diff options
| author | Vladimir Davydov <vdavydov@parallels.com> | 2014-06-04 16:07:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-04 16:54:00 -0700 |
| commit | 2ee06468702e0742114823a537510cd6f038cacc (patch) | |
| tree | 223fa43073e8b6e500a0abeb52c690beea173498 | |
| parent | 613813e8985bb76bd27937bfa54faf9e9be95a52 (diff) | |
| download | linux-2ee06468702e0742114823a537510cd6f038cacc.tar.bz2 | |
Documentation/memcg: warn about incomplete kmemcg state
Kmemcg is currently under development and lacks some important features.
In particular, it does not have support of kmem reclaim on memory pressure
inside cgroup, which practically makes it unusable in real life. Let's
warn about it in both Kconfig and Documentation to prevent complaints
arising.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | Documentation/cgroups/memory.txt | 5 | ||||
| -rw-r--r-- | init/Kconfig | 6 |
2 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 1829c65f8371..4937e6fff9b4 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -270,6 +270,11 @@ When oom event notifier is registered, event will be delivered. 2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM) +WARNING: Current implementation lacks reclaim support. That means allocation + attempts will fail when close to the limit even if there are plenty of + kmem available for reclaim. That makes this option unusable in real + life so DO NOT SELECT IT unless for development purposes. + With the Kernel memory extension, the Memory Controller is able to limit the amount of kernel memory used by the system. Kernel memory is fundamentally different than user memory, since it can't be swapped out, which makes it diff --git a/init/Kconfig b/init/Kconfig index 9d3585bb2a7a..4a1822a1a680 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -996,6 +996,12 @@ config MEMCG_KMEM the kmem extension can use it to guarantee that no group of processes will ever exhaust kernel resources alone. + WARNING: Current implementation lacks reclaim support. That means + allocation attempts will fail when close to the limit even if there + are plenty of kmem available for reclaim. That makes this option + unusable in real life so DO NOT SELECT IT unless for development + purposes. + config CGROUP_HUGETLB bool "HugeTLB Resource Controller for Control Groups" depends on RESOURCE_COUNTERS && HUGETLB_PAGE |