On Wed 25-03-20 09:14:07, Jason Gunthorpe wrote: > On Wed, Mar 25, 2020 at 09:01:17AM +0100, Michal Hocko wrote: > > > > I'm going to put this in linux-next to see if there are any reports of > > > > the pr_warn failing. > > > > > > > > Michal, are you happy with this solution now? > > > > > > It's been a month in linux-next now, with no complaints. If there are > > > no comments I will go ahead to send it in the hmm PR. > > > > I will not block this but it still looks like a wrong approach. A more > > robust solution would be to allow calling invalidate_range_end even for > > the failing invalidate_start. > > That requires reliably walking a rcu list backwards under rcu. I don't > have a good feeling about that algorithm. Do you know of a solution? No, not really. I would be pushing for it if I had. Maybe we want a different data structure than the RCU list. But... > Since we don't actually have any users that care about this any more, > I felt this testable solution was better. ... you are right that this is probably the best short term workaround. -- Michal Hocko SUSE Labs
