Blame jemalloc/include/jemalloc/internal/mutex_pool.h

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#ifndef JEMALLOC_INTERNAL_MUTEX_POOL_H
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#define JEMALLOC_INTERNAL_MUTEX_POOL_H
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#include "jemalloc/internal/hash.h"
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#include "jemalloc/internal/mutex.h"
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#include "jemalloc/internal/witness.h"
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/* We do mod reductions by this value, so it should be kept a power of 2. */
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#define MUTEX_POOL_SIZE 256
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typedef struct mutex_pool_s mutex_pool_t;
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struct mutex_pool_s {
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	malloc_mutex_t mutexes[MUTEX_POOL_SIZE];
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};
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bool mutex_pool_init(mutex_pool_t *pool, const char *name, witness_rank_t rank);
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/* Internal helper - not meant to be called outside this module. */
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static inline malloc_mutex_t *
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mutex_pool_mutex(mutex_pool_t *pool, uintptr_t key) {
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	size_t hash_result[2];
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	hash(&key, sizeof(key), 0xd50dcc1b, hash_result);
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	return &pool->mutexes[hash_result[0] % MUTEX_POOL_SIZE];
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}
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static inline void
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mutex_pool_assert_not_held(tsdn_t *tsdn, mutex_pool_t *pool) {
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	for (int i = 0; i < MUTEX_POOL_SIZE; i++) {
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		malloc_mutex_assert_not_owner(tsdn, &pool->mutexes[i]);
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	}
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}
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/*
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 * Note that a mutex pool doesn't work exactly the way an embdedded mutex would.
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 * You're not allowed to acquire mutexes in the pool one at a time.  You have to
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 * acquire all the mutexes you'll need in a single function call, and then
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 * release them all in a single function call.
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 */
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static inline void
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mutex_pool_lock(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key) {
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	mutex_pool_assert_not_held(tsdn, pool);
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	malloc_mutex_t *mutex = mutex_pool_mutex(pool, key);
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	malloc_mutex_lock(tsdn, mutex);
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}
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static inline void
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mutex_pool_unlock(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key) {
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	malloc_mutex_t *mutex = mutex_pool_mutex(pool, key);
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	malloc_mutex_unlock(tsdn, mutex);
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	mutex_pool_assert_not_held(tsdn, pool);
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}
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static inline void
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mutex_pool_lock2(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key1,
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    uintptr_t key2) {
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	mutex_pool_assert_not_held(tsdn, pool);
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	malloc_mutex_t *mutex1 = mutex_pool_mutex(pool, key1);
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	malloc_mutex_t *mutex2 = mutex_pool_mutex(pool, key2);
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	if ((uintptr_t)mutex1 < (uintptr_t)mutex2) {
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		malloc_mutex_lock(tsdn, mutex1);
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		malloc_mutex_lock(tsdn, mutex2);
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	} else if ((uintptr_t)mutex1 == (uintptr_t)mutex2) {
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		malloc_mutex_lock(tsdn, mutex1);
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	} else {
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		malloc_mutex_lock(tsdn, mutex2);
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		malloc_mutex_lock(tsdn, mutex1);
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	}
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}
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static inline void
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mutex_pool_unlock2(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key1,
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    uintptr_t key2) {
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	malloc_mutex_t *mutex1 = mutex_pool_mutex(pool, key1);
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	malloc_mutex_t *mutex2 = mutex_pool_mutex(pool, key2);
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	if (mutex1 == mutex2) {
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		malloc_mutex_unlock(tsdn, mutex1);
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	} else {
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		malloc_mutex_unlock(tsdn, mutex1);
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		malloc_mutex_unlock(tsdn, mutex2);
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	}
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	mutex_pool_assert_not_held(tsdn, pool);
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}
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static inline void
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mutex_pool_assert_owner(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key) {
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	malloc_mutex_assert_owner(tsdn, mutex_pool_mutex(pool, key));
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}
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#endif /* JEMALLOC_INTERNAL_MUTEX_POOL_H */