X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=Documentation%2Fvm%2Fslub.rst;h=289d231cee97266f01dcc8c2271bd66875361c5a;hb=060807f841ac94d3826ce6fa3b4f3831cd0c015b;hp=4eee598555c997ede3ba93d4e6d3af499e2e3025;hpb=d3590ebf6f91350192737dd1d1b219c05277f067;p=linux-2.6-microblaze.git

diff --git a/Documentation/vm/slub.rst b/Documentation/vm/slub.rst
index 4eee598555c9..289d231cee97 100644
--- a/Documentation/vm/slub.rst
+++ b/Documentation/vm/slub.rst
@@ -41,6 +41,11 @@ slub_debug=<Debug-Options>,<slab name1>,<slab name2>,...
 	Enable options only for select slabs (no spaces
 	after a comma)
 
+Multiple blocks of options for all slabs or selected slabs can be given, with
+blocks of options delimited by ';'. The last of "all slabs" blocks is applied
+to all slabs except those that match one of the "select slabs" block. Options
+of the first "select slabs" blocks that matches the slab's name are applied.
+
 Possible debug options are::
 
 	F		Sanity checks on (enables SLAB_DEBUG_CONSISTENCY_CHECKS
@@ -83,17 +88,33 @@ 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::
+You can apply different options to different list of slab names, using blocks
+of options. This will enable red zoning for dentry and user tracking for
+kmalloc. All other slabs will not get any debugging enabled::
+
+	slub_debug=Z,dentry;U,kmalloc-*
+
+You can also enable options (e.g. sanity checks and poisoning) for all caches
+except some that are deemed too performance critical and don't need to be
+debugged by specifying global debug options followed by a list of slab names
+with "-" as options::
+
+	slub_debug=FZ;-,zs_handle,zspage
+
+The state of each debug option for a slab can be found in the respective files
+under::
 
 	/sys/kernel/slab/<slab name>/
 
-Look at the writable files. Writing 1 to them will enable the
-corresponding debug option. All options can be set on a slab that does
-not contain objects. If the slab already contains objects then sanity checks
-and tracing may only be enabled. The other options may cause the realignment
-of objects.
+If the file contains 1, the option is enabled, 0 means disabled. The debug
+options from the ``slub_debug`` parameter translate to the following files::
+
+	F	sanity_checks
+	Z	red_zone
+	P	poison
+	U	store_user
+	T	trace
+	A	failslab
 
 Careful with tracing: It may spew out lots of information and never stop if
 used on the wrong slab.