Re: [PATCH] sched/wait: introduce endmark in __wake_up_common

[Matthew Wilcox]

On Tue, Oct 10, 2023 at 11:28:33AM +0800, Bin Lai wrote:
> Without this patch applied, it can cause the waker to fall into an
> infinite loop in some cases. The commit 2554db916586 ("sched/wait: Break
> up long wake list walk") introduces WQ_FLAG_BOOKMARK to break up long
> wake list walk. When the number of walked entries reach 64, the waker
> will record scan position and release the queue lock, which reduces
> interrupts and rescheduling latency.

Maybe we could try removing bookmarks instead?  There was a thread a
while ago where we agreed they weren't actually useful any more.

Patches to follow ...