On Wed, Jan 23, 2008 at 12:27:47PM -0800, Christoph Lameter wrote: > There are still dirty bit issues.
Yes, but no big issues given ->invalidate_page is fully capable of running set_page_dirty if needed. > > The window that you must close with that bitflag is the request coming > > from the remote node to map the page after the linux pte has been > > cleared. If you map the page in a remote node after the linux pte has > > been cleared ->invalidate_page won't be called again because the page > > will look unmapped in the linux VM. Now invalidate_page will clear the > > bitflag, so the map requests will block. But where exactly you know > > that the linux pte has been cleared so you can "unblock" the map > > requests? If a page is not mapped by some linux pte, mm/rmap.c will > > never be called and this is why any notification in mm/rmap.c should > > track the "address space" and not the "physical page". > > The subsystem needs to establish proper locking for that case. How? I Your answer was to have the subsystem-fault wait PG_exported to return ON... when later you told me the subsystem-fault is the thing supposed to set PG_exported ON again... Perhaps you really could invent a proper locking to make your #v1 workable somehow but I didn't see a sign of it yet. Infact I'm not so sure if all will be race-free with invalidate_page_after (given you pretend to call it outside the PT lock so concurrent linux minor faults can happen in parallel of your invalidate_page_after) but at least it has a better chance to work without having to invent much new complex locking. > It also deals f.e. with page dirty status. I think you should consider if you can also build a rmap per-MM like KVM does and index it by the virtual address like KVM does. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
