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mdbx: refine mdb_env_sync().

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Change-Id: I37e6079a94a20624e65aed3e2e599bb4490afcc0
This commit is contained in:
Leo Yuriev 2016-03-13 18:48:21 +03:00
parent 4d9c0657d9
commit 14ddec2051
1 changed files with 17 additions and 20 deletions
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37
mdb.c
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@ -2588,31 +2588,28 @@ mdb_env_sync(MDB_env *env, int force)
return EACCES;
head = mdb_meta_head_r(env);
if (force || head->mm_mapsize != env->me_mapsize)
flags &= MDB_WRITEMAP;
/* LY: just only for 'early sync' to reduce writer latency */
if (env->me_sync_threshold && env->me_sync_pending >= env->me_sync_threshold)
flags &= MDB_WRITEMAP;
if ((flags & MDB_NOSYNC) == 0) {
/* LY: early sync before acquiring the mutex,
* this reduces latency for writer */
if (flags & MDB_WRITEMAP) {
if (msync(env->me_map, env->me_mapsize,
(flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC))
return errno;
} else if (fdatasync(env->me_fd))
return errno;
/* LY: head may be changed during the sync. */
head = mdb_meta_head_r(env);
}
if (! META_IS_WEAK(head) && env->me_sync_pending == 0
&& env->me_mapsize == head->mm_mapsize)
/* LY: nothing to do */
return MDB_SUCCESS;
if (force || head->mm_mapsize != env->me_mapsize
|| (env->me_sync_threshold && env->me_sync_pending >= env->me_sync_threshold))
flags &= MDB_WRITEMAP;
/* LY: early sync before acquiring the mutex to reduce writer's latency */
if (env->me_sync_pending > env->me_psize * 16 && (flags & MDB_NOSYNC) == 0) {
if (flags & MDB_WRITEMAP) {
size_t used_size = env->me_psize * (head->mm_last_pg + 1);
rc = msync(env->me_map, used_size,
(flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC);
} else {
rc = fdatasync(env->me_fd);
}
if (unlikely(rc))
return errno;
}
mutex = MDB_MUTEX(env, w);
rc = mdb_mutex_lock(env, mutex);
if (unlikely(rc))