On (05/08/08 09:12), Dave Hansen didst pronounce: > On Tue, 2008-08-05 at 12:11 +0100, Mel Gorman wrote: > > See, that's great until you start dealing with MAP_SHARED|MAP_ANONYMOUS. > > To get that right between children, you end up something very fs-like > > when the child needs to fault in a page that is already populated by the > > parent. I strongly suspect we end up back at hugetlbfs backing it :/ > > Yeah, but the case I'm worried about is plain anonymous. We already > have the fs to back SHARED|ANONYMOUS, and they're not really > anonymous. :) > > This patch *really* needs anonymous pages, and it kinda shoehorns them > in with the filesystem. Stacks aren't shared at all, so this is a > perfect example of where we can forget the fs, right? >
Ok sure, you could do direct inserts for MAP_PRIVATE as conceptually it suits this patch. However, I don't see what you gain. By reusing hugetlbfs, we get things like proper reservations which we can do for MAP_PRIVATE these days. Again, we could call that sort of thing directly if the reservation layer was split out separate from hugetlbfs but I still don't see the gain for all that churn. What am I missing? -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
