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authorJohannes Berg <johannes.berg@intel.com>2021-02-24 12:01:04 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 13:38:27 -0800
commitca220593208d8c433a761738461c31b1bf0be1f9 (patch)
tree257913870a8c9b7537da75d8abbc34b81eb3575c /mm/slub.c
parent0b41163407e2f3f44d6ed455ebfb1534df23f4a6 (diff)
mm/slub: disable user tracing for kmemleak caches by default
If kmemleak is enabled, it uses a kmem cache for its own objects. These objects are used to hold information kmemleak uses, including a stack trace. If slub_debug is also turned on, each of them has *another* stack trace, so the overhead adds up, and on my tests (on ARCH=um, admittedly) 2/3rds of the allocations end up being doing the stack tracing. Turn off SLAB_STORE_USER if SLAB_NOLEAKTRACE was given, to avoid storing the essentially same data twice. Link: https://lkml.kernel.org/r/20210113215114.d94efa13ba30.I117b6764e725b3192318bbcf4269b13b709539ae@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 5d8d5d21e5d3..a7c453bf7156 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1413,6 +1413,15 @@ slab_flags_t kmem_cache_flags(unsigned int object_size,
size_t len;
char *next_block;
slab_flags_t block_flags;
+ slab_flags_t slub_debug_local = slub_debug;
+
+ /*
+ * If the slab cache is for debugging (e.g. kmemleak) then
+ * don't store user (stack trace) information by default,
+ * but let the user enable it via the command line below.
+ */
+ if (flags & SLAB_NOLEAKTRACE)
+ slub_debug_local &= ~SLAB_STORE_USER;
len = strlen(name);
next_block = slub_debug_string;
@@ -1447,7 +1456,7 @@ slab_flags_t kmem_cache_flags(unsigned int object_size,
}
}
- return flags | slub_debug;
+ return flags | slub_debug_local;
}
#else /* !CONFIG_SLUB_DEBUG */
static inline void setup_object_debug(struct kmem_cache *s,