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Filename Latest commit message Latest commit date
Tejun Heo 01fb58bcba slab: remove synchronous synchronize_sched() from memcg cache deactivation path
With kmem cgroup support enabled, kmem_caches can be created and
destroyed frequently and a great number of near empty kmem_caches can
accumulate if there are a lot of transient cgroups and the system is not
under memory pressure.  When memory reclaim starts under such
conditions, it can lead to consecutive deactivation and destruction of
many kmem_caches, easily hundreds of thousands on moderately large
systems, exposing scalability issues in the current slab management
code.  This is one of the patches to address the issue.

slub uses synchronize_sched() to deactivate a memcg cache.
synchronize_sched() is an expensive and slow operation and doesn't scale
when a huge number of caches are destroyed back-to-back.  While there
used to be a simple batching mechanism, the batching was too restricted
to be helpful.

This patch implements slab_deactivate_memcg_cache_rcu_sched() which slub
can use to schedule sched RCU callback instead of performing
synchronize_sched() synchronously while holding cgroup_mutex.  While
this adds online cpus, mems and slab_mutex operations, operating on
these locks back-to-back from the same kworker, which is what's gonna
happen when there are many to deactivate, isn't expensive at all and
this gets rid of the scalability problem completely.

Link: http://lkml.kernel.org/r/20170117235411.9408-9-tj@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jay Vana <jsvana@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22 16:41:27 -08:00
arch parisc: use generic current.h 2017-02-22 16:41:27 -08:00
block block: use for_each_thread() in sys_ioprio_set()/sys_ioprio_get() 2017-02-22 16:41:27 -08:00
certs
crypto
Documentation TTY/Serial driver patches for 4.11-rc1 2017-02-22 12:17:25 -08:00
drivers mm, dax: change pmd_fault() to take only vmf parameter 2017-02-22 16:41:26 -08:00
firmware
fs 9p: fix a potential acl leak 2017-02-22 16:41:27 -08:00
include slab: remove synchronous synchronize_sched() from memcg cache deactivation path 2017-02-22 16:41:27 -08:00
init char/misc driver patches for 4.11-rc1 2017-02-22 11:38:22 -08:00
ipc
kernel kernel/watchdog.c: do not hardcode CPU 0 as the initial thread 2017-02-22 16:41:27 -08:00
lib dma-debug: add comment for failed to check map error 2017-02-22 16:41:26 -08:00
mm slab: remove synchronous synchronize_sched() from memcg cache deactivation path 2017-02-22 16:41:27 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
scripts scripts/tags.sh: include arch/Kconfig* for tags generation 2017-02-22 16:41:26 -08:00
security driver core patches for 4.11-rc1 2017-02-22 11:44:32 -08:00
sound
tools tools/vm: add missing Makefile rules 2017-02-22 16:41:26 -08:00
usr
virt
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS dax: update MAINTAINERS entries for FS DAX 2017-02-22 16:41:26 -08:00
Makefile
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.