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authorKirill A. Shutemov <kirill@shutemov.name>2010-03-10 15:22:24 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-12 15:52:37 -0800
commit2e72b6347c9459e6cff5634ddc815485bae6985f (patch)
tree48ceef47f2cd0d33f2a1dd816c1a05ca2cb3e0e2 /Documentation/cgroups
parent378ce724bc2a0ef1243e11c09d58a70bb6be007a (diff)
downloadlinux-linaro-android-2e72b6347c9459e6cff5634ddc815485bae6985f.tar.gz
memcg: implement memory thresholds
It allows to register multiple memory and memsw thresholds and gets notifications when it crosses. To register a threshold application need: - create an eventfd; - open memory.usage_in_bytes or memory.memsw.usage_in_bytes; - write string like "<event_fd> <memory.usage_in_bytes> <threshold>" to cgroup.event_control. Application will be notified through eventfd when memory usage crosses threshold in any direction. It's applicable for root and non-root cgroup. It uses stats to track memory usage, simmilar to soft limits. It checks if we need to send event to userspace on every 100 page in/out. I guess it's good compromise between performance and accuracy of thresholds. [akpm@linux-foundation.org: coding-style fixes] [nishimura@mxp.nes.nec.co.jp: fix documentation merge issue] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Vladislav Buzov <vbuzov@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Alexander Shishkin <virtuoso@slind.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/cgroups')
-rw-r--r--Documentation/cgroups/memory.txt19
1 files changed, 18 insertions, 1 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 1f59a1a38bd..268ab08222d 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -468,7 +468,24 @@ Note: More type of pages(e.g. file cache, shmem,) will be supported by other
- All of moving charge operations are done under cgroup_mutex. It's not good
behavior to hold the mutex too long, so we may need some trick.
-9. TODO
+9. Memory thresholds
+
+Memory controler implements memory thresholds using cgroups notification
+API (see cgroups.txt). It allows to register multiple memory and memsw
+thresholds and gets notifications when it crosses.
+
+To register a threshold application need:
+ - create an eventfd using eventfd(2);
+ - open memory.usage_in_bytes or memory.memsw.usage_in_bytes;
+ - write string like "<event_fd> <memory.usage_in_bytes> <threshold>" to
+ cgroup.event_control.
+
+Application will be notified through eventfd when memory usage crosses
+threshold in any direction.
+
+It's applicable for root and non-root cgroup.
+
+10. TODO
1. Add support for accounting huge pages (as a separate controller)
2. Make per-cgroup scanner reclaim not-shared pages first