linux/include
Minchan Kim 02c6de8d75 mm: cma: discard clean pages during contiguous allocation instead of migration
Drop clean cache pages instead of migration during alloc_contig_range() to
minimise allocation latency by reducing the amount of migration that is
necessary.  It's useful for CMA because latency of migration is more
important than evicting the background process's working set.  In
addition, as pages are reclaimed then fewer free pages for migration
targets are required so it avoids memory reclaiming to get free pages,
which is a contributory factor to increased latency.

I measured elapsed time of __alloc_contig_migrate_range() which migrates
10M in 40M movable zone in QEMU machine.

Before - 146ms, After - 7ms

[akpm@linux-foundation.org: fix nommu build]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Mel Gorman <mgorman@suse.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Rik van Riel <riel@redhat.com>
Tested-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09 16:22:43 +09:00
..
acpi Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-10-08 07:14:06 +09:00
asm-generic thp: introduce pmdp_invalidate() 2012-10-09 16:22:29 +09:00
clocksource arm64: Generic timers support 2012-09-17 13:42:20 +01:00
crypto
drm Merge branch 'drm-intel-fixes' of git://people.freedesktop.org/~danvet/drm-intel into drm-next 2012-10-07 21:13:54 +10:00
keys
linux mm: cma: discard clean pages during contiguous allocation instead of migration 2012-10-09 16:22:43 +09:00
math-emu
media Merge branch 'exynos-drm-next' of git://git.infradead.org/users/kmpark/linux-samsung into drm-next 2012-10-07 21:06:33 +10:00
memory
misc
mtd
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-10-06 03:11:59 +09:00
pcmcia
ras
rdma IB/core: Add ib_find_exact_cached_pkey() 2012-09-30 20:33:30 -07:00
rxrpc
scsi Prepared for main script 2012-10-03 13:45:43 -07:00
sound Sound updates for 3.7-rc1 2012-10-09 07:07:14 +09:00
target
trace mm: remove __GFP_NO_KSWAPD 2012-10-09 16:22:15 +09:00
uapi UAPI: (Scripted) Disintegrate include/drm 2012-10-04 18:21:50 +01:00
video ARM: clps711x: Remove board support for CEIVA 2012-09-28 21:14:08 +02:00
xen Features: 2012-10-07 07:13:01 +09:00
Kbuild