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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-22 09:13:24 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-22 09:13:24 -0700 |
commit | e17fdf5c6778ff77d93dd769910992e4073b9348 (patch) | |
tree | d1a7ca2b1faf4301b39300fbd82f9b91e605a77e /include/asm-generic | |
parent | 95211279c5ad00a317c98221d7e4365e02f20836 (diff) | |
parent | a240ada241dafe290e7532d1ddeb98fdf1419068 (diff) | |
download | linux-3.10-e17fdf5c6778ff77d93dd769910992e4073b9348.tar.gz linux-3.10-e17fdf5c6778ff77d93dd769910992e4073b9348.tar.bz2 linux-3.10-e17fdf5c6778ff77d93dd769910992e4073b9348.zip |
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/asm changes from Ingo Molnar
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Include probe_roms.h in probe_roms.c
x86/32: Print control and debug registers for kerenel context
x86: Tighten dependencies of CPU_SUP_*_32
x86/numa: Improve internode cache alignment
x86: Fix the NMI nesting comments
x86-64: Improve insn scheduling in SAVE_ARGS_IRQ
x86-64: Fix CFI annotations for NMI nesting code
bitops: Add missing parentheses to new get_order macro
bitops: Optimise get_order()
bitops: Adjust the comment on get_order() to describe the size==0 case
x86/spinlocks: Eliminate TICKET_MASK
x86-64: Handle byte-wise tail copying in memcpy() without a loop
x86-64: Fix memcpy() to support sizes of 4Gb and above
x86-64: Fix memset() to support sizes of 4Gb and above
x86-64: Slightly shorten copy_page()
Diffstat (limited to 'include/asm-generic')
-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 */ |