Mel Gorman 72403b4a0f mm: numa: return the number of base pages altered by protection changes ... Commit 0255d49184 ("mm: Account for a THP NUMA hinting update as one PTE update") was added to account for the number of PTE updates when marking pages prot_numa. task_numa_work was using the old return value to track how much address space had been updated. Altering the return value causes the scanner to do more work than it is configured or documented to in a single unit of work. This patch reverts that commit and accounts for the number of THP updates separately in vmstat. It is up to the administrator to interpret the pair of values correctly. This is a straight-forward operation and likely to only be of interest when actively debugging NUMA balancing problems. The impact of this patch is that the NUMA PTE scanner will scan slower when THP is enabled and workloads may converge slower as a result. On the flip size system CPU usage should be lower than recent tests reported. This is an illustrative example of a short single JVM specjbb test specjbb 3.12.0 3.12.0 vanilla acctupdates TPut 1 26143.00 ( 0.00%) 25747.00 ( -1.51%) TPut 7 185257.00 ( 0.00%) 183202.00 ( -1.11%) TPut 13 329760.00 ( 0.00%) 346577.00 ( 5.10%) TPut 19 442502.00 ( 0.00%) 460146.00 ( 3.99%) TPut 25 540634.00 ( 0.00%) 549053.00 ( 1.56%) TPut 31 512098.00 ( 0.00%) 519611.00 ( 1.47%) TPut 37 461276.00 ( 0.00%) 474973.00 ( 2.97%) TPut 43 403089.00 ( 0.00%) 414172.00 ( 2.75%) 3.12.0 3.12.0 vanillaacctupdates User 5169.64 5184.14 System 100.45 80.02 Elapsed 252.75 251.85 Performance is similar but note the reduction in system CPU time. While this showed a performance gain, it will not be universal but at least it'll be behaving as documented. The vmstats are obviously different but here is an obvious interpretation of them from mmtests. 3.12.0 3.12.0 vanillaacctupdates NUMA page range updates 1408326 11043064 NUMA huge PMD updates 0 21040 NUMA PTE updates 1408326 291624 "NUMA page range updates" == nr_pte_updates and is the value returned to the NUMA pte scanner. NUMA huge PMD updates were the number of THP updates which in combination can be used to calculate how many ptes were updated from userspace. Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Alex Thorlton <athorlton@sgi.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2013-11-13 12:09:11 +09:00
..
acpi	ACPI, CPER: Update cper info	2013-10-21 15:12:00 -07:00
asm-generic	GPIO bulk changes for the v3.13 development cycle	2013-11-12 15:50:46 +09:00
clocksource	drivers: clocksource: add support for ARM architected timer event stream	2013-09-26 09:48:00 +01:00
crypto
drm	Revert "drm: mark context support as a legacy subsystem"	2013-09-20 08:32:59 +10:00
dt-bindings	The clock changes for 3.13 are an even mix of framework improvements &	2013-11-12 16:11:47 +09:00
keys
kvm
linux	mm: numa: return the number of base pages altered by protection changes	2013-11-13 12:09:11 +09:00
math-emu
media
memory
misc
net	ipv6: reset dst.expires value when clearing expire flag	2013-10-25 19:26:59 -04:00
pcmcia
ras
rdma
rxrpc
scsi	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending	2013-09-12 16:11:45 -07:00
sound	Merge remote-tracking branch 'asoc/topic/twl4030' into asoc-next	2013-11-08 10:43:40 +00:00
target	target/iscsi: Bump versions to v4.1.0	2013-09-10 20:23:37 -07:00
trace	mm: get rid of unnecessary overhead of trace_mm_page_alloc_extfrag()	2013-11-13 12:09:10 +09:00
uapi	sound updates for 3.13-rc1	2013-11-12 15:29:53 +09:00
video	video: exynos_dp: remove non-DT support for Exynos Display Port	2013-10-16 13:48:09 -07:00
xen
Kbuild