[RFC] [PATCH 4/4] Add soft limit documentation

[Balbir Singh <balbir@linux.vnet.ibm.com>]

Add documentation for the soft limit feature.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
---

 Documentation/controllers/memory.txt |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff -puN Documentation/controllers/memory.txt~memory-controller-add-soft-limit-documentation Documentation/controllers/memory.txt
--- linux-2.6.24/Documentation/controllers/memory.txt~memory-controller-add-soft-limit-documentation	2008-02-13 18:45:40.000000000 +0530
+++ linux-2.6.24-balbir/Documentation/controllers/memory.txt	2008-02-13 18:49:58.000000000 +0530
@@ -201,6 +201,22 @@ The memory.force_empty gives an interfac
 
 will drop all charges in cgroup. Currently, this is maintained for test.
 
+The file memory.soft_limit_in_bytes allows users to set soft limits. A soft
+limit is set in a manner similar to limit. The limit feature described
+earlier is a hard limit, a group can never exceed it's hard limit. A soft
+limit on the other hand can be exceeded. A group will be shrunk back
+to it's soft limit, when there is memory pressure/contention.
+
+Ideally the soft limit should always be set to a value smaller than the
+hard limit. However, the code does not force the user to do so. The soft
+limit can be greater than the hard limit; then the soft limit has
+no meaning in that setup, since the group will alwasy be restrained to its
+hard limit.
+
+Example setting of soft limit
+
+# echo -n 100M > memory.soft_limit_in_bytes
+
 4. Testing
 
 Balbir posted lmbench, AIM9, LTP and vmmstress results [10] and [11].
_

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL

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