Messages in this thread Patch in this message | | | From | Matthew Wilcox <> | Subject | [PATCH 1/3] bitmap: Optimise bitmap_set and bitmap_clear of a single bit | Date | Wed, 7 Jun 2017 07:29:22 -0700 |
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From: Matthew Wilcox <mawilcox@microsoft.com>
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.
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> --- include/linux/bitmap.h | 23 ++++++++++++++++++++--- lib/bitmap.c | 8 ++++---- 2 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 3b77588a9360..4e0f0c8167af 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 0b66f0e5eb6b..6e354a6d0dbb 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 -- 2.11.0
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