On Tue, May 13, 2008 at 10:06:44PM +1000, Nick Piggin wrote: > On Thursday 08 May 2008 10:38, Robin Holt wrote: > > In order to invalidate the remote page table entries, we need to message > > (uses XPC) to the remote side. The remote side needs to acquire the > > importing process's mmap_sem and call zap_page_range(). Between the > > messaging and the acquiring a sleeping lock, I would argue this will > > require sleeping locks in the path prior to the mmu_notifier invalidate_* > > callouts(). > > Why do you need to take mmap_sem in order to shoot down pagetables of > the process? It would be nice if this can just be done without > sleeping.
We are trying to shoot down page tables of a different process running on a different instance of Linux running on Numa-link connected portions of the same machine. The messaging is clearly going to require sleeping. Are you suggesting we need to rework XPC communications to not require sleeping? I think that is going to be impossible since the transfer engine requires a sleeping context. Additionally, the call to zap_page_range expects to have the mmap_sem held. I suppose we could use something other than zap_page_range and atomically clear the process page tables. Doing that will not alleviate the need to sleep for the messaging to the other partitions. Thanks, Robin _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
