PA->PAC: Move in decay functions.

This commit is contained in:
David Goldblatt 2020-06-03 14:43:28 -07:00 committed by David Goldblatt
parent 4ee75be3a3
commit 6a2774719f
6 changed files with 230 additions and 44 deletions

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@ -137,39 +137,6 @@ bool pa_shrink(tsdn_t *tsdn, pa_shard_t *shard, edata_t *edata, size_t old_size,
void pa_dalloc(tsdn_t *tsdn, pa_shard_t *shard, edata_t *edata,
bool *generated_dirty);
/*
* All purging functions require holding decay->mtx. This is one of the few
* places external modules are allowed to peek inside pa_shard_t internals.
*/
/*
* Decays the number of pages currently in the ecache. This might not leave the
* ecache empty if other threads are inserting dirty objects into it
* concurrently with the call.
*/
void pa_decay_all(tsdn_t *tsdn, pa_shard_t *shard, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache, bool fully_decay);
/*
* Updates decay settings for the current time, and conditionally purges in
* response (depending on decay_purge_setting). Returns whether or not the
* epoch advanced.
*/
bool pa_maybe_decay_purge(tsdn_t *tsdn, pa_shard_t *shard, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache,
pac_decay_purge_setting_t decay_purge_setting);
/*
* Gets / sets the maximum amount that we'll grow an arena down the
* grow-retained pathways (unless forced to by an allocaction request).
*
* Set new_limit to NULL if it's just a query, or old_limit to NULL if you don't
* care about the previous value.
*
* Returns true on error (if the new limit is not valid).
*/
bool pa_shard_retain_grow_limit_get_set(tsdn_t *tsdn, pa_shard_t *shard,
size_t *old_limit, size_t *new_limit);
/******************************************************************************/
/*
* Various bits of "boring" functionality that are still part of this module,

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@ -81,6 +81,7 @@ struct pac_s {
ecache_t ecache_muzzy;
ecache_t ecache_retained;
base_t *base;
emap_t *emap;
edata_cache_t *edata_cache;
@ -103,7 +104,7 @@ struct pac_s {
atomic_zu_t extent_sn_next;
};
bool pac_init(tsdn_t *tsdn, pac_t *pac, unsigned ind, emap_t *emap,
bool pac_init(tsdn_t *tsdn, pac_t *pac, base_t *base, emap_t *emap,
edata_cache_t *edata_cache, nstime_t *cur_time, ssize_t dirty_decay_ms,
ssize_t muzzy_decay_ms, pac_stats_t *pac_stats, malloc_mutex_t *stats_mtx);
bool pac_retain_grow_limit_get_set(tsdn_t *tsdn, pac_t *pac, size_t *old_limit,
@ -126,4 +127,37 @@ pac_mapped(pac_t *pac) {
return atomic_load_zu(&pac->stats->pac_mapped, ATOMIC_RELAXED);
}
/*
* All purging functions require holding decay->mtx. This is one of the few
* places external modules are allowed to peek inside pa_shard_t internals.
*/
/*
* Decays the number of pages currently in the ecache. This might not leave the
* ecache empty if other threads are inserting dirty objects into it
* concurrently with the call.
*/
void pac_decay_all(tsdn_t *tsdn, pac_t *pac, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache, bool fully_decay);
/*
* Updates decay settings for the current time, and conditionally purges in
* response (depending on decay_purge_setting). Returns whether or not the
* epoch advanced.
*/
bool pac_maybe_decay_purge(tsdn_t *tsdn, pac_t *pac, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache,
pac_decay_purge_setting_t decay_purge_setting);
/*
* Gets / sets the maximum amount that we'll grow an arena down the
* grow-retained pathways (unless forced to by an allocaction request).
*
* Set new_limit to NULL if it's just a query, or old_limit to NULL if you don't
* care about the previous value.
*
* Returns true on error (if the new limit is not valid).
*/
bool pac_retain_grow_limit_get_set(tsdn_t *tsdn, pac_t *pac, size_t *old_limit,
size_t *new_limit);
#endif /* JEMALLOC_INTERNAL_PAC_H */

