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Re: [Qemu-devel] [PATCH] virtio: Report real progress in VQ aio poll han
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From: |
Stefan Hajnoczi |
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Subject: |
Re: [Qemu-devel] [PATCH] virtio: Report real progress in VQ aio poll handler |
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Date: |
Mon, 13 Feb 2017 16:35:12 +0000 |
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User-agent: |
Mutt/1.7.1 (2016-10-04) |
On Thu, Feb 09, 2017 at 04:40:47PM +0800, Fam Zheng wrote:
> In virtio_queue_host_notifier_aio_poll, not all "!virtio_queue_empty()"
> cases are making true progress.
>
> Currently the offending one is virtio-scsi event queue, whose handler
> does nothing if no event is pending. As a result aio_poll() will spin on
> the "non-empty" VQ and take 100% host CPU.
>
> Fix this by reporting actual progress from virtio queue aio handlers.
>
> Reported-by: Ed Swierk <address@hidden>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> hw/block/dataplane/virtio-blk.c | 4 ++--
> hw/block/virtio-blk.c | 12 ++++++++++--
> hw/scsi/virtio-scsi-dataplane.c | 14 +++++++-------
> hw/scsi/virtio-scsi.c | 14 +++++++++++---
> hw/virtio/virtio.c | 15 +++++++++------
> include/hw/virtio/virtio-blk.h | 2 +-
> include/hw/virtio/virtio-scsi.h | 6 +++---
> include/hw/virtio/virtio.h | 4 ++--
> 8 files changed, 45 insertions(+), 26 deletions(-)
Reviewed-by: Stefan Hajnoczi <address@hidden>
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