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

[lai bin]

Yes,  you are right. Now that bookmarks weren't actually useful any
more, removing  bookmarks  is a better way to address the livelocks.

Matthew Wilcox <willy@xxxxxxxxxxxxx> 于2023年10月10日周二 11:58写道：
>
> 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 ...