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[99.254.114.190]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-460d3c3aff7sm22359231cf.12.2024.10.21.14.18.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2024 14:18:15 -0700 (PDT) Date: Mon, 21 Oct 2024 17:18:13 -0400 From: Peter Xu To: Michael Tokarev Cc: qemu-devel@nongnu.org, Vitaly Kuznetsov , Fabiano Rosas , Prasad Pandit , Julia Suvorova , Juraj Marcin , Paolo Bonzini , David Hildenbrand , qemu-stable , Zhiyi Guo Subject: Re: [PATCH v4 1/4] KVM: Dynamic sized kvm memslots array Message-ID: References: <20240917163835.194664-1-peterx@redhat.com> <20240917163835.194664-2-peterx@redhat.com> <52cc6540-b1ff-495e-9b98-98f13ecbf380@tls.msk.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.421, 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_H2=-1.699, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=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 Mon, Oct 21, 2024 at 10:05:23PM +0300, Michael Tokarev wrote: > 21.10.2024 17:37, Peter Xu wrote: > > Michael, > > > > On Fri, Oct 18, 2024 at 06:38:53PM +0300, Michael Tokarev wrote: > > > Looking at this from qemu-stable PoV, I'm not 100% sure this change is good > > > for stable-7.2 series, because 7.2 lacks v8.1.0-1571-g5b23186a95 > > > "kvm: Return number of free memslots" commit, which was a preparation for > > > for memory devices that consume multiple memslots. > > > > > > I did a backport of this change (currently it is at the tip of staging-7.2 > > > branch of https://gitlab.com/mjt0k/qemu.git) - I had to tweak context and > > > also to remove now-unused local variable in kvm-all.c. It builds and the > > > tests run fine, but I'm not really sure it does what it is intended to do. > > > > > > Should anything else be picked up for 7.2 for all this to work, or should > > > this change not be back-ported to 7.2 ? > > > > > > (for more recent releases, everything looks ok). > > > > I don't remember anything this series logically depends on (besides any > > context-wise change). > > Well, 7.2 is a bit old by now, and the commit I already mentioned above is > also quite old, - at the time you started working on this series, this > commit (v8.1.0-1571-g5b23186a95) has been in the tree for a long time > already. This change might be relevant here or might be not. That specific commit (5b23186a95) shouldn't be relevant. > > > If there's uncertainty / challenge from backporting to some stable branches > > from your POV, we can still keep things simple and skip the series, as it's > > only a perf regression and only happens during live migrations (which can > > enlarge the downtime, for example) but not daily VM use. > > For this change alone, I did the backport, I just am not sure it makes sense. > > It would be great if you take a look, including the change I mentioned above > (it isn't in 7.2), there: https://gitlab.com/mjt0k/qemu/-/commits/staging-7.2 > Or we can just drop it for 7.2 per the above. I checked the backport, it looks all good. Thanks, -- Peter Xu