From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 41F3DCCF9F8 for ; Fri, 7 Nov 2025 23:36:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 61B828E0010; Fri, 7 Nov 2025 18:36:05 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5F2A88E0006; Fri, 7 Nov 2025 18:36:05 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4E1BC8E0010; Fri, 7 Nov 2025 18:36:05 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 385A28E0006 for ; Fri, 7 Nov 2025 18:36:05 -0500 (EST) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 033EF12CD6E for ; Fri, 7 Nov 2025 23:36:04 +0000 (UTC) X-FDA: 84085421490.14.ED0E230 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) by imf21.hostedemail.com (Postfix) with ESMTP id 0D4151C000F for ; Fri, 7 Nov 2025 23:36:02 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=mIiN5q75; spf=pass (imf21.hostedemail.com: domain of yanjun.zhu@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=yanjun.zhu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762558563; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=0qQGWs6LpN4unSynWVZhzKi98tWARU4nt/0dAsCAu7Q=; b=0Ggf5OtKTnAiKaiy6ib7zeSx3bmddaUCydLwXl9MRO/+8Sbx9jETxnBYXQ+xBpkxvjS0IN W7xn3xmtJyT6BrcuJGiuko0lbKmgnpmP5tLloZWzZOjZ/hEQmSd0SoOLv+FOEKvUw3cDOi y43/J4HE7TCs4PawBlnQtzdx2+PglrY= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=mIiN5q75; spf=pass (imf21.hostedemail.com: domain of yanjun.zhu@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=yanjun.zhu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762558563; a=rsa-sha256; cv=none; b=GhTs/NoibprcUnn390HdebdAx8sPlJg6ZEutzcW8XrQ+NnqJY+xsiwpnFXoe1UkdQBJVA4 SyjwSJzcyQXde38ZjunhdNUv9jYOIM69KRfepAEoGjU/M4ShatoZEecW1whkAl6fKeLPUe BL7QZPDQ2B2jhhOTbu5Dh0Vg5COGIuY= Message-ID: <029090cf-9a4d-4f79-b857-04c3ada83323@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1762558560; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0qQGWs6LpN4unSynWVZhzKi98tWARU4nt/0dAsCAu7Q=; b=mIiN5q75lCcf4two/6jp3fr1UONOvcNFCZELHORZjTZkHsbOJO9x9ckTDX0TcH1xMG5rhV QkiPWcQQN3A01vmtyJlDXfZfzuXQEcmdyLTiQ4ZPqy2Hx8ncAy0QNM8yZvrVetu+BsV5zo 4n2Gew0vzxo30idUCWKmG8Dbk1su/Sg= Date: Fri, 7 Nov 2025 15:35:55 -0800 MIME-Version: 1.0 Subject: Re: [PATCH v9 1/9] kho: make debugfs interface optional To: Pasha Tatashin 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 References: <20251101142325.1326536-1-pasha.tatashin@soleen.com> <20251101142325.1326536-2-pasha.tatashin@soleen.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "Yanjun.Zhu" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 0D4151C000F X-Stat-Signature: zeo79mzxw9jhun6zektkh8m1d4tcbc5q X-Rspam-User: X-HE-Tag: 1762558562-89275 X-HE-Meta: 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 NNEGXilw iXCBwNDT0S8UF2NsLLCcJ0EQNIeDD22ojq7kRSMSfWpmKjRyXx3xEMVGNYXavmiE+YgJGmlLh1Jny2eBCYLA5+sHfC/oXGH1F/n4YjLKHNg+qktD+jDBKTSQuqAxOhSfIliHY/ZgBMXJp/FP7nGzRraTzg9CYzDgnKgItWjp+qqcapfPFWtJJxDmuxzD9erAFGmSFK1tLO4J1UcNCQzDujOs3x1GTWyAU/y6bv40iPjr/1aQ6g7zMwSIOqniTQQCQnnfAM+9pp+Xq6lSVi+Vhs1Bibg== 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 11/7/25 4:02 AM, Pasha Tatashin wrote: > On Fri, Nov 7, 2025 at 7:00 AM Pasha Tatashin wrote: >>> Hi, Pasha >>> >>> In our previous discussion, we talked about counting the number of times >>> 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 Thanks a lot. I’ve carefully read this commit: https://github.com/soleen/linux/commit/60205b9a95c319dc9965f119303a1d83f0ff08fa. To be honest, I’d like to run some tests with who/luo, including the selftest for kho/luo. Could you please share the steps with me? If the testing steps have already been documented somewhere, could you please share the link? Best Regards, Yanjun.Zhu