On 10/13/2011 11:18 AM, Greg Thelen wrote:

On Mon, Oct 10, 2011 at 3:24 AM, Glauber Costa[off-list ref]  wrote:

quoted

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 06eb6d9..bf00cd2 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt

...

quoted

@@ -255,6 +262,31 @@ When oom event notifier is registered, event will be delivered.
   per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by
   zone->lru_lock, it has no lock of its own.

+2.7 Kernel Memory Extension (CONFIG_CGROUP_MEM_RES_CTLR_KMEM)
+
+ With the Kernel memory extension, the Memory Controller is able to limit

Extra leading space before 'With'.

quoted

+the amount of kernel memory used by the system. Kernel memory is fundamentally
+different than user memory, since it can't be swapped out, which makes it
+possible to DoS the system by consuming too much of this precious resource.
+Kernel memory limits are not imposed for the root cgroup.
+
+Memory limits as specified by the standard Memory Controller may or may not
+take kernel memory into consideration. This is achieved through the file
+memory.independent_kmem_limit. A Value different than 0 will allow for kernel

s/Value/value/

quoted

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3508777..d25c5cb 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

...

quoted

+static int kmem_limit_independent_write(struct cgroup *cont, struct cftype *cft,
+                                       u64 val)
+{
+       cgroup_lock();
+       mem_cgroup_from_cont(cont)->kmem_independent_accounting = !!val;
+       cgroup_unlock();

I do not think cgroup_lock,unlock are needed here.  The cont and
associated cgroup should be guaranteed by the caller to be valid.
Does this lock provide some other synchronization?

Yeah, I think I was being overcautious.

With the following comments addressed, can I add your Reviewed-by to 
this one ?

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