mirror of
https://github.com/MariaDB/server.git
synced 2025-01-22 23:04:20 +01:00
5608a737ea
No point to issue RELEASE memory barrier in os_thread_create_func(): thread creation is full memory barrier. No point to issue os_wmb in rw_lock_set_waiter_flag() and rw_lock_reset_waiter_flag(): this is deadcode and it is unlikely operational anyway. If atomic builtins are unavailable - memory barriers are most certainly unavailable too. RELEASE memory barrier is definitely abused in buf_pool_withdraw_blocks(): most probably it was supposed to commit volatile variable update, which is not what memory barriers actually do. To operate properly it needs corresponding ACQUIRE barrier without an associated atomic operation anyway. ACQUIRE memory barrier is definitely abused in log_write_up_to(): most probably it was supposed to synchronize dirty read of log_sys->write_lsn. To operate properly it needs corresponding RELEASE barrier without an associated atomic operation anyway. Removed a bunch of ACQUIRE memory barriers from InnoDB rwlocks. They're meaningless without corresponding RELEASE memory barriers. Valid usage example of memory barriers without an associated atomic operation: http://en.cppreference.com/w/cpp/atomic/atomic_thread_fence |
||
|---|---|---|
| .. | ||
| os0event.cc | ||
| os0file.cc | ||
| os0proc.cc | ||
| os0thread.cc | ||