From: Kyle McMartin <kyle@mcmartin.ca>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Kyle McMartin <kyle@mcmartin.ca>,
Andrew Morton <akpm@linux-foundation.org>,
Shaohua Li <shaohua.li@intel.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Christoph Lameter <cl@linux.com>,
David Rientjes <rientjes@google.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter threshold when memory is low
Date: Mon, 29 Nov 2010 10:22:30 -0500 [thread overview]
Message-ID: <20101129152230.GH15818@bombadil.infradead.org> (raw)
In-Reply-To: <20101129150824.GF13268@csn.ul.ie>
On Mon, Nov 29, 2010 at 03:08:24PM +0000, Mel Gorman wrote:
> Ouch! I have been unable to create an exact copy of your kernel source as
> I'm not running Fedora. From a partial conversion of a source RPM, I saw no
> changes related to mm/vmscan.c. Is this accurate? I'm trying to establish
> if this is a mainline bug as well.
>
Sorry, if you extract the source rpm you should get the patched
sources... Aside from a few patches to mm/mmap for execshield, mm/* is
otherwise untouched from the latest stable 2.6.35 kernels.
If you git clone git://pkgs.fedoraproject.org/kernel and check out the
origin/f14/master branch, it has all the patches we apply (based on the
'ApplyPatch' lines in kernel.spec
> Second, I see all the stack traces are marked with "?" making them
> unreliable. Is that anything to be concerned about?
>
Hrm, I don't think it is, I think the ones with '?' are just artifacts
because we don't have a proper unwinder. Oh! Thanks! I just found a bug
in our configs... We don't have CONFIG_FRAME_POINTER set because
CONFIG_DEBUG_KERNEL got unset in the 'production' configs... I'll fix
that up.
> I see that one user has reported that the patches fixed the problem for him
> but I fear that this might be a co-incidence or that the patches close a
> race of some description. Specifically, I'm trying to identify if there is
> a situation where kswapd() constantly loops checking watermarks and never
> calling cond_resched(). This could conceivably happen if kswapd() is always
> checking sleeping_prematurely() at a higher order where as balance_pgdat()
> is always checks the watermarks at the lower order. I'm not seeing how this
> could happen in 2.6.35.6 though. If Fedora doesn't have special changes,
> it might mean that these patches do need to go into -stable as the
> cost of zone_page_state_snapshot() is far higher on larger machines than
> previously reported.
>
Yeah, I am a bit surprised as well. Luke seems to have quite a large
machine... I haven't seen any kswapd lockups there on my 18G machine
using the same kernel. :< (Possibly it's just not stressed enough
though.)
Thanks for looking into this!
Kyle
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next prev parent reply other threads:[~2010-11-29 15:23 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-27 8:47 [PATCH 0/2] Reduce the amount of time spent in watermark-related functions Mel Gorman
2010-10-27 8:47 ` [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter threshold when memory is low Mel Gorman
2010-10-27 20:16 ` Christoph Lameter
2010-10-28 1:09 ` KAMEZAWA Hiroyuki
2010-10-28 9:49 ` Mel Gorman
2010-10-28 9:58 ` KAMEZAWA Hiroyuki
2010-11-14 8:53 ` [PATCH] set_pgdat_percpu_threshold() don't use for_each_online_cpu KOSAKI Motohiro
2010-11-15 10:26 ` Mel Gorman
2010-11-15 14:04 ` Christoph Lameter
2010-11-16 9:58 ` Mel Gorman
2010-11-17 0:07 ` Andrew Morton
2010-11-19 15:29 ` Christoph Lameter
2010-11-23 8:32 ` KOSAKI Motohiro
2010-11-01 7:06 ` [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter threshold when memory is low KOSAKI Motohiro
2010-11-26 16:06 ` Kyle McMartin
2010-11-29 9:56 ` Mel Gorman
2010-11-29 13:16 ` Kyle McMartin
2010-11-29 15:08 ` Mel Gorman
2010-11-29 15:22 ` Kyle McMartin [this message]
2010-11-29 15:26 ` Kyle McMartin
2010-11-29 15:58 ` Mel Gorman
2010-12-23 22:18 ` David Rientjes
2010-12-23 22:35 ` Andrew Morton
2010-12-23 23:00 ` Kyle McMartin
2010-12-23 23:07 ` David Rientjes
2010-12-23 23:17 ` Andrew Morton
2010-10-27 8:47 ` [PATCH 2/2] mm: vmstat: Use a single setter function and callback for adjusting percpu thresholds Mel Gorman
2010-10-27 20:13 ` Christoph Lameter
2010-10-28 1:10 ` KAMEZAWA Hiroyuki
2010-11-01 7:06 ` KOSAKI Motohiro
-- strict thread matches above, loose matches on Subject: below --
2010-10-28 15:13 [PATCH 0/2] Reduce the amount of time spent in watermark-related functions V4 Mel Gorman
2010-10-28 15:13 ` [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter threshold when memory is low Mel Gorman
2010-10-28 22:04 ` Andrew Morton
2010-10-29 10:12 ` Mel Gorman
2010-10-29 19:40 ` Andrew Morton
2010-11-02 0:53 ` Shaohua Li
2010-11-09 11:33 ` Mel Gorman
2010-11-09 16:48 ` Christoph Lameter
2010-10-29 14:58 ` Christoph Lameter
2010-10-29 18:25 ` Andrew Morton
2010-10-29 19:33 ` Christoph Lameter
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