From: Christoph Lameter <cl@linux.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake
Date: Wed, 1 Sep 2010 19:39:43 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1009011935040.20518@router.home> (raw)
In-Reply-To: <20100902092628.D065.A69D9226@jp.fujitsu.com>
On Thu, 2 Sep 2010, KOSAKI Motohiro wrote:
> > nr_free_pages += delta;
> > if (nr_free_pages < 0)
> > nr_free_pages = 0;
>
> nr_free_pages is unsined. this wouldn't works ;)
The VM counters are signed and must be signed otherwise the deferred
update scheme would cause desasters. For treatment in the page allocator
these may be converted to unsigned.
The effect needs to be the same as retrieving a global or
zone ZVC counter. Which is currently implemented in the following way:
static inline unsigned long zone_page_state(struct zone *zone,
enum zone_stat_item item)
{
long x = atomic_long_read(&zone->vm_stat[item]);
#ifdef CONFIG_SMP
if (x < 0)
x = 0;
#endif
return x;
}
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next prev parent reply other threads:[~2010-09-02 0:39 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-31 17:37 [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V3 Mel Gorman
2010-08-31 17:37 ` [PATCH 1/3] mm: page allocator: Update free page counters after pages are placed on the free list Mel Gorman
2010-08-31 18:17 ` Christoph Lameter
2010-09-01 7:10 ` Mel Gorman
2010-08-31 23:27 ` KOSAKI Motohiro
2010-08-31 17:37 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-08-31 18:20 ` Christoph Lameter
2010-08-31 23:37 ` KOSAKI Motohiro
2010-09-01 7:24 ` Mel Gorman
2010-09-01 7:33 ` KOSAKI Motohiro
2010-09-01 20:16 ` Christoph Lameter
2010-09-01 20:34 ` Mel Gorman
2010-09-02 0:24 ` Christoph Lameter
2010-09-02 0:26 ` KOSAKI Motohiro
2010-09-02 0:39 ` Christoph Lameter [this message]
2010-09-02 0:54 ` Christoph Lameter
2010-09-02 0:43 ` Christoph Lameter
2010-09-02 0:49 ` KOSAKI Motohiro
2010-09-02 8:51 ` Mel Gorman
2010-08-31 17:37 ` [PATCH 3/3] mm: page allocator: Drain per-cpu lists after direct reclaim allocation fails Mel Gorman
2010-08-31 18:26 ` Christoph Lameter
-- strict thread matches above, loose matches on Subject: below --
2010-09-03 9:08 [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V4 Mel Gorman
2010-09-03 9:08 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-09-03 22:55 ` Andrew Morton
2010-09-03 23:17 ` Christoph Lameter
2010-09-03 23:28 ` Andrew Morton
2010-09-04 0:54 ` Christoph Lameter
2010-09-05 18:12 ` Mel Gorman
2010-08-23 8:00 [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V2 Mel Gorman
2010-08-23 8:00 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-08-23 12:56 ` Christoph Lameter
2010-08-23 13:03 ` Mel Gorman
2010-08-23 13:41 ` Christoph Lameter
2010-08-23 13:55 ` Mel Gorman
2010-08-23 16:04 ` Christoph Lameter
2010-08-23 16:13 ` Mel Gorman
2010-08-16 9:42 [RFC PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator Mel Gorman
2010-08-16 9:42 ` [PATCH 2/3] mm: page allocator: Calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake Mel Gorman
2010-08-16 9:43 ` Mel Gorman
2010-08-16 14:47 ` Rik van Riel
2010-08-16 16:06 ` Johannes Weiner
2010-08-17 2:26 ` Minchan Kim
2010-08-17 10:42 ` Mel Gorman
2010-08-17 15:01 ` Minchan Kim
2010-08-17 15:05 ` Mel Gorman
2010-08-17 10:16 ` Mel Gorman
2010-08-17 11:05 ` Johannes Weiner
2010-08-17 14:20 ` Minchan Kim
2010-08-18 8:51 ` Mel Gorman
2010-08-18 14:57 ` Minchan Kim
2010-08-19 8:06 ` Mel Gorman
2010-08-19 10:33 ` Minchan Kim
2010-08-19 10:38 ` Mel Gorman
2010-08-19 14:01 ` Minchan Kim
2010-08-19 14:09 ` Mel Gorman
2010-08-19 14:34 ` Minchan Kim
2010-08-19 15:07 ` Mel Gorman
2010-08-19 15:22 ` Minchan Kim
2010-08-19 15:40 ` Mel Gorman
2010-08-19 15:44 ` Minchan Kim
2010-08-19 15:46 ` Minchan Kim
2010-08-19 16:06 ` Mel Gorman
2010-08-19 16:45 ` Minchan Kim
2010-08-18 2:59 ` KAMEZAWA Hiroyuki
2010-08-18 15:55 ` Christoph Lameter
2010-08-19 0:07 ` KAMEZAWA Hiroyuki
2010-08-19 19:00 ` Christoph Lameter
2010-08-19 23:49 ` KAMEZAWA Hiroyuki
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