From: Stephen Rothwell <sfr@canb.auug.org.au>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andres Lagar-Cavilla <andreslc@google.com>,
Yang Shi <yang.shi@linaro.org>, Ning Qu <quning@gmail.com>,
Mika Penttila <mika.penttila@nextfour.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH mmotm 3/5] huge tmpfs recovery: tweak shmem_getpage_gfp to fill team fix
Date: Thu, 21 Apr 2016 09:50:21 +1000 [thread overview]
Message-ID: <20160421095021.422d54ed@canb.auug.org.au> (raw)
In-Reply-To: <alpine.LSU.2.11.1604161629520.1907@eggly.anvils>
Hi Hugh,
On Sat, 16 Apr 2016 16:33:07 -0700 (PDT) Hugh Dickins <hughd@google.com> wrote:
>
> Please add this fix after my 27/31, your
> huge-tmpfs-recovery-tweak-shmem_getpage_gfp-to-fill-team.patch
> for later merging into it. Great catch by Mika Penttila, a bug which
> prevented some unusual cases from being recovered into huge pages as
> intended: an initially sparse head would be set PageTeam only after
> this check. But the check is guarding against a racing disband, which
> cannot happen before the head is published as PageTeam, plus we have
> an additional reference on the head which keeps it safe throughout:
> so very easily fixed.
>
> Reported-by: Mika Penttila <mika.penttila@nextfour.com>
> Signed-off-by: Hugh Dickins <hughd@google.com>
> ---
> mm/shmem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2938,7 +2938,7 @@ repeat:
> page = *pagep;
> lock_page(page);
> head = page - (index & (HPAGE_PMD_NR-1));
> - if (!PageTeam(head)) {
> + if (!PageTeam(head) && page != head) {
> error = -ENOENT;
> goto decused;
> }
Added to linux-next today.
--
Cheers,
Stephen Rothwell
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next prev parent reply other threads:[~2016-04-20 23:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-16 23:27 [PATCH mmotm 1/5] huge tmpfs: try to allocate huge pages split into a " Hugh Dickins
2016-04-16 23:29 ` [PATCH mmotm 2/5] huge tmpfs: fix mlocked meminfo track huge unhuge mlocks fix Hugh Dickins
2016-04-20 23:48 ` Stephen Rothwell
2016-04-16 23:33 ` [PATCH mmotm 3/5] huge tmpfs recovery: tweak shmem_getpage_gfp to fill team fix Hugh Dickins
2016-04-20 23:50 ` Stephen Rothwell [this message]
2016-04-16 23:38 ` [PATCH mmotm 4/5] huge tmpfs: avoid premature exposure of new pagetable revert Hugh Dickins
2016-04-20 23:55 ` Stephen Rothwell
2016-04-16 23:41 ` [PATCH mmotm 5/5] huge tmpfs: add shmem_pmd_fault() Hugh Dickins
2016-04-17 0:46 ` Kirill A. Shutemov
2016-04-17 1:21 ` Hugh Dickins
2016-04-20 23:56 ` Stephen Rothwell
2016-04-20 23:45 ` [PATCH mmotm 1/5] huge tmpfs: try to allocate huge pages split into a team fix Stephen Rothwell
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