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AJvYcCUN0ah9To61hVJAfhq7P2AKSUVh5dw345NbBhwMypaOAUKnSMsVWr28jN9trIH71VMoW9TcFGDCgA==@kvack.org X-Gm-Message-State: AOJu0YwfZazAVpMflOv4jNQ2XVbueL/AlEHvfgqvuiNKUobUBQ+ziBwV WIUvhuapRePG/bceENg3+UEOTi52XYpEU9EZWk9ucJq7Mm40MhWEslDUFL9dBKPUqBZRjnxKMph QzgKc8hnPG/71qgN2Qfn35DvsHvZnrJZtaCQyPw== X-Gm-Gg: ASbGnctVHQ/zeqAvrVAU5T/6O7p8tUaDsaqf5Z6az3p6akNJxQHTJhcIv96/UrLRVgR 7tEY6zOwERee+KiUGTYLAOxJ4IF8RZIdqwuaB0+NkDb9xh3hJd/veTqtF/S3kqZhA2z0Z9A== X-Google-Smtp-Source: AGHT+IEWLXbbE35/NH7CqFs9Aene/KOrNSHj6kBiOSxP6T7AhYHyVwGrjMz5VAE9dQe0u6W8V5wpkpW0r78/dGV9jWk= X-Received: by 2002:a05:622a:1195:b0:460:8e3b:6790 with SMTP id d75a77b69052e-47167c10096mr111860501cf.48.1739060642643; Sat, 08 Feb 2025 16:24:02 -0800 (PST) MIME-Version: 1.0 References: <20250206132754.2596694-1-rppt@kernel.org> <20250206162939.a1f86fb835f1eeb7ed73ff1c@linux-foundation.org> In-Reply-To: From: Pasha Tatashin Date: Sat, 8 Feb 2025 19:23:25 -0500 X-Gm-Features: AWEUYZm4sw7r0YqYCsAlTqJTyIoFI_gwgSC8Xqrde5SyZs_ybRNGci9xB-WlypE Message-ID: Subject: Re: [PATCH v4 00/14] kexec: introduce Kexec HandOver (KHO) To: Baoquan He Cc: Andrew Morton , Mike Rapoport , linux-kernel@vger.kernel.org, Alexander Graf , Andy Lutomirski , Anthony Yznaga , Arnd Bergmann , Ashish Kalra , Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Dave Hansen , David Woodhouse , Eric Biederman , Ingo Molnar , James Gowans , Jonathan Corbet , Krzysztof Kozlowski , Mark Rutland , Paolo Bonzini , "H. Peter Anvin" , Peter Zijlstra , Pratyush Yadav , Rob Herring , Rob Herring , Saravana Kannan , Stanislav Kinsburskii , Steven Rostedt , Thomas Gleixner , Tom Lendacky , Usama Arif , Will Deacon , devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, changyuanl@google.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: A8827A0004 X-Stat-Signature: 8q66t6mc5wfxab1cuypgidr6ptjsqx83 X-HE-Tag: 1739060643-332772 X-HE-Meta: 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 TITYeBmb b3kWWrSbNmmdTwhJ1fIFVmN/Z6kH9cI6jNf/gBIu1h9jQUsSB6wjuUeuhq5uUDmJLa/QqD3I0U9UymOWwDNqQjv2gXtatA3cV/ReA6xVE15K+di0XBfI1AhgVDYx1r27Pe9L5pzdhXSODiolbLzUW+3OlXeDwXE31DrTVeNUIcZGZFDEt/trFN5gAJMVEAYfCMFwNkkjzPBCZ3JgH/G5YH6XGUCtZQ3Zae0VU1Sdx8MwU1Mhxb39dmclj/U9NQyQLE1KqJzu/IzGheGI5ATrPICWE/id4gWXa5QvWpRoEggntUiZ58HDM/5rxvjYtRL4WejuwDzs3SqNpR5KXr4Lr69VUc4Br5GfNI380bdfL5P4if9N5oD5/f2RfwYyR/LenqFxmm+N6sezBYStcOJy/Kjka7KM3RhCQct0gd4QGWDe91u0HNxP9GttmWSbsR0M03QhGRpzXNcnztNzlnaAFlQ1wvkugejETdVGA X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Feb 7, 2025 at 8:38=E2=80=AFPM Baoquan He wrote: > > On 02/06/25 at 08:28pm, Pasha Tatashin wrote: > > On Thu, Feb 6, 2025 at 7:29=E2=80=AFPM Andrew Morton wrote: > > > > > > On Thu, 6 Feb 2025 15:27:40 +0200 Mike Rapoport wr= ote: > > > > > > > This a next version of Alex's "kexec: Allow preservation of ftrace = buffers" > > > > series (https://lore.kernel.org/all/20240117144704.602-1-graf@amazo= n.com), > > > > just to make things simpler instead of ftrace we decided to preserv= e > > > > "reserve_mem" regions. > > > > > > > > The patches are also available in git: > > > > https://git.kernel.org/rppt/h/kho/v4 > > > > > > > > > > > > Kexec today considers itself purely a boot loader: When we enter th= e new > > > > kernel, any state the previous kernel left behind is irrelevant and= the > > > > new kernel reinitializes the system. > > > > > > I tossed this into mm.git for some testing and exposure. > > > > > > What merge path are you anticipating? > > > > > > Review activity seems pretty thin thus far? > > > > KHO is going to be discussed at the upcoming lsfmm, we are also > > planning to send v5 of this patch series (discussed with Mike > > Rapoport) in a couple of weeks. It will include enhancements needed > > for the hypervisor live update scenario: > > So is this V4 still a RFC if v5 will be sent by plan? Should we hold the > reviewing until v5? Or this series is a infrustructure building, v5 will > add more details as you listed as below. I am a little confused. We will modify the existing patches and send as v5 because some interfaces are going to be changed*. Otherwise, v5 will make KHO a lot more flexible as it will allow to use the tree all the time while the system is running instead of only once during the activation phase. * Changing interfaces is optional, but decision whether to change will be discussed at Hypervisor Live Update on Feb 10th: https://lore.kernel.org/all/26a4b7ca-93a6-30e2-923b-f551ced03d62@google.com= / > > > > > 1. Allow nodes to be added to the KHO tree at any time > > 2. Remove "activate" (I will also send a live update framework that > > provides the activate functionality). > > 3. Allow serialization during shutdown. > > 4. Decouple KHO from kexec_file_load(), as kexec_file_load() should > > not be used during live update blackout time. > > 5. Enable multithreaded serialization by using hash-table as an > > intermediate step before conversion to FDT. >