From: Andrea Arcangeli <aarcange@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Gerd Hoffmann <kraxel@redhat.com>,
qemu-devel@nongnu.org, kvm-devel <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [RFC] Replace posix-aio with custom thread pool
Date: Fri, 12 Dec 2008 15:24:35 +0100 [thread overview]
Message-ID: <20081212142435.GL6809@random.random> (raw)
In-Reply-To: <20081210190810.GG18814@random.random>
On Wed, Dec 10, 2008 at 08:08:10PM +0100, Andrea Arcangeli wrote:
> On Wed, Dec 10, 2008 at 12:50:17PM -0600, Anthony Liguori wrote:
> > But opening twice means that you lose coherency with NFS.
>
> Not sure why. They're not running from different nfs clients. If this
I just got confirmation from Trond that from nfs point of view,
opening the file multiple times or duping it, is the same as I
expected (all it matters is that the inode is the same so the
pagecache radix tree is the same etc..). So opening the file each time
a thread starts, would provide a local f_pos and it would work fine on
older/current kernels too. In theory other nfs clients should also
behave. Not sure what's best, if to hack around the bdrv api and open
the file multiple times or wait for preadv/pwritev.
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Gerd Hoffmann <kraxel@redhat.com>,
kvm-devel <kvm@vger.kernel.org>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RFC] Replace posix-aio with custom thread pool
Date: Fri, 12 Dec 2008 15:24:35 +0100 [thread overview]
Message-ID: <20081212142435.GL6809@random.random> (raw)
In-Reply-To: <20081210190810.GG18814@random.random>
On Wed, Dec 10, 2008 at 08:08:10PM +0100, Andrea Arcangeli wrote:
> On Wed, Dec 10, 2008 at 12:50:17PM -0600, Anthony Liguori wrote:
> > But opening twice means that you lose coherency with NFS.
>
> Not sure why. They're not running from different nfs clients. If this
I just got confirmation from Trond that from nfs point of view,
opening the file multiple times or duping it, is the same as I
expected (all it matters is that the inode is the same so the
pagecache radix tree is the same etc..). So opening the file each time
a thread starts, would provide a local f_pos and it would work fine on
older/current kernels too. In theory other nfs clients should also
behave. Not sure what's best, if to hack around the bdrv api and open
the file multiple times or wait for preadv/pwritev.
next prev parent reply other threads:[~2008-12-12 14:24 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-05 21:21 [RFC] Replace posix-aio with custom thread pool Anthony Liguori
2008-12-05 21:21 ` [Qemu-devel] " Anthony Liguori
2008-12-06 9:03 ` Blue Swirl
2008-12-06 18:26 ` Jamie Lokier
2008-12-08 18:23 ` Anthony Liguori
2008-12-08 18:23 ` Anthony Liguori
2008-12-09 15:51 ` Gerd Hoffmann
2008-12-09 16:01 ` Anthony Liguori
2008-12-10 16:44 ` Andrea Arcangeli
2008-12-10 17:21 ` Anthony Liguori
2008-12-10 17:21 ` Anthony Liguori
2008-12-10 17:29 ` Gerd Hoffmann
2008-12-10 18:50 ` Anthony Liguori
2008-12-10 19:08 ` Andrea Arcangeli
2008-12-10 19:08 ` Andrea Arcangeli
2008-12-11 13:12 ` Andrea Arcangeli
2008-12-11 15:24 ` Gerd Hoffmann
2008-12-11 15:24 ` Gerd Hoffmann
2008-12-11 15:53 ` Andrea Arcangeli
2008-12-11 15:53 ` Andrea Arcangeli
2008-12-11 16:11 ` Gerd Hoffmann
2008-12-11 16:11 ` Gerd Hoffmann
2008-12-11 16:49 ` Andrea Arcangeli
2008-12-11 16:49 ` Andrea Arcangeli
2008-12-11 17:20 ` Gerd Hoffmann
2008-12-11 17:20 ` Gerd Hoffmann
2008-12-11 18:11 ` Andrea Arcangeli
2008-12-11 18:11 ` Andrea Arcangeli
2008-12-11 20:38 ` Gerd Hoffmann
2008-12-11 20:38 ` Gerd Hoffmann
2008-12-11 20:40 ` Anthony Liguori
2008-12-12 8:23 ` Jens Axboe
2008-12-12 8:23 ` Jens Axboe
2008-12-12 11:51 ` Andrea Arcangeli
2008-12-12 11:51 ` Andrea Arcangeli
2008-12-12 11:54 ` Jens Axboe
2008-12-12 11:54 ` Jens Axboe
2008-12-12 14:13 ` Andrea Arcangeli
2008-12-12 14:13 ` Andrea Arcangeli
2008-12-12 14:24 ` Anthony Liguori
2008-12-12 14:24 ` Anthony Liguori
2008-12-12 16:33 ` Chris Wright
2008-12-12 16:33 ` Chris Wright
2008-12-12 16:51 ` Anthony Liguori
2008-12-12 16:51 ` Anthony Liguori
2008-12-12 16:52 ` Chris Wright
2008-12-12 16:52 ` Chris Wright
2008-12-11 21:32 ` Christoph Hellwig
2008-12-12 0:27 ` Andrea Arcangeli
2008-12-12 0:27 ` Andrea Arcangeli
2008-12-11 21:30 ` Christoph Hellwig
2008-12-11 16:41 ` Anthony Liguori
2008-12-11 16:41 ` Anthony Liguori
2008-12-12 14:24 ` Andrea Arcangeli [this message]
2008-12-12 14:24 ` Andrea Arcangeli
2008-12-12 14:35 ` Anthony Liguori
2008-12-12 14:35 ` Anthony Liguori
2008-12-12 15:44 ` Andrea Arcangeli
2008-12-12 15:44 ` Andrea Arcangeli
2008-12-12 16:49 ` Anthony Liguori
2008-12-12 16:49 ` Anthony Liguori
2008-12-12 17:09 ` Andrea Arcangeli
2008-12-12 17:09 ` Andrea Arcangeli
2008-12-12 17:25 ` Anthony Liguori
2008-12-12 17:25 ` Anthony Liguori
2008-12-12 17:52 ` Andrea Arcangeli
2008-12-12 17:52 ` Andrea Arcangeli
2008-12-12 18:17 ` Anthony Liguori
2008-12-12 18:17 ` Anthony Liguori
2008-12-12 18:26 ` Andrea Arcangeli
2008-12-12 20:12 ` Gerd Hoffmann
2008-12-12 20:17 ` Anthony Liguori
2008-12-12 20:35 ` Gerd Hoffmann
2008-12-09 17:16 ` Avi Kivity
2008-12-17 14:44 ` Ian Jackson
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