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authorVladimir Davydov <vdavydov@parallels.com>2015-04-01 10:30:36 -0400
committerJonathan Corbet <corbet@lwn.net>2015-04-11 09:23:31 -0400
commit197175427a221fe3200f7727ea35e261727e7228 (patch)
tree4ed58a8512f9bc41908727859c6694a86466830e /Documentation/cgroups
parent82c91e87642dd6f88b9d9b1e5cc09232b6701eb0 (diff)
Documentation/memcg: update memcg/kmem status
Memcg/kmem reclaim support has been finally merged. Reflect this in the documentation. Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/cgroups')
-rw-r--r--Documentation/cgroups/memory.txt8
1 files changed, 3 insertions, 5 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index a22df3ad35ff..f456b4315e86 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -275,11 +275,6 @@ When oom event notifier is registered, event will be delivered.
275 275
2762.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM) 2762.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM)
277 277
278WARNING: Current implementation lacks reclaim support. That means allocation
279 attempts will fail when close to the limit even if there are plenty of
280 kmem available for reclaim. That makes this option unusable in real
281 life so DO NOT SELECT IT unless for development purposes.
282
283With the Kernel memory extension, the Memory Controller is able to limit 278With the Kernel memory extension, the Memory Controller is able to limit
284the amount of kernel memory used by the system. Kernel memory is fundamentally 279the amount of kernel memory used by the system. Kernel memory is fundamentally
285different than user memory, since it can't be swapped out, which makes it 280different than user memory, since it can't be swapped out, which makes it
@@ -345,6 +340,9 @@ set:
345 In this case, the admin could set up K so that the sum of all groups is 340 In this case, the admin could set up K so that the sum of all groups is
346 never greater than the total memory, and freely set U at the cost of his 341 never greater than the total memory, and freely set U at the cost of his
347 QoS. 342 QoS.
343 WARNING: In the current implementation, memory reclaim will NOT be
344 triggered for a cgroup when it hits K while staying below U, which makes
345 this setup impractical.
348 346
349 U != 0, K >= U: 347 U != 0, K >= U:
350 Since kmem charges will also be fed to the user counter and reclaim will be 348 Since kmem charges will also be fed to the user counter and reclaim will be