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From: Luis Chamberlain <mcgrof@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>,
	Bart Van Assche <bvanassche@acm.org>,
	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, 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
Date: Thu, 20 Mar 2025 14:50:19 -0700	[thread overview]
Message-ID: <Z9yNm5bvfaGo-Zsv@bombadil.infradead.org> (raw)
In-Reply-To: <20250320163804.GA21242@lst.de>

On Thu, Mar 20, 2025 at 05:38:04PM +0100, Christoph Hellwig wrote:
> On Thu, Mar 20, 2025 at 09:58:47AM -0600, Keith Busch wrote:
> > I allocate out of hugetlbfs to reliably send direct IO at this size
> > because the nvme driver's segment count is limited to 128.
> 
> It also works pretty well for buffered I/O for file systems supporting
> larger folios.  I can trivially create 1MB folios in the page cache
> on XFS and then do I/O on them.

Right, but try DIO or io-uring cmd. The two step dma API seems to help us
bridge this gap and provide parity.

  Luis


  reply	other threads:[~2025-03-20 21:50 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-20 11:41 Luis Chamberlain
2025-03-20 12:11 ` Matthew Wilcox
2025-03-20 13:29   ` Daniel Gomez
2025-03-20 14:31     ` Matthew Wilcox
2025-03-20 13:47 ` Daniel Gomez
2025-03-20 14:54   ` Christoph Hellwig
2025-03-21  9:14     ` Daniel Gomez
2025-03-20 14:18 ` Christoph Hellwig
2025-03-20 15:37   ` Bart Van Assche
2025-03-20 15:58     ` Keith Busch
2025-03-20 16:13       ` Kanchan Joshi
2025-03-20 16:38       ` Christoph Hellwig
2025-03-20 21:50         ` Luis Chamberlain [this message]
2025-03-20 21:46       ` Luis Chamberlain
2025-03-20 21:40   ` Luis Chamberlain
2025-03-20 18:46 ` Ritesh Harjani
2025-03-20 21:30   ` Darrick J. Wong
2025-03-21  2:13     ` Ritesh Harjani
2025-03-21  3:05       ` Darrick J. Wong
2025-03-21  4:56         ` Theodore Ts'o
2025-03-21  5:00           ` Christoph Hellwig
2025-03-21 18:39             ` Ritesh Harjani
2025-03-21 16:38       ` Keith Busch
2025-03-21 17:21         ` Ritesh Harjani
2025-03-21 18:55           ` Keith Busch

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