From: Paolo Bonzini <pbonzini@redhat.com>
To: bharata@linux.vnet.ibm.com
Cc: Kevin Wolf <kwolf@redhat.com>,
Anthony Liguori <aliguori@us.ibm.com>,
Anand Avati <aavati@redhat.com>,
Vijay Bellur <vbellur@redhat.com>,
Stefan Hajnoczi <stefanha@gmail.com>,
Harsh Bora <harsh@linux.vnet.ibm.com>,
Amar Tumballi <amarts@redhat.com>,
qemu-devel@nongnu.org, "Richard W.M. Jones" <rjones@redhat.com>,
Blue Swirl <blauwirbel@gmail.com>, Avi Kivity <avi@redhat.com>,
Daniel Veillard <veillard@redhat.com>
Subject: [Qemu-devel] O_DIRECT on glusterfs (was Re: [PATCH v9 4/4] block: Support GlusterFS as a QEMU block backend)
Date: Wed, 03 Oct 2012 17:50:08 +0200 [thread overview]
Message-ID: <506C5EB0.50508@redhat.com> (raw)
In-Reply-To: <20120924091340.GN18470@in.ibm.com>
Il 24/09/2012 11:13, Bharata B Rao ha scritto:
> +
> + if ((bdrv_flags & BDRV_O_NOCACHE)) {
> + open_flags |= O_DIRECT;
> + }
> +
If I understand correctly what I was told, this prevents the brick
server from using its own buffer cache. This is quite different from
what we do for example over NFS (where the host does no caching, but
nothing prevents it on the remote server).
I think these 3 lines should be removed. We're bypassing the host
buffer cache just by virtue of using a userspace driver, and that's what
cache=none cares about.
Paolo
next prev parent reply other threads:[~2012-10-03 15:50 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-24 9:10 [Qemu-devel] [PATCH v9 0/4] GlusterFS support in QEMU - v9 Bharata B Rao
2012-09-24 9:10 ` [Qemu-devel] [PATCH v9 1/4] aio: Fix qemu_aio_wait() to maintain correct walking_handlers count Bharata B Rao
2012-09-24 9:12 ` [Qemu-devel] [PATCH v9 2/4] qemu: URI parsing library Bharata B Rao
2012-09-24 10:27 ` Richard W.M. Jones
2012-09-24 11:11 ` Paolo Bonzini
2012-09-27 9:03 ` Avi Kivity
2012-09-27 9:07 ` Paolo Bonzini
2012-10-02 4:59 ` Daniel Veillard
2012-10-02 6:16 ` Paolo Bonzini
2012-09-24 9:12 ` [Qemu-devel] [PATCH v9 3/4] configure: Add a config option for GlusterFS as block backend Bharata B Rao
2012-09-24 9:13 ` [Qemu-devel] [PATCH v9 4/4] block: Support GlusterFS as a QEMU " Bharata B Rao
2012-09-24 9:26 ` Paolo Bonzini
2012-09-24 9:44 ` Bharata B Rao
2012-09-26 10:00 ` Kevin Wolf
2012-09-26 10:08 ` Paolo Bonzini
2012-09-26 16:11 ` Bharata B Rao
2012-09-26 16:38 ` Paolo Bonzini
2012-09-27 6:41 ` Bharata B Rao
2012-09-27 7:19 ` Paolo Bonzini
2012-09-27 8:28 ` Bharata B Rao
2012-09-27 8:31 ` Paolo Bonzini
2012-10-03 15:50 ` Paolo Bonzini [this message]
2012-10-03 17:58 ` [Qemu-devel] O_DIRECT on glusterfs (was Re: [PATCH v9 4/4] block: Support GlusterFS as a QEMU block backend) Anand Avati
2012-10-03 18:17 ` Paolo Bonzini
2012-10-03 18:17 ` Anand Avati
2012-10-03 18:27 ` Paolo Bonzini
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