From: Matthew Wilcox <willy@infradead.org>
To: Yang Shi <shy828301@gmail.com>
Cc: "Jue Wang" <juew@google.com>, "Hugh Dickins" <hughd@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
"Linux FS-devel Mailing List" <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"Linux MM" <linux-mm@kvack.org>,
"HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.com>,
"Oscar Salvador" <osalvador@suse.de>,
"Peter Xu" <peterx@redhat.com>
Subject: Re: [v5 PATCH 6/6] mm: hwpoison: handle non-anonymous THP correctly
Date: Tue, 2 Nov 2021 03:49:18 +0000 [thread overview]
Message-ID: <YYC1Phb5eFn9hJfG@casper.infradead.org> (raw)
In-Reply-To: <CAHbLzkp7mN0ePsZiSY4obA_cVqmReSnDd6tF-yxRAmALBzzKAw@mail.gmail.com>
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.
next prev parent reply other threads:[~2021-11-02 3:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 19:38 [v5 PATCH 6/6] mm: hwpoison: handle non-anonymous THP correctly Jue Wang
2021-11-01 20:11 ` Yang Shi
2021-11-02 3:49 ` Matthew Wilcox [this message]
2021-11-02 16:41 ` Yang Shi
-- strict thread matches above, loose matches on Subject: below --
2021-10-20 21:07 [v5 PATCH 0/6] Solve silent data loss caused by poisoned page cache (shmem/tmpfs) Yang Shi
2021-10-20 21:07 ` [v5 PATCH 6/6] mm: hwpoison: handle non-anonymous THP correctly Yang Shi
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