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Now that Christoph Lameter's atomic_long_t support is merged in mainline, might as well convert asm-generic/local.h to use it, so the same code can be used for both sizes of 32 and 64-bit unsigned longs. akpm sayeth: Q: Is there any particular reason why these routines weren't simply implemented with local_save/restore_flags, if they are only meant to guarantee atomicity to the local cpu? I'm sure on most platforms this would be more efficient than using an atomic... A: The whole _point_ of local_t is to avoid local_irq_disable(). It's designed to exploit the fact that many CPUs can do incs and decs in a way which is atomic wrt local interrupts, but not atomic wrt SMP. But this patch makes sense, because asm-generic/local.h is just a fallback implementation for architectures which either cannot perform these local-irq-atomic operations, or its maintainers haven't yet got around to implementing them. We need more work done on local_t in the 2.6.17 timeframe - they're defined as unsigned long, but some architectures implement them as signed long. Signed-off-by: Kyle McMartin <kyle@parisc-linux.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
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