diff options
| author | Matthew Wilcox <mawilcox@microsoft.com> | 2017-07-10 15:51:29 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-10 16:32:34 -0700 |
| commit | e5af323c9badd5dc09af7ccf9d45616ebffc623c (patch) | |
| tree | da5f5087eb7c2eb2c5953bd34e5facc714de9d67 | |
| parent | 3cc78125a081bb79eb38f3e9a585e5a81bb81cb1 (diff) | |
| download | linux-e5af323c9badd5dc09af7ccf9d45616ebffc623c.tar.gz | |
bitmap: optimise bitmap_set and bitmap_clear of a single bit
We have eight users calling bitmap_clear for a single bit and seventeen
calling bitmap_set for a single bit. Rather than fix all of them to
call __clear_bit or __set_bit, turn bitmap_clear and bitmap_set into
inline functions and make this special case efficient.
Link: http://lkml.kernel.org/r/20170628153221.11322-3-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/bitmap.h | 23 | ||||
| -rw-r--r-- | lib/bitmap.c | 8 | ||||
| -rw-r--r-- | lib/test_bitmap.c | 3 |
3 files changed, 24 insertions, 10 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 3b77588a93602..4e0f0c8167af7 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -112,9 +112,8 @@ extern int __bitmap_intersects(const unsigned long *bitmap1, extern int __bitmap_subset(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int nbits); extern int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits); - -extern void bitmap_set(unsigned long *map, unsigned int start, int len); -extern void bitmap_clear(unsigned long *map, unsigned int start, int len); +extern void __bitmap_set(unsigned long *map, unsigned int start, int len); +extern void __bitmap_clear(unsigned long *map, unsigned int start, int len); extern unsigned long bitmap_find_next_zero_area_off(unsigned long *map, unsigned long size, @@ -315,6 +314,24 @@ static __always_inline int bitmap_weight(const unsigned long *src, unsigned int return __bitmap_weight(src, nbits); } +static __always_inline void bitmap_set(unsigned long *map, unsigned int start, + unsigned int nbits) +{ + if (__builtin_constant_p(nbits) && nbits == 1) + __set_bit(start, map); + else + __bitmap_set(map, start, nbits); +} + +static __always_inline void bitmap_clear(unsigned long *map, unsigned int start, + unsigned int nbits) +{ + if (__builtin_constant_p(nbits) && nbits == 1) + __clear_bit(start, map); + else + __bitmap_clear(map, start, nbits); +} + static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src, unsigned int shift, int nbits) { diff --git a/lib/bitmap.c b/lib/bitmap.c index 08c6ef3a2b6fc..9a532805364b6 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -251,7 +251,7 @@ int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) } EXPORT_SYMBOL(__bitmap_weight); -void bitmap_set(unsigned long *map, unsigned int start, int len) +void __bitmap_set(unsigned long *map, unsigned int start, int len) { unsigned long *p = map + BIT_WORD(start); const unsigned int size = start + len; @@ -270,9 +270,9 @@ void bitmap_set(unsigned long *map, unsigned int start, int len) *p |= mask_to_set; } } -EXPORT_SYMBOL(bitmap_set); +EXPORT_SYMBOL(__bitmap_set); -void bitmap_clear(unsigned long *map, unsigned int start, int len) +void __bitmap_clear(unsigned long *map, unsigned int start, int len) { unsigned long *p = map + BIT_WORD(start); const unsigned int size = start + len; @@ -291,7 +291,7 @@ void bitmap_clear(unsigned long *map, unsigned int start, int len) *p &= ~mask_to_clear; } } -EXPORT_SYMBOL(bitmap_clear); +EXPORT_SYMBOL(__bitmap_clear); /** * bitmap_find_next_zero_area_off - find a contiguous aligned zero area diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index 252d3bddbe7de..2526a2975c51b 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -333,9 +333,6 @@ static void __init test_bitmap_u32_array_conversions(void) } } -#define __bitmap_set(a, b, c) bitmap_set(a, b, c) -#define __bitmap_clear(a, b, c) bitmap_clear(a, b, c) - static void noinline __init test_mem_optimisations(void) { DECLARE_BITMAP(bmap1, 1024); |