diff options
| author | Johannes Berg <johannes.berg@intel.com> | 2021-02-24 23:01:04 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-25 00:38:27 +0300 |
| commit | ca220593208d8c433a761738461c31b1bf0be1f9 (patch) | |
| tree | 257913870a8c9b7537da75d8abbc34b81eb3575c | |
| parent | 0b41163407e2f3f44d6ed455ebfb1534df23f4a6 (diff) | |
| download | linux-ca220593208d8c433a761738461c31b1bf0be1f9.tar.xz | |
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>
| -rw-r--r-- | mm/slub.c | 11 |
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, |