Re: [patch] smp-2.3.30-A1, mb(), wmb(), rmb()

Linus Torvalds (
Thu, 25 Nov 1999 09:33:55 -0800 (PST)

Ingo, I think your "mb()" could just be

#define mb() do { \
int __dummy; \
asm volatile("movl %%eax,%0":"=m" (&dummy): :"memory"); \
} while (0)

which instead of using a read-modify-write cycle and a long immediate just
uses a single write-cycle. It makes gcc allocate a word on the stack, and
sometimes that might be unnecessary, but it should be smaller and faster.
You might want to check out code generation..


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