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server-skynet-source-3rd-je.../include/jemalloc/internal/mutex_pool_inlines.h

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Protect the rtree/extent interactions with a mutex pool. Instead of embedding a lock bit in rtree leaf elements, we associate extents with a small set of mutexes. This gets us two things: - We can use the system mutexes. This (hypothetically) protects us from priority inversion, and lets us stop doing a backoff/sleep loop, instead opting for precise wakeups from the mutex. - Cuts down on the number of mutex acquisitions we have to do (from 4 in the worst case to two). We end up simplifying most of the rtree code (which no longer has to deal with locking or concurrency at all), at the cost of additional complexity in the extent code: since the mutex protecting the rtree leaf elements is determined by reading the extent out of those elements, the initial read is racy, so that we may acquire an out of date mutex. We re-check the extent in the leaf after acquiring the mutex to protect us from this race.
2017-05-16 05:23:51 +08:00
#ifndef JEMALLOC_INTERNAL_MUTEX_POOL_INLINES_H
#define JEMALLOC_INTERNAL_MUTEX_POOL_INLINES_H
#include "jemalloc/internal/hash.h"
Header refactoring: unify and de-catchall mutex module
2017-05-24 03:28:19 +08:00
#include "jemalloc/internal/mutex.h"
Protect the rtree/extent interactions with a mutex pool. Instead of embedding a lock bit in rtree leaf elements, we associate extents with a small set of mutexes. This gets us two things: - We can use the system mutexes. This (hypothetically) protects us from priority inversion, and lets us stop doing a backoff/sleep loop, instead opting for precise wakeups from the mutex. - Cuts down on the number of mutex acquisitions we have to do (from 4 in the worst case to two). We end up simplifying most of the rtree code (which no longer has to deal with locking or concurrency at all), at the cost of additional complexity in the extent code: since the mutex protecting the rtree leaf elements is determined by reading the extent out of those elements, the initial read is racy, so that we may acquire an out of date mutex. We re-check the extent in the leaf after acquiring the mutex to protect us from this race.
2017-05-16 05:23:51 +08:00
#include "jemalloc/internal/mutex_pool_structs.h"
Header refactoring: unify and de-catchall witness code.
2017-05-23 10:32:04 +08:00
#include "jemalloc/internal/witness.h"
Protect the rtree/extent interactions with a mutex pool. Instead of embedding a lock bit in rtree leaf elements, we associate extents with a small set of mutexes. This gets us two things: - We can use the system mutexes. This (hypothetically) protects us from priority inversion, and lets us stop doing a backoff/sleep loop, instead opting for precise wakeups from the mutex. - Cuts down on the number of mutex acquisitions we have to do (from 4 in the worst case to two). We end up simplifying most of the rtree code (which no longer has to deal with locking or concurrency at all), at the cost of additional complexity in the extent code: since the mutex protecting the rtree leaf elements is determined by reading the extent out of those elements, the initial read is racy, so that we may acquire an out of date mutex. We re-check the extent in the leaf after acquiring the mutex to protect us from this race.
2017-05-16 05:23:51 +08:00
/*
* This file really combines "inlines" and "externs", but only transitionally.
*/
bool mutex_pool_init(mutex_pool_t *pool, const char *name, witness_rank_t rank);
static inline malloc_mutex_t *
mutex_pool_mutex(mutex_pool_t *pool, uintptr_t key) {
size_t hash_result[2];
hash(&key, sizeof(key), 0xd50dcc1b, hash_result);
return &pool->mutexes[hash_result[0] % MUTEX_POOL_SIZE];
}
static inline void
mutex_pool_assert_not_held(tsdn_t *tsdn, mutex_pool_t *pool) {
for (int i = 0; i < MUTEX_POOL_SIZE; i++) {
malloc_mutex_assert_not_owner(tsdn, &pool->mutexes[i]);
}
}
/*
* Note that a mutex pool doesn't work exactly the way an embdedded mutex would.
* You're not allowed to acquire mutexes in the pool one at a time. You have to
* acquire all the mutexes you'll need in a single function call, and then
* release them all in a single function call.
*/
static inline void
mutex_pool_lock(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key) {
mutex_pool_assert_not_held(tsdn, pool);
malloc_mutex_t *mutex = mutex_pool_mutex(pool, key);
malloc_mutex_lock(tsdn, mutex);
}
static inline void
mutex_pool_unlock(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key) {
malloc_mutex_t *mutex = mutex_pool_mutex(pool, key);
malloc_mutex_unlock(tsdn, mutex);
mutex_pool_assert_not_held(tsdn, pool);
}
static inline void
mutex_pool_lock2(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key1,
uintptr_t key2) {
mutex_pool_assert_not_held(tsdn, pool);
malloc_mutex_t *mutex1 = mutex_pool_mutex(pool, key1);
malloc_mutex_t *mutex2 = mutex_pool_mutex(pool, key2);
if ((uintptr_t)mutex1 < (uintptr_t)mutex2) {
malloc_mutex_lock(tsdn, mutex1);
malloc_mutex_lock(tsdn, mutex2);
} else if ((uintptr_t)mutex1 == (uintptr_t)mutex2) {
malloc_mutex_lock(tsdn, mutex1);
} else {
malloc_mutex_lock(tsdn, mutex2);
malloc_mutex_lock(tsdn, mutex1);
}
}
static inline void
mutex_pool_unlock2(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key1,
uintptr_t key2) {
malloc_mutex_t *mutex1 = mutex_pool_mutex(pool, key1);
malloc_mutex_t *mutex2 = mutex_pool_mutex(pool, key2);
if (mutex1 == mutex2) {
malloc_mutex_unlock(tsdn, mutex1);
} else {
malloc_mutex_unlock(tsdn, mutex1);
malloc_mutex_unlock(tsdn, mutex2);
}
mutex_pool_assert_not_held(tsdn, pool);
}
static inline void
mutex_pool_assert_owner(tsdn_t *tsdn, mutex_pool_t *pool, uintptr_t key) {
malloc_mutex_assert_owner(tsdn, mutex_pool_mutex(pool, key));
}
#endif /* JEMALLOC_INTERNAL_MUTEX_POOL_INLINES_H */
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