Subject: + documentation-memcg-warn-about-incomplete-kmemcg-state.patch added to -mm tree To: vdavydov@xxxxxxxxxxxxx,hannes@xxxxxxxxxxx,mhocko@xxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Mon, 21 Apr 2014 13:38:29 -0700 The patch titled Subject: Documentation/memcg: warn about incomplete kmemcg state has been added to the -mm tree. Its filename is documentation-memcg-warn-about-incomplete-kmemcg-state.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/documentation-memcg-warn-about-incomplete-kmemcg-state.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/documentation-memcg-warn-about-incomplete-kmemcg-state.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/cgroups/memory.txt | 5 +++++ init/Kconfig | 6 ++++++ 2 files changed, 11 insertions(+) diff -puN Documentation/cgroups/memory.txt~documentation-memcg-warn-about-incomplete-kmemcg-state Documentation/cgroups/memory.txt --- a/Documentation/cgroups/memory.txt~documentation-memcg-warn-about-incomplete-kmemcg-state +++ a/Documentation/cgroups/memory.txt @@ -270,6 +270,11 @@ When oom event notifier is registered, e 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 -puN init/Kconfig~documentation-memcg-warn-about-incomplete-kmemcg-state init/Kconfig --- a/init/Kconfig~documentation-memcg-warn-about-incomplete-kmemcg-state +++ a/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 _ Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are slub-fix-memcg_propagate_slab_attrs.patch slb-charge-slabs-to-kmemcg-explicitly.patch mm-get-rid-of-__gfp_kmemcg.patch mm-get-rid-of-__gfp_kmemcg-fix.patch slab-document-kmalloc_order.patch memcg-un-export-__memcg_kmem_get_cache.patch mem-hotplug-implement-get-put_online_mems.patch slab-get_online_mems-for-kmem_cache_createdestroyshrink.patch documentation-memcg-warn-about-incomplete-kmemcg-state.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html