kmem: add slab-specific documentation about the kmem controller

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 5b5b631437789018758bdde63a5db6689cb7164e..8b8c28b9864c58f4c23ac199036fc260fc32cd6f 100644 (file)
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -301,6 +301,13 @@ to trigger slab reclaim when those limits are reached.
 kernel memory, we prevent new processes from being created when the kernel
 memory usage is too high.
 
 kernel memory, we prevent new processes from being created when the kernel
 memory usage is too high.
 

+* slab pages: pages allocated by the SLAB or SLUB allocator are tracked. A copy
+of each kmem_cache is created everytime the cache is touched by the first time
+from inside the memcg. The creation is done lazily, so some objects can still be
+skipped while the cache is being created. All objects in a slab page should
+belong to the same memcg. This only fails to hold when a task is migrated to a
+different memcg during the page allocation by the cache.
+

 * sockets memory pressure: some sockets protocols have memory pressure
 thresholds. The Memory Controller allows them to be controlled individually
 per cgroup, instead of globally.
 * sockets memory pressure: some sockets protocols have memory pressure
 thresholds. The Memory Controller allows them to be controlled individually
 per cgroup, instead of globally.