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From: Matthew Wilcox <willy@infradead.org>
To: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: linux-fsdevel@vger.kernel.org, jack@suse.com, hch@infradead.org,
	linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org,
	linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org,
	sagi@grimberg.me, avi@scylladb.com, axboe@kernel.dk,
	linux-api@vger.kernel.org, Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: Re: [PATCH 3/8] nowait aio: return if direct write will trigger writeback
Date: Thu, 16 Mar 2017 06:20:52 -0700	[thread overview]
Message-ID: <20170316132052.GG4033@bombadil.infradead.org> (raw)
In-Reply-To: <20170315215107.5628-4-rgoldwyn@suse.de>

On Wed, Mar 15, 2017 at 04:51:02PM -0500, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@suse.com>
> 
> Find out if the write will trigger a wait due to writeback. If yes,
> return -EAGAIN.
> 
> This introduces a new function filemap_range_has_page() which
> returns true if the file's mapping has a page within the range
> mentioned.
> 
> Return -EINVAL for buffered AIO: there are multiple causes of
> delay such as page locks, dirty throttling logic, page loading
> from disk etc. which cannot be taken care of.

Also, this patch only touches the write path; we have a similar call to
write_and_wait_range() in generic_file_read_iter().

Actually, why do we even have that?  Why can't we satisfy an O_DIRECT
read from the cache?

  parent reply	other threads:[~2017-03-16 13:20 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-15 21:50 [PATCH 0/8 v3] No wait AIO Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 1/8] nowait aio: Introduce IOCB_RW_FLAG_NOWAIT Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 2/8] nowait aio: Return if cannot get hold of i_rwsem Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 3/8] nowait aio: return if direct write will trigger writeback Goldwyn Rodrigues
2017-03-16 13:08   ` Matthew Wilcox
2017-03-16 13:46     ` Goldwyn Rodrigues
2017-03-16 13:20   ` Matthew Wilcox [this message]
     [not found]     ` <20170316132052.GG4033-PfSpb0PWhxZc2C7mugBRk2EX/6BAtgUQ@public.gmane.org>
2017-03-16 13:46       ` Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 4/8] nowait-aio: Introduce IOMAP_NOWAIT Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 5/8] nowait aio: return on congested block device Goldwyn Rodrigues
     [not found]   ` <20170315215107.5628-6-rgoldwyn-l3A5Bk7waGM@public.gmane.org>
2017-03-16 14:33     ` Jens Axboe
2017-03-17  2:03       ` Ming Lei
2017-03-17 12:23       ` Goldwyn Rodrigues
     [not found]       ` <eee4683d-9f44-434f-b97f-b0b24c7b3dab-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2017-03-24 11:32         ` Goldwyn Rodrigues
2017-03-24 14:39           ` Jens Axboe
2017-03-16 21:31     ` Dave Chinner
2017-03-17 12:23       ` Goldwyn Rodrigues
2017-03-20 17:33         ` Jan Kara
2017-03-15 21:51 ` [PATCH 6/8] nowait aio: ext4 Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 7/8] nowait aio: xfs Goldwyn Rodrigues
2017-03-15 21:51 ` [PATCH 8/8] nowait aio: btrfs Goldwyn Rodrigues
2017-04-03 18:52 [PATCH 0/8 v4] No wait AIO Goldwyn Rodrigues
2017-04-03 18:53 ` [PATCH 3/8] nowait aio: return if direct write will trigger writeback Goldwyn Rodrigues
2017-04-14 12:02 [PATCH 0/8 v6] No wait AIO Goldwyn Rodrigues
2017-04-14 12:02 ` [PATCH 3/8] nowait aio: return if direct write will trigger writeback Goldwyn Rodrigues
2017-05-09 12:22 [PATCH 0/8 v7] No wait AIO Goldwyn Rodrigues
2017-05-09 12:22 ` [PATCH 3/8] nowait aio: return if direct write will trigger writeback Goldwyn Rodrigues
2017-05-11  7:42   ` Christoph Hellwig

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