talos-obmc-linux/tools/lib/find_bit.c, branch dev-4.13

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

tools lib: Add for_each_clear_bit macro

2016-10-24T14:07:33+00:00

Adding for_each_clear_bit macro plus all its the necessary backbone functions. Taken from related kernel code. It will be used in following patch. Signed-off-by: Jiri Olsa Cc: Adrian Hunter Cc: David Ahern Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-cayv2zbqi0nlmg5sjjxs1775@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

tools lib: Sync tools/lib/find_bit.c with the kernel

2016-01-08T15:35:41+00:00

Need to move the bitmap.[ch] things from tools/perf/ to tools/lib, will be done in the next patches. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: George Spelvin Cc: Namhyung Kim Cc: Rasmus Villemoes Cc: Wang Nan Cc: Yury Norov Link: http://lkml.kernel.org/n/tip-5fys65wkd7gu8j7a7xgukc5t@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

tools lib: Move find_next_bit.c to tools/lib/

2016-01-08T15:35:35+00:00

The commit that introduced it should've moved it to the same place, plus the 'tools/' prefix, but instead moved it to a bogus tools/lib/util/ directory, being the only file there. Move it to tools/lib/find_bit.c, picking the name for the file where these routines live since: 8f6f19dd5143 ("lib: move find_last_bit to lib/find_next_bit.c") Next step is to make tools/lib/find_bit.c to differ from lib/find_bit.c just in removing what is not used by tools/. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: George Spelvin Cc: Namhyung Kim Cc: Rasmus Villemoes Cc: Wang Nan Cc: Yury Norov Link: http://lkml.kernel.org/n/tip-p391cex5mqvahp4pwrton87n@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo