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authorVlastimil Babka <vbabka@suse.cz>2020-08-06 23:18:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 11:33:22 -0700
commite17f1dfba37b84b574ae91e809ae3804fe5b29b9 (patch)
tree7e401a00ebf8b58b60c49a55c41b987a3fc93d3c /Documentation/vm
parent221503e1281f8a7d67eacbb6dc99db95acdf806c (diff)
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mm, slub: extend slub_debug syntax for multiple blocks
Patch series "slub_debug fixes and improvements". The slub_debug kernel boot parameter can either apply a single set of options to all caches or a list of caches. There is a use case where debugging is applied for all caches and then disabled at runtime for specific caches, for performance and memory consumption reasons [1]. As runtime changes are dangerous, extend the boot parameter syntax so that multiple blocks of either global or slab-specific options can be specified, with blocks delimited by ';'. This will also support the use case of [1] without runtime changes. For details see the updated Documentation/vm/slub.rst [1] https://lore.kernel.org/r/1383cd32-1ddc-4dac-b5f8-9c42282fa81c@codeaurora.org [weiyongjun1@huawei.com: make parse_slub_debug_flags() static] Link: http://lkml.kernel.org/r/20200702150522.4940-1-weiyongjun1@huawei.com Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Jann Horn <jannh@google.com> Cc: Roman Gushchin <guro@fb.com> Cc: Vijayanand Jitta <vjitta@codeaurora.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Link: http://lkml.kernel.org/r/20200610163135.17364-2-vbabka@suse.cz Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/vm')
-rw-r--r--Documentation/vm/slub.rst18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/vm/slub.rst b/Documentation/vm/slub.rst
index 4eee598555c9..cfccb258cf42 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
@@ -83,6 +88,19 @@ switch off debugging for such caches by default, use::
slub_debug=O
+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
+
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::