linux-stable/include
Mel Gorman 24cf72518c vmscan: count the number of times zone_reclaim() scans and fails
On NUMA machines, the administrator can configure zone_reclaim_mode that
is a more targetted form of direct reclaim.  On machines with large NUMA
distances for example, a zone_reclaim_mode defaults to 1 meaning that
clean unmapped pages will be reclaimed if the zone watermarks are not
being met.

There is a heuristic that determines if the scan is worthwhile but it is
possible that the heuristic will fail and the CPU gets tied up scanning
uselessly.  Detecting the situation requires some guesswork and
experimentation so this patch adds a counter "zreclaim_failed" to
/proc/vmstat.  If during high CPU utilisation this counter is increasing
rapidly, then the resolution to the problem may be to set
/proc/sys/vm/zone_reclaim_mode to 0.

[akpm@linux-foundation.org: name things consistently]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:46 -07:00
..
acpi Merge branch 'drm-intel-next' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel 2009-04-28 17:21:20 -07:00
asm-generic Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-06-15 03:02:23 -07:00
crypto
drm Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2009-06-12 18:09:18 -07:00
keys
linux vmscan: count the number of times zone_reclaim() scans and fails 2009-06-16 19:47:46 -07:00
math-emu
media
mtd
net pkt_sched: Rename PSCHED_US2NS and PSCHED_NS2US 2009-06-15 02:31:47 -07:00
pcmcia
rdma
rxrpc
scsi Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-06-15 03:02:23 -07:00
sound Merge branch 'topic/pcm-jiffies-check' into for-linus 2009-06-10 07:26:41 +02:00
trace Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-06-15 03:02:23 -07:00
video fb: add support of LCD display controller on pxa168/910 (base layer) 2009-06-13 00:09:09 +08:00
xen
Kbuild