From: Eric Blake <eblake@redhat.com>
To: Alberto Garcia <berto@igalia.com>, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-block@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>,
Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] block: disable I/O limits at the beginning of bdrv_close()
Date: Fri, 25 Sep 2015 08:22:26 -0600 [thread overview]
Message-ID: <560558A2.3020804@redhat.com> (raw)
In-Reply-To: <1443188504-20296-1-git-send-email-berto@igalia.com>
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On 09/25/2015 07:41 AM, Alberto Garcia wrote:
> Disabling I/O limits from a BDS also drains all pending throttled
> requests, so it should be done at the beginning of bdrv_close() with
> the rest of the bdrv_drain() calls before the BlockDriver is closed.
Can this be abused? If I have a guest running in a cloud where the cloud
provider has put severe throttling limits on me, but lets me hotplug to
my heart's content, couldn't I just repeatedly plug/unplug the disk to
get around the throttling (every time I unplug, all writes flush at full
speed, then I immediately replug to start batching up a new set of
writes). In other words, shouldn't the draining still be throttled, to
prevent my abuse?
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2015-09-25 14:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-25 13:41 [Qemu-devel] [PATCH] block: disable I/O limits at the beginning of bdrv_close() Alberto Garcia
2015-09-25 14:22 ` Eric Blake [this message]
2015-09-25 14:31 ` Alberto Garcia
2015-09-28 0:18 ` Fam Zheng
2015-09-28 9:04 ` Alberto Garcia
2015-09-29 19:51 ` Andrey Korolyov
2015-09-29 12:50 ` Kevin Wolf
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