* [PATCH] mmc: card: don't use PF_MEMALLOC
@ 2016-03-16 11:43 Martin Kepplinger
2016-03-16 14:41 ` Jens Axboe
0 siblings, 1 reply; 4+ messages in thread
From: Martin Kepplinger @ 2016-03-16 11:43 UTC (permalink / raw)
To: ulf.hansson, axboe, chuanxiao.dong, fabf
Cc: linux-mmc, linux-kernel, Martin Kepplinger
PF_MEMALLOC is assigned to processes by mm. If drivers prevent memory
reclaim and mm is not in control, strange hang-up or OOM Killer invocation
could happen.
Signed-off-by: Martin Kepplinger <martink@posteo.de>
---
I use MMC cards with this change perfectly fine. As I understand it,
even *if* PF_MEMALLOC has a real reason to be here, I think it should
be very well documented.
drivers/mmc/card/queue.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 6f4323c..be71249 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -51,8 +51,6 @@ static int mmc_queue_thread(void *d)
struct mmc_queue *mq = d;
struct request_queue *q = mq->queue;
- current->flags |= PF_MEMALLOC;
-
down(&mq->thread_sem);
do {
struct request *req = NULL;
--
2.1.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] mmc: card: don't use PF_MEMALLOC
2016-03-16 11:43 [PATCH] mmc: card: don't use PF_MEMALLOC Martin Kepplinger
@ 2016-03-16 14:41 ` Jens Axboe
2016-03-16 15:07 ` Martin Kepplinger
0 siblings, 1 reply; 4+ messages in thread
From: Jens Axboe @ 2016-03-16 14:41 UTC (permalink / raw)
To: Martin Kepplinger, ulf.hansson, chuanxiao.dong, fabf
Cc: linux-mmc, linux-kernel
On 03/16/2016 04:43 AM, Martin Kepplinger wrote:
> PF_MEMALLOC is assigned to processes by mm. If drivers prevent memory
> reclaim and mm is not in control, strange hang-up or OOM Killer invocation
> could happen.
>
> Signed-off-by: Martin Kepplinger <martink@posteo.de>
> ---
> I use MMC cards with this change perfectly fine. As I understand it,
> even *if* PF_MEMALLOC has a real reason to be here, I think it should
> be very well documented.
Did you try swap on mmcblk?
--
Jens Axboe
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mmc: card: don't use PF_MEMALLOC
2016-03-16 14:41 ` Jens Axboe
@ 2016-03-16 15:07 ` Martin Kepplinger
2016-03-16 15:12 ` Jens Axboe
0 siblings, 1 reply; 4+ messages in thread
From: Martin Kepplinger @ 2016-03-16 15:07 UTC (permalink / raw)
To: Jens Axboe, ulf.hansson, chuanxiao.dong, fabf; +Cc: linux-mmc, linux-kernel
Am 2016-03-16 um 15:41 schrieb Jens Axboe:
> On 03/16/2016 04:43 AM, Martin Kepplinger wrote:
>> PF_MEMALLOC is assigned to processes by mm. If drivers prevent memory
>> reclaim and mm is not in control, strange hang-up or OOM Killer
>> invocation
>> could happen.
>>
>> Signed-off-by: Martin Kepplinger <martink@posteo.de>
>> ---
>> I use MMC cards with this change perfectly fine. As I understand it,
>> even *if* PF_MEMALLOC has a real reason to be here, I think it should
>> be very well documented.
>
> Did you try swap on mmcblk?
>
No I haven't even thought about that :) If you know it can be necessary
in that case, it's obviously fine. A comment would still be good though.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mmc: card: don't use PF_MEMALLOC
2016-03-16 15:07 ` Martin Kepplinger
@ 2016-03-16 15:12 ` Jens Axboe
0 siblings, 0 replies; 4+ messages in thread
From: Jens Axboe @ 2016-03-16 15:12 UTC (permalink / raw)
To: Martin Kepplinger, ulf.hansson, chuanxiao.dong, fabf
Cc: linux-mmc, linux-kernel
On 03/16/2016 08:07 AM, Martin Kepplinger wrote:
> Am 2016-03-16 um 15:41 schrieb Jens Axboe:
>> On 03/16/2016 04:43 AM, Martin Kepplinger wrote:
>>> PF_MEMALLOC is assigned to processes by mm. If drivers prevent memory
>>> reclaim and mm is not in control, strange hang-up or OOM Killer
>>> invocation
>>> could happen.
>>>
>>> Signed-off-by: Martin Kepplinger <martink@posteo.de>
>>> ---
>>> I use MMC cards with this change perfectly fine. As I understand it,
>>> even *if* PF_MEMALLOC has a real reason to be here, I think it should
>>> be very well documented.
>>
>> Did you try swap on mmcblk?
>>
>
> No I haven't even thought about that :) If you know it can be necessary
> in that case, it's obviously fine. A comment would still be good though.
That's why it is there! So yes, adding a comment to that effect would be
a better path forward.
--
Jens Axboe
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-03-16 15:14 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2016-03-16 11:43 [PATCH] mmc: card: don't use PF_MEMALLOC Martin Kepplinger
2016-03-16 14:41 ` Jens Axboe
2016-03-16 15:07 ` Martin Kepplinger
2016-03-16 15:12 ` Jens Axboe
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