Re: [RFC PATCH] asynchronous page fault.

[Peter Zijlstra]

On Mon, 2009-12-28 at 09:36 +0900, KAMEZAWA Hiroyuki wrote:
> Hmm ? for single-thread apps ? This patch's purpose is not for lockless
> lookup, it's just a part of work. My purpose is avoiding false-sharing.

False sharing in the sense of the mmap_sem cacheline containing other
variables? How could that ever be a problem for a single threaded
application?

For multi-threaded apps the contention on that cacheline is the largest
issue, and moving it to a vma cacheline doesn't seem like a big
improvement.

You want something much finer grained than vmas, there's lots of apps
working on a single (or very few) vma(s). Leaving you with pretty much
the same cacheline contention. Only now its a different cacheline.

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