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authorMatthew Wilcox <mawilcox@microsoft.com>2017-07-10 15:51:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-10 16:32:34 -0700
commite5af323c9badd5dc09af7ccf9d45616ebffc623c (patch)
treeda5f5087eb7c2eb2c5953bd34e5facc714de9d67
parent3cc78125a081bb79eb38f3e9a585e5a81bb81cb1 (diff)
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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.h23
-rw-r--r--lib/bitmap.c8
-rw-r--r--lib/test_bitmap.c3
3 files changed, 24 insertions, 10 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 08c6ef3a2b6f..9a532805364b 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 252d3bddbe7d..2526a2975c51 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);