diff options
| author | Hyeonggon Yoo <42.hyeyoo@gmail.com> | 2021-06-28 19:34:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-29 10:53:46 -0700 |
| commit | 588c7fa022d7b2361500ead5660d9a1a2ecd9b7d (patch) | |
| tree | 88f55c414b5c602711d90ff0731db7464e7823a8 /include/linux/slab.h | |
| parent | 3d8e374c6d46a648333b9ef87983bc726f8e56bc (diff) | |
mm, slub: change run-time assertion in kmalloc_index() to compile-time
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.
[42.hyeyoo@gmail.com: fix support for clang 10]
Link: https://lkml.kernel.org/r/20210518181247.GA10062@hyeyoo
[vbabka@suse.cz: fix false-positive assert in kernel/bpf/local_storage.c]
Link: https://lkml.kernel.org/r/bea97388-01df-8eac-091b-a3c89b4a4a09@suse.czLink: https://lkml.kernel.org/r/20210511173448.GA54466@hyeyoo
[elver@google.com: kfence fix]
Link: https://lkml.kernel.org/r/20210512195227.245000695c9014242e9a00e5@linux-foundation.org
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Marco Elver <elver@google.com>
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: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/slab.h')
| -rw-r--r-- | include/linux/slab.h | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h index 0c97d788762c..bc9ab3a5a017 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -346,8 +346,14 @@ 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: __kmalloc_index() is compile-time optimized, and not runtime optimized; + * typical usage is via kmalloc_index() and therefore evaluated at compile-time. + * Callers where !size_is_constant should only be test modules, where runtime + * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab(). */ -static __always_inline unsigned int kmalloc_index(size_t size) +static __always_inline unsigned int __kmalloc_index(size_t size, + bool size_is_constant) { if (!size) return 0; @@ -382,12 +388,17 @@ 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(); + + if ((IS_ENABLED(CONFIG_CC_IS_GCC) || CONFIG_CLANG_VERSION >= 110000) + && !IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant) + BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()"); + else + BUG(); /* Will never be reached. Needed because the compiler may complain */ return -1; } +#define kmalloc_index(s) __kmalloc_index(s, true) #endif /* !CONFIG_SLOB */ void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc; |