent_hooks,
extent_t *extent) {
size_t extent_size = extent_size_get(extent);
extent_dalloc_wrapper(tsdn, arena,
r_extent_hooks, extent);
if (config_stats) {
/* Update stats accordingly. */
arena_stats_lock(tsdn, &arena->stats);
arena_stats_add_u64(tsdn, &arena->stats,
&arena->decay_dirty.stats->nmadvise, 1);
arena_stats_add_u64(tsdn, &arena->stats,
&arena->decay_dirty.stats->purged, extent_size >> LG_PAGE);
arena_stats_sub_zu(tsdn, &arena->stats, &arena->stats.mapped,
extent_size);
arena_stats_unlock(tsdn, &arena->stats);
}
}
JEMALLOC_ALWAYS_INLINE void * JEMALLOC_ALWAYS_INLINE void *
arena_malloc(tsdn_t *tsdn, arena_t *arena, size_t size, szind_t ind, bool zero, arena_malloc(tsdn_t *tsdn, arena_t *arena, size_t size, szind_t ind, bool zero,
tcache_t *tcache, bool slow_path) { tcache_t *tcache, bool slow_path) {

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@ -1708,6 +1708,7 @@ extent_record(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
extent = extent_try_coalesce(tsdn, arena, r_extent_hooks, extent = extent_try_coalesce(tsdn, arena, r_extent_hooks,
rtree_ctx, extents, extent, NULL, growing_retained); rtree_ctx, extents, extent, NULL, growing_retained);
} else if (extent_size_get(extent) >= SC_LARGE_MINCLASS) { } else if (extent_size_get(extent) >= SC_LARGE_MINCLASS) {
assert(extents == &arena->extents_dirty);
/* Always coalesce large extents eagerly. */ /* Always coalesce large extents eagerly. */
bool coalesced; bool coalesced;
do { do {
@ -1716,6 +1717,12 @@ extent_record(tsdn_t *tsdn, arena_t *arena, extent_hooks_t **r_extent_hooks,
r_extent_hooks, rtree_ctx, extents, extent, r_extent_hooks, rtree_ctx, extents, extent,
&coalesced, growing_retained); &coalesced, growing_retained);
} while (coalesced); } while (coalesced);
if (extent_size_get(extent) >= oversize_threshold) {
/* Shortcut to purge the oversize extent eagerly. */
malloc_mutex_unlock(tsdn, &extents->mtx);
arena_decay_extent(tsdn, arena, r_extent_hooks, extent);
return;
}
} }
extent_deactivate_locked(tsdn, arena, extents, extent); extent_deactivate_locked(tsdn, arena, extents, extent);

View File

@ -121,6 +121,12 @@ get_arena_dirty_npurge(unsigned arena_ind) {
return get_arena_npurge_impl("stats.arenas.0.dirty_npurge", arena_ind); return get_arena_npurge_impl("stats.arenas.0.dirty_npurge", arena_ind);
} }
static uint64_t
get_arena_dirty_purged(unsigned arena_ind) {
do_epoch();
return get_arena_npurge_impl("stats.arenas.0.dirty_purged", arena_ind);
}
static uint64_t static uint64_t
get_arena_muzzy_npurge(unsigned arena_ind) { get_arena_muzzy_npurge(unsigned arena_ind) {
do_epoch(); do_epoch();
@ -559,7 +565,7 @@ TEST_BEGIN(test_decay_now) {
TEST_END TEST_END
TEST_BEGIN(test_decay_never) { TEST_BEGIN(test_decay_never) {
test_skip_if(check_background_thread_enabled()); test_skip_if(check_background_thread_enabled() || !config_stats);
unsigned arena_ind = do_arena_create(-1, -1); unsigned arena_ind = do_arena_create(-1, -1);
int flags = MALLOCX_ARENA(arena_ind) | MALLOCX_TCACHE_NONE; int flags = MALLOCX_ARENA(arena_ind) | MALLOCX_TCACHE_NONE;
@ -579,8 +585,8 @@ TEST_BEGIN(test_decay_never) {
dallocx(ptrs[i], flags); dallocx(ptrs[i], flags);
size_t pdirty = get_arena_pdirty(arena_ind); size_t pdirty = get_arena_pdirty(arena_ind);
size_t pmuzzy = get_arena_pmuzzy(arena_ind); size_t pmuzzy = get_arena_pmuzzy(arena_ind);
assert_zu_gt(pdirty, pdirty_prev, assert_zu_gt(pdirty + (size_t)get_arena_dirty_purged(arena_ind),
"Expected dirty pages to increase."); pdirty_prev, "Expected dirty pages to increase.");
assert_zu_eq(pmuzzy, 0, "Unexpected muzzy pages"); assert_zu_eq(pmuzzy, 0, "Unexpected muzzy pages");
pdirty_prev = pdirty; pdirty_prev = pdirty;
} }