From: Pekka Enberg <penberg@kernel.org>
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: David Mackey <tdmackey@twitter.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
rientjes@google.com, Andi Kleen <ak@linux.intel.com>,
cl@linux.com
Subject: Re: [PATCH v5] slab/mempolicy: always use local policy from interrupt context
Date: Wed, 20 Jun 2012 10:02:29 +0300 [thread overview]
Message-ID: <CAOJsxLGcndOEEDzeKJaEiLrwV779R+hv2dPvqBrxbr0FzczpUg@mail.gmail.com> (raw)
In-Reply-To: <4FDEE4E6.6030205@gmail.com>
On Mon, Jun 18, 2012 at 11:20 AM, KOSAKI Motohiro
<kosaki.motohiro@gmail.com> wrote:
> (6/9/12 5:40 AM), David Mackey wrote:
>> From: Andi Kleen<ak@linux.intel.com>
>>
>> From: Andi Kleen<ak@linux.intel.com>
>>
>> slab_node() could access current->mempolicy from interrupt context.
>> However there's a race condition during exit where the mempolicy
>> is first freed and then the pointer zeroed.
>>
>> Using this from interrupts seems bogus anyways. The interrupt
>> will interrupt a random process and therefore get a random
>> mempolicy. Many times, this will be idle's, which noone can change.
>>
>> Just disable this here and always use local for slab
>> from interrupts. I also cleaned up the callers of slab_node a bit
>> which always passed the same argument.
>>
>> I believe the original mempolicy code did that in fact,
>> so it's likely a regression.
>>
>> v2: send version with correct logic
>> v3: simplify. fix typo.
>> Reported-by: Arun Sharma<asharma@fb.com>
>> Cc: penberg@kernel.org
>> Cc: cl@linux.com
>> Signed-off-by: Andi Kleen<ak@linux.intel.com>
>> [tdmackey@twitter.com: Rework control flow based on feedback from
>> cl@linux.com, fix logic, and cleanup current task_struct reference]
>> Signed-off-by: David Mackey<tdmackey@twitter.com>
>
> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Applied, thanks!
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prev parent reply other threads:[~2012-06-20 7:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1338438844-5022-1-git-send-email-andi@firstfloor.org>
2012-06-09 9:40 ` David Mackey
2012-06-10 2:19 ` David Rientjes
2012-06-17 1:11 ` David Rientjes
2012-06-17 10:37 ` Pekka Enberg
2012-06-11 15:05 ` Christoph Lameter
2012-06-18 8:20 ` KOSAKI Motohiro
2012-06-20 7:02 ` Pekka Enberg [this message]
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