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From: Paolo Bonzini <pbonzini@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	Jan Kiszka <jan.kiszka@web.de>, xming <xmingske@gmail.com>,
	Gerd Hoffmann <kraxel@redhat.com>,
	kvm@vger.kernel.org, qemu-devel <qemu-devel@