From: Alex Bligh <alex@alex.org.uk>
To: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
Cc: linux-nfs@vger.kernel.org, ian.campbell@citrix.com,
Alex Bligh <alex@alex.org.uk>
Subject: Re: Fatal crash with NFS, AIO & tcp retransmit
Date: Mon, 21 Jan 2013 17:29:35 +0000 [thread overview]
Message-ID: <50A25C98A7223D35C994B64D@Ximines.local> (raw)
In-Reply-To: <4FA345DA4F4AE44899BD2B03EEEC2FA915C1781E@SACEXCMBX04-PRD.hq.netapp.com>
Trond,
--On 21 January 2013 17:20:36 +0000 "Myklebust, Trond"
<Trond.Myklebust@netapp.com> wrote:
> That is correct. If you want zero-copy, then O_DIRECT is your thing
> (with or without aio). Otherwise, the kernel will always write to disk
> by copying through the page cache.
Thanks. From the crash dump it appeared to be accessing mapped memory
somehow, so I'll see whether QEMU is in fact using O_DIRECT contrary
to documentation.
--
Alex Bligh
next prev parent reply other threads:[~2013-01-21 17:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-21 13:06 Fatal crash with NFS, AIO & tcp retransmit Alex Bligh
2013-01-21 14:38 ` Myklebust, Trond
2013-01-21 15:01 ` Alex Bligh
2013-01-21 15:10 ` Alex Bligh
2013-01-21 15:21 ` Ian Campbell
2013-01-25 13:45 ` Alex Bligh
2013-01-21 15:50 ` Myklebust, Trond
2013-01-21 15:54 ` Ian Campbell
2013-01-21 17:12 ` Alex Bligh
2013-01-21 17:20 ` Myklebust, Trond
2013-01-21 17:29 ` Alex Bligh [this message]
2013-01-23 15:22 ` Alex Bligh
2013-01-23 15:34 ` Myklebust, Trond
2013-01-23 17:33 ` Alex Bligh
2013-01-23 17:37 ` Myklebust, Trond
2013-01-23 17:42 ` Alex Bligh
2013-01-23 17:48 ` Peter Staubach
2013-01-23 18:13 ` Myklebust, Trond
2013-01-23 19:37 ` Alex Bligh
2013-01-24 10:42 ` Ian Campbell
2013-01-24 12:00 ` Alex Bligh
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