Messages in this thread | | | Date | Wed, 7 Mar 2007 10:18:23 +0100 | From | Nick Piggin <> | Subject | Re: [patch 4/6] mm: merge populate and nopage into fault (fixes nonlinear) |
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On Wed, Mar 07, 2007 at 01:07:56AM -0800, Andrew Morton wrote: > On Wed, 07 Mar 2007 09:51:57 +0100 Miklos Szeredi <miklos@szeredi.hu> wrote: > > > > > Dirty page accounting doesn't work either on > > > > non-linear mappings > > > > > > It doesn't? Confused - these things don't have anything to do with each > > > other do they? > > > > Look in page_mkclean(). Where does it handle non-linear mappings? > > > > OK, I'd forgotten about that. It won't break dirty memory accounting, > but it'll potentially break dirty memory balancing. > > If we have the wrong page (due to nonlinear), page_check_address() will > fail and we'll leave the pte dirty. That puts us back to the pre-2.6.17 > algorithms and I guess it'll break the msync guarantees. > > Peter, I thought we went through the nonlinear problem ages ago and decided > it was OK?
msync breakage is bad, but otherwise I don't know that we care about dirty page writeout efficiency.
But I think we discovered that those msync changes are bogus anyway becuase there is a small race window where pte could be dirtied without page being set dirty?
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