romenskiy2012/jemalloc
1
0
Fork 0
mirror of https://github.com/jemalloc/jemalloc.git synced 2026-07-18 14:47:18 +03:00
Code Issues Projects Releases Packages Wiki Activity

Move background thread state operations into background thread modules.

Browse source 
Move operations touch background thread's lifecycle and states back into
its own module.
This commit is contained in:
guangli-dai 2026-06-28 15:19:47 -07:00 • committed by Guangli Dai
parent 01df5c96e0
commit f1f0792370
5 changed files with 97 additions and 49 deletions
Download patch file Download diff file Expand all files Collapse all files

19
include/jemalloc/internal/background_thread.h
View file

@ -76,6 +76,25 @@ bool background_thread_stats_read(
tsdn_t *tsdn, background_thread_stats_t *stats);
void background_thread_ctl_init(tsdn_t *tsdn);
/*
* Arena-reset lifecycle bracket (owned by the bg-thread module so the
* started<->paused state machine is mutated only inside the module). begin()
* acquires the global background_thread_lock and RETURNS WITH IT HELD;
* finish() releases it. The lock intentionally spans the whole arena-reset
* body across the two calls. Pass arena_ind (not an arena_t *): the destroy
* path frees the arena before calling finish().
*/
void background_thread_arena_reset_begin(tsd_t *tsd, unsigned arena_ind);
void background_thread_arena_reset_finish(tsd_t *tsd, unsigned arena_ind);
/*
* Serialize a rare admin operation against the background thread by holding the
* per-arena info mutex (have_background_thread-gated). Used by
* arena_set_extent_hooks to fence pa_shard_disable_hpa.
*/
void background_thread_serialize_lock(tsd_t *tsd, unsigned arena_ind);
void background_thread_serialize_unlock(tsd_t *tsd, unsigned arena_ind);
#ifdef JEMALLOC_PTHREAD_CREATE_WRAPPER
extern int pthread_create_wrapper(pthread_t *__restrict, const pthread_attr_t *,
void *(*)(void *), void *__restrict);

6
include/jemalloc/internal/background_thread_inlines.h
View file

@ -22,12 +22,6 @@ background_thread_enabled_set(tsdn_t *tsdn, bool state) {
background_thread_enabled_set_impl(state);
}
JEMALLOC_ALWAYS_INLINE background_thread_info_t *
arena_background_thread_info_get(arena_t *arena) {
unsigned arena_ind = arena_ind_get(arena);
return &background_thread_info[arena_ind % max_background_threads];
}
JEMALLOC_ALWAYS_INLINE background_thread_info_t *
background_thread_info_get(size_t ind) {
return &background_thread_info[ind % max_background_threads];

16
src/arena.c
View file

@ -1427,17 +1427,17 @@ arena_get_ehooks(const arena_t *arena) {
extent_hooks_t *
arena_set_extent_hooks(
tsd_t *tsd, arena_t *arena, extent_hooks_t *extent_hooks) {
background_thread_info_t *info;
if (have_background_thread) {
info = arena_background_thread_info_get(arena);
malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
}
/*
* Serialize disabling the HPA against the background thread via the
* module-owned bracket (have_background_thread-gated internally) rather
* than reaching into info->mtx directly.
*/
unsigned arena_ind = arena_ind_get(arena);
background_thread_serialize_lock(tsd, arena_ind);
/* No using the HPA now that we have the custom hooks. */
pa_shard_disable_hpa(tsd_tsdn(tsd), &arena->pa_shard);
extent_hooks_t *ret = base_extent_hooks_set(arena->base, extent_hooks);
if (have_background_thread) {
malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
}
background_thread_serialize_unlock(tsd, arena_ind);
return ret;
}

