The patch titled
memcg: memory cgroup hierarchy documentation
has been removed from the -mm tree. Its filename was
memory-cgroup-hierarchy-documentation-v4.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memcg: memory cgroup hierarchy documentation
From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Documentation updates for hierarchy support
Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: YAMAMOTO Takashi <yamamoto@xxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Pavel Emelianov <xemul@xxxxxxxxxx>
Cc: Dhaval Giani <dhaval@xxxxxxxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/controllers/memory.txt | 38 ++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)
diff -puN Documentation/controllers/memory.txt~memory-cgroup-hierarchy-documentation-v4 Documentation/controllers/memory.txt
--- a/Documentation/controllers/memory.txt~memory-cgroup-hierarchy-documentation-v4
+++ a/Documentation/controllers/memory.txt
@@ -289,8 +289,44 @@ will be charged as a new owner of it.
Because rmdir() moves all pages to parent, some out-of-use page caches can be
moved to the parent. If you want to avoid that, force_empty will be useful.
+6. Hierarchy support
-6. TODO
+The memory controller supports a deep hierarchy and hierarchical accounting.
+The hierarchy is created by creating the appropriate cgroups in the
+cgroup filesystem. Consider for example, the following cgroup filesystem
+hierarchy
+
+ root
+ / | \
+ / | \
+ a b c
+ | \
+ | \
+ d e
+
+In the diagram above, with hierarchical accounting enabled, all memory
+usage of e, is accounted to its ancestors up until the root (i.e, c and root),
+that has memory.use_hierarchy enabled. If one of the ancestors goes over its
+limit, the reclaim algorithm reclaims from the tasks in the ancestor and the
+children of the ancestor.
+
+6.1 Enabling hierarchical accounting and reclaim
+
+The memory controller by default disables the hierarchy feature. Support
+can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup
+
+# echo 1 > memory.use_hierarchy
+
+The feature can be disabled by
+
+# echo 0 > memory.use_hierarchy
+
+NOTE1: Enabling/disabling will fail if the cgroup already has other
+cgroups created below it.
+
+NOTE2: This feature can be enabled/disabled per subtree.
+
+7. TODO
1. Add support for accounting huge pages (as a separate controller)
2. Make per-cgroup scanner reclaim not-shared pages first
_
Patches currently in -mm which might be from balbir@xxxxxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
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