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mdbx: rework support for ThreadSanitizer.

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Change-Id: I6a1cc980fa835215d2051f68bbf8580b747e6d6b
This commit is contained in:
Leo Yuriev 2016-03-03 14:40:25 +03:00
parent c809b2e12c
commit 9d775b0a36
1 changed files with 64 additions and 20 deletions
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84
mdb.c
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@ -1883,7 +1883,7 @@ static MDB_meta* mdb_meta_head_w(MDB_env *env) {
return a; return a;
} }
static ATTRIBUTE_NO_SANITIZE_THREAD /* LY: avoid tsan-trap by meta->mm_txnid */ static
MDB_meta* mdb_meta_head_r(MDB_env *env) { 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;
@ -1893,15 +1893,26 @@ MDB_meta* mdb_meta_head_r(MDB_env *env) {
while(1) { while(1) {
#ifdef __SANITIZE_THREAD__ #ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex); pthread_mutex_lock(&tsan_mutex);
pthread_mutex_unlock(&tsan_mutex);
#endif #endif
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 (likely(a->mm_txnid == head_txnid)) if (likely(a->mm_txnid == head_txnid)) {
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
return a; return a;
if (likely(b->mm_txnid == head_txnid)) }
if (likely(b->mm_txnid == head_txnid)) {
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
return b; return b;
}
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
/* LY: got a race on env->me_txns->mti_txnid with mdb_env_sync0() */ /* LY: got a race on env->me_txns->mti_txnid with mdb_env_sync0() */
#if defined(__i386__) || defined(__x86_64__) #if defined(__i386__) || defined(__x86_64__)
@ -1933,9 +1944,12 @@ static int mdb_meta_lt(MDB_meta* a, MDB_meta* b) {
} }
/** Find oldest txnid still referenced. */ /** Find oldest txnid still referenced. */
static ATTRIBUTE_NO_SANITIZE_THREAD /* LY: avoid tsan-trap by reader[].mr_txnid */ static
txnid_t mdb_find_oldest(MDB_env *env, int *laggard) txnid_t mdb_find_oldest(MDB_env *env, int *laggard)
{ {
#ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex);
#endif
int i, reader; int i, reader;
MDB_reader *r = env->me_txns->mti_readers; MDB_reader *r = env->me_txns->mti_readers;
txnid_t oldest = env->me_txns->mti_txnid; txnid_t oldest = env->me_txns->mti_txnid;
@ -1956,6 +1970,9 @@ txnid_t mdb_find_oldest(MDB_env *env, int *laggard)
} }
} }
} }
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
if (laggard) if (laggard)
*laggard = reader; *laggard = reader;
@ -2729,22 +2746,25 @@ mdb_reader_pid(MDB_env *env, int op, pid_t pid)
} }
} }
static ATTRIBUTE_NO_SANITIZE_THREAD static
txnid_t lead_txnid__tsan_workaround(MDB_txn *txn, MDB_reader *r) txnid_t lead_txnid(MDB_txn *txn, MDB_reader *r)
{ {
while(1) { /* LY: Retry on a race, ITS#7970. */ while(1) { /* LY: Retry on a race, ITS#7970. */
MDB_meta *meta = mdb_meta_head_r(txn->mt_env); MDB_meta *meta = mdb_meta_head_r(txn->mt_env);
#ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex);
#endif
txnid_t lead = meta->mm_txnid; txnid_t lead = meta->mm_txnid;
r->mr_txnid = lead; r->mr_txnid = lead;
mdb_coherent_barrier(); mdb_coherent_barrier();
/* Copy the DB info and flags */ /* Copy the DB info and flags */
memcpy(txn->mt_dbs, meta->mm_dbs, CORE_DBS * sizeof(MDB_db)); memcpy(txn->mt_dbs, meta->mm_dbs, CORE_DBS * sizeof(MDB_db));
txn->mt_next_pgno = meta->mm_last_pg+1; txn->mt_next_pgno = meta->mm_last_pg+1;
if (likely(lead == txn->mt_env->me_txns->mti_txnid)) { txnid_t snap = txn->mt_env->me_txns->mti_txnid;
#ifdef __SANITIZE_THREAD__ #ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex); pthread_mutex_unlock(&tsan_mutex);
pthread_mutex_unlock(&tsan_mutex);
#endif #endif
if (likely(lead == snap)) {
return lead; return lead;
} }
#if defined(__i386__) || defined(__x86_64__) #if defined(__i386__) || defined(__x86_64__)
@ -2839,11 +2859,18 @@ mdb_txn_renew0(MDB_txn *txn, unsigned flags)
r->mr_txnid = ~(txnid_t)0; r->mr_txnid = ~(txnid_t)0;
r->mr_tid = tid; r->mr_tid = tid;
mdb_coherent_barrier(); mdb_coherent_barrier();
if (i == nr) #ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex);
#endif
if (i == nr) {
env->me_txns->mti_numreaders = ++nr; env->me_txns->mti_numreaders = ++nr;
}
if (env->me_close_readers < nr) if (env->me_close_readers < nr)
