linux/include/asm-x86/bitops_32.h, branch master

x86: finalize bitops unification

2008-04-26T17:21:17Z

include/asm-x86/bitops_32.h and include/asm-x86/bitops_64.h are now almost identical. The 64-bit version sets ARCH_HAS_FAST_MULTIPLIER and has an extra inline function set_bit_string. The define currently has no influence on the generated code, but it can be argued that setting it on i386 is the right thing to do anyhow. The addition of the extra inline function on i386 does not hurt either. Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar

x86, UML: remove x86-specific implementations of find_first_bit

2008-04-26T17:21:17Z

x86 has been switched to the generic versions of find_first_bit and find_first_zero_bit, but the original versions were retained. This patch just removes the now unused x86-specific versions. also update UML. Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar

x86: generic versions of find_first_(zero_)bit, convert i386

2008-04-26T17:21:16Z

Generic versions of __find_first_bit and __find_first_zero_bit are introduced as simplified versions of __find_next_bit and __find_next_zero_bit. Their compilation and use are guarded by a new config variable GENERIC_FIND_FIRST_BIT. The generic versions of find_first_bit and find_first_zero_bit are implemented in terms of the newly introduced __find_first_bit and __find_first_zero_bit. This patch does not remove the i386-specific implementation, but it does switch i386 to use the generic functions by setting GENERIC_FIND_FIRST_BIT=y for X86_32. Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar

x86: merge the simple bitops and move them to bitops.h

2008-04-26T17:21:16Z

Some of those can be written in such a way that the same inline assembly can be used to generate both 32 bit and 64 bit code. For ffs and fls, x86_64 unconditionally used the cmov instruction and i386 unconditionally used a conditional branch over a mov instruction. In the current patch I chose to select the version based on the availability of the cmov instruction instead. A small detail here is that x86_64 did not previously set CONFIG_X86_CMOV=y. Improved comments for ffs, ffz, fls and variations. Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar

x86: change x86 to use generic find_next_bit

2008-04-26T17:21:16Z

The versions with inline assembly are in fact slower on the machines I tested them on (in userspace) (Athlon XP 2800+, p4-like Xeon 2.8GHz, AMD Opteron 270). The i386-version needed a fix similar to 06024f21 to avoid crashing the benchmark. Benchmark using: gcc -fomit-frame-pointer -Os. For each bitmap size 1...512, for each possible bitmap with one bit set, for each possible offset: find the position of the first bit starting at offset. If you follow ;). Times include setup of the bitmap and checking of the results. Athlon Xeon Opteron 32/64bit x86-specific: 0m3.692s 0m2.820s 0m3.196s / 0m2.480s generic: 0m2.622s 0m1.662s 0m2.100s / 0m1.572s If the bitmap size is not a multiple of BITS_PER_LONG, and no set (cleared) bit is found, find_next_bit (find_next_zero_bit) returns a value outside of the range [0, size]. The generic version always returns exactly size. The generic version also uses unsigned long everywhere, while the x86 versions use a mishmash of int, unsigned (int), long and unsigned long. Using the generic version does give a slightly bigger kernel, though. defconfig: text data bss dec hex filename x86-specific: 4738555 481232 626688 5846475 5935cb vmlinux (32 bit) generic: 4738621 481232 626688 5846541 59360d vmlinux (32 bit) x86-specific: 5392395 846568 724424 6963387 6a40bb vmlinux (64 bit) generic: 5392458 846568 724424 6963450 6a40fa vmlinux (64 bit) Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar

include/asm-x86/bitops_32.h: checkpatch cleanups - formatting only

2008-04-17T15:41:21Z

Signed-off-by: Joe Perches Signed-off-by: Ingo Molnar

x86: partial unification of asm-x86/bitops.h

2008-01-30T12:30:55Z

This unifies the set/clear/test bit functions of asm/bitops.h. I have not attempted to merge the bit-finding functions, since they rely on the machine word size and can't be easily restructured to work generically without a lot of #ifdefs. In particular, the 64-bit code can assume the presence of conditional move instructions, whereas 32-bit needs to be more careful. The inline assembly for the bit operations has been changed to remove explicit sizing hints on the instructions, so the assembler will pick the appropriate instruction forms depending on the architecture and the context. Signed-off-by: Jeremy Fitzhardinge Cc: Andi Kleen Cc: Linus Torvalds Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

x86: bitops_32.h style cleanups

2008-01-30T12:30:32Z

Coding style cleanups in x86/bitops_32.h: - drop space in "* addr" - whitespace & indentation fixes - spello fixes Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner

bitops kernel-doc: inline instead of macro

2007-10-25T23:16:26Z

Use duplicated inline functions for test_and_set_bit_lock() on x86 instead of #define macros, thus avoiding a bad example. This allows kernel-doc to run cleanly instead of terminating with an error: Error(linux-2.6.24-rc1//include/asm-x86/bitops_32.h:188): cannot understand prototype: 'test_and_set_bit_lock test_and_set_bit ' Signed-off-by: Randy Dunlap Signed-off-by: Linus Torvalds

x86: lock bitops

2007-10-23T20:37:22Z

I missed an obvious one! x86 CPUs are defined not to reorder stores past earlier loads, so there is no hardware memory barrier required to implement a release-consistent store (all stores are, by definition). So ditch the generic lock bitops, and implement optimised versions for x86, which removes the mfence from __clear_bit_unlock (which is already a useful primitive for SLUB). Signed-off-by: Nick Piggin Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner