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SubjectRe: [PATCH]: 1/4 batch mark_page_accessed()
Marcelo Tosatti <marcelo.tosatti@cyclades.com> wrote:
>
> > I don't think that atomic_inc will be particularly
> > costly. generic_file_{write,read}() call find_get_page() just before
> > calling mark_page_accessed(), so cache-line with page reference counter
> > is most likely still exclusive owned by this CPU.
>
> Assuming that is true - what could cause the slowdown?

It isn't true. Atomic ops have a considerable overhead, and this is
unrelated to cache misses. This is especially true of p4's.

Now, that overhead may be justified. Needs more study.
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