diff options
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/getorder.h | 40 |
1 files changed, 28 insertions, 12 deletions
diff --git a/include/asm-generic/getorder.h b/include/asm-generic/getorder.h index 76e9687a3c86..e0fb4bf9f160 100644 --- a/include/asm-generic/getorder.h +++ b/include/asm-generic/getorder.h @@ -4,6 +4,25 @@ #ifndef __ASSEMBLY__ #include <linux/compiler.h> +#include <linux/log2.h> + +/* + * Runtime evaluation of get_order() + */ +static inline __attribute_const__ +int __get_order(unsigned long size) +{ + int order; + + 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 @@ -27,18 +46,15 @@ * This function may be used to initialise variables with compile time * evaluations of constants. */ -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); - return order; -} +#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__ */ |