Re: page allocation failure message kernel 2.6.31.4 (tty-related)

[Pekka Enberg <penberg@cs.helsinki.fi>]

On Thu, Oct 22, 2009 at 1:59 PM, Mel Gorman <mel@csn.ul.ie> wrote:
>> There's subtleties like where rt tasks are given ALLOC_HARDER even when
>> in_interrupt() that are different from previous kernels and could reduce
>> the amount of ALLOC_HIGH and ALLOC_HARDER memory that can be allocated.
>>
>
> /me checks again
>
> I think you're right. Correct it with something like?
>
> ==== CUT HERE ====
> From bca71e94e10cd93771ec5b17eccb817dd0c85360 Mon Sep 17 00:00:00 2001
> From: Mel Gorman <mel@csn.ul.ie>
> Date: Thu, 22 Oct 2009 11:55:14 +0100
> Subject: [PATCH] page allocator: Do not allow interrupts to use ALLOC_HARDER
>
> Commit 341ce06f69abfafa31b9468410a13dbd60e2b237 altered watermark logic
> slightly by allowing rt_tasks that are handling an interrupt to set
> ALLOC_HARDER. This patch brings the watermark logic more in line with
> 2.6.30.
>
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>

Good catch.

Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>

Can we have some of the people that are hitting the OOM problems test
this patch in combination with this patch:

http://patchwork.kernel.org/patch/54215/

Mel, can you also resend these page allocator patches to Andrew? I
haven't seen him pick the above patch in -mm and we probably want to
get fixes into -stable soon because distributors seem to be basing
their next releases on 2.6.31...

> ---
>  mm/page_alloc.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index a3e5fed..3ecf819 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1769,7 +1769,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
>                 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
>                 */
>                alloc_flags &= ~ALLOC_CPUSET;
> -       } else if (unlikely(rt_task(p)))
> +       } else if (unlikely(rt_task(p)) && !in_interrupt())
>                alloc_flags |= ALLOC_HARDER;
>
>        if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
> --
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