Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
  slub: fix slab_pad_check()
  slub: release kobject if sysfs_create_group failed in sysfs_slab_add
  SLUB: fix ARCH_KMALLOC_MINALIGN cases 64 and 256
  SLUB: Fix some coding style issues
  SLUB: Drop write permission to /proc/slabinfo
  slab: remove duplicate kmem_cache_init_late() declarations
  slub: change kmem_cache->align to record the real alignment
  slub: use size and objsize orders to disable debug flags
  slub: add option to disable higher order debugging slabs

1 files changed, 10 insertions, 0 deletions

diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
index bb1f5c6e28b3..510917ff59ed 100644
--- a/Documentation/vm/slub.txt
+++ b/Documentation/vm/slub.txt
@@ -41,6 +41,8 @@ Possible debug options are
 	P		Poisoning (object and padding)
 	U		User tracking (free and alloc)
 	T		Trace (please only use on single slabs)
+	O		Switch debugging off for caches that would have
+			caused higher minimum slab orders
 	-		Switch all debugging off (useful if the kernel is
 			configured with CONFIG_SLUB_DEBUG_ON)
 
@@ -59,6 +61,14 @@ to the dentry cache with
 
 	slub_debug=F,dentry
 
+Debugging options may require the minimum possible slab order to increase as
+a result of storing the metadata (for example, caches with PAGE_SIZE object
+sizes).  This has a higher liklihood of resulting in slab allocation errors
+in low memory situations or if there's high fragmentation of memory.  To
+switch off debugging for such caches by default, use
+
+	slub_debug=O
+
 In case you forgot to enable debugging on the kernel command line: It is
 possible to enable debugging manually when the kernel is up. Look at the
 contents of: