linux-kernel - Re: [PATCH 2/3] page allocator: Do not allow interrupts to use ALLOC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20091027130924.fa903f5a.akpm@linux-foundation.org>
Date:	Tue, 27 Oct 2009 13:09:24 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Mel Gorman <mel@....ul.ie>
Cc:	stable@...nel.org, linux-kernel@...r.kernel.org,
	"linux-mm@...ck.org\"" <linux-mm@...ck.org>,
	Frans Pop <elendil@...net.nl>, Jiri Kosina <jkosina@...e.cz>,
	Sven Geggus <lists@...hsschwanzdomain.de>,
	Karol Lewandowski <karol.k.lewandowski@...il.com>,
	Tobias Oetiker <tobi@...iker.ch>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Pekka Enberg <penberg@...helsinki.fi>,
	Rik van Riel <riel@...hat.com>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Stephan von Krawczynski <skraw@...net.com>,
	"Kernel Testers List <kernel-testers@...r.kernel.org>, Mel Gorman <mel@....ul.ie>"@linux-foundation.org
Subject: Re: [PATCH 2/3] page allocator: Do not allow interrupts to use
 ALLOC_HARDER

On Tue, 27 Oct 2009 13:40:32 +0000
Mel Gorman <mel@....ul.ie> wrote:

> 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.
> 
> [rientjes@...gle.com: Spotted the problem]
> Signed-off-by: Mel Gorman <mel@....ul.ie>
> Reviewed-by: Pekka Enberg <penberg@...helsinki.fi>
> Reviewed-by: Rik van Riel <riel@...hat.com>
> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> ---
>  mm/page_alloc.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index dfa4362..7f2aa3e 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))) {

What are the runtime-observeable effects of this change?

The description is a bit waffly-sounding for a -stable backportable
thing, IMO.  What reason do the -stable maintainers and users have to
believe that this patch is needed, and an improvement?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/