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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 346A1C6FA8F for ; Wed, 30 Aug 2023 06:12:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=C17CSiq7ZyvUGxE22YPogzYFTDGvENNZvb5qYTXpt3M=; b=T4I5ejV7JkAVkH 3pE+P5J98Mxy+mOyF9U4W6KoF//nsii3+33LqKIwSKKXTkV/t2jhU9+llLJkc5p90+Xy/VJWZI4yv zJiajrrzRkBaBVEwFXJy3ZYK3p3Bii8JDtHBmb5C8GOgFjB0KIwO4OhT0NCeL5hdk/gwnVU+ByUil YBQvlPK250D+YSLLI1FYyBgLA4Lt52xYBmUCpgWN3rDEXZYXikLpb3Y6i+uYbX4vrfsT/0peaIR+E 9Yy4vPOZWTRpcR4UdPUEHkse8VP/znHYICextjsIa4IzxgfoTr+hvvArm/IGYF0BT3Dbj1Nm1ysQb 2fDFokl92ruzhJfGNN1A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qbER6-00Ctmn-0x; Wed, 30 Aug 2023 06:12:16 +0000 Received: from out-246.mta0.migadu.com ([91.218.175.246]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qbER2-00Ctld-3D for linux-mtd@lists.infradead.org; Wed, 30 Aug 2023 06:12:14 +0000 Message-ID: <642de4e6-801d-fcad-a7ce-bfc6dec3b6e5@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1693375918; 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=JMzOvVHk770qYz+7D4bRM3eiaC0WBb12Z/fuZleaQ2g=; b=n8qZNKHDJ8ZkQN8s6YCFhUc5vlrIehXvAzssrfT4lOFAEgM70y7j9ccF+kTN544/il9mhv /Qwyv0zoAHdwAPeCdmanHqcxV7A/7XcL4G5u9c/o5+tWUqR2xZIKUSlHotdEAwwwHhjWvg KLK2CGyPGmGk32bcLUct3rbhOUMJhk8= Date: Wed, 30 Aug 2023 14:11:31 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 07/11] vfs: add nowait parameter for file_accessed() Content-Language: en-US To: Matthew Wilcox Cc: io-uring@vger.kernel.org, Jens Axboe , Dominique Martinet , Pavel Begunkov , Christian Brauner , Alexander Viro , Stefan Roesch , Clay Harris , Dave Chinner , "Darrick J . Wong" , linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-cachefs@redhat.com, ecryptfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, codalist@coda.cs.cmu.edu, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, devel@lists.orangefs.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-mtd@lists.infradead.org, Wanpeng Li References: <20230827132835.1373581-1-hao.xu@linux.dev> <20230827132835.1373581-8-hao.xu@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Hao Xu In-Reply-To: X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230829_231213_180902_DC5A617E X-CRM114-Status: GOOD ( 15.65 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On 8/29/23 19:53, Matthew Wilcox wrote: > On Tue, Aug 29, 2023 at 03:46:13PM +0800, Hao Xu wrote: >> On 8/28/23 05:32, Matthew Wilcox wrote: >>> On Sun, Aug 27, 2023 at 09:28:31PM +0800, Hao Xu wrote: >>>> From: Hao Xu >>>> >>>> Add a boolean parameter for file_accessed() to support nowait semantics. >>>> Currently it is true only with io_uring as its initial caller. >>> >>> So why do we need to do this as part of this series? Apparently it >>> hasn't caused any problems for filemap_read(). >>> >> >> We need this parameter to indicate if nowait semantics should be enforced in >> touch_atime(), There are locks and maybe IOs in it. > > That's not my point. We currently call file_accessed() and > touch_atime() for nowait reads and nowait writes. You haven't done > anything to fix those. > > I suspect you can trim this patchset down significantly by avoiding > fixing the file_accessed() problem. And then come back with a later > patchset that fixes it for all nowait i/o. Or do a separate prep series I'm ok to do that. > first that fixes it for the existing nowait users, and then a second > series to do all the directory stuff. > > I'd do the first thing. Just ignore the problem. Directory atime > updates cause I/O so rarely that you can afford to ignore it. Almost > everyone uses relatime or nodiratime. Hi Matthew, The previous discussion shows this does cause issues in real producations: https://lore.kernel.org/io-uring/2785f009-2ebb-028d-8250-d5f3a30510f0@gmail.com/#:~:text=fwiw%2C%20we%27ve%20just%20recently%20had%20similar%20problems%20with%20io_uring%20read/write ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/