x86: lock bitops

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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 <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

...

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Nick Piggin 2007-10-19 07:13:02 +02:00 • committed by Thomas Gleixner

parent ea5806559f

commit 418ccbe37f

2 changed files with 83 additions and 2 deletions

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43

include/asm-x86/bitops_32.h

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42

include/asm-x86/bitops_64.h

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