From: David Rientjes <rientjes@google.com>
To: Shaohua Li <shaohua.li@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>, Christoph Lameter <cl@linux.com>,
linux-mm@kvack.org
Subject: Re: zone state overhead
Date: Tue, 28 Sep 2010 22:06:38 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1009282157100.9677@chino.kir.corp.google.com> (raw)
In-Reply-To: <1285735638.27440.23.camel@sli10-conroe.sh.intel.com>
On Wed, 29 Sep 2010, Shaohua Li wrote:
> > diff --git a/mm/vmstat.c b/mm/vmstat.c
> > --- a/mm/vmstat.c
> > +++ b/mm/vmstat.c
> > @@ -154,7 +154,7 @@ static void refresh_zone_stat_thresholds(void)
> > tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
> > max_drift = num_online_cpus() * threshold;
> > if (max_drift > tolerate_drift)
> > - zone->percpu_drift_mark = high_wmark_pages(zone) +
> > + zone->percpu_drift_mark = low_wmark_pages(zone) +
> > max_drift;
> > }
> > }
> I'm afraid not. I tried Christoph's patch, which doesn't help.
> in that patch, the threshold = 6272/2 = 3136. and the percpu_drift_mark
> is 3136 + 2161 < 8073
>
I think my patch is conceptually correct based on the real risk that Mel
was describing. With Christoph's patch the threshold would have been 49
(max_drift is 3136), which would also increase the the cacheline bounce
for zone_page_state_add(), but the penalty of zone_page_state_snapshot()
is probably much higher.
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next prev parent reply other threads:[~2010-09-29 5:06 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-28 5:08 Shaohua Li
2010-09-28 12:39 ` Christoph Lameter
2010-09-28 13:30 ` Mel Gorman
2010-09-28 13:40 ` Christoph Lameter
2010-09-28 13:51 ` Mel Gorman
2010-09-28 14:08 ` Christoph Lameter
2010-09-29 3:02 ` Shaohua Li
2010-09-29 4:02 ` David Rientjes
2010-09-29 4:47 ` Shaohua Li
2010-09-29 5:06 ` David Rientjes [this message]
2010-09-29 10:03 ` Mel Gorman
2010-09-29 14:12 ` Christoph Lameter
2010-09-29 14:17 ` Mel Gorman
2010-09-29 14:34 ` Christoph Lameter
2010-09-29 14:41 ` Mel Gorman
2010-09-29 14:45 ` Mel Gorman
2010-09-29 14:54 ` Christoph Lameter
2010-09-29 14:52 ` Christoph Lameter
2010-09-29 19:44 ` David Rientjes
2010-10-08 15:29 ` Mel Gorman
2010-10-09 0:58 ` Shaohua Li
2010-10-11 8:56 ` Mel Gorman
2010-10-12 1:05 ` Shaohua Li
2010-10-12 16:25 ` Mel Gorman
2010-10-13 2:41 ` Shaohua Li
2010-10-13 12:09 ` Mel Gorman
2010-10-13 3:36 ` KOSAKI Motohiro
2010-10-13 6:25 ` [RFC][PATCH 0/3] mm: reserve max drift pages at boot time instead using zone_page_state_snapshot() KOSAKI Motohiro
2010-10-13 6:27 ` [RFC][PATCH 1/3] mm, mem-hotplug: recalculate lowmem_reserve when memory hotplug occur KOSAKI Motohiro
2010-10-13 6:39 ` KAMEZAWA Hiroyuki
2010-10-13 12:59 ` Mel Gorman
2010-10-14 2:44 ` KOSAKI Motohiro
2010-10-13 6:28 ` [RFC][PATCH 2/3] mm: update pcp->stat_threshold " KOSAKI Motohiro
2010-10-13 6:40 ` KAMEZAWA Hiroyuki
2010-10-13 13:02 ` Mel Gorman
2010-10-13 6:32 ` [RFC][PATCH 3/3] mm: reserve max drift pages at boot time instead using zone_page_state_snapshot() KOSAKI Motohiro
2010-10-13 13:19 ` Mel Gorman
2010-10-14 2:39 ` KOSAKI Motohiro
2010-10-18 10:43 ` Mel Gorman
2010-10-13 7:10 ` [experimental][PATCH] mm,vmstat: per cpu stat flush too when per cpu page cache flushed KOSAKI Motohiro
2010-10-13 7:16 ` KAMEZAWA Hiroyuki
2010-10-13 13:22 ` Mel Gorman
2010-10-14 2:50 ` KOSAKI Motohiro
2010-10-15 17:31 ` Christoph Lameter
2010-10-18 9:27 ` KOSAKI Motohiro
2010-10-18 15:44 ` Christoph Lameter
2010-10-19 1:10 ` KOSAKI Motohiro
2010-10-18 11:08 ` Mel Gorman
2010-10-19 1:34 ` KOSAKI Motohiro
2010-10-19 9:06 ` Mel Gorman
2010-10-18 15:51 ` Christoph Lameter
2010-10-19 0:43 ` KOSAKI Motohiro
2010-10-13 11:24 ` zone state overhead Mel Gorman
2010-10-14 3:07 ` KOSAKI Motohiro
2010-10-18 10:39 ` Mel Gorman
2010-10-19 1:16 ` KOSAKI Motohiro
2010-10-19 9:08 ` Mel Gorman
2010-10-22 14:12 ` Mel Gorman
2010-10-22 15:23 ` Christoph Lameter
2010-10-22 18:45 ` Mel Gorman
2010-10-22 15:27 ` Christoph Lameter
2010-10-22 18:46 ` Mel Gorman
2010-10-22 20:01 ` Christoph Lameter
2010-10-25 4:46 ` KOSAKI Motohiro
2010-10-27 8:19 ` Mel Gorman
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