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 lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (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 58B97CCFA05 for ; Fri, 7 Nov 2025 13:37:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.sourceforge.net; s=beta; h=Content-Transfer-Encoding:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Subject:In-Reply-To:MIME-Version:References:Message-ID:To:From:Date:Sender: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=N0uZD1n9e1GFXzeByPspxND8ngT59Bu/ZMEhXH+YrOQ=; b=HrDaZw1sdm83a71G3gK0oaxdNG c9kNSrGf0i4f9nBDg7U7E6/EygdAsXKfWqMcoQoeXyBCpy9qW7ds5QipfzoIUMNdemUlzPftRd9TO BoHfZBgMtJw60SZg1NupDvbPF7RLR3PtiAsOoQeQqAM/hdLZOHp9v3NfLFYS5W//7MOk=; Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1vHMf5-0005Qw-QN; Fri, 07 Nov 2025 13:37:55 +0000 Received: from [172.30.29.66] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1vHMf4-0005Qp-84 for linux-f2fs-devel@lists.sourceforge.net; Fri, 07 Nov 2025 13:37:54 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=In-Reply-To:Content-Type:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=4fW4ByonwXrt8CCQV5evrDbXfC526l8bUSvhPi4LoTk=; b=gS7hvXIm0WtXSXInLoMEnAkayi Bmu6m5r6sWHg05URmHhZld950kDmYhJymqVgBavyJ+C8oe9Ya/NIItJsXu99sX88fIe3RF8JHpfUs liF16i0bfkQmgxyThcOVB7qUl1j9MJflgQ9LISkQygRs7XKUsbU4AyP3FgnSLC2yNFe8=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To :From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=4fW4ByonwXrt8CCQV5evrDbXfC526l8bUSvhPi4LoTk=; b=HrY2xosL9XNTFsGSMXVIBnZSNB g0cheWEtLnhzAkmYqWand8O+7w4Gl451Hb6sJoBufBQcsZhRKZagsqR8WpzEvdV1Gsh+x869EO1Xi c5D4fN2CIQT+4voLg/x/FuA+Nf1cfM1JOyUGextkKyYHMSxNSRN/RR57oMqQJVhd8fXQ=; Received: from verein.lst.de ([213.95.11.211]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1vHMf3-00074n-JG for linux-f2fs-devel@lists.sourceforge.net; Fri, 07 Nov 2025 13:37:54 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 6E374227AAE; Fri, 7 Nov 2025 14:37:42 +0100 (CET) Date: Fri, 7 Nov 2025 14:37:42 +0100 From: Christoph Hellwig To: Kundan Kumar Message-ID: <20251107133742.GA5596@lst.de> References: <20251014120845.2361-1-kundan.kumar@samsung.com> <20251022043930.GC2371@lst.de> <20251029060932.GS4015566@frogsfrogsfrogs> <20251029085526.GA32407@lst.de> <91367b76-e48b-46b4-b10b-43dfdd8472fa@samsung.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <91367b76-e48b-46b4-b10b-43dfdd8472fa@samsung.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Headers-End: 1vHMf3-00074n-JG Subject: Re: [f2fs-dev] [PATCH v2 00/16] Parallelizing filesystem writeback X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ritesh.list@gmail.com, vishak.g@samsung.com, jack@suse.cz, "Darrick J. Wong" , amir73il@gmail.com, Dave Chinner , gfs2@lists.linux.dev, linux-mm@kvack.org, clm@meta.com, Christoph Hellwig , dave@stgolabs.net, agruenba@redhat.com, miklos@szeredi.hu, gost.dev@samsung.com, willy@infradead.org, anuj20.g@samsung.com, linux-nfs@vger.kernel.org, viro@zeniv.linux.org.uk, jaegeuk@kernel.org, axboe@kernel.dk, brauner@kernel.org, linux-f2fs-devel@lists.sourceforge.net, mcgrof@kernel.org, anna@kernel.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, trondmy@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Fri, Nov 07, 2025 at 02:54:42PM +0530, Kundan Kumar wrote: > Predicting the Allocation Group (AG) for aged filesystems and passing > this information to per-AG writeback threads appears to be a complex > task. Yes. But in the end aged file systems are what will see most usage. Fresh file systems look nice in benchmarks, but they aren't what users will mostly deal with. > To segregate these I/O requests by AG, it is necessary to associate > AG-specific information with the pages/folios in the page cache. Two > possible approaches are: > (1) storing AG information in the folio->private field, or > (2) introducing new markers in the xarray to track AG-specific data. > > The AG-affined writeback thread processes specific pages from the page > cache marked for its AG. Is this a viable approach, or are there > alternative solutions that could be more effective? Or maybe the per-AG scheme isn't that great after all and we just need some other simple sharding scheme? Of course lock contention will be nicer on a per-AG basis, but as you found out actually mapping high-level writeback to AGs is pretty hard. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel