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Re: [Qemu-devel] [QEMU PATCH 0/2] virtio-blk: writeback cache enable imp
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [QEMU PATCH 0/2] virtio-blk: writeback cache enable improvements |
Date: |
Mon, 23 Jul 2012 18:32:38 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120615 Thunderbird/13.0.1 |
Il 03/07/2012 15:20, Paolo Bonzini ha scritto:
> These patches let virtio-blk use the new support for toggling the cache
> mode between writethrough and writeback.
>
> The first patch introduces a new feature bit and configuration field to
> do this. The second patch disables writeback caching for guests that do
> not negotiate VIRTIO_BLK_F_WCACHE (meaning that they cannot send flush
> requests), so that limited or older guests are now safe wrt power losses.
> VIRTIO_BLK_F_FLUSH has been introduced in Linux 2.6.32 (in 2009) and was
> backported to RHEL/CentOS 5.6 (in 2010).
>
> The Windows drivers (which work by emulating SCSI on top of virtio-blk)
> have bugs in this area, which I reported on the Red Hat Bugzilla as
> bugs 837321 and 837324. With these patches they will suffer a
> performance hit but gain correctness.
>
> Paolo Bonzini (2):
> virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE
> virtio-blk: disable write cache if not negotiated
Ping - Anthony, mst?
Paolo
- [Qemu-devel] [PATCH 1/2] virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE, (continued)
- [Qemu-devel] [PATCH 1/2] virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE, Paolo Bonzini, 2012/07/03
- [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated, Paolo Bonzini, 2012/07/03
- Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated, Kevin Wolf, 2012/07/03
- Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated, Paolo Bonzini, 2012/07/03
- Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated, Kevin Wolf, 2012/07/04
- Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated, Paolo Bonzini, 2012/07/04
- Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated, Kevin Wolf, 2012/07/04
- Re: [Qemu-devel] [PATCH 2/2] virtio-blk: disable write cache if not negotiated, Paolo Bonzini, 2012/07/04
Re: [Qemu-devel] [QEMU PATCH 0/2] virtio-blk: writeback cache enable improvements,
Paolo Bonzini <=