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[99.254.121.117]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6b764654cb7sm33881246d6.55.2024.07.16.15.02.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jul 2024 15:02:53 -0700 (PDT) Date: Tue, 16 Jul 2024 18:02:50 -0400 From: Peter Xu To: Prasad Pandit Cc: qemu-devel@nongnu.org, Fabiano Rosas , Jason Wang , "Michael S . Tsirkin" , mcoqueli@redhat.com, Prasad Pandit Subject: Re: [PATCH 0/2] Postcopy migration and vhost-user errors Message-ID: References: <20240711131424.181615-1-ppandit@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Jul 16, 2024 at 03:44:54PM +0530, Prasad Pandit wrote: > Hello Peter, > > On Mon, 15 Jul 2024 at 19:10, Peter Xu wrote: > > IMHO it's better we debug and fix all the issues before merging this one, > > otherwise we may overlook something. > > * Well we don't know where the issue is, not sure where the fix may go > in, ex. if the issue turns out to be how virsh(1) invokes > migrate-postcopy, fix may go in virsh(1). Patches in this series > anyway don't help to fix the migration convergence issue, so they > could be reviewed independently I guess. I still think we should find a complete solution before merging anything, because I'm not 100% confident the issue to be further investigated is irrelevant to this patch. No strong opinions, I'll leave that to Michael to decide. > > > You could pass over the patch to whoever going to debug this, so it will be included in the whole set to be > > posted when the bug is completely fixed. > > * Yes, this patch series is linked there. > > > The protocol should have no restriction on the thread model of a front-end. > > It only describes the wire protocol. > > > > IIUC the protocol was designed to be serialized by nature (where there's no > > request ID, so we can't match reply to any of the previous response), then > > the front-end can manage the threads well to serialize all the requests, > > like using this rwlock. > > * I see, okay. The simple protocol definition seems to indicate that > it is meant for one front-end/back-end pair. If we are dividing the > front-end across multiple threads, maybe we need a document to > describe those threads and how they work, at least for the QEMU > (front-end) side. Because the back-end could be a non-QEMU process, we > can not do much there. (just thinking) IMHO that's not part of the protocol but impl details, so the current doc looks all fine to me. Thanks, -- Peter Xu