On Fri, 19 Oct 2007, Nick Piggin wrote: > Of course, we can avoid the fence altogether on x86 as well, because > it simply isn't needed for release semantics. So we can generally switch to using wmb there? __clear_bit_unlock: A write barrier is sufficient for release semantics Switch the smb_mb that causes a fence instruction to be issued on x86 to a write barrier which issues no instruction on x86. Signed-off-by: Christoph Lameter <clameter@xxxxxxx> Index: linux-2.6/include/asm-generic/bitops/lock.h =================================================================== --- linux-2.6.orig/include/asm-generic/bitops/lock.h 2007-10-19 04:08:58.000000000 -0700 +++ linux-2.6/include/asm-generic/bitops/lock.h 2007-10-19 04:09:17.000000000 -0700 @@ -37,7 +37,7 @@ do { \ */ #define __clear_bit_unlock(nr, addr) \ do { \ - smp_mb(); \ + smp_wmb(); \ __clear_bit(nr, addr); \ } while (0) - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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