On Mon 21-04-14 11:47:00, Vladimir Davydov wrote: > 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@xxxxxxxxxxxxx> Thanks! This should have been merged log time ago... Acked-by: Michal Hocko <mhocko@xxxxxxx> > --- > Documentation/cgroups/memory.txt | 5 +++++ > init/Kconfig | 6 ++++++ > 2 files changed, 11 insertions(+) > > diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt > index 2622115276aa..af3cdfa3c07a 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 427ba60d638f..4d6e645c8ad4 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -993,6 +993,12 @@ 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 > -- > 1.7.10.4 > -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>