env->me_close_readers = nr; env->me_close_readers = nr;
r->mr_pid = pid; r->mr_pid = pid;
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
mdb_mutex_unlock(env, rmutex); mdb_mutex_unlock(env, rmutex);
new_notls = MDB_END_SLOT; new_notls = MDB_END_SLOT;
@ -2854,7 +2881,7 @@ mdb_txn_renew0(MDB_txn *txn, unsigned flags)
} }
} }
txn->mt_txnid = lead_txnid__tsan_workaround(txn, r); txn->mt_txnid = lead_txnid(txn, r);
txn->mt_u.reader = r; txn->mt_u.reader = r;
txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */ txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
} else { } else {
@ -2865,11 +2892,13 @@ mdb_txn_renew0(MDB_txn *txn, unsigned flags)
#ifdef __SANITIZE_THREAD__ #ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex); pthread_mutex_lock(&tsan_mutex);
pthread_mutex_unlock(&tsan_mutex);
#endif #endif
MDB_meta *meta = mdb_meta_head_w(env); MDB_meta *meta = mdb_meta_head_w(env);
txn->mt_txnid = meta->mm_txnid + 1; txn->mt_txnid = meta->mm_txnid + 1;
txn->mt_flags = flags; txn->mt_flags = flags;
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
#if MDB_DEBUG #if MDB_DEBUG
if (unlikely(txn->mt_txnid == mdb_debug_edge)) { if (unlikely(txn->mt_txnid == mdb_debug_edge)) {
@ -3159,6 +3188,9 @@ mdb_txn_end(MDB_txn *txn, unsigned mode)
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) { if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
if (txn->mt_u.reader) { if (txn->mt_u.reader) {
#ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex);
#endif
txn->mt_u.reader->mr_txnid = ~(txnid_t)0; txn->mt_u.reader->mr_txnid = ~(txnid_t)0;
if (!(env->me_flags & MDB_NOTLS)) { if (!(env->me_flags & MDB_NOTLS)) {
txn->mt_u.reader = NULL; /* txn does not own reader */ txn->mt_u.reader = NULL; /* txn does not own reader */
@ -3166,6 +3198,9 @@ mdb_txn_end(MDB_txn *txn, unsigned mode)
txn->mt_u.reader->mr_pid = 0; txn->mt_u.reader->mr_pid = 0;
txn->mt_u.reader = NULL; txn->mt_u.reader = NULL;
} /* else txn owns the slot until it does MDB_END_SLOT */ } /* else txn owns the slot until it does MDB_END_SLOT */
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
} }
mdb_coherent_barrier(); mdb_coherent_barrier();
txn->mt_numdbs = 0; /* prevent further DBI activity */ txn->mt_numdbs = 0; /* prevent further DBI activity */
@ -4188,6 +4223,9 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
mdb_debug("writing meta page %d for root page %zu", mdb_debug("writing meta page %d for root page %zu",
offset >= env->me_psize, pending->mm_dbs[MAIN_DBI].md_root); offset >= env->me_psize, pending->mm_dbs[MAIN_DBI].md_root);
if (env->me_flags & MDB_WRITEMAP) { if (env->me_flags & MDB_WRITEMAP) {
#ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex);
#endif
tail->mm_datasync_sign = MDB_DATASIGN_WEAK; tail->mm_datasync_sign = MDB_DATASIGN_WEAK;
tail->mm_txnid = 0; tail->mm_txnid = 0;
mdb_coherent_barrier(); mdb_coherent_barrier();
@ -4221,8 +4259,21 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
goto fail; goto fail;
} }
mdb_invalidate_cache(env->me_map + offset, sizeof(MDB_meta)); mdb_invalidate_cache(env->me_map + offset, sizeof(MDB_meta));
#ifdef __SANITIZE_THREAD__
pthread_mutex_lock(&tsan_mutex);
#endif
} }
/* Memory ordering issues are irrelevant; since the entire writer
* is wrapped by wmutex, all of these changes will become visible
* after the wmutex is unlocked. Since the DB is multi-version,
* readers will get consistent data regardless of how fresh or
* how stale their view of these values is.
*/
env->me_txns->mti_txnid = pending->mm_txnid; env->me_txns->mti_txnid = pending->mm_txnid;
#ifdef __SANITIZE_THREAD__
pthread_mutex_unlock(&tsan_mutex);
#endif
/* LY: step#3 - sync meta-pages. */ /* LY: step#3 - sync meta-pages. */
if ((flags & (MDB_NOSYNC | MDB_NOMETASYNC)) == 0) { if ((flags & (MDB_NOSYNC | MDB_NOMETASYNC)) == 0) {
@ -4256,13 +4307,6 @@ mdb_env_sync0(MDB_env *env, unsigned flags, MDB_meta *pending)
} }
} }
/* Memory ordering issues are irrelevant; since the entire writer
* is wrapped by wmutex, all of these changes will become visible
* after the wmutex is unlocked. Since the DB is multi-version,
* readers will get consistent data regardless of how fresh or
* how stale their view of these values is.
*/
env->me_txns->mti_txnid = pending->mm_txnid;
return MDB_SUCCESS; return MDB_SUCCESS;
fail: fail: