From: "Michael S. Tsirkin" <mst@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "chenliang (T)" <chenliang88@huawei.com>,
Avi Kivity <avi@cloudius-systems.com>,
"Huangweidong (C)" <weidong.huang@huawei.com>,
Gleb Natapov <gleb@redhat.com>, KVM <kvm@vger.kernel.org>,
"Zhanghaoyu (A)" <haoyu.zhang@huawei.com>,
Luonengjun <luonengjun@huawei.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Gonglei (Arei)" <arei.gonglei@huawei.com>,
"Gaowei (UVP)" <gao.gaowei@huawei.com>
Subject: Re: [Qemu-devel] hotplug: VM got stuck when attaching a pass-through device to the non-pass-through VM for the first time
Date: Tue, 18 Feb 2014 12:51:59 +0200 [thread overview]
Message-ID: <20140218105159.GD8114@redhat.com> (raw)
In-Reply-To: <5303390B.50903@redhat.com>
On Tue, Feb 18, 2014 at 11:42:19AM +0100, Paolo Bonzini wrote:
> Il 18/02/2014 11:38, Michael S. Tsirkin ha scritto:
> >What if you detach and re-attach?
> >Is it fast then?
> >If yes this means the issue is COW breaking that occurs
> >with get_user_pages, not translation as such.
> >Try hugepages with prealloc - does it help?
>
> I agree it's either COW breaking or (similarly) locking pages that
> the guest hasn't touched yet.
>
> You can use prealloc or "-rt mlock=on" to avoid this problem.
>
> Paolo
Or the new shared flag - IIRC shared VMAs don't do COW either.
next prev parent reply other threads:[~2014-02-18 10:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-18 2:38 [Qemu-devel] hotplug: VM got stuck when attaching a pass-through device to the non-pass-through VM for the first time Zhanghaoyu (A)
2014-02-18 10:38 ` Michael S. Tsirkin
2014-02-18 10:42 ` Paolo Bonzini
2014-02-18 10:51 ` Michael S. Tsirkin [this message]
2014-02-18 11:05 ` Paolo Bonzini
2014-02-18 11:16 ` Michael S. Tsirkin
2014-02-24 11:38 ` Zhanghaoyu (A)
2014-02-18 11:17 ` Zhanghaoyu (A)
2014-02-18 10:59 ` Zhanghaoyu (A)
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