From 1a466e5631bfb6e0b61b0e821b134e260fbfeb87 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Sat, 17 May 2014 23:19:26 +1000 Subject: [PATCH] memcg: document memory.low_limit_in_bytes Describe low_limit_in_bytes and its effect. Signed-off-by: Michal Hocko Cc: Johannes Weiner Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Cc: Greg Thelen Cc: Michel Lespinasse Cc: Tejun Heo Cc: Hugh Dickins Cc: Roman Gushchin Signed-off-by: Andrew Morton --- Documentation/cgroups/memory.txt | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 1e5f666b6df2..e44de7c712e6 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -57,6 +57,7 @@ Brief summary of control files. memory.memsw.usage_in_bytes # show current res_counter usage for memory+Swap (See 5.5 for details) memory.limit_in_bytes # set/show limit of memory usage + memory.low_limit_in_bytes # set/show low limit for memory reclaim memory.memsw.limit_in_bytes # set/show limit of memory+Swap usage memory.failcnt # show the number of memory usage hits limits memory.memsw.failcnt # show the number of memory+Swap hits limits @@ -244,7 +245,15 @@ global VM. Cgroups can get reclaimed basically under two conditions to select and kill the bulkiest task in the hiearchy. (See 10. OOM Control below.) -Note2: When panic_on_oom is set to "2", the whole system will panic. +Groups might be also protected from both global and limit reclaim by +low_limit_in_bytes knob. If the limit is non-zero the reclaim logic +doesn't include groups (and their subgroups - see 6. Hierarchy support) +which are bellow the low limit if there is other eligible cgroup in the +reclaimed hierarchy. If all groups which participate reclaim are under +their low limits then all of them are reclaimed and the low limit is +ignored. + +Note: When panic_on_oom is set to "2", the whole system will panic. When oom event notifier is registered, event will be delivered to the root of the memory pressure which cannot be handled (See oom_control section) -- 2.39.2