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On Wed, Nov 02, 2005 at 10:02:49PM +0000, Hugh Dickins wrote: > On Thu, 3 Nov 2005, Benjamin Herrenschmidt wrote: > > On Wed, 2005-11-02 at 21:41 +0000, Hugh Dickins wrote: > > > The only extant problem here is if the pages are private, and you > > > fork while this is going on, and the parent user process writes to the > > > area before completion: then COW leaves the child with the page being > > > DMAed into, giving the parent a copied page which may be incomplete. > > > > Won't happen, and if it does, it's a user error to rely on that working, > > so it doesn't matter. > > I wish everyone else would see it that way! (But some people do > have valid scenarios where it can't just be ruled out completely.) > I am one of those people :) Last discussion about this issue ended without resolution, but I remember you mentioned the possibility to leave ptes writable in parent during fork for private pages mapped for DMA. Is this approach acceptable? -- Gleb. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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