Alexander van Heukelum 64970b68d2 x86, generic: optimize find_next_(zero_)bit for small constant-size bitmaps ... This moves an optimization for searching constant-sized small bitmaps form x86_64-specific to generic code. On an i386 defconfig (the x86#testing one), the size of vmlinux hardly changes with this applied. I have observed only four places where this optimization avoids a call into find_next_bit: In the functions return_unused_surplus_pages, alloc_fresh_huge_page, and adjust_pool_surplus, this patch avoids a call for a 1-bit bitmap. In __next_cpu a call is avoided for a 32-bit bitmap. That's it. On x86_64, 52 locations are optimized with a minimal increase in code size: Current #testing defconfig: 146 x bsf, 27 x find_next_*bit text data bss dec hex filename 5392637 846592 724424 6963653 6a41c5 vmlinux After removing the x86_64 specific optimization for find_next_*bit: 94 x bsf, 79 x find_next_*bit text data bss dec hex filename 5392358 846592 724424 6963374 6a40ae vmlinux After this patch (making the optimization generic): 146 x bsf, 27 x find_next_*bit text data bss dec hex filename 5392396 846592 724424 6963412 6a40d4 vmlinux [ tglx@linutronix.de: build fixes ] Signed-off-by: Ingo Molnar <mingo@elte.hu>		2008-04-26 19:21:16 +02:00
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__ffs.h	[PATCH] bitops: generic __ffs()	2006-03-26 08:57:10 -08:00
atomic.h	define first set of BIT* macros	2007-10-19 11:53:42 -07:00
ext2-atomic.h	[PATCH] bitops: generic ext2_{set,clear}_bit_atomic()	2006-03-26 08:57:11 -08:00
ext2-non-atomic.h	ext4: Add ext4_find_next_bit()	2008-01-28 23:58:27 -05:00
ffs.h	[PATCH] bitops: generic ffs()	2006-03-26 08:57:11 -08:00
ffz.h	[PATCH] bitops: generic ffz()	2006-03-26 08:57:10 -08:00
find.h	x86, generic: optimize find_next_(zero_)bit for small constant-size bitmaps	2008-04-26 19:21:16 +02:00
fls64.h	[PATCH] fix error: __u32 undeclared	2006-03-26 08:57:11 -08:00
fls.h	[PATCH] bitops: generic fls()	2006-03-26 08:57:10 -08:00
hweight.h	[PATCH] fix error: __u32 undeclared	2006-03-26 08:57:11 -08:00
le.h	ext4: Add ext4_find_next_bit()	2008-01-28 23:58:27 -05:00
lock.h	bitops: introduce lock ops	2007-10-18 14:37:29 -07:00
minix-le.h	[PATCH] bitops: generic minix_{test,set,test_and_clear,test,find_first_zero}_bit()	2006-03-26 08:57:11 -08:00
minix.h	[PATCH] bitops: generic minix_{test,set,test_and_clear,test,find_first_zero}_bit()	2006-03-26 08:57:11 -08:00
non-atomic.h	define first set of BIT* macros	2007-10-19 11:53:42 -07:00
sched.h	sched: simplify sched_find_first_bit()	2007-07-09 18:52:00 +02:00