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From: Alberto Garcia <berto@igalia.com>
To: Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	pbonzini@redhat.com, qemu-devel@nongnu.org,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] block/throttle: Use host clock type
Date: Fri, 13 Mar 2015 13:23:29 +0100	[thread overview]
Message-ID: <20150313122329.GA9419@igalia.com> (raw)
In-Reply-To: <1426228529-15969-1-git-send-email-famz@redhat.com>

On Fri, Mar 13, 2015 at 02:35:29PM +0800, Fam Zheng wrote:

> Throttle timers won't make any progress when VCPU is not running,
> which is prone to stall the request queue in cases like utils,
> qtest, suspending, and live migration, unless carefully handled.

Yes, this can be easily reproduced by stopping the VM and starting a
block-commit job. If the I/O in that device is throttled then the job
will be stalled.

Then there's also the situation that we discussed in IRC: if the
block-commit job is ongoing and then we stop the VM, then the rest of
the data will be committed bypassing the throttling settings.  But
that's not related to these changes.

> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block.c               |  2 +-
>  tests/test-throttle.c | 14 +++++++-------
>  2 files changed, 8 insertions(+), 8 deletions(-)

Reviewed-By: Alberto Garcia <berto@igalia.com>

Berto

  parent reply	other threads:[~2015-03-13 12:24 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-13  6:35 [Qemu-devel] [PATCH] block/throttle: Use host clock type Fam Zheng
2015-03-13  8:08 ` Paolo Bonzini
2015-03-13  8:27   ` Fam Zheng
2015-03-13 11:09     ` Paolo Bonzini
2015-03-13 11:43       ` Fam Zheng
2015-03-13 12:23 ` Alberto Garcia [this message]
2015-03-13 12:28   ` Paolo Bonzini
2015-03-16  2:15     ` Fam Zheng
2015-03-16 15:18   ` Kevin Wolf
2015-03-16 16:08 ` Kevin Wolf

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