From: Andi Kleen <andi@firstfloor.org>
To: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
kosaki.motohiro@gmail.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Andrew Morton <akpm@google.com>,
Dave Jones <davej@redhat.com>, Mel Gorman <mgorman@suse.de>,
stable@vger.kernel.org, hughd@google.com, sivanich@sgi.com,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
andi@firstfloor.org
Subject: Re: [PATCH 0/6] mempolicy memory corruption fixlet
Date: Wed, 30 May 2012 20:46:38 +0200 [thread overview]
Message-ID: <20120530184638.GU27374@one.firstfloor.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1205301328550.31768@router.home>
On Wed, May 30, 2012 at 01:34:21PM -0500, Christoph Lameter wrote:
> On Wed, 30 May 2012, Linus Torvalds wrote:
>
> > On Wed, May 30, 2012 at 2:02 AM, <kosaki.motohiro@gmail.com> wrote:
> > >
> > > So, I think we should reconsider about shared mempolicy completely.
> >
> > Quite frankly, I'd prefer that approach. The code is subtle and
> > horribly bug-fraught, and I absolutely detest the way it looks too.
> > Reading your patches was actually somewhat painful.
>
> It is so bad mostly because the integration of shared memory policies with
> cpusets is not really working. Using either in isolation is ok especially
> shared mempolicies do not play well with cpusets.
Yes the cpusets did some horrible things.
I always regretted that cpusets were no done with custom node lists.
That would have been much cleaner and also likely faster than what we have.
> > If we could just remove the support for it entirely, that would be
> > *much* preferable to continue working with this code.
>
> Well shm support needs memory policies to spread data across nodes etc.
> AFAICT support was put in due to requirements to support large database
> vendors (oracle). Andi?
Yes we need shared policy for the big databases.
Maybe we could stop supporting cpusets with that though. Not sure they
really use that.
> Its not going to be easy to remove.
Shared policies? I don't think you can remove them.
cpusets+shared policy? maybe, but still will be hard.
-Andi
>
--
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next prev parent reply other threads:[~2012-05-30 18:46 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-30 9:02 [PATCH 0/6] mempolicy memory corruption fixlet kosaki.motohiro
2012-05-30 9:02 ` [PATCH 1/6] Revert "mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages" kosaki.motohiro
2012-05-30 19:17 ` Christoph Lameter
2012-05-30 19:39 ` KOSAKI Motohiro
2012-05-30 19:44 ` Christoph Lameter
2012-05-31 6:49 ` KOSAKI Motohiro
2012-05-30 9:02 ` [PATCH 2/6] mempolicy: Kill all mempolicy sharing kosaki.motohiro
2012-05-30 19:41 ` Christoph Lameter
2012-05-30 19:46 ` KOSAKI Motohiro
2012-05-30 19:48 ` Andi Kleen
2012-05-30 20:31 ` Andi Kleen
2012-05-30 20:58 ` KOSAKI Motohiro
2012-05-30 9:02 ` [PATCH 3/6] mempolicy: fix a race in shared_policy_replace() kosaki.motohiro
2012-05-30 9:02 ` [PATCH 4/6] mempolicy: fix refcount leak in mpol_set_shared_policy() kosaki.motohiro
2012-05-30 9:02 ` [PATCH 5/6] mempolicy: fix a memory corruption by refcount imbalance in alloc_pages_vma() kosaki.motohiro
2012-05-30 20:37 ` Andi Kleen
2012-05-30 9:02 ` [PATCH 6/6] MAINTAINERS: Added MEMPOLICY entry kosaki.motohiro
2012-05-30 19:27 ` Christoph Lameter
2012-05-30 18:26 ` [PATCH 0/6] mempolicy memory corruption fixlet Linus Torvalds
2012-05-30 18:34 ` Christoph Lameter
2012-05-30 18:46 ` Andi Kleen [this message]
2012-05-30 18:50 ` Christoph Lameter
2012-05-30 19:32 ` Andi Kleen
2012-05-30 19:42 ` Christoph Lameter
2012-05-30 19:52 ` Andi Kleen
2012-05-30 20:00 ` KOSAKI Motohiro
2012-05-30 21:22 ` Ben Hutchings
2012-05-30 21:25 ` KOSAKI Motohiro
2012-05-30 19:54 ` KOSAKI Motohiro
2012-05-30 20:10 ` Andi Kleen
2012-05-30 20:16 ` KOSAKI Motohiro
2012-06-01 0:45 ` david
2012-06-01 13:51 ` Christoph Lameter
2012-06-01 19:31 ` david
2012-06-01 19:37 ` KOSAKI Motohiro
2012-06-05 19:02 ` Linus Torvalds
2012-06-05 19:17 ` Andrew Morton
2012-06-06 19:10 ` KOSAKI Motohiro
2012-05-30 19:03 ` Linus Torvalds
2012-05-30 20:10 ` KOSAKI Motohiro
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