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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43DF5EB64D7 for ; Wed, 21 Jun 2023 11:34:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9EE478D0002; Wed, 21 Jun 2023 07:34:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 977338D0001; Wed, 21 Jun 2023 07:34:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 817508D0002; Wed, 21 Jun 2023 07:34:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 6DC578D0001 for ; Wed, 21 Jun 2023 07:34:16 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 44ED216093D for ; Wed, 21 Jun 2023 11:34:16 +0000 (UTC) X-FDA: 80926546512.03.9FD0A06 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by imf10.hostedemail.com (Postfix) with ESMTP id D88BCC001C for ; Wed, 21 Jun 2023 11:34:12 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=none; dmarc=none; spf=none (imf10.hostedemail.com: domain of penguin-kernel@I-love.SAKURA.ne.jp has no SPF policy when checking 202.181.97.72) smtp.mailfrom=penguin-kernel@I-love.SAKURA.ne.jp ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1687347254; 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; bh=8cbugJ+ScV6K+RGaMEEthsvZQ9DfE7bTEIk+1fMF11I=; b=TZJ/fr76YM3c4vaq0wMSgEIq0DD6hcxhODC39zWkTX19Qb7UtaWCt51pW03421yoMUeYWU AXL7ErL3yMLqN601MDqhLj2/hfoNO9y3Zz9ev1wSI+WArP4H9b3KGMmMqcYUPNuVy4ku+p okcrhePI27zQGv6iExUThWClMdiGn+M= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=none; dmarc=none; spf=none (imf10.hostedemail.com: domain of penguin-kernel@I-love.SAKURA.ne.jp has no SPF policy when checking 202.181.97.72) smtp.mailfrom=penguin-kernel@I-love.SAKURA.ne.jp ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1687347254; a=rsa-sha256; cv=none; b=tZECJZAuEiv4rHGzznE2cb4y/IBM4HwapSAjgBw8duk9MYiZQbIuWFicSsQRHNPELZfmnG IPeCc5R0hqngscQ429CJMhQomz2T3ytUfk/b9TRODzcoSlB2d9OYNn3cnMy877oK5UQ1K5 dDn+IR1heZeSNa2TV7wuzvOw344o3wc= Received: from fsav313.sakura.ne.jp (fsav313.sakura.ne.jp [153.120.85.144]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 35LBXbL7050025; Wed, 21 Jun 2023 20:33:37 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav313.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav313.sakura.ne.jp); Wed, 21 Jun 2023 20:33:37 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav313.sakura.ne.jp) Received: from [192.168.1.6] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 35LBXbMT050022 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Wed, 21 Jun 2023 20:33:37 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <0e9fc992-8e05-2e63-b3b1-d8d3ce89fc16@I-love.SAKURA.ne.jp> Date: Wed, 21 Jun 2023 20:33:35 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH] mm/page_alloc: Use write_seqlock_irqsave() instead write_seqlock() + local_irq_save(). Content-Language: en-US To: Sebastian Andrzej Siewior , linux-mm@kvack.org Cc: "Luis Claudio R. Goncalves" , Andrew Morton , Mel Gorman , Michal Hocko , Thomas Gleixner , Petr Mladek References: <20230621104034.HT6QnNkQ@linutronix.de> From: Tetsuo Handa In-Reply-To: <20230621104034.HT6QnNkQ@linutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: D88BCC001C X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 81qd5um4tmhh54idrytb8kpy79jcko5p X-HE-Tag: 1687347252-377518 X-HE-Meta: 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 SfMrTKQ7 2k44YQSs1KmosvOI1TbjfFlAbBdkbnlVWo7Jh1vug2hZuJhhLCO4XAJgxb0QrUcyIL4HaMPxmclIyPokjSWWoZqEKaL0VcrTRFosfdqP6QF5a7IMOJ8MlhuIlmFiFM6ABMoX0guPLIGEpI4EQur636oDgtUwLV/lAIaPFfziwwRKvVgIiiLpZ1U1Jz5T6kSSAQrsfDn1qua1/2QzBjYxOGt1tc59DuJ2dcy1uMxnfDCFAOHL3hBrIiUsCSLCjo9fSzvhyoT5WUO/m/18= 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: On 2023/06/21 19:40, Sebastian Andrzej Siewior wrote: > printk_deferred_enter() has to be invoked in non-migrate-able context to > ensure that deferred printing is enabled and disabled on the same CPU. I can't catch. local_irq_save(flags); makes non-migrate-able context because sleeping is not allowed while IRQ is disabled, doesn't it? > This is the case after zonelist_update_seq has been acquired. > > Acquire zonelist_update_seq with write_seqlock_irqsave() and then defer > printk output. What guarantees that write_seqlock_irqsave() never calls printk() (e.g. lockdep warning) before printk_deferred_enter() takes effect?