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Re: [Qemu-devel] KVM call agenda for June 28
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] KVM call agenda for June 28 |
Date: |
Thu, 30 Jun 2011 16:52:00 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 |
Am 30.06.2011 16:36, schrieb Marcelo Tosatti:
>> 4. Live block copy API and high-level control - the main code that
>> adds the live block copy feature. Existing patches by Marcelo, can be
>> restructured to use common core by Marcelo.
>
> Can use your proposed block_stream interface, with a "block_switch"
> command on top, so:
>
> 1) management creates copy.img with backing file current.img, allows
> access
> 2) management issues "block_switch dev copy.img"
> 3) management issues "block_stream dev base"
Isn't this block_switch command the same as the existing snapshot_blkdev?
> Thought of implementing "block_stream" command by reopening device with
>
> blkstream:imagename.img
>
> Then:
>
> AIO_READ:
> - for each cluster in request:
> - if allocated-or-in-final-base, read.
> - check write queue, if present wait on it, if not, add "copy"
> entry to write queue.
> - issue cluster sized read from source.
> - on completion:
> - copy data to original read buffer, complete it.
> - if not cancelled, write cluster to destination.
>
> AIO_WRITE
> for each cluster in request:
> - check write queue, cancel/wait for "copy" entry.
> - add "guest" entry to write queue.
> - issue write to destination.
> - on completion:
> - remove write queue entry.
>
>
> With the 0...END background read, once it completes write final base
> file for image.
>
> So block_stream/block_stream_cancel/block_stream_status commands, the
> background read and the rebase -u update can be separate from the block
> driver.
The way how it works looks good to me, I'm just not entirely sure about
the right place to implement it. I think request queueing and copy on
read could be useful outside blkstream, too.
Kevin
- Re: [Qemu-devel] KVM call agenda for June 28, (continued)
- Re: [Qemu-devel] KVM call agenda for June 28, Stefan Hajnoczi, 2011/06/28
- Re: [Qemu-devel] KVM call agenda for June 28, Marcelo Tosatti, 2011/06/28
- Re: [Qemu-devel] KVM call agenda for June 28, Stefan Hajnoczi, 2011/06/29
- Re: [Qemu-devel] KVM call agenda for June 28, Kevin Wolf, 2011/06/29
- Re: [Qemu-devel] KVM call agenda for June 28, Stefan Hajnoczi, 2011/06/29
- Re: [Qemu-devel] KVM call agenda for June 28, Marcelo Tosatti, 2011/06/29
- Re: [Qemu-devel] KVM call agenda for June 28, Stefan Hajnoczi, 2011/06/30
- Re: [Qemu-devel] KVM call agenda for June 28, Kevin Wolf, 2011/06/30
- Re: [Qemu-devel] KVM call agenda for June 28, Stefan Hajnoczi, 2011/06/30
- Re: [Qemu-devel] KVM call agenda for June 28, Marcelo Tosatti, 2011/06/30
- Re: [Qemu-devel] KVM call agenda for June 28,
Kevin Wolf <=
- Re: [Qemu-devel] KVM call agenda for June 28, Marcelo Tosatti, 2011/06/30
Re: [Qemu-devel] KVM call agenda for June 28, Anthony Liguori, 2011/06/28