ISAR/libmdbx
3
0
Fork 0
mirror of https://github.com/isar/libmdbx.git synced 2025-02-01 05:48:22 +08:00
Code Issues Packages Projects Releases Wiki Activity

mdbx: avoid tsan-trap in mdb_meta_head_r().

Browse Source 
Change-Id: I594c13e1fe908f8afdc663d349cfc4cf634bba77
This commit is contained in:
Leo Yuriev 2015-12-06 13:37:45 +03:00
parent 5bc0a76899
commit 4e5d5ef935
1 changed files with 11 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
mdb.c
View File

@ -1857,17 +1857,18 @@ static MDB_meta* mdb_meta_head_w(MDB_env *env) {
return a; return a;
} }
static MDB_meta* mdb_meta_head_r(MDB_env *env) { static ATTRIBUTE_NO_SANITIZE_THREAD /* LY: avoid tsan-trap by meta->mm_txnid */
MDB_meta* mdb_meta_head_r(MDB_env *env) {
MDB_meta* a = METAPAGE_1(env); MDB_meta* a = METAPAGE_1(env);
MDB_meta* b = METAPAGE_2(env), *h; MDB_meta* b = METAPAGE_2(env), *h;
txnid_t head_txnid; txnid_t head_txnid;
int loop = 0, rc; int loop = 0, rc;
do { while(1) {
head_txnid = env->me_txns->mti_txnid; head_txnid = env->me_txns->mti_txnid;
mdb_assert(env, a->mm_txnid != b->mm_txnid || head_txnid == 0); mdb_assert(env, a->mm_txnid != b->mm_txnid || head_txnid == 0);
if (a->mm_txnid == head_txnid) if (likely(a->mm_txnid == head_txnid))
return a; return a;
if (likely(b->mm_txnid == head_txnid)) if (likely(b->mm_txnid == head_txnid))
return b; return b;
@ -1877,9 +1878,13 @@ static MDB_meta* mdb_meta_head_r(MDB_env *env) {
__asm__ __volatile__("pause"); __asm__ __volatile__("pause");
#endif #endif
mdb_coherent_barrier(); mdb_coherent_barrier();
if (loop > 2) loop += 1;
pthread_yield(); if(likely(loop < 3))
} while (++loop < 5); continue;
if(unlikely(loop > 5))
break;
pthread_yield();
}
rc = mdb_mutex_lock(env, MDB_MUTEX(env, w)); rc = mdb_mutex_lock(env, MDB_MUTEX(env, w));
h = mdb_meta_head_w(env); h = mdb_meta_head_w(env);