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@ -443,8 +443,8 @@ arena_decay_ms_set(tsdn_t *tsdn, arena_t *arena, decay_t *decay,
pac_decay_purge_setting_t decay_purge =
arena_decide_unforced_decay_purge_setting(
/* is_background_thread */ false);
pa_maybe_decay_purge(tsdn, &arena->pa_shard, decay, decay_stats, ecache,
decay_purge);
pac_maybe_decay_purge(tsdn, &arena->pa_shard.pac, decay, decay_stats,
ecache, decay_purge);
malloc_mutex_unlock(tsdn, &decay->mtx);
return false;
@ -472,8 +472,8 @@ arena_decay_impl(tsdn_t *tsdn, arena_t *arena, decay_t *decay,
bool is_background_thread, bool all) {
if (all) {
malloc_mutex_lock(tsdn, &decay->mtx);
pa_decay_all(tsdn, &arena->pa_shard, decay, decay_stats, ecache,
/* fully_decay */ all);
pac_decay_all(tsdn, &arena->pa_shard.pac, decay, decay_stats,
ecache, /* fully_decay */ all);
malloc_mutex_unlock(tsdn, &decay->mtx);
/*
* The previous pa_decay_all call may not have actually decayed
@ -499,7 +499,7 @@ arena_decay_impl(tsdn_t *tsdn, arena_t *arena, decay_t *decay,
}
pac_decay_purge_setting_t decay_purge =
arena_decide_unforced_decay_purge_setting(is_background_thread);
bool epoch_advanced = pa_maybe_decay_purge(tsdn, &arena->pa_shard,
bool epoch_advanced = pac_maybe_decay_purge(tsdn, &arena->pa_shard.pac,
decay, decay_stats, ecache, decay_purge);
size_t npages_new;
if (epoch_advanced) {
@ -1401,8 +1401,8 @@ bool
arena_retain_grow_limit_get_set(tsd_t *tsd, arena_t *arena, size_t *old_limit,
size_t *new_limit) {
assert(opt_retain);
return pa_shard_retain_grow_limit_get_set(tsd_tsdn(tsd),
&arena->pa_shard, old_limit, new_limit);
return pac_retain_grow_limit_get_set(tsd_tsdn(tsd),
&arena->pa_shard.pac, old_limit, new_limit);
}
unsigned

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@ -29,7 +29,7 @@ pa_shard_init(tsdn_t *tsdn, pa_shard_t *shard, emap_t *emap, base_t *base,
if (edata_cache_init(&shard->edata_cache, base)) {
return true;
}
if (pac_init(tsdn, &shard->pac, ind, emap, &shard->edata_cache,
if (pac_init(tsdn, &shard->pac, base, emap, &shard->edata_cache,
cur_time, dirty_decay_ms, muzzy_decay_ms, &stats->pac_stats,
stats_mtx)) {
return true;

