The patch titled
SLUB: support slub_debug on by default
has been added to the -mm tree. Its filename is
slub-support-slub_debug-on-by-default.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: SLUB: support slub_debug on by default
From: Christoph Lameter <clameter@xxxxxxx>
Add a new configuration variable
CONFIG_SLUB_DEBUG_ON
If set then the kernel will be booted by default with slab debugging
switched on. Similar to CONFIG_SLAB_DEBUG. By default slab debugging
is available but must be enabled by specifying "slub_debug" as a
kernel parameter.
Also add support to switch off slab debugging for a kernel that was
built with CONFIG_SLUB_DEBUG_ON. This works by specifying
slub_debug=-
as a kernel parameter.
Dave Jones wanted this feature.
http://marc.info/?l=linux-kernel&m=118072189913045&w=2
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 38 ++++++------
Documentation/vm/slub.txt | 2
lib/Kconfig.debug | 13 ++++
mm/slub.c | 79 ++++++++++++++++----------
4 files changed, 87 insertions(+), 45 deletions(-)
diff -puN Documentation/kernel-parameters.txt~slub-support-slub_debug-on-by-default Documentation/kernel-parameters.txt
--- a/Documentation/kernel-parameters.txt~slub-support-slub_debug-on-by-default
+++ a/Documentation/kernel-parameters.txt
@@ -1628,35 +1628,39 @@ and is between 256 and 4096 characters.
slram= [HW,MTD]
- slub_debug [MM, SLUB]
- Enabling slub_debug allows one to determine the culprit
- if slab objects become corrupted. Enabling slub_debug
- creates guard zones around objects and poisons objects
- when not in use. Also tracks the last alloc / free.
- For more information see Documentation/vm/slub.txt.
+ slub_debug[=options[,slabs]] [MM, SLUB]
+ Enabling slub_debug allows one to determine the
+ culprit if slab objects become corrupted. Enabling
+ slub_debug can create guard zones around objects and
+ may poison objects when not in use. Also tracks the
+ last alloc / free. For more information see
+ Documentation/vm/slub.txt.
slub_max_order= [MM, SLUB]
- Determines the maximum allowed order for slabs. Setting
- this too high may cause fragmentation.
- For more information see Documentation/vm/slub.txt.
+ Determines the maximum allowed order for slabs.
+ A high setting may cause OOMs due to memory
+ fragmentation. For more information see
+ Documentation/vm/slub.txt.
slub_min_objects= [MM, SLUB]
- The minimum objects per slab. SLUB will increase the
- slab order up to slub_max_order to generate a
- sufficiently big slab to satisfy the number of objects.
- The higher the number of objects the smaller the overhead
- of tracking slabs.
+ The minimum number of objects per slab. SLUB will
+ increase the slab order up to slub_max_order to
+ generate a sufficiently large slab able to contain
+ the number of objects indicated. The higher the number
+ of objects the smaller the overhead of tracking slabs
+ and the less frequently locks need to be acquired.
For more information see Documentation/vm/slub.txt.
slub_min_order= [MM, SLUB]
Determines the mininum page order for slabs. Must be
- lower than slub_max_order
+ lower than slub_max_order.
For more information see Documentation/vm/slub.txt.
slub_nomerge [MM, SLUB]
- Disable merging of slabs of similar size. May be
+ Disable merging of slabs with similar size. May be
necessary if there is some reason to distinguish
- allocs to different slabs.
+ allocs to different slabs. Debug options disable
+ merging on their own.
For more information see Documentation/vm/slub.txt.
smart2= [HW]
diff -puN Documentation/vm/slub.txt~slub-support-slub_debug-on-by-default Documentation/vm/slub.txt
--- a/Documentation/vm/slub.txt~slub-support-slub_debug-on-by-default
+++ a/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)
+ - Switch all debugging off (useful if the kernel is
+ configured with CONFIG_SLUB_DEBUG_ON)
F.e. in order to boot just with sanity checks and red zoning one would specify:
diff -puN lib/Kconfig.debug~slub-support-slub_debug-on-by-default lib/Kconfig.debug
--- a/lib/Kconfig.debug~slub-support-slub_debug-on-by-default
+++ a/lib/Kconfig.debug
@@ -143,6 +143,19 @@ config DEBUG_SLAB_LEAK
bool "Memory leak debugging"
depends on DEBUG_SLAB
+config SLUB_DEBUG_ON
+ bool "SLUB debugging on by default"
+ depends on SLUB && SLUB_DEBUG
+ default n
+ help
+ Boot with debugging on by default. SLUB boots by default with
+ the runtime debug capabilities switched off. Enabling this is
+ equivalent to specifying the "slub_debug" parameter on boot.
+ There is no support for more fine grained debug control like
+ possible with slub_debug=xxx. SLUB debugging may be switched
+ off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
+ "slub_debug=-".
