From: Christoph Lameter <cl@linux.com>
To: Bron Gondwana <brong@fastmail.fm>
Cc: Robert Mueller <robm@fastmail.fm>,
Shaohua Li <shaohua.li@intel.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>, Mel Gorman <mel@csn.ul.ie>
Subject: Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad for file/email/web servers
Date: Fri, 17 Sep 2010 09:22:00 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1009170916130.11900@router.home> (raw)
In-Reply-To: <20100917140916.GA8474@brong.net>
On Sat, 18 Sep 2010, Bron Gondwana wrote:
> > From the first look that seems to be the problem. You do not need to be
> > bound to a particular cpu, the scheduler will just leave a single process
> > on the same cpu by default. If you then allocate all memory only from this
> > process then you get the scenario that you described.
>
> Huh? Which bit of forking server makes you think one process is allocating
> lots of memory? They're opening and reading from files. Unless you're
> calling the kernel a "single process".
I have no idea what your app does. The data that I glanced over looks as
if most allocations happen for a particular memory node and since the
memory is optimized to be local to that node other memory is not used
intensively. This can occur because of allocations through one process /
thread that is always running on the same cpu and therefore always
allocates from the memory node local to that cpu.
It can also happen f.e. if a driver always allocates memory local to the
I/O bus that it is using.
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next prev parent reply other threads:[~2010-09-17 14:22 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1284349152.15254.1394658481@webmail.messagingengine.com>
2010-09-16 10:01 ` KOSAKI Motohiro
2010-09-16 17:06 ` Christoph Lameter
2010-09-17 0:50 ` Robert Mueller
2010-09-17 6:01 ` Shaohua Li
2010-09-17 7:32 ` Robert Mueller
2010-09-17 13:56 ` Christoph Lameter
2010-09-17 14:09 ` Bron Gondwana
2010-09-17 14:22 ` Christoph Lameter [this message]
2010-09-17 23:01 ` Bron Gondwana
2010-09-20 9:34 ` Mel Gorman
2010-09-20 23:41 ` Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/web servers Rob Mueller
2010-09-21 9:04 ` Mel Gorman
2010-09-21 14:14 ` Christoph Lameter
2010-09-22 3:44 ` Rob Mueller
2010-09-27 2:01 ` KOSAKI Motohiro
2010-09-27 13:53 ` Christoph Lameter
2010-09-27 23:17 ` Robert Mueller
2010-09-28 12:35 ` Christoph Lameter
2010-09-28 12:42 ` Bron Gondwana
2010-09-28 12:49 ` Christoph Lameter
2010-09-30 7:05 ` Andi Kleen
2010-10-04 12:45 ` KOSAKI Motohiro
2010-10-04 13:07 ` Christoph Lameter
2010-10-05 5:32 ` KOSAKI Motohiro
2010-10-04 19:43 ` David Rientjes
2010-09-21 1:05 ` Default zone_reclaim_mode = 1 on NUMA kernel is bad for file/email/web servers KAMEZAWA Hiroyuki
2010-09-27 2:04 ` KOSAKI Motohiro
2010-09-27 2:06 ` KAMEZAWA Hiroyuki
2010-09-23 11:44 ` Balbir Singh
2010-09-30 8:38 ` Bron Gondwana
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