187
src/pac.c
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@ -3,10 +3,16 @@
#include "jemalloc/internal/pac.h"
static ehooks_t *
pac_ehooks_get(pac_t *pac) {
return base_ehooks_get(pac->base);
}
bool
pac_init(tsdn_t *tsdn, pac_t *pac, unsigned ind, emap_t *emap,
pac_init(tsdn_t *tsdn, pac_t *pac, base_t *base, emap_t *emap,
edata_cache_t *edata_cache, nstime_t *cur_time, ssize_t dirty_decay_ms,
ssize_t muzzy_decay_ms, pac_stats_t *pac_stats, malloc_mutex_t *stats_mtx) {
unsigned ind = base_ind_get(base);
/*
* Delay coalescing for dirty extents despite the disruptive effect on
* memory layout for best-fit extent allocation, since cached extents
@ -45,6 +51,7 @@ pac_init(tsdn_t *tsdn, pac_t *pac, unsigned ind, emap_t *emap,
return true;
}
pac->base = base;
pac->emap = emap;
pac->edata_cache = edata_cache;
pac->stats = pac_stats;
@ -76,3 +83,181 @@ pac_retain_grow_limit_get_set(tsdn_t *tsdn, pac_t *pac, size_t *old_limit,
return false;
}
static size_t
pac_stash_decayed(tsdn_t *tsdn, pac_t *pac, ecache_t *ecache,
size_t npages_limit, size_t npages_decay_max, edata_list_t *result) {
witness_assert_depth_to_rank(tsdn_witness_tsdp_get(tsdn),
WITNESS_RANK_CORE, 0);
ehooks_t *ehooks = pac_ehooks_get(pac);
/* Stash extents according to npages_limit. */
size_t nstashed = 0;
while (nstashed < npages_decay_max) {
edata_t *edata = ecache_evict(tsdn, pac, ehooks, ecache,
npages_limit);
if (edata == NULL) {
break;
}
edata_list_append(result, edata);
nstashed += edata_size_get(edata) >> LG_PAGE;
}
return nstashed;
}
static size_t
pac_decay_stashed(tsdn_t *tsdn, pac_t *pac, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache, bool fully_decay,
edata_list_t *decay_extents) {
bool err;
size_t nmadvise = 0;
size_t nunmapped = 0;
size_t npurged = 0;
ehooks_t *ehooks = pac_ehooks_get(pac);
bool try_muzzy = !fully_decay && pac_muzzy_decay_ms_get(pac) != 0;
for (edata_t *edata = edata_list_first(decay_extents); edata !=
NULL; edata = edata_list_first(decay_extents)) {
edata_list_remove(decay_extents, edata);
size_t size = edata_size_get(edata);
size_t npages = size >> LG_PAGE;
nmadvise++;
npurged += npages;
switch (ecache->state) {
case extent_state_active:
not_reached();
case extent_state_dirty:
if (try_muzzy) {
err = extent_purge_lazy_wrapper(tsdn, ehooks,
edata, /* offset */ 0, size);
if (!err) {
ecache_dalloc(tsdn, pac, ehooks,
&pac->ecache_muzzy, edata);
break;
}
}
JEMALLOC_FALLTHROUGH;
case extent_state_muzzy:
extent_dalloc_wrapper(tsdn, pac, ehooks, edata);
nunmapped += npages;
break;
case extent_state_retained:
default:
not_reached();
}
}
if (config_stats) {
LOCKEDINT_MTX_LOCK(tsdn, *pac->stats_mtx);
locked_inc_u64(tsdn, LOCKEDINT_MTX(*pac->stats_mtx),
&decay_stats->npurge, 1);
locked_inc_u64(tsdn, LOCKEDINT_MTX(*pac->stats_mtx),
&decay_stats->nmadvise, nmadvise);
locked_inc_u64(tsdn, LOCKEDINT_MTX(*pac->stats_mtx),
&decay_stats->purged, npurged);
LOCKEDINT_MTX_UNLOCK(tsdn, *pac->stats_mtx);
atomic_fetch_sub_zu(&pac->stats->pac_mapped,
nunmapped << LG_PAGE, ATOMIC_RELAXED);
}
return npurged;
}
/*
* npages_limit: Decay at most npages_decay_max pages without violating the
* invariant: (ecache_npages_get(ecache) >= npages_limit). We need an upper
* bound on number of pages in order to prevent unbounded growth (namely in
* stashed), otherwise unbounded new pages could be added to extents during the
* current decay run, so that the purging thread never finishes.
*/
static void
pac_decay_to_limit(tsdn_t *tsdn, pac_t *pac, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache, bool fully_decay,
size_t npages_limit, size_t npages_decay_max) {
witness_assert_depth_to_rank(tsdn_witness_tsdp_get(tsdn),
WITNESS_RANK_CORE, 1);
if (decay->purging || npages_decay_max == 0) {
return;
}
decay->purging = true;
malloc_mutex_unlock(tsdn, &decay->mtx);
edata_list_t decay_extents;
edata_list_init(&decay_extents);
size_t npurge = pac_stash_decayed(tsdn, pac, ecache, npages_limit,
npages_decay_max, &decay_extents);
if (npurge != 0) {
size_t npurged = pac_decay_stashed(tsdn, pac, decay,
decay_stats, ecache, fully_decay, &decay_extents);
assert(npurged == npurge);
}
malloc_mutex_lock(tsdn, &decay->mtx);
decay->purging = false;
}
void
pac_decay_all(tsdn_t *tsdn, pac_t *pac, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache, bool fully_decay) {
malloc_mutex_assert_owner(tsdn, &decay->mtx);
pac_decay_to_limit(tsdn, pac, decay, decay_stats, ecache, fully_decay,
/* npages_limit */ 0, ecache_npages_get(ecache));
}
static void
pac_decay_try_purge(tsdn_t *tsdn, pac_t *pac, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache,
size_t current_npages, size_t npages_limit) {
if (current_npages > npages_limit) {
pac_decay_to_limit(tsdn, pac, decay, decay_stats, ecache,
/* fully_decay */ false, npages_limit,
current_npages - npages_limit);
}
}
bool
pac_maybe_decay_purge(tsdn_t *tsdn, pac_t *pac, decay_t *decay,
pac_decay_stats_t *decay_stats, ecache_t *ecache,
pac_decay_purge_setting_t decay_purge_setting) {
malloc_mutex_assert_owner(tsdn, &decay->mtx);
/* Purge all or nothing if the option is disabled. */
ssize_t decay_ms = decay_ms_read(decay);
if (decay_ms <= 0) {
if (decay_ms == 0) {
pac_decay_to_limit(tsdn, pac, decay, decay_stats,
ecache, /* fully_decay */ false,
/* npages_limit */ 0, ecache_npages_get(ecache));
}
return false;
}
/*
* If the deadline has been reached, advance to the current epoch and
* purge to the new limit if necessary. Note that dirty pages created
* during the current epoch are not subject to purge until a future
* epoch, so as a result purging only happens during epoch advances, or
* being triggered by background threads (scheduled event).
*/
nstime_t time;
nstime_init_update(&time);
size_t npages_current = ecache_npages_get(ecache);
bool epoch_advanced = decay_maybe_advance_epoch(decay, &time,
npages_current);
if (decay_purge_setting == PAC_DECAY_PURGE_ALWAYS
|| (epoch_advanced && decay_purge_setting
== PAC_DECAY_PURGE_ON_EPOCH_ADVANCE)) {
size_t npages_limit = decay_npages_limit_get(decay);
pac_decay_try_purge(tsdn, pac, decay, decay_stats, ecache,
npages_current, npages_limit);
}
return epoch_advanced;
}

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@ -88,7 +88,7 @@ do_alloc_free_purge(void *arg) {
&generated_dirty);
malloc_mutex_lock(TSDN_NULL,
&test_data->shard.pac.decay_dirty.mtx);
pa_decay_all(TSDN_NULL, &test_data->shard,
pac_decay_all(TSDN_NULL, &test_data->shard.pac,
&test_data->shard.pac.decay_dirty,
&test_data->shard.pac.stats->decay_dirty,
&test_data->shard.pac.ecache_dirty, true);