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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 Subject: Re: [PATCH v4 00/14] kexec: introduce Kexec HandOver (KHO) Message-ID: References: <20250206132754.2596694-1-rppt@kernel.org> <20250206162939.a1f86fb835f1eeb7ed73ff1c@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Rspam-User: X-Rspamd-Queue-Id: E6248120002 X-Stat-Signature: 94iqu7ewwbjgxcqg3yhjuc71qe61934c X-Rspamd-Server: rspam03 X-HE-Tag: 1739070494-778231 X-HE-Meta: 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 Rb5jzIT2 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 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 02/08/25 at 07:23pm, Pasha Tatashin wrote: > On Fri, Feb 7, 2025 at 8:38 PM Baoquan He wrote: > > > > On 02/06/25 at 08:28pm, Pasha Tatashin wrote: > > > On Thu, Feb 6, 2025 at 7:29 PM Andrew Morton wrote: > > > > > > > > On Thu, 6 Feb 2025 15:27:40 +0200 Mike Rapoport wrote: > > > > > > > > > This a next version of Alex's "kexec: Allow preservation of ftrace buffers" > > > > > series (https://lore.kernel.org/all/20240117144704.602-1-graf@amazon.com), > > > > > just to make things simpler instead of ftrace we decided to preserve > > > > > "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 the 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/ Ah, this is what I would like to know about the difference between v4 and v5. Thanks for the information, and looking forward to seeing the v5 update. > > > > > > > > > 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. > > >