From: Al Viro <viro@ZenIV.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: axboe@kernel.dk, Milosz Tanski <milosz@adfin.com>,
Goldwyn Rodrigues <rgoldwyn@suse.com>,
mgorman@suse.de, Volker.Lendecke@sernet.de,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: non-blockling buffered reads
Date: Fri, 30 Jun 2017 00:46:57 +0100 [thread overview]
Message-ID: <20170629234657.GO10672@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20170629212503.15110-1-hch@lst.de>
On Thu, Jun 29, 2017 at 02:25:00PM -0700, Christoph Hellwig wrote:
> This series resurrects the old patches from Milosz to implement
> non-blocking buffered reads. Thanks to the non-blocking AIO code from
> Goldwyn the implementation becomes pretty much trivial. As that
> implementation is in the block tree I would suggest that we merge
> these patches through the block tree as well. I've also forward
> ported the test Milosz sent for recent xfsprogs to verify it works
> properly, but I'll still have to address the review comments for it.
> I'll also volunteer to work with Goldwyn to properly document the
> RWF_NOWAIT flag in the man page including this change.
Hmm... It's not quite non-blocking, though - copy_page_to_iter() can
bloody well block, as any copying to userland. I'm not saying that
it's a significant problem (if you are reading into something that
had been mmaped from NFS server, etc., you are getting what you'd
asked for), but it's worth documenting.
next prev parent reply other threads:[~2017-06-29 23:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-29 21:25 non-blockling buffered reads Christoph Hellwig
2017-06-29 21:25 ` [PATCH 1/3] fs: pass iocb to do_generic_file_read Christoph Hellwig
2017-06-29 21:25 ` [PATCH 2/3] fs: support IOCB_NOWAIT in generic_file_buffered_read Christoph Hellwig
2017-06-29 21:25 ` [PATCH 3/3] fs: support RWF_NOWAIT for buffered reads Christoph Hellwig
2017-06-30 3:43 ` Goldwyn Rodrigues
2017-06-29 23:46 ` Al Viro [this message]
2017-06-30 0:34 ` non-blockling " Christoph Hellwig
2017-06-30 1:12 ` Milosz Tanski
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