From: Linus Torvalds <torvalds@linux-foundation.org>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: Hugh Dickins <hughd@google.com>, Mel Gorman <mgorman@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Petr Holasek <pholasek@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH] ksm: make rmap walks more scalable
Date: Thu, 20 Dec 2012 14:26:43 -0800 [thread overview]
Message-ID: <CA+55aFxfS0SBbRBRULX4Hm7a-xOY7ebJ=Ncu2cAdH2xvcZFO+Q@mail.gmail.com> (raw)
In-Reply-To: <50D387FD.4020008@oracle.com>
On Thu, Dec 20, 2012 at 1:49 PM, Sasha Levin <sasha.levin@oracle.com> wrote:
> On 12/19/2012 08:44 PM, Hugh Dickins wrote:
>> The rmap walks in ksm.c are like those in rmap.c:
>> they can safely be done with anon_vma_lock_read().
>>
>> Signed-off-by: Hugh Dickins <hughd@google.com>
>> ---
>
> Hi Hugh,
>
> This patch didn't fix the ksm oopses I'm seeing.
>
> This is with both patches applied:
Looks like another NULL mm pointer in ksmd.. Hugh fixed one in
2832bc19f666 ("sched: numa: ksm: fix oops in task_numa_placment()"),
this looks like more of the same.
At a guess, it looks like get_mergeable_page() has a rmap_item with no
mm. No idea how that happened. Hugh? Some race due to something that
depended on the mmap_sem being exclusive, rather than for
read-ownership?
Linus
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next prev parent reply other threads:[~2012-12-20 22:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-20 1:42 [PATCH] sched: numa: ksm: fix oops in task_numa_placment() Hugh Dickins
2012-12-20 1:44 ` [PATCH] ksm: make rmap walks more scalable Hugh Dickins
2012-12-20 11:17 ` Mel Gorman
2012-12-20 21:49 ` Sasha Levin
2012-12-20 22:26 ` Linus Torvalds [this message]
2012-12-20 22:40 ` Hugh Dickins
2012-12-20 22:37 ` Hugh Dickins
2012-12-20 22:43 ` Sasha Levin
2012-12-21 0:36 ` Petr Holasek
2012-12-21 2:35 ` Hugh Dickins
2012-12-20 11:14 ` [PATCH] sched: numa: ksm: fix oops in task_numa_placment() Mel Gorman
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