failslab: add ability to filter slab caches

This patch allow to inject faults only for specific slabs.
In order to preserve default behavior cache filter is off by
default (all caches are faulty).

One may define specific set of slabs like this:
# mark skbuff_head_cache as faulty
echo 1 > /sys/kernel/slab/skbuff_head_cache/failslab
# Turn on cache filter (off by default)
echo 1 > /sys/kernel/debug/failslab/cache-filter
# Turn on fault injection
echo 1 > /sys/kernel/debug/failslab/times
echo 1 > /sys/kernel/debug/failslab/probability

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

1 files changed, 1 insertions, 0 deletions

diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
index b37300edf27c..07375e73981a 100644
--- a/Documentation/vm/slub.txt
+++ b/Documentation/vm/slub.txt
@@ -41,6 +41,7 @@ Possible debug options are
         P               Poisoning (object and padding)
         U               User tracking (free and alloc)
         T               Trace (please only use on single slabs)
+        A               Toggle failslab filter mark for the cache
         O               Switch debugging off for caches that would have
                         caused higher minimum slab orders
         -               Switch all debugging off (useful if the kernel is