On 7/11/24 6:39 AM, Ming Lei wrote:
There are only two WRITE on 'cleared': - xchg(&map->cleared, 0) in sbitmap_deferred_clear() - set_bit() in sbitmap_deferred_clear_bit() xchg() supposes to provide such protection already.
Hi Ming, The comment above 'swap_lock' in this patch is as follows: /** * @swap_lock: Held while swapping word <-> cleared */ In other words, 'swap_lock' is used to serialize *code*. Using synchronization objects to serialize code is known as an anti-pattern, something that shouldn't be done. Synchronization objects should be used to serialize access to data. Hence my question whether it would be appropriate to protect all 'cleared' changes with the newly introduced spinlock. Thanks, Bart.
