]>
Commit | Line | Data |
---|---|---|
fd4fd5aa SR |
1 | #ifndef _ASM_GENERIC_PAGE_H |
2 | #define _ASM_GENERIC_PAGE_H | |
3 | ||
4 | #ifdef __KERNEL__ | |
5 | #ifndef __ASSEMBLY__ | |
6 | ||
39d61db0 | 7 | #include <linux/log2.h> |
fd4fd5aa | 8 | |
39d61db0 DH |
9 | /* |
10 | * non-const pure 2^n version of get_order | |
11 | * - the arch may override these in asm/bitops.h if they can be implemented | |
12 | * more efficiently than using the arch log2 routines | |
13 | * - we use the non-const log2() instead if the arch has defined one suitable | |
14 | */ | |
15 | #ifndef ARCH_HAS_GET_ORDER | |
16 | static inline __attribute__((const)) | |
17 | int __get_order(unsigned long size, int page_shift) | |
fd4fd5aa | 18 | { |
39d61db0 DH |
19 | #if BITS_PER_LONG == 32 && defined(ARCH_HAS_ILOG2_U32) |
20 | int order = __ilog2_u32(size) - page_shift; | |
21 | return order >= 0 ? order : 0; | |
22 | #elif BITS_PER_LONG == 64 && defined(ARCH_HAS_ILOG2_U64) | |
23 | int order = __ilog2_u64(size) - page_shift; | |
24 | return order >= 0 ? order : 0; | |
25 | #else | |
fd4fd5aa SR |
26 | int order; |
27 | ||
39d61db0 | 28 | size = (size - 1) >> (page_shift - 1); |
fd4fd5aa SR |
29 | order = -1; |
30 | do { | |
31 | size >>= 1; | |
32 | order++; | |
33 | } while (size); | |
34 | return order; | |
39d61db0 | 35 | #endif |
fd4fd5aa | 36 | } |
39d61db0 DH |
37 | #endif |
38 | ||
39 | /** | |
40 | * get_order - calculate log2(pages) to hold a block of the specified size | |
41 | * @n - size | |
42 | * | |
43 | * calculate allocation order based on the current page size | |
44 | * - this can be used to initialise global variables from constant data | |
45 | */ | |
46 | #define get_order(n) \ | |
47 | ( \ | |
48 | __builtin_constant_p(n) ? \ | |
49 | ((n < (1UL << PAGE_SHIFT)) ? 0 : ilog2(n) - PAGE_SHIFT) : \ | |
50 | __get_order(n, PAGE_SHIFT) \ | |
51 | ) | |
fd4fd5aa SR |
52 | |
53 | #endif /* __ASSEMBLY__ */ | |
54 | #endif /* __KERNEL__ */ | |
55 | ||
56 | #endif /* _ASM_GENERIC_PAGE_H */ |