diff options
author | Ingo Molnar <mingo@kernel.org> | 2012-04-14 13:18:27 +0200 |
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committer | Ingo Molnar <mingo@kernel.org> | 2012-04-14 13:19:04 +0200 |
commit | 6ac1ef482d7ae0c690f1640bf6eb818ff9a2d91e (patch) | |
tree | 021cc9f6b477146fcebe6f3be4752abfa2ba18a9 /include/asm-generic/getorder.h | |
parent | 682968e0c425c60f0dde37977e5beb2b12ddc4cc (diff) | |
parent | a385ec4f11bdcf81af094c03e2444ee9b7fad2e5 (diff) |
Merge branch 'perf/core' into perf/uprobes
Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/asm-generic/getorder.h')
-rw-r--r-- | include/asm-generic/getorder.h | 53 |
1 files changed, 45 insertions, 8 deletions
diff --git a/include/asm-generic/getorder.h b/include/asm-generic/getorder.h index 67e7245dc9b..65e4468ac53 100644 --- a/include/asm-generic/getorder.h +++ b/include/asm-generic/getorder.h @@ -4,21 +4,58 @@ #ifndef __ASSEMBLY__ #include <linux/compiler.h> +#include <linux/log2.h> -/* Pure 2^n version of get_order */ -static inline __attribute_const__ int get_order(unsigned long size) +/* + * Runtime evaluation of get_order() + */ +static inline __attribute_const__ +int __get_order(unsigned long size) { int order; - size = (size - 1) >> (PAGE_SHIFT - 1); - order = -1; - do { - size >>= 1; - order++; - } while (size); + size--; + size >>= PAGE_SHIFT; +#if BITS_PER_LONG == 32 + order = fls(size); +#else + order = fls64(size); +#endif return order; } +/** + * get_order - Determine the allocation order of a memory size + * @size: The size for which to get the order + * + * Determine the allocation order of a particular sized block of memory. This + * is on a logarithmic scale, where: + * + * 0 -> 2^0 * PAGE_SIZE and below + * 1 -> 2^1 * PAGE_SIZE to 2^0 * PAGE_SIZE + 1 + * 2 -> 2^2 * PAGE_SIZE to 2^1 * PAGE_SIZE + 1 + * 3 -> 2^3 * PAGE_SIZE to 2^2 * PAGE_SIZE + 1 + * 4 -> 2^4 * PAGE_SIZE to 2^3 * PAGE_SIZE + 1 + * ... + * + * The order returned is used to find the smallest allocation granule required + * to hold an object of the specified size. + * + * The result is undefined if the size is 0. + * + * This function may be used to initialise variables with compile time + * evaluations of constants. + */ +#define get_order(n) \ +( \ + __builtin_constant_p(n) ? ( \ + ((n) == 0UL) ? BITS_PER_LONG - PAGE_SHIFT : \ + (((n) < (1UL << PAGE_SHIFT)) ? 0 : \ + ilog2((n) - 1) - PAGE_SHIFT + 1) \ + ) : \ + __get_order(n) \ +) + #endif /* __ASSEMBLY__ */ #endif /* __ASM_GENERIC_GETORDER_H */ |