From: Christoph Hellwig <hch@lst.de>
To: axboe@fb.com
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: block device direct I/O fast path
Date: Mon, 31 Oct 2016 11:59:23 -0600
Message-Id: <1477936765-8828-1-git-send-email-hch@lst.de>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 692
Lines: 12

Hi Jens,

this small series adds a fasth path to the block device direct I/O
code.  It uses new magic created by Kent to avoid allocating an array
for the pages, and as part of that allows small, non-aio direct I/O
requests to be done without memory allocations or atomic ops and with
a minimal cache footprint.  It's basically a cut down version of the
new iomap direct I/O code, and in the future it might also make sense
to move the main direct I/O code to a similar model.  But indepedent
of that it's always worth to optimize the case of small, non-I/O
requests as allocating the bio and biovec on stack and a trivial
completion handler will always win over a full blown implementation.