Johannes Weiner 55779ec759 mm: fix vm-scalability regression in cgroup-aware workingset code ... Commit 23047a96d7 ("mm: workingset: per-cgroup cache thrash detection") added a page->mem_cgroup lookup to the cache eviction, refault, and activation paths, as well as locking to the activation path, and the vm-scalability tests showed a regression of -23%. While the test in question is an artificial worst-case scenario that doesn't occur in real workloads - reading two sparse files in parallel at full CPU speed just to hammer the LRU paths - there is still some optimizations that can be done in those paths. Inline the lookup functions to eliminate calls. Also, page->mem_cgroup doesn't need to be stabilized when counting an activation; we merely need to hold the RCU lock to prevent the memcg from being freed. This cuts down on overhead quite a bit: 23047a96d7 063f6715e77a7be5770d6081fe ---------------- -------------------------- %stddev %change %stddev \ | \ 21621405 +- 0% +11.3% 24069657 +- 2% vm-scalability.throughput [linux@roeck-us.net: drop unnecessary include file] [hannes@cmpxchg.org: add WARN_ON_ONCE()s] Link: http://lkml.kernel.org/r/20160707194024.GA26580@cmpxchg.org Link: http://lkml.kernel.org/r/20160624175101.GA3024@cmpxchg.org Reported-by: Ye Xiaolong <xiaolong.ye@intel.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2016-07-28 16:07:41 -07:00
..
acpi	Merge branches 'acpi-processor', 'acpi-cppc', 'acpi-apei' and 'acpi-sleep'	2016-07-25 13:42:25 +02:00
asm-generic	Merge branch 'akpm' (patches from Andrew)	2016-07-26 19:55:54 -07:00
clocksource	…
crypto	A number of improvements for the /dev/random driver; the most	2016-07-27 15:11:55 -07:00
drm	Merge branch 'drm-vmwgfx-fixes' of git://people.freedesktop.org/~syeh/repos_linux into drm-fixes	2016-07-15 13:51:55 +10:00
dt-bindings	…
keys	…
kvm	…
linux	mm: fix vm-scalability regression in cgroup-aware workingset code	2016-07-28 16:07:41 -07:00
math-emu	…
media	[media] doc-rst: add some needed escape codes	2016-07-23 08:05:02 -03:00
memory	…
misc	…
net	net_sched: get rid of struct tcf_common	2016-07-25 21:49:20 -07:00
pcmcia	…
ras	…
rdma	…
rxrpc	…
scsi	fcoe: implement FIP VLAN responder	2016-07-20 19:49:41 -04:00
soc	…
sound	…
target	…
trace	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2016-07-27 12:03:20 -07:00
uapi	media updates for v4.8-rc1	2016-07-27 14:58:31 -07:00
video	…
xen	xen: add static initialization of steal_clock op to xen_time_ops	2016-07-26 14:07:06 +01:00
Kbuild	…