Re: [patch] SMP alternatives

From: Linus Torvalds
Date: Wed Nov 23 2005 - 17:22:12 EST




On Wed, 23 Nov 2005, H. Peter Anvin wrote:
>
> Yes. Any shared mmaps may require working lock.

Not "any". Only writable shared mmap. Which is actually the rare case.

Even then, we might want to have such processes have a way to say "I don't
do futexes in this mmap" or similar. Quite often, writable shared mmaps
aren't interested in locked cycles - they are there to just write things
to disk, and all the serialization is done in the kernel when the user
does a "munmap()" or a "msync()".

Linus
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