66
src/background_thread.c
View file

@ -34,6 +34,72 @@ size_t max_background_threads;
/* Thread info per-index. */
background_thread_info_t *background_thread_info;
/******************************************************************************/
/*
* Config-independent lifecycle/state-ownership helpers. Defined
* unconditionally and gated at runtime on have_background_thread, so callers in
* ctl.c / arena.c never touch background_thread_lock or info->state directly;
* they compile to runtime no-ops when !have_background_thread.
*/
void
background_thread_arena_reset_begin(tsd_t *tsd, unsigned arena_ind) {
/* Temporarily disable the background thread during arena reset. */
if (have_background_thread) {
/*
* Hold background_thread_lock across the whole arena-reset
* body (acquired here, released in _finish) so a concurrent
* background_threads_enable() cannot start a background
* thread mid-reset. This must happen whenever the feature
* is compiled in (have_background_thread), even when the
* thread is not currently enabled; the state transition
* below is separately gated on background_thread_enabled().
*/
malloc_mutex_lock(tsd_tsdn(tsd), &background_thread_lock);
if (background_thread_enabled()) {
background_thread_info_t *info =
background_thread_info_get(arena_ind);
assert(info->state == background_thread_started);
malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
info->state = background_thread_paused;
malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
}
}
}
void
background_thread_arena_reset_finish(tsd_t *tsd, unsigned arena_ind) {
if (have_background_thread) {
if (background_thread_enabled()) {
background_thread_info_t *info =
background_thread_info_get(arena_ind);
assert(info->state == background_thread_paused);
malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
info->state = background_thread_started;
malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
}
malloc_mutex_unlock(tsd_tsdn(tsd), &background_thread_lock);
}
}
void
background_thread_serialize_lock(tsd_t *tsd, unsigned arena_ind) {
if (have_background_thread) {
background_thread_info_t *info =
background_thread_info_get(arena_ind);
malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
}
}
void
background_thread_serialize_unlock(tsd_t *tsd, unsigned arena_ind) {
if (have_background_thread) {
background_thread_info_t *info =
background_thread_info_get(arena_ind);
malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
}
}
/******************************************************************************/
#ifdef JEMALLOC_PTHREAD_CREATE_WRAPPER

39
src/ctl.c
View file

@ -2798,37 +2798,6 @@ arena_i_reset_destroy_helper(tsd_t *tsd, const size_t *mib, size_t miblen,
return ret;
}
static void
arena_reset_prepare_background_thread(tsd_t *tsd, unsigned arena_ind) {
/* Temporarily disable the background thread during arena reset. */
if (have_background_thread) {
malloc_mutex_lock(tsd_tsdn(tsd), &background_thread_lock);
if (background_thread_enabled()) {
background_thread_info_t *info =
background_thread_info_get(arena_ind);
assert(info->state == background_thread_started);
malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
info->state = background_thread_paused;
malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
}
}
}
static void
arena_reset_finish_background_thread(tsd_t *tsd, unsigned arena_ind) {
if (have_background_thread) {
if (background_thread_enabled()) {
background_thread_info_t *info =
background_thread_info_get(arena_ind);
assert(info->state == background_thread_paused);
malloc_mutex_lock(tsd_tsdn(tsd), &info->mtx);
info->state = background_thread_started;
malloc_mutex_unlock(tsd_tsdn(tsd), &info->mtx);
}
malloc_mutex_unlock(tsd_tsdn(tsd), &background_thread_lock);
}
}
static int
arena_i_reset_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
size_t *oldlenp, void *newp, size_t newlen) {
@ -2842,9 +2811,9 @@ arena_i_reset_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
return ret;
}
arena_reset_prepare_background_thread(tsd, arena_ind);
background_thread_arena_reset_begin(tsd, arena_ind);
arena_reset(tsd, arena);
arena_reset_finish_background_thread(tsd, arena_ind);
background_thread_arena_reset_finish(tsd, arena_ind);
return ret;
}
@ -2871,7 +2840,7 @@ arena_i_destroy_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
goto label_return;
}
arena_reset_prepare_background_thread(tsd, arena_ind);
background_thread_arena_reset_begin(tsd, arena_ind);
/* Merge stats after resetting and purging arena. */
arena_reset(tsd, arena);
arena_decay(tsd_tsdn(tsd), arena, false, true);
@ -2885,7 +2854,7 @@ arena_i_destroy_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
/* Record arena index for later recycling via arenas.create. */
ql_elm_new(ctl_arena, destroyed_link);
ql_tail_insert(&ctl_arenas->destroyed, ctl_arena, destroyed_link);
arena_reset_finish_background_thread(tsd, arena_ind);
background_thread_arena_reset_finish(tsd, arena_ind);
assert(ret == 0);
label_return: