diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/storage/buffer/bufmgr.c | 29 |
1 files changed, 3 insertions, 26 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index 4b9fd76294d..327ddb7adc8 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -3267,7 +3267,6 @@ UnpinBufferNoOwner(BufferDesc *buf) ref->refcount--; if (ref->refcount == 0) { - uint32 buf_state; uint32 old_buf_state; /* @@ -3285,33 +3284,11 @@ UnpinBufferNoOwner(BufferDesc *buf) */ Assert(!LWLockHeldByMe(BufferDescriptorGetContentLock(buf))); - /* - * Decrement the shared reference count. - * - * Since buffer spinlock holder can update status using just write, - * it's not safe to use atomic decrement here; thus use a CAS loop. - * - * TODO: The above requirement does not hold anymore, in a future - * commit this will be rewritten to release the pin in a single atomic - * operation. - */ - old_buf_state = pg_atomic_read_u32(&buf->state); - for (;;) - { - if (old_buf_state & BM_LOCKED) - old_buf_state = WaitBufHdrUnlocked(buf); - - buf_state = old_buf_state; - - buf_state -= BUF_REFCOUNT_ONE; - - if (pg_atomic_compare_exchange_u32(&buf->state, &old_buf_state, - buf_state)) - break; - } + /* decrement the shared reference count */ + old_buf_state = pg_atomic_fetch_sub_u32(&buf->state, BUF_REFCOUNT_ONE); /* Support LockBufferForCleanup() */ - if (buf_state & BM_PIN_COUNT_WAITER) + if (old_buf_state & BM_PIN_COUNT_WAITER) WakePinCountWaiter(buf); ForgetPrivateRefCountEntry(ref); |