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lib/bitmap.c: micro-optimization for __bitmap_complement()

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Use BITS_TO_LONGS() macro to avoid calculation of reminder (bits %
BITS_PER_LONG) On ARM64 it saves 5 instruction for function - 16 before
and 11 after.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Yury Norov <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Yury Norov authored and Linus Torvalds committed 2018-06-07 17:34:39 -07:00
1 parent 0455c74788
commit ca1250bbd4
1 file changed
+1 -4
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lib/bitmap.c
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@@ -64,12 +64,9 @@ EXPORT_SYMBOL(__bitmap_equal);
void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
{
unsigned int k, lim = bits/BITS_PER_LONG;
unsigned int k, lim = BITS_TO_LONGS(bits);
for (k = 0; k < lim; ++k)
dst[k] = ~src[k];
if (bits % BITS_PER_LONG)
dst[k] = ~src[k];
}
EXPORT_SYMBOL(__bitmap_complement);