lib/find_bit.c: micro-optimise find_next_*_bit

2017-02-25T01:46:57+00:00

This saves 32 bytes on my x86-64 build, mostly due to alignment considerations and sharing more code between find_next_bit and find_next_zero_bit, but it does save a couple of instructions. There's really two parts to this commit: - First, the first half of the test: (!nbits || start >= nbits) is trivially a subset of the second half, since nbits and start are both unsigned - Second, while looking at the disassembly, I noticed that GCC was predicting the branch taken. Since this is a failure case, it's clearly the less likely of the two branches, so add an unlikely() to override GCC's heuristics. [mawilcox@microsoft.com: v2] Link: http://lkml.kernel.org/r/1483709016-1834-1-git-send-email-mawilcox@linuxonhyperv.com Link: http://lkml.kernel.org/r/1483709016-1834-1-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox Acked-by: Yury Norov Acked-by: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: rename lib/find_next_bit.c to lib/find_bit.c

2015-04-17T13:03:54+00:00

This file contains implementation for all find_*_bit{,_le} So giving it more generic name looks reasonable. Signed-off-by: Yury Norov Reviewed-by: Rasmus Villemoes Reviewed-by: George Spelvin Cc: Alexey Klimov Cc: David S. Miller Cc: Daniel Borkmann Cc: Hannes Frederic Sowa Cc: Lai Jiangshan Cc: Mark Salter Cc: AKASHI Takahiro Cc: Thomas Graf Cc: Valentin Rothberg Cc: Chris Wilson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/linux.git/lib/find_bit.c, branch v4.14.149

lib/find_bit.c: micro-optimise find_next_*_bit

lib: rename lib/find_next_bit.c to lib/find_bit.c