> My understanding of the code is that fork will end-up calling > copy_page_range() on all VMA, and copy_page_range() calls > mmu_notifier_invalidate_range_start() if is_cow_mapping() is true, > which should be the case here. So you should get some invalidate events > on fork.
Yes, I agree (that's what the second half of my email tried to say). However, that doesn't help if the parent process is actively doing RDMA on the range being invalidated -- the MPI library or whatever will get the invalidate event via ummunotify, but what can it do? The event is basically saying "your data is going to the wrong place" and I don't see what useful thing MPI could do with that. As I said, it does mean that MPI can invalidate cached registrations for COWed memory, which might be useful in case a parent forks and then touches memory it used to use for RDMA, but I think that's the easier part of the fork/COW problem. - R. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
