From: Kevin Wolf <kwolf@redhat.com>
To: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RFC 3/6] block: wait for overlapping requests
Date: Thu, 03 Nov 2011 15:17:36 +0100 [thread overview]
Message-ID: <4EB2A280.3080806@redhat.com> (raw)
In-Reply-To: <1318866452-30026-4-git-send-email-stefanha@linux.vnet.ibm.com>
Am 17.10.2011 17:47, schrieb Stefan Hajnoczi:
> When copy-on-read is enabled it is necessary to wait for overlapping
> requests before issuing new requests. This prevents races between the
> copy-on-read and a write request.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
This doesn't only order guest request against COR requests, but also
makes guest requests wait on each other. It's probably not a big
problem, but if we had to optimise performance with COR later, this is
something to remember.
Doing an optimisation that only requests of different type are ordered
wouldn't be too hard, though maybe avoiding starvation of the other type
could get a bit harder.
Let's leave it as it is for now.
Kevin
next prev parent reply other threads:[~2011-11-03 14:14 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-17 15:47 [Qemu-devel] [RFC 0/6] block: generic copy-on-read Stefan Hajnoczi
2011-10-17 15:47 ` [Qemu-devel] [RFC 1/6] block: add request tracking Stefan Hajnoczi
2011-11-02 16:30 ` Kevin Wolf
2011-11-03 7:57 ` Stefan Hajnoczi
2011-11-07 11:00 ` Zhi Yong Wu
2011-11-07 11:41 ` Stefan Hajnoczi
2011-11-08 6:13 ` Zhi Yong Wu
2011-10-17 15:47 ` [Qemu-devel] [RFC 2/6] block: add bdrv_set_copy_on_read() Stefan Hajnoczi
2011-11-02 16:36 ` Kevin Wolf
2011-11-03 8:01 ` Stefan Hajnoczi
2011-10-17 15:47 ` [Qemu-devel] [RFC 3/6] block: wait for overlapping requests Stefan Hajnoczi
2011-10-18 13:48 ` Marcelo Tosatti
2011-10-20 17:34 ` Stefan Hajnoczi
2011-11-03 14:17 ` Kevin Wolf [this message]
2011-10-17 15:47 ` [Qemu-devel] [RFC 4/6] block: request overlap detection Stefan Hajnoczi
2011-11-07 11:49 ` Zhi Yong Wu
2011-11-07 14:37 ` Stefan Hajnoczi
2011-11-08 6:34 ` Zhi Yong Wu
2011-11-08 8:16 ` Stefan Hajnoczi
2011-11-08 9:49 ` Zhi Yong Wu
2011-10-17 15:47 ` [Qemu-devel] [RFC 5/6] block: core copy-on-read logic Stefan Hajnoczi
2011-10-18 14:00 ` Marcelo Tosatti
2011-10-20 17:40 ` Stefan Hajnoczi
2011-10-18 14:03 ` Marcelo Tosatti
2011-11-03 14:30 ` Kevin Wolf
2011-10-17 15:47 ` [Qemu-devel] [RFC 6/6] block: add -drive copy-on-read=on|off Stefan Hajnoczi
2011-11-03 14:32 ` Kevin Wolf
2011-11-03 16:21 ` Stefan Hajnoczi
2011-11-01 14:28 ` [Qemu-devel] [RFC 0/6] block: generic copy-on-read Stefan Hajnoczi
2011-11-01 15:07 ` Marcelo Tosatti
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4EB2A280.3080806@redhat.com \
--to=kwolf@redhat.com \
--cc=mtosatti@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=stefanha@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).