From: Matthew Wilcox <willy@infradead.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Ming Lei <tom.leiming@gmail.com>,
Vlastimil Babka <vbabka@suse.cz>,
Dave Chinner <david@fromorbit.com>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
"open list:XFS FILESYSTEM" <linux-xfs@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Dave Chinner <dchinner@redhat.com>,
Christoph Hellwig <hch@lst.de>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Aaron Lu <aaron.lu@intel.com>, Christopher Lameter <cl@linux.com>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-block <linux-block@vger.kernel.org>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH] xfs: allocate sector sized IO buffer via page_frag_alloc
Date: Tue, 26 Feb 2019 05:02:30 -0800 [thread overview]
Message-ID: <20190226130230.GD11592@bombadil.infradead.org> (raw)
In-Reply-To: <20190226123545.GA6163@ming.t460p>
On Tue, Feb 26, 2019 at 08:35:46PM +0800, Ming Lei wrote:
> On Tue, Feb 26, 2019 at 04:12:09AM -0800, Matthew Wilcox wrote:
> > On Tue, Feb 26, 2019 at 07:12:49PM +0800, Ming Lei wrote:
> > > The buffer needs to be device block size aligned for dio, and now the block
> > > size can be 512, 1024, 2048 and 4096.
> >
> > Why does the block size make a difference? This requirement is due to
> > some storage devices having shoddy DMA controllers. Are you saying there
> > are devices which can't even do 512-byte aligned I/O?
>
> Direct IO requires that, see do_blockdev_direct_IO().
>
> This issue can be triggered when running xfs over loop/dio. We could
> fallback to buffered IO under this situation, but not sure it is the
> only case.
Wait, we're imposing a ridiculous amount of complexity on XFS for no
reason at all? We should just change this to 512-byte alignment. Tying
it to the blocksize of the device never made any sense.
next prev parent reply other threads:[~2019-02-26 13:04 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-25 4:09 [PATCH] xfs: allocate sector sized IO buffer via page_frag_alloc Ming Lei
2019-02-25 4:36 ` Dave Chinner
2019-02-25 8:46 ` Ming Lei
2019-02-25 10:03 ` Ming Lei
2019-02-25 20:11 ` Dave Chinner
2019-02-25 13:15 ` Vlastimil Babka
2019-02-25 20:26 ` Dave Chinner
2019-02-26 2:22 ` Ming Lei
2019-02-26 3:02 ` Dave Chinner
2019-02-26 3:27 ` Matthew Wilcox
2019-02-26 4:58 ` Dave Chinner
2019-02-26 9:33 ` Ming Lei
2019-02-26 10:06 ` Vlastimil Babka
2019-02-26 10:06 ` Vlastimil Babka
2019-02-26 11:12 ` Ming Lei
2019-02-26 11:12 ` Ming Lei
2019-02-26 12:12 ` Matthew Wilcox
2019-02-26 12:35 ` Ming Lei
2019-02-26 13:02 ` Matthew Wilcox [this message]
2019-02-26 13:42 ` Ming Lei
2019-02-26 14:04 ` Matthew Wilcox
2019-02-26 16:14 ` Darrick J. Wong
2019-02-26 16:19 ` Matthew Wilcox
2019-02-27 1:41 ` Ming Lei
2019-02-27 7:07 ` Vlastimil Babka
2019-03-08 8:18 ` Christoph Hellwig
2019-02-27 21:38 ` Dave Chinner
2019-02-26 15:30 ` Christopher Lameter
2019-02-26 15:30 ` Christopher Lameter
2019-02-26 20:45 ` Dave Chinner
2019-02-27 1:50 ` Ming Lei
2019-02-27 3:41 ` Dave Chinner
2019-02-26 15:20 ` Christopher Lameter
2019-02-26 15:20 ` Christopher Lameter
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