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authorYury Norov <yury.norov@gmail.com>2022-09-18 06:07:12 +0300
committerYury Norov <yury.norov@gmail.com>2022-09-26 22:19:12 +0300
commit24291caf8447f6fc060c8d00136bdc30ee207f38 (patch)
tree13d0a9d2b34cc58777852bce8ed9732c3882e669 /lib/bitmap.c
parent70a1cb106d9410f1f37e0261728e46722b74c29f (diff)
downloadlinux-24291caf8447f6fc060c8d00136bdc30ee207f38.tar.xz
lib/bitmap: add bitmap_weight_and()
The function calculates Hamming weight of (bitmap1 & bitmap2). Now we have to do like this: tmp = bitmap_alloc(nbits); bitmap_and(tmp, map1, map2, nbits); weight = bitmap_weight(tmp, nbits); bitmap_free(tmp); This requires additional memory, adds pressure on alloc subsystem, and way less cache-friendly than just: weight = bitmap_weight_and(map1, map2, nbits); The following patches apply it for cpumask functions. Signed-off-by: Yury Norov <yury.norov@gmail.com>
Diffstat (limited to 'lib/bitmap.c')
-rw-r--r--lib/bitmap.c30
1 files changed, 21 insertions, 9 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index d56e275db73e..3fc2e338ec30 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -333,20 +333,32 @@ bool __bitmap_subset(const unsigned long *bitmap1,
}
EXPORT_SYMBOL(__bitmap_subset);
+#define BITMAP_WEIGHT(FETCH, bits) \
+({ \
+ unsigned int __bits = (bits), idx, w = 0; \
+ \
+ for (idx = 0; idx < __bits / BITS_PER_LONG; idx++) \
+ w += hweight_long(FETCH); \
+ \
+ if (__bits % BITS_PER_LONG) \
+ w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits)); \
+ \
+ w; \
+})
+
unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
{
- unsigned int k, lim = bits/BITS_PER_LONG, w = 0;
-
- for (k = 0; k < lim; k++)
- w += hweight_long(bitmap[k]);
-
- if (bits % BITS_PER_LONG)
- w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
-
- return w;
+ return BITMAP_WEIGHT(bitmap[idx], bits);
}
EXPORT_SYMBOL(__bitmap_weight);
+unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
+ const unsigned long *bitmap2, unsigned int bits)
+{
+ return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits);
+}
+EXPORT_SYMBOL(__bitmap_weight_and);
+
void __bitmap_set(unsigned long *map, unsigned int start, int len)
{
unsigned long *p = map + BIT_WORD(start);