user/sven/linux.git/include/asm-generic/bitops/__fls.h, branch v3.2.30Linux Kernel
https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v3.2.302009-01-13T17:56:30Zx86, generic: mark complex bitops.h inlines as __always_inline2009-01-13T17:56:30ZAndi Kleenandi@firstfloor.org2009-01-12T22:01:15Zurn:sha1:c8399943bdb70fef78798b97f975506ecc99e039
Impact: reduce kernel image size
Hugh Dickins noticed that older gcc versions when the kernel
is built for code size didn't inline some of the bitops.
Mark all complex x86 bitops that have more than a single
asm statement or two as always inline to avoid this problem.
Probably should be done for other architectures too.
Ingo then found a better fix that only requires
a single line change, but it unfortunately only
works on gcc 4.3.
On older gccs the original patch still makes a ~0.3% defconfig
difference with CONFIG_OPTIMIZE_INLINING=y.
With gcc 4.1 and a defconfig like build:
6116998 1138540 883788 8139326 7c323e vmlinux-oi-with-patch
6137043 1138540 883788 8159371 7c808b vmlinux-optimize-inlining
~20k / 0.3% difference.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
generic: introduce a generic __fls implementation2008-04-26T17:21:16ZAlexander van Heukelumheukelum@mailshack.com2008-03-15T17:30:57Zurn:sha1:7d9dff22e8ad06ad330968c9e3d3a2fb55a5f9c3
Add a generic __fls implementation in the same spirit as
the generic __ffs one. It finds the last (most significant)
set bit in the given long value.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>