linux/include
Mel Gorman c33d6c06f6 mm, page_alloc: avoid looking up the first zone in a zonelist twice
The allocator fast path looks up the first usable zone in a zonelist and
then get_page_from_freelist does the same job in the zonelist iterator.
This patch preserves the necessary information.

                                             4.6.0-rc2                  4.6.0-rc2
                                        fastmark-v1r20             initonce-v1r20
  Min      alloc-odr0-1               364.00 (  0.00%)           359.00 (  1.37%)
  Min      alloc-odr0-2               262.00 (  0.00%)           260.00 (  0.76%)
  Min      alloc-odr0-4               214.00 (  0.00%)           214.00 (  0.00%)
  Min      alloc-odr0-8               186.00 (  0.00%)           186.00 (  0.00%)
  Min      alloc-odr0-16              173.00 (  0.00%)           173.00 (  0.00%)
  Min      alloc-odr0-32              165.00 (  0.00%)           165.00 (  0.00%)
  Min      alloc-odr0-64              161.00 (  0.00%)           162.00 ( -0.62%)
  Min      alloc-odr0-128             159.00 (  0.00%)           161.00 ( -1.26%)
  Min      alloc-odr0-256             168.00 (  0.00%)           170.00 ( -1.19%)
  Min      alloc-odr0-512             180.00 (  0.00%)           181.00 ( -0.56%)
  Min      alloc-odr0-1024            190.00 (  0.00%)           190.00 (  0.00%)
  Min      alloc-odr0-2048            196.00 (  0.00%)           196.00 (  0.00%)
  Min      alloc-odr0-4096            202.00 (  0.00%)           202.00 (  0.00%)
  Min      alloc-odr0-8192            206.00 (  0.00%)           205.00 (  0.49%)
  Min      alloc-odr0-16384           206.00 (  0.00%)           205.00 (  0.49%)

The benefit is negligible and the results are within the noise but each
cycle counts.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19 19:12:14 -07:00
..
acpi Merge branches 'acpi-pci', 'acpi-misc' and 'acpi-tools' 2016-05-16 16:45:48 +02:00
asm-generic arch: fix has_transparent_hugepage() 2016-05-19 19:12:14 -07:00
clocksource
crypto
drm
dt-bindings ARM: SoC driver updates for v4.7 2016-05-18 13:14:02 -07:00
keys
kvm
linux mm, page_alloc: avoid looking up the first zone in a zonelist twice 2016-05-19 19:12:14 -07:00
math-emu
media [media] media: rc: reduce size of struct ir_raw_event 2016-05-07 10:34:17 -03:00
memory
misc
net switchdev: pass pointer to fib_info instead of copy 2016-05-17 13:58:49 -04:00
pcmcia
ras
rdma
rxrpc
scsi
soc ARM: SoC driver updates for v4.7 2016-05-18 13:14:02 -07:00
sound
target
trace SCSI misc on 20160517 2016-05-18 16:38:59 -07:00
uapi media updates for v4.7-rc1 2016-05-18 17:03:51 -07:00
video
xen
Kbuild