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 A3330C28B30 for ; Thu, 20 Mar 2025 14:18:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2E855280002; Thu, 20 Mar 2025 10:18:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 270B0280001; Thu, 20 Mar 2025 10:18:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1136A280002; Thu, 20 Mar 2025 10:18:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id E3D47280001 for ; Thu, 20 Mar 2025 10:18:54 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 11AF458A76 for ; Thu, 20 Mar 2025 14:18:57 +0000 (UTC) X-FDA: 83242135914.12.89F5D20 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf05.hostedemail.com (Postfix) with ESMTP id 2E146100020 for ; Thu, 20 Mar 2025 14:18:53 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=none; spf=pass (imf05.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1742480334; 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; bh=FcOd1teDAu0tt10RweynkAG7cHWHNhCrPRw/g5bX7q4=; b=yof4jPVk6OrbxvF3Vq/aKJfBwi8Vo02S+0Rs/yTFMIX81Rcr7ZkdpcumpaQkS703kfFORa VW/qlia8UD1mZ/UVyyacbBuWHDF9sAhTxM8Wza6DQcv5/YvRwmZulJDDkHR4qnMyepS2pX 7V4W3dupQh5T5GOQTVKcMDe1Vew5WBQ= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=none; spf=pass (imf05.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1742480334; a=rsa-sha256; cv=none; b=48HQJfTve0VrhNIg4qoXKi6r21g8Ii0J0+nEqnu9XvceBKUuddQ/Fa9t8wenh4fhHdicqE 09njPIMHPi2meoFqzOJoYrWQ5O+vHGSFxa457+E0cIhgdnC6Pku4XbCUmSZ2KWGIUS/VbW DoPUSod2ayV+WA8rQ4T0h/EatERATcw= Received: by verein.lst.de (Postfix, from userid 2407) id CE86768AA6; Thu, 20 Mar 2025 15:18:47 +0100 (CET) Date: Thu, 20 Mar 2025 15:18:46 +0100 From: Christoph Hellwig To: Luis Chamberlain Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, lsf-pc@lists.linux-foundation.org, david@fromorbit.com, leon@kernel.org, hch@lst.de, kbusch@kernel.org, sagi@grimberg.me, axboe@kernel.dk, joro@8bytes.org, brauner@kernel.org, hare@suse.de, willy@infradead.org, djwong@kernel.org, john.g.garry@oracle.com, ritesh.list@gmail.com, p.raghav@samsung.com, gost.dev@samsung.com, da.gomez@samsung.com Subject: Re: [LSF/MM/BPF TOPIC] breaking the 512 KiB IO boundary on x86_64 Message-ID: <20250320141846.GA11512@lst.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Stat-Signature: egqzj3b3wy5m59w749ep1kdyeph3j9i4 X-Rspamd-Queue-Id: 2E146100020 X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1742480333-612000 X-HE-Meta: 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 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 Thu, Mar 20, 2025 at 04:41:11AM -0700, Luis Chamberlain wrote: > We've been constrained to a max single 512 KiB IO for a while now on x86_64. No, we absolutely haven't. I'm regularly seeing multi-MB I/O on both SCSI and NVMe setup. > This is due to the number of DMA segments and the segment size. In nvme the max_segment_size is UINT_MAX, and for most SCSI HBAs it is fairly large as well.