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 E8CECCD5BD5 for ; Wed, 27 May 2026 06:28:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 32B156B00A1; Wed, 27 May 2026 02:28:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 308326B00A2; Wed, 27 May 2026 02:28:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 240076B00A3; Wed, 27 May 2026 02:28:35 -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 14FA46B00A1 for ; Wed, 27 May 2026 02:28:35 -0400 (EDT) Received: from smtpin15.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay03.hostedemail.com (Postfix) with ESMTP id AE7A5A0543 for ; Wed, 27 May 2026 06:28:34 +0000 (UTC) X-FDA: 84812220948.15.E9810E6 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf01.hostedemail.com (Postfix) with ESMTP id 1B2D440012 for ; Wed, 27 May 2026 06:28:32 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=nS7j8vx2; dmarc=pass (policy=none) header.from=infradead.org; spf=none (imf01.hostedemail.com: domain of BATV+e9735a96feccf8b5d28d+8312+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+e9735a96feccf8b5d28d+8312+infradead.org+hch@bombadil.srs.infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1779863313; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Ka/9L3mGRr/AbgLqT0X1N/LKODg56XkQXKLxkU0UHzU=; b=x7X6up3brqE8GzzGjKDS3kmBQsC+aKrAY5T8D/yW7t7k7pSt8rK84S2cg65QeJGZMU7+Ca o6iePvV47HPDq0JkLurfkgjnkCSjshlT+/gFCjbWrTnHD+99bZzXz7yduuzzaduEp/Bchs qDcDLYMOE3uB8QLmmUrcqWsfJRnmXeQ= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=nS7j8vx2; dmarc=pass (policy=none) header.from=infradead.org; spf=none (imf01.hostedemail.com: domain of BATV+e9735a96feccf8b5d28d+8312+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+e9735a96feccf8b5d28d+8312+infradead.org+hch@bombadil.srs.infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1779863313; a=rsa-sha256; cv=none; b=Ed/3PUZw4iRCGuvVn5evZ4bzoS/QV7WWSgCellahmuhOYRRdEGi0o91OhYz8MLNw81sPX2 OLOUJ+UWLk6+Bfav877q1SJLKcO48p5XyCYzAnPsGad7J0Wdhl95uMF0jb9zc0lbPyQGSE ZomlfvzKDk6t82TcVnGQRbeeAWQ8z7I= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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; bh=Ka/9L3mGRr/AbgLqT0X1N/LKODg56XkQXKLxkU0UHzU=; b=nS7j8vx2eymE0ZSZoDXuT2yyfB /S4PFwuANnKUoJp7Giy3+PPZL2gSAx1o/0tYaYdwpEB5m5NxnKmi0la7rA+Kdjp8Tg0DTzC3wbrdb p0SdCWxYoxDL4R+uCloO+ntIkscwqjOUheJxRyg6k3URoBMbJg02NwWXHUDRHOhOsoUcznSjqCr7R nzTIsYlAv+FvrDCQTadRi0C0ba3pnNgQPJvhBxUeWgi03KEwJcO3vfxYgKtesqiYn6VhwjAlat7Im ccYCea5H39rArdAXYTH8KgLSGMAdaGm9wmifOC0WrWvLVA7yRspaKDM4ho8hHu1TqWsRqsxOjMKHA XhyVjWPw==; Received: from hch by bombadil.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux)) id 1wS7ki-00000003Ozf-3Lht; Wed, 27 May 2026 06:28:28 +0000 Date: Tue, 26 May 2026 23:28:28 -0700 From: Christoph Hellwig To: Bart Van Assche Cc: Theodore Tso , Jaegeuk Kim , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Matthew Wilcox , linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Akilesh Kailash , Christian Brauner Subject: Re: [f2fs-dev] [PATCH v2] f2fs: another way to set large folio by remembering inode number Message-ID: References: <20260521155748.GA79343@macsyma-wired.lan> <20260522141115.GA8258@macsyma-wired.lan> <20260522224108.GA18663@macsyma-wired.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 1B2D440012 X-Stat-Signature: 3mj9c4dutzyac9xf55aqz1kjuk6pi4bw X-Rspam-User: X-HE-Tag: 1779863312-330868 X-HE-Meta: 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 yFiuBtjr 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, May 26, 2026 at 09:14:52AM -0700, Bart Van Assche wrote: > On 5/26/26 6:42 AM, Theodore Tso wrote: > > It seems... surprising that the additional I/O operations are actually > > throttloing UFS device bandwidth by 2x (4GB/s vs 2GB/s). Have you dug > > into why this is happening, and whether there is anything that can be > > optimized below the file system? > The layers below the filesystem (block, SCSI, UFS) is what I'm > responsible for in the Pixel team and I can assure you that these are > highly optimized. > > Since the transfer size used in Jaegeuk's tests is much larger than 4 > KiB, how many CPU cycles are used per IO by the layers below the > filesystem is not limiting the transfer bandwidth. I'm honestly not sure what discussion we have here. Larger I/O is pretty much always more efficient. If you submit smaller I/O you need more merging to build it back up larger, and more I/Os. Which is exaxtly why we need large folio support everywhere, as it makes a huge difference in I/O performance.