+
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
diff -puN mm/slub.c~slub-support-slub_debug-on-by-default mm/slub.c
--- a/mm/slub.c~slub-support-slub_debug-on-by-default
+++ a/mm/slub.c
@@ -323,7 +323,11 @@ static inline int slab_index(void *p, st
/*
* Debug settings:
*/
+#ifdef CONFIG_SLUB_DEBUG_ON
+static int slub_debug = DEBUG_DEFAULT_FLAGS;
+#else
static int slub_debug;
+#endif
static char *slub_debug_slabs;
@@ -888,38 +892,57 @@ fail:
static int __init setup_slub_debug(char *str)
{
- if (!str || *str != '=')
- slub_debug = DEBUG_DEFAULT_FLAGS;
- else {
- str++;
- if (*str == 0 || *str == ',')
- slub_debug = DEBUG_DEFAULT_FLAGS;
- else
- for( ;*str && *str != ','; str++)
- switch (*str) {
- case 'f' : case 'F' :
- slub_debug |= SLAB_DEBUG_FREE;
- break;
- case 'z' : case 'Z' :
- slub_debug |= SLAB_RED_ZONE;
- break;
- case 'p' : case 'P' :
- slub_debug |= SLAB_POISON;
- break;
- case 'u' : case 'U' :
- slub_debug |= SLAB_STORE_USER;
- break;
- case 't' : case 'T' :
- slub_debug |= SLAB_TRACE;
- break;
- default:
- printk(KERN_ERR "slub_debug option '%c' "
- "unknown. skipped\n",*str);
- }
+ slub_debug = DEBUG_DEFAULT_FLAGS;
+ if (*str++ != '=' || !*str)
+ /*
+ * No options specified. Switch on full debugging.
+ */
+ goto out;
+
+ if (*str == ',')
+ /*
+ * No options but restriction on slabs. This means full
+ * debugging for slabs matching a pattern.
+ */
+ goto check_slabs;
+
+ slub_debug = 0;
+ if (*str == '-')
+ /*
+ * Switch off all debugging measures.
+ */
+ goto out;
+
+ /*
+ * Determine which debug features should be switched on
+ */
+ for ( ;*str && *str != ','; str++) {
+ switch (*str) {
+ case 'f' : case 'F' :
+ slub_debug |= SLAB_DEBUG_FREE;
+ break;
+ case 'z' : case 'Z' :
+ slub_debug |= SLAB_RED_ZONE;
+ break;
+ case 'p' : case 'P' :
+ slub_debug |= SLAB_POISON;
+ break;
+ case 'u' : case 'U' :
+ slub_debug |= SLAB_STORE_USER;
+ break;
+ case 't' : case 'T' :
+ slub_debug |= SLAB_TRACE;
+ break;
+ default:
+ printk(KERN_ERR "slub_debug option '%c' "
+ "unknown. skipped\n",*str);
+ }
}
+check_slabs:
if (*str == ',')
slub_debug_slabs = str + 1;
+out:
return 1;
}
_
Patches currently in -mm which might be from clameter@xxxxxxx are
origin.patch
mount-t-tmpfs-o-mpol=-check-nodes-online.patch
slab-fix-alien-cache-handling.patch
fix-gregkh-driver-dmi-based-module-autoloading.patch
git-ubi.patch
quicklist-support-for-x86_64.patch
change-zonelist-order-zonelist-order-selection-logic.patch
change-zonelist-order-zonelist-order-selection-logic-add-check_highest_zone-to-build_zonelists_in_zone_order.patch
change-zonelist-order-v6-zonelist-fix.patch
change-zonelist-order-auto-configuration.patch
change-zonelist-order-documentaion.patch
make-proc-slabinfo-use-seq_list_xxx-helpers.patch
make-proc-slabinfo-use-seq_list_xxx-helpers-fix.patch
remove-the-deprecated-kmem_cache_t-typedef-from-slabh.patch
slub-use-ilog2-instead-of-series-of-constant-comparisons.patch
slub-support-slub_debug-on-by-default.patch
slub-support-slub_debug-on-by-default-tidy.patch
add-__gfp_movable-for-callers-to-flag-allocations-from-high-memory-that-may-be-migrated.patch
group-short-lived-and-reclaimable-kernel-allocations.patch
fix-calculation-in-move_freepages_block-for-counting-pages.patch
breakout-page_order-to-internalh-to-avoid-special-knowledge-of-the-buddy-allocator.patch
do-not-depend-on-max_order-when-grouping-pages-by-mobility.patch
print-out-statistics-in-relation-to-fragmentation-avoidance-to-proc-pagetypeinfo.patch
have-kswapd-keep-a-minimum-order-free-other-than-order-0.patch
have-kswapd-keep-a-minimum-order-free-other-than-order-0-fix.patch
only-check-absolute-watermarks-for-alloc_high-and-alloc_harder-allocations.patch
slub-mm-only-make-slub-the-default-slab-allocator.patch
slub-exploit-page-mobility-to-increase-allocation-order.patch
slub-reduce-antifrag-max-order.patch
slub-reduce-antifrag-max-order-use-antifrag-constant-instead-of-hardcoding-page-order.patch
slub-change-error-reporting-format-to-follow-lockdep-loosely.patch
slub-change-error-reporting-format-to-follow-lockdep-loosely-fix.patch
hexdump-more-output-formatting.patch
define-config_bounce-to-avoid-useless-inclusion-of-bounce-buffer.patch
define-new-percpu-interface-for-shared-data.patch
use-the-new-percpu-interface-for-shared-data.patch
revoke-core-code.patch
mm-implement-swap-prefetching.patch
rename-gfp_high_movable-to-gfp_highuser_movable-prefetch.patch
print-out-page_owner-statistics-in-relation-to-fragmentation-avoidance.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
