On Tue, Feb 19, 2008 at 09:43:57AM +0100, Nick Piggin wrote: > So I implemented mmu notifiers slightly differently. Andrea's mmu notifiers > are rather similar. However I have tried to make a point of minimising the > impact the the core mm/. I don't see why we need to invalidate or flush > anything when changing the pte to be _more_ permissive, and I don't > understand the need for invalidate_begin/invalidate_end pairs at all. > What I have done is basically create it so that the notifiers get called > basically in the same place as the normal TLB flushing is done, and nowhere > else.
Because XPMEM needs to be able to sleep during its callout. For that, we need to move this outside of the page table lock and suddenly we need the begin/end pair again. There was considerable discussion about this exact point numerous times. We tried to develop the most inclusive design possible. Our design would even be extendable to IB, assuming they made some very disruptive changes to their MPI and communication libraries. IB would suffer the same problems XPMEM does in that the TLB entries need to be removed on a remote host which is operating completely independently. Thanks, Robin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
