diff options
| author | Hyeonggon Yoo <42.hyeyoo@gmail.com> | 2021-05-14 10:39:27 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2021-05-14 10:39:27 +1000 |
| commit | ff3daafe3fd3e54c8cf6aeb865099c7bb02e5c51 (patch) | |
| tree | c9bea3b7e5d58a00f9a4281fae57435c33eea4f7 | |
| parent | f32aeffdb407b6390ef17ccac87e1a1a76663354 (diff) | |
| download | linux-next-ff3daafe3fd3e54c8cf6aeb865099c7bb02e5c51.tar.gz | |
mm, slub: change run-time assertion in kmalloc_index() to compile-time
Notice: this object is not reachable from any branch.
Currently when size is not supported by kmalloc_index, compiler will
generate a run-time BUG() while compile-time error is also possible, and
better. So change BUG to BUILD_BUG_ON_MSG to make compile-time check
possible.
Also remove code that allocates more than 32MB because current
implementation supports only up to 32MB.
Link: https://lkml.kernel.org/r/20210511173448.GA54466@hyeyoo
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Notice: this object is not reachable from any branch.
| -rw-r--r-- | include/linux/slab.h | 7 | ||||
| -rw-r--r-- | mm/slab_common.c | 7 |
2 files changed, 8 insertions, 6 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h index 0c97d788762cf..27d1425645575 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -346,6 +346,9 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags) * 1 = 65 .. 96 bytes * 2 = 129 .. 192 bytes * n = 2^(n-1)+1 .. 2^n + * + * Note: there's no need to optimize kmalloc_index because it's evaluated + * in compile-time. */ static __always_inline unsigned int kmalloc_index(size_t size) { @@ -382,8 +385,8 @@ static __always_inline unsigned int kmalloc_index(size_t size) if (size <= 8 * 1024 * 1024) return 23; if (size <= 16 * 1024 * 1024) return 24; if (size <= 32 * 1024 * 1024) return 25; - if (size <= 64 * 1024 * 1024) return 26; - BUG(); + + BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()"); /* Will never be reached. Needed because the compiler may complain */ return -1; diff --git a/mm/slab_common.c b/mm/slab_common.c index a4a571428c511..b0e50a33c0e48 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -755,8 +755,8 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) /* * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. - * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is - * kmalloc-67108864. + * kmalloc_index() supports up to 2^25=32MB, so the final entry of the table is + * kmalloc-32M. */ const struct kmalloc_info_struct kmalloc_info[] __initconst = { INIT_KMALLOC_INFO(0, 0), @@ -784,8 +784,7 @@ const struct kmalloc_info_struct kmalloc_info[] __initconst = { INIT_KMALLOC_INFO(4194304, 4M), INIT_KMALLOC_INFO(8388608, 8M), INIT_KMALLOC_INFO(16777216, 16M), - INIT_KMALLOC_INFO(33554432, 32M), - INIT_KMALLOC_INFO(67108864, 64M) + INIT_KMALLOC_INFO(33554432, 32M) }; /* |