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AJvYcCX7E0LqYpzDFvya155dRZEXE5ou0PwL5dXdqpJSddC1NTn7PbNKT6sAYic7jyyLYSr6aHG0Ih1v/Q==@kvack.org X-Gm-Message-State: AOJu0YzFVmfzeYBOsz/tzFgUBv/YzAqRFRK/lShjJmlBYzQmfAIPYLCx YmqSLPf08wx0akMsRU3QXNbV00qWANdEhULA5BTyYW7OHZyZ6RxD9VxQ7u8RPtiGoFc/fdmvaRz KDA5l0ldF+TPDJUlg+MZjuUE+Y22f17t7AilDM+q/4A== X-Gm-Gg: ASbGncsLt9jfE6gmwX/t1tyRhBS12ra+gvqnRY+7Y1aYZ5a6jpFDHhB1XGo/j/qoaSv +wEVO4RokvQnvpQ/VoAywJ2NDOhBSxc+EU8XWxSxOACUiPA1zPgZhgDw5JvWMlO1Ul5H2ysi2xs RD1Bt3IOpJzmqnOetLSwVHt0AOf/oNftb9n9CeA63TTDVbH+fgBvjxJ0mO/QMeEnB7DsWN2P9MY HEfgVPR4Si0KviuQLkQHQoVhKCUbrRRdARti2T0Y8pI/812EFVseJ4H8Wbq990Xh7JG X-Google-Smtp-Source: AGHT+IFqhmWJ0cizgg2FabCJ2Y+psCwYYmTaIqkaXVpc8XQgBzLaJv45nRBMIXurahATrE3jLrd63/YppCZUaEvDwmI= X-Received: by 2002:a17:907:1c0a:b0:b72:26ec:c8db with SMTP id a640c23a62f3a-b72c0ae2034mr313773866b.30.1762517009090; Fri, 07 Nov 2025 04:03:29 -0800 (PST) MIME-Version: 1.0 References: <20251101142325.1326536-1-pasha.tatashin@soleen.com> <20251101142325.1326536-2-pasha.tatashin@soleen.com> In-Reply-To: From: Pasha Tatashin Date: Fri, 7 Nov 2025 07:02:53 -0500 X-Gm-Features: AWmQ_bnQfOkuuqF_U_UCQyVPI35A_f2RSjbVr-3UOfrbEvw6xE0HnRxARqEhO_0 Message-ID: Subject: Re: [PATCH v9 1/9] kho: make debugfs interface optional To: Zhu Yanjun Cc: akpm@linux-foundation.org, brauner@kernel.org, corbet@lwn.net, graf@amazon.com, jgg@ziepe.ca, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, masahiroy@kernel.org, ojeda@kernel.org, pratyush@kernel.org, rdunlap@infradead.org, rppt@kernel.org, tj@kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: 516qbyuaan7ipt81ejm79ofijwtdui9z X-Rspam-User: X-Rspamd-Queue-Id: 9DA328001B X-Rspamd-Server: rspam10 X-HE-Tag: 1762517010-349100 X-HE-Meta: U2FsdGVkX1+URjY+eq+C/s8EOgym8i3gU4qaTYT+gPfIGabPpXxcxSRRUKlIHQ8Kjl7S6hUogvEZWT9+a+QP5zPCR2IeW783APpLFgPpDyrB3mS9WOHZNPPgwv/GSENq2vSYUpKx+f7wuQVijRygIql1SbUdFlZxf0KXc818epzUK7WoeSuan1N8Gib73x6BbBEvqTMDif0g3nxIn0KARaMS5aiGmJkfie7H9zuEjPGJegSr9+7v+TgDwj7zU7sSAmjJQbHlgPD3tpG0ujsweHOSN+OdGGtAKWWt8bZKh4//NEsnkGuOIQvRpI/o0CvjJs3CLcsyHVmJ/w0eLQsq/4S7TyeYAZT8NjsJwoB7zFdCQZTP+WW2mYEe9gLMJBsQDiGpQzJS9uKGl4WZoaniPP2ZgzleeR31Z1pARcoVVTgAQlJnO4/2Eij98cypS559CY1Lc4QWqQdK9lfVF+k1MBZFFykUUJsAs1i+/9MTEmMqdOorVd59XMU2DtIBCkmlJ57ftaOFh9XNAJoZyTBo3zXM5Ip4ppbXA+3/edLbI7dJHQaUyuLKdAvA+Neji3dDz3jJAbbkDSDBE5oNbars3wK0gzm9RhDOxvIqmvph5/DrRWBU6s9n8swHjXX7ls1JkPPsttCUeERLJ1W8/PcB5AvENoqhwDoDHegQX0jo7n7PsmCyWbPHLhBJZAaeWvJCgwkrm1ERlNvyhdwcp2CSkZrMltFstfvnowr9JKxoOBB7khYfnr8qvkY4YGY9+FRQ60p1j/ny+8hbeIyxNUrx57XBjAzWMzZZkBcqH9XrjSF/GbqoVv+YSOyMb0PwxnUNW2ETCn44uca+sfGeVrqy35kvae8cHRuXFOJzgdEnQa/znfPqwUg8vAfnTwmYcdE/AGTVXFEYit8eBXjMT1T3x3w98TQU0ezsbSXk3Flc5+puNjG+/n2PGN3Ix9tMpLS8sYPAIpF8j5sjvBSYe+e NL4HeRoh 6dVDNvoNptkgkjCWw8dtruOuZcmg2ilCD3pUUyShX5E6ALHrdZvN+LwbYv55lf9eMl5+t50pBcXFXqSZWuOfHGC3Atk9hKOoj3Aum0sQZ2GcasI33sDUUSL4CMVWSc2C+SKts259SK7ZG2ZMfkl3TCL/qkEOoRGm35e3KCUswVKB3rq9BuI6hLQo5EM+nV2VGCaTooLg1j38MoWMOpUxEUmNba1+h7bQV7mRILOVoGbI/H/0= 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, Nov 7, 2025 at 7:00=E2=80=AFAM Pasha Tatashin wrote: > > > Hi, Pasha > > > > In our previous discussion, we talked about counting the number of time= s > > the kernel is rebooted via kexec. At that time, you suggested adding a > > variable in debugfs to keep track of this count. > > However, since debugfs is now optional, where would be an appropriate > > place to store this variable? > > It is an optional config and can still be enabled if the live update > reboot number value needs to be accessed through debugfs. However, > given that debugfs does not guarantee a stable interface, tooling > should not be built to require these interfaces. > > In the WIP LUO [1] I have, I pr_info() the live update number during > boot and also store it in the incoming LUO FDT tree, which can also be > accessed through this optional debugfs interface. > > The pr_info message appears like this during boot: > [ 0.000000] luo: Retrieved live update data, liveupdate number: 17 > > Pasha Forgot to add link to WIP LUOv5: [1] https://github.com/soleen/linux/tree/luo/v5rc04