Files
jemalloc/include/jemalloc/internal/background_thread.h
guangli-dai f1f0792370 Move background thread state operations into background thread modules.
Move operations touch background thread's lifecycle and states back into
its own module.
2026-07-16 21:52:34 -07:00

106 lines
4.1 KiB
C

#ifndef JEMALLOC_INTERNAL_BACKGROUND_THREAD_H
#define JEMALLOC_INTERNAL_BACKGROUND_THREAD_H
#include "jemalloc/internal/jemalloc_preamble.h"
#include "jemalloc/internal/base.h"
#include "jemalloc/internal/mutex.h"
#if defined(JEMALLOC_BACKGROUND_THREAD) || defined(JEMALLOC_LAZY_LOCK)
# define JEMALLOC_PTHREAD_CREATE_WRAPPER
#endif
#define BACKGROUND_THREAD_INDEFINITE_SLEEP UINT64_MAX
#define MAX_BACKGROUND_THREAD_LIMIT MALLOCX_ARENA_LIMIT
#define DEFAULT_NUM_BACKGROUND_THREAD 4
typedef enum {
background_thread_stopped,
background_thread_started,
/* Thread waits on the global lock when paused (for arena_reset). */
background_thread_paused,
} background_thread_state_t;
struct background_thread_info_s {
#ifdef JEMALLOC_BACKGROUND_THREAD
/* Background thread is pthread specific. */
pthread_t thread;
pthread_cond_t cond;
#endif
malloc_mutex_t mtx;
background_thread_state_t state;
/* When true, it means no wakeup scheduled. */
atomic_b_t indefinite_sleep;
/* Next scheduled wakeup time (absolute time in ns). */
nstime_t next_wakeup;
/*
* Since the last background thread run, newly added number of pages
* that need to be purged by the next wakeup. This is adjusted on
* epoch advance, and is used to determine whether we should signal the
* background thread to wake up earlier.
*/
size_t npages_to_purge_new;
/* Stats: total number of runs since started. */
uint64_t tot_n_runs;
/* Stats: total sleep time since started. */
nstime_t tot_sleep_time;
};
typedef struct background_thread_info_s background_thread_info_t;
struct background_thread_stats_s {
size_t num_threads;
uint64_t num_runs;
nstime_t run_interval;
mutex_prof_data_t max_counter_per_bg_thd;
};
typedef struct background_thread_stats_s background_thread_stats_t;
extern bool opt_background_thread;
extern size_t opt_max_background_threads;
extern malloc_mutex_t background_thread_lock;
extern atomic_b_t background_thread_enabled_state;
extern size_t n_background_threads;
extern size_t max_background_threads;
extern background_thread_info_t *background_thread_info;
bool background_thread_create(tsd_t *tsd, unsigned arena_ind);
bool background_threads_enable(tsd_t *tsd);
bool background_threads_disable(tsd_t *tsd);
bool background_thread_is_started(background_thread_info_t *info);
void background_thread_wakeup_early(
background_thread_info_t *info, nstime_t *remaining_sleep);
void background_thread_prefork0(tsdn_t *tsdn);
void background_thread_prefork1(tsdn_t *tsdn);
void background_thread_postfork_parent(tsdn_t *tsdn);
void background_thread_postfork_child(tsdn_t *tsdn);
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);
#endif
bool background_thread_boot0(void);
bool background_thread_boot1(tsdn_t *tsdn, base_t *base);
#endif /* JEMALLOC_INTERNAL_BACKGROUND_THREAD_H */