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Reduce rw_lock_debug_mutex contention

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rw_lock_own(), rw_lock_own_flagged(): Traverse the rw_lock_t::debug_list
only after quickly checking if the thread is holding X-latch or SX-latch.
This commit is contained in:
Marko Mäkelä 2019-09-27 14:22:59 +03:00
parent 4ec0c346b8
commit 718fcee0a3
1 changed files with 22 additions and 2 deletions
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24
storage/innobase/sync/sync0rw.cc
View file

@ -999,13 +999,22 @@ rw_lock_own(
ut_ad(lock);
ut_ad(rw_lock_validate(lock));
const os_thread_id_t thread_id = os_thread_get_curr_id();
if (!os_thread_eq(lock->writer_thread, thread_id)) {
} else if (lock_type == RW_LOCK_X && rw_lock_get_x_lock_count(lock)) {
return TRUE;
} else if (lock_type == RW_LOCK_SX && rw_lock_get_sx_lock_count(lock)) {
return TRUE;
}
rw_lock_debug_mutex_enter();
for (const rw_lock_debug_t* info = UT_LIST_GET_FIRST(lock->debug_list);
info != NULL;
info = UT_LIST_GET_NEXT(list, info)) {
if (os_thread_eq(info->thread_id, os_thread_get_curr_id())
if (os_thread_eq(info->thread_id, thread_id)
&& info->pass == 0
&& info->lock_type == lock_type) {
@ -1030,12 +1039,23 @@ bool rw_lock_own_flagged(const rw_lock_t* lock, rw_lock_flags_t flags)
{
ut_ad(rw_lock_validate(lock));
const os_thread_id_t thread_id = os_thread_get_curr_id();
if (!os_thread_eq(lock->writer_thread, thread_id)) {
} else if ((flags & RW_LOCK_FLAG_X)
&& rw_lock_get_x_lock_count(lock)) {
return true;
} else if ((flags & RW_LOCK_FLAG_SX)
&& rw_lock_get_sx_lock_count(lock)) {
return true;
}
rw_lock_debug_mutex_enter();
for (rw_lock_debug_t* info = UT_LIST_GET_FIRST(lock->debug_list);
info != NULL;
info = UT_LIST_GET_NEXT(list, info)) {
if (!os_thread_eq(info->thread_id, os_thread_get_curr_id())
if (!os_thread_eq(info->thread_id, thread_id)
|| info->pass) {
continue;
}