lkml.org 
[lkml]   [2021]   [Nov]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [v5 PATCH 6/6] mm: hwpoison: handle non-anonymous THP correctly
On Mon, Nov 01, 2021 at 01:11:33PM -0700, Yang Shi wrote:
> On Mon, Nov 1, 2021 at 12:38 PM Jue Wang <juew@google.com> wrote:
> >
> > A related bug but whose fix may belong to a separate series:
> >
> > split_huge_page fails when invoked concurrently on the same THP page.
> >
> > It's possible that multiple memory errors on the same THP get consumed
> > by multiple threads and come down to split_huge_page path easily.
>
> Yeah, I think it should be a known problem since the very beginning.
> The THP split requires to pin the page and does check if the refcount
> is expected or not and freezes the refcount if it is expected. So if
> two concurrent paths try to split the same THP, one will fail due to
> the pin from the other path, but the other one will succeed.

No, they can both fail, if the timing is just right, because they each
have a refcount, so neither will succeed.

\
 
 \ /
  Last update: 2021-11-02 04:52    [W:0.064 / U:0.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site