Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear)

Nick Piggin
2007-03-07T15:01:08Z

On Wed, Mar 07, 2007 at 03:34:27PM +0100, Peter Zijlstra wrote:
> On Wed, 2007-03-07 at 14:52 +0100, Peter Zijlstra wrote:
>
> > True. We could even guesstimate the nonlinear dirty pages by subtracting
> > the result of page_mkclean() from page_mapcount() and force an
> > msync(MS_ASYNC) on said mapping (or all (nonlinear) mappings of the
> > related file) when some threshold gets exceeded.
>
> Almost, but not quite, we'd need to extract another value from the
> page_mkclean() run, the actual number of mappings encountered. The
> return value only sums the number of dirty mappings encountered.
>
> s390 would already work I guess.
>
> Certainly doable.

But if we restrict it to root only, and have a note in the man page
about it, then it really isn't worth cluttering up the kernel.