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Thu, 09 Oct 2025 05:01:50 -0700 (PDT) MIME-Version: 1.0 References: <20250807014442.3829950-1-pasha.tatashin@soleen.com> <20250807014442.3829950-20-pasha.tatashin@soleen.com> In-Reply-To: From: Pasha Tatashin Date: Thu, 9 Oct 2025 08:01:13 -0400 X-Gm-Features: AS18NWB0gqbxGnAmt0TyUGPWI9yXOeOjTQwVBIB2xaJy4b4dnuqgnZXYRRh26fc Message-ID: Subject: Re: [PATCH v3 19/30] liveupdate: luo_sysfs: add sysfs state monitoring To: Pratyush Yadav Cc: "yanjun.zhu" , jasonmiu@google.com, graf@amazon.com, changyuanl@google.com, rppt@kernel.org, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, zhangguopeng@kylinos.cn, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: B84AB10000C X-Stat-Signature: b6gxosd3e38uyg8gmomixqah6ed7hhra X-Rspam-User: X-HE-Tag: 1760011316-968968 X-HE-Meta: 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 EIETIRf3 q9C011dNVgw/rhRWL6kYzzL8so/4UlSip0kjEj8IsBniQJN8Zf2wZAY22hg== 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: > > Because the window of kernel live update is short, it is difficult to statistics > > how many times the kernel is live updated. > > > > Is it possible to add a variable to statistics the times that the kernel is live > > updated? > > The kernel doesn't do the live update on its own. The process is driven > and sequenced by userspace. So if you want to keep statistics, you > should do it from your userspace (luod maybe?). I don't see any need for > this in the kernel. > One use case I can think of is including information in kdump or the backtrace warning/panic messages about how many times this machine has been live-updated. In the past, I've seen bugs (related to memory corruption) that occurred only after several kexecs, not on the first one. With live updates, especially while the code is being stabilized, I imagine we might have a similar situation. For that reason, it could be useful to have a count in the dmesg logs showing how many times this machine has been live-updated. While this information is also available in userspace, it would be simpler for kernel developers triaging these issues if everything were in one place. Pasha