linux/include
Vlastimil Babka 002f290627 cpuset: use static key better and convert to new API
An important function for cpusets is cpuset_node_allowed(), which
optimizes on the fact if there's a single root CPU set, it must be
trivially allowed.  But the check "nr_cpusets() <= 1" doesn't use the
cpusets_enabled_key static key the right way where static keys eliminate
branching overhead with jump labels.

This patch converts it so that static key is used properly.  It's also
switched to the new static key API and the checking functions are
converted to return bool instead of int.  We also provide a new variant
__cpuset_zone_allowed() which expects that the static key check was
already done and they key was enabled.  This is needed for
get_page_from_freelist() where we want to also avoid the relatively
slower check when ALLOC_CPUSET is not set in alloc_flags.

The impact on the page allocator microbenchmark is less than expected
but the cleanup in itself is worthwhile.

                                             4.6.0-rc2                  4.6.0-rc2
                                       multcheck-v1r20               cpuset-v1r20
  Min      alloc-odr0-1               348.00 (  0.00%)           348.00 (  0.00%)
  Min      alloc-odr0-2               254.00 (  0.00%)           254.00 (  0.00%)
  Min      alloc-odr0-4               213.00 (  0.00%)           213.00 (  0.00%)
  Min      alloc-odr0-8               186.00 (  0.00%)           183.00 (  1.61%)
  Min      alloc-odr0-16              173.00 (  0.00%)           171.00 (  1.16%)
  Min      alloc-odr0-32              166.00 (  0.00%)           163.00 (  1.81%)
  Min      alloc-odr0-64              162.00 (  0.00%)           159.00 (  1.85%)
  Min      alloc-odr0-128             160.00 (  0.00%)           157.00 (  1.88%)
  Min      alloc-odr0-256             169.00 (  0.00%)           166.00 (  1.78%)
  Min      alloc-odr0-512             180.00 (  0.00%)           180.00 (  0.00%)
  Min      alloc-odr0-1024            188.00 (  0.00%)           187.00 (  0.53%)
  Min      alloc-odr0-2048            194.00 (  0.00%)           193.00 (  0.52%)
  Min      alloc-odr0-4096            199.00 (  0.00%)           198.00 (  0.50%)
  Min      alloc-odr0-8192            202.00 (  0.00%)           201.00 (  0.50%)
  Min      alloc-odr0-16384           203.00 (  0.00%)           202.00 (  0.49%)

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Zefan Li <lizefan@huawei.com>
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 cpuset: use static key better and convert to new API 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 IB/security: Restrict use of the write() interface 2016-04-28 12:03:16 -04:00
rxrpc
scsi
soc ARM: SoC driver updates for v4.7 2016-05-18 13:14:02 -07:00
sound ALSA: hda - Update BCLK also at hotplug for i915 HSW/BDW 2016-04-26 10:11:11 +02:00
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