From 99445602d63e765fb247477e9bc250c4acceddc7 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Wed, 14 May 2014 10:01:43 +1000 Subject: [PATCH] mm-memcontrol-remove-hierarchy-restrictions-for-swappiness-and-oom_control-fix Update Documentation/cgroups/memory.txt Signed-off-by: Johannes Weiner Cc: Michal Hocko Cc: Tejun Heo Cc: David Rientjes Signed-off-by: Andrew Morton --- Documentation/cgroups/memory.txt | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 2622115276aa..1829c65f8371 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -535,17 +535,15 @@ Note: 5.3 swappiness -Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only. +Similar to /proc/sys/vm/swappiness, but only affecting reclaim that is +triggered by this cgroup's hard limit. The tunable in the root cgroup +corresponds to the global swappiness setting. + Please note that unlike the global swappiness, memcg knob set to 0 really prevents from any swapping even if there is a swap storage available. This might lead to memcg OOM killer if there are no file pages to reclaim. -Following cgroups' swappiness can't be changed. -- root cgroup (uses /proc/sys/vm/swappiness). -- a cgroup which uses hierarchy and it has other cgroup(s) below it. -- a cgroup which uses hierarchy and not the root of hierarchy. - 5.4 failcnt A memory cgroup provides memory.failcnt and memory.memsw.failcnt files. @@ -754,7 +752,6 @@ You can disable the OOM-killer by writing "1" to memory.oom_control file, as: #echo 1 > memory.oom_control -This operation is only allowed to the top cgroup of a sub-hierarchy. If OOM-killer is disabled, tasks under cgroup will hang/sleep in memory cgroup's OOM-waitqueue when they request accountable memory. -- 2.39.5