Re: [PATCH -next RFC v2 8/8] sbitmap: wake up the number of threads based on required tags

[Bart Van Assche]

On 4/9/22 00:01, yukuai (C) wrote:
> For the race that new threads are waited after get_wake_nr() and before
> wake_up_nr() in situation (b), I can't figure out how this can be
> problematic [ ... ]

If the atomic_dec_return() statement in __sbq_wake_up() returns a value 
that is less than or equal to zero, wake_batch waiters should be woken 
up or I/O will hang until sbitmap_queue_wake_all() is called. That last 
function should not be called unless there is no alternative.

Thanks,

Bart.