diff options
| author | Tejun Heo <tj@kernel.org> | 2017-02-08 10:26:01 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2017-02-09 21:52:52 +1100 |
| commit | 7c3caa9445df2d09d40de0d065aa4c8dcab4e12e (patch) | |
| tree | afdb2b4901b3626b0a87e8d18235f50c387dca68 /init | |
| parent | c24bdcaca00cae864d3794c9083670334d893b76 (diff) | |
slub: make sysfs directories for memcg sub-caches optional
SLUB creates a per-cache directory under /sys/kernel/slab which hosts a
bunch of debug files. Usually, there aren't that many caches on a system
and this doesn't really matter; however, if memcg is in use, each cache
can have per-cgroup sub-caches. SLUB creates the same directories for
these sub-caches under /sys/kernel/slab/$CACHE/cgroup.
Unfortunately, because there can be a lot of cgroups, active or draining,
the product of the numbers of caches, cgroups and files in each directory
can reach a very high number - hundreds of thousands is commonplace.
Millions and beyond aren't difficult to reach either.
What's under /sys/kernel/slab is primarily for debugging and the
information and control on the a root cache already cover its sub-caches.
While having a separate directory for each sub-cache can be helpful for
development, it doesn't make much sense to pay this amount of overhead by
default.
This patch introduces a boot parameter slub_memcg_sysfs which determines
whether to create sysfs directories for per-memcg sub-caches. It also
adds CONFIG_SLUB_MEMCG_SYSFS_ON which determines the boot parameter's
default value and defaults to 0.
Link: http://lkml.kernel.org/r/20170204145203.GB26958@mtj.duckdns.org
Signed-off-by: Tejun Heo <tj@kernel.org>
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>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index 4dd8bd232a1d..baa7dc0fa1d8 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1786,6 +1786,20 @@ config SLUB_DEBUG SLUB sysfs support. /sys/slab will not exist and there will be no support for cache validation etc. +config SLUB_MEMCG_SYSFS_ON + default n + bool "Enable memcg SLUB sysfs support by default" if EXPERT + depends on SLUB && SYSFS && MEMCG + help + SLUB creates a directory under /sys/kernel/slab for each + allocation cache to host info and debug files. If memory + cgroup is enabled, each cache can have per memory cgroup + caches. SLUB can create the same sysfs directories for these + caches under /sys/kernel/slab/CACHE/cgroup but it can lead + to a very high number of debug files being created. This is + controlled by slub_memcg_sysfs boot parameter and this + config option determines the parameter's default value. + config COMPAT_BRK bool "Disable heap randomization" default y |