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From: Jens Axboe <axboe@kernel.dk>
To: Matthew Wilcox <willy@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Linux-MM <linux-mm@kvack.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-block <linux-block@vger.kernel.org>,
	Chris Mason <clm@fb.com>, Dave Chinner <david@fromorbit.com>,
	Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCHSET v3 0/5] Support for RWF_UNCACHED
Date: Wed, 11 Dec 2019 19:38:54 -0700	[thread overview]
Message-ID: <9269b4e0-829c-8b95-61ff-f3922c6380f6@kernel.dk> (raw)
In-Reply-To: <20191212022155.GQ32169@bombadil.infradead.org>

On 12/11/19 7:21 PM, Matthew Wilcox wrote:
> On Wed, Dec 11, 2019 at 07:03:40PM -0700, Jens Axboe wrote:
>> Tested and cleaned a bit, and added truncate protection through
>> inode_dio_begin()/inode_dio_end().
>>
>> https://git.kernel.dk/cgit/linux-block/commit/?h=buffered-uncached&id=6dac80bc340dabdcbfb4230b9331e52510acca87
>>
>> This is much faster than the previous page cache dance, and I _think_
>> we're ok as long as we block truncate and hole punching.
> 
> What about races between UNCACHED and regular buffered IO?  Seems like
> we might end up sending overlapping writes to the device?

The UNCACHED out-of-page-cache IO is just for reads, it's not writes. The
write part is still using the same approach as earlier, though now I bet
it looks kinda slow compared to the read side...

-- 
Jens Axboe



  reply	other threads:[~2019-12-12  2:39 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-11 15:29 [PATCHSET v3 0/5] Support for RWF_UNCACHED Jens Axboe
2019-12-11 15:29 ` [PATCH 1/5] fs: add read support " Jens Axboe
2019-12-11 15:29 ` [PATCH 2/5] mm: make generic_perform_write() take a struct kiocb Jens Axboe
2019-12-11 15:29 ` [PATCH 3/5] mm: make buffered writes work with RWF_UNCACHED Jens Axboe
2019-12-11 15:29 ` [PATCH 4/5] iomap: pass in the write_begin/write_end flags to iomap_actor Jens Axboe
2019-12-11 17:19   ` Linus Torvalds
2019-12-11 15:29 ` [PATCH 5/5] iomap: support RWF_UNCACHED for buffered writes Jens Axboe
2019-12-11 17:19   ` Matthew Wilcox
2019-12-11 18:05     ` Jens Axboe
2019-12-12 22:34   ` Dave Chinner
2019-12-13  0:54     ` Jens Axboe
2019-12-13  0:57       ` Jens Axboe
2019-12-16  4:17         ` Dave Chinner
2019-12-17 14:31           ` Jens Axboe
2019-12-18  0:49             ` Dave Chinner
2019-12-18  1:01               ` Jens Axboe
2019-12-11 17:37 ` [PATCHSET v3 0/5] Support for RWF_UNCACHED Linus Torvalds
2019-12-11 17:56   ` Jens Axboe
2019-12-11 19:14     ` Linus Torvalds
2019-12-11 19:34     ` Jens Axboe
2019-12-11 20:03       ` Linus Torvalds
2019-12-11 20:08         ` Jens Axboe
2019-12-11 20:18           ` Linus Torvalds
2019-12-11 23:41             ` Jens Axboe
2019-12-12  1:08               ` Linus Torvalds
2019-12-12  1:11                 ` Jens Axboe
2019-12-12  1:22                   ` Linus Torvalds
2019-12-12  1:29                     ` Jens Axboe
2019-12-12  1:41                       ` Linus Torvalds
2019-12-12  1:56                         ` Matthew Wilcox
2019-12-12  2:47                           ` Linus Torvalds
2019-12-12 17:52                             ` Matthew Wilcox
2019-12-12 18:29                               ` Linus Torvalds
2019-12-12 20:05                                 ` Matthew Wilcox
2019-12-12  1:41                       ` Jens Axboe
2019-12-12  1:49                         ` Linus Torvalds
2019-12-12  1:09               ` Jens Axboe
2019-12-12  2:03                 ` Jens Axboe
2019-12-12  2:10                   ` Jens Axboe
2019-12-12  2:21                   ` Matthew Wilcox
2019-12-12  2:38                     ` Jens Axboe [this message]
2019-12-12 22:18                 ` Dave Chinner
2019-12-13  1:32                   ` Chris Mason
2020-01-07 17:42                     ` Christoph Hellwig
2020-01-08 14:09                       ` Chris Mason
2020-02-01 10:33                     ` Andres Freund
2019-12-11 20:43           ` Matthew Wilcox
2019-12-11 20:04       ` Jens Axboe
2019-12-12 10:44 ` Martin Steigerwald
2019-12-12 15:16   ` Jens Axboe
2019-12-12 21:45     ` Martin Steigerwald
2019-12-12 22:15       ` Jens Axboe
2019-12-12 22:18     ` Linus Torvalds

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