From: Kevin Wolf <kwolf@redhat.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: "prerna@linux.vnet.ibm.com Anthony Liguori" <aliguori@us.ibm.com>,
Christoph Hellwig <hch@lst.de>,
qemu-devel@nongnu.org
Subject: [Qemu-devel] Re: [PATCH 1/4] block: clarify the meaning of BDRV_O_NOCACHE
Date: Thu, 17 Mar 2011 10:07:35 +0100 [thread overview]
Message-ID: <4D81CF57.9000300@redhat.com> (raw)
In-Reply-To: <AANLkTim=+ELwL1pc=4ASb133qUEXt+-Dj0XZBA=GXj5S@mail.gmail.com>
Am 16.03.2011 18:00, schrieb Stefan Hajnoczi:
> On Wed, Mar 16, 2011 at 2:08 PM, Christoph Hellwig <hch@lst.de> wrote:
>> On Wed, Mar 16, 2011 at 09:42:37AM +0000, Stefan Hajnoczi wrote:
>>> - writethrough = ((flags & BDRV_O_CACHE_MASK) == 0);
>>> + writethrough = ((flags & (BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)) == 0);
>>
>> or rather
>>
>> writethrough = ((flags & (BDRV_O_CACHE_WB) != );
>>
>> but yes, this code had sneaked in since my initial version.
>
> My intention was that if we don't care about honoring flushes then we
> might as well use Qcow2Cache. But yes, just checking for cache mode
> is the clearest.
You mean for a possible writethrough mode with BDRV_O_NO_FLUSH set? Such
a mode doesn't make a lot of sense to me.
Kevin
next prev parent reply other threads:[~2011-03-17 9:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-15 14:10 [Qemu-devel] [PATCH, RFC 0/4] allow guest control of the volatile write cache Christoph Hellwig
2011-03-15 14:11 ` [Qemu-devel] [PATCH 1/4] block: clarify the meaning of BDRV_O_NOCACHE Christoph Hellwig
2011-03-16 9:42 ` [Qemu-devel] " Stefan Hajnoczi
2011-03-16 9:55 ` Kevin Wolf
2011-03-16 14:08 ` Christoph Hellwig
2011-03-16 17:00 ` Stefan Hajnoczi
2011-03-17 9:07 ` Kevin Wolf [this message]
2011-03-17 9:18 ` Stefan Hajnoczi
2011-03-15 14:11 ` [Qemu-devel] [PATCH 2/4] block: add a helper to change writeback mode on the fly Christoph Hellwig
2011-03-15 14:11 ` [Qemu-devel] [PATCH 3/4] ide: wire up setfeatures cache control Christoph Hellwig
2011-03-15 14:11 ` [Qemu-devel] [PATCH 4/4] virtio-blk: add runtime " Christoph Hellwig
2011-03-16 9:49 ` [Qemu-devel] Re: [PATCH 2/4] block: add a helper to change writeback mode on the fly Stefan Hajnoczi
2011-03-16 9:59 ` Kevin Wolf
2011-03-17 14:44 ` [Qemu-devel] " Daniel P. Berrange
2011-03-17 15:11 ` Kevin Wolf
2011-03-17 16:44 ` Stefan Hajnoczi
2011-03-19 8:28 ` Blue Swirl
2011-03-15 14:16 ` [Qemu-devel] [PATCH, RFC] virtio_blk: add cache control support Christoph Hellwig
2011-03-16 4:09 ` [Qemu-devel] " Rusty Russell
2011-03-16 14:09 ` Christoph Hellwig
2011-03-17 5:06 ` Rusty Russell
2011-03-17 14:21 ` Christoph Hellwig
2011-03-24 0:11 ` Rusty Russell
2011-03-24 3:11 ` Anthony Liguori
2011-03-24 3:05 ` Anthony Liguori
2011-03-24 9:54 ` Christian Borntraeger
2011-03-25 5:08 ` Rusty Russell
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