From: "Roger Pau Monné" <roger.pau@citrix.com>
To: xu cong <congxumail@gmail.com>, xen-devel@lists.xensource.com
Subject: Re: Does blkback bypass Dom0's memory buffer?
Date: Wed, 5 Feb 2014 09:46:58 +0100 [thread overview]
Message-ID: <52F1FA82.6080101@citrix.com> (raw)
In-Reply-To: <CA+hYhXvMiMn3i6oF=5dO_A2qHo=s=g+PDFeJ-9K=HmeNrkq8mw@mail.gmail.com>
On 04/02/14 22:15, xu cong wrote:
> Does blkback thread bypass Dom0's memory buffer? If I write in DomU
> without O_Direct, the data will be buffered in DomU's memory cache then
> be flushed to disk. Will them be buffered in Dom0's memory again? How
> about the netback? Thanks.
Blkback will not do any kind of buffering itself, the request is read
from the shared ring and passed to the underlying device using
submit_bio. If you want to make sure your data has hit the disk you
should issue a flush operation (see "feature-flush-cache" in blkif.h)
Roger.
prev parent reply other threads:[~2014-02-05 8:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-04 21:15 Does blkback bypass Dom0's memory buffer? xu cong
2014-02-05 0:09 ` Wei Liu
2014-02-05 0:23 ` xu cong
2014-02-05 0:30 ` xu cong
2014-02-05 8:46 ` Roger Pau Monné [this message]
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