From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 3 Aug 2017 20:24:43 +0300 From: Mike Rapoport To: Andrea Arcangeli Cc: Michal Hocko , Andrew Morton , "Dr. David Alan Gilbert" , Pavel Emelyanov , linux-mm , lkml , stable@vger.kernel.org Subject: Re: [PATCH] userfaultfd_zeropage: return -ENOSPC in case mm has gone References: <1501136819-21857-1-git-send-email-rppt@linux.vnet.ibm.com> <20170731122204.GB4878@dhcp22.suse.cz> <20170731133247.GK29716@redhat.com> <20170731134507.GC4829@dhcp22.suse.cz> <20170802123440.GD17905@rapoport-lnx> <20170802155522.GB21775@redhat.com> <20170802162248.GA3476@dhcp22.suse.cz> <20170802164001.GF21775@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170802164001.GF21775@redhat.com> Message-Id: <20170803172442.GA1026@rapoport-lnx> Sender: owner-linux-mm@kvack.org List-ID: On Wed, Aug 02, 2017 at 06:40:01PM +0200, Andrea Arcangeli wrote: > On Wed, Aug 02, 2017 at 06:22:49PM +0200, Michal Hocko wrote: > > ESRCH refers to "no such process". Strictly speaking userfaultfd code is > > about a mm which is gone but that is a mere detail. In fact the owner of > > Well this whole issue about which retval, is about a mere detail in > the first place, so I don't think you can discount all other mere > details as irrelevant in the evaluation of a change to solve a mere > detail. > > > But as I've said, this might be really risky to change. My impression > > was that userfaultfd is not widely used yet and those can be fixed > > easily but if that is not the case then we have to live with the current > > ENOSPC. > > The only change would be for userfaultfd non cooperative mode, and > CRIU is the main user of that. So I think it is up to Mike to decide, > I'm fine either ways. I certainly agree ESRCH could be a slightly > better fit, I only wanted to clarify it's not a 100% match either. I'm Ok with updating the code and the man page as long as Michal takes the blame if anything but CRIU breaks :) Now, seriously, I believe there are not many users of non-cooperative uffd if at all and it is very unlikely anybody has it in production. I'll send a patch with s/ENOSPC/ESRCH in the next few days. -- Sincerely yours, Mike. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org