linux/include
Johannes Weiner d778df51c0 mm: vmscan: save work scanning (almost) empty LRU lists
In certain cases (kswapd reclaim, memcg target reclaim), a fixed minimum
amount of pages is scanned from the LRU lists on each iteration, to make
progress.

Do not make this minimum bigger than the respective LRU list size,
however, and save some busy work trying to isolate and reclaim pages
that are not there.

Empty LRU lists are quite common with memory cgroups in NUMA
environments because there exists a set of LRU lists for each zone for
each memory cgroup, while the memory of a single cgroup is expected to
stay on just one node.  The number of expected empty LRU lists is thus

  memcgs * (nodes - 1) * lru types

Each attempt to reclaim from an empty LRU list does expensive size
comparisons between lists, acquires the zone's lru lock etc.  Avoid
that.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Satoru Moriya <satoru.moriya@hds.com>
Cc: Simon Jeons <simon.jeons@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-23 17:50:09 -08:00
..
acpi Merge branch 'acpi-cleanup' 2013-02-15 13:58:30 +01:00
asm-generic Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2013-02-21 17:54:03 -08:00
clocksource arm: arch_timer: add missing inline in stub function 2013-02-11 15:16:05 -08:00
crypto
drm
keys
linux mm: vmscan: save work scanning (almost) empty LRU lists 2013-02-23 17:50:09 -08:00
math-emu
media
memory
misc
net Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-02-21 17:40:58 -08:00
pcmcia
ras
rdma
rxrpc
scsi
sound ASoC: Final updates for v3.9 2013-02-16 15:48:48 +01:00
target
trace ACPI and power management updates for 3.9-rc1 2013-02-20 11:26:56 -08:00
uapi Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid 2013-02-21 17:41:38 -08:00
video video: s3c-fb: fix typo in definition of VIDCON1_VSTATUS_FRONTPORCH value 2013-02-21 17:22:18 -08:00
xen
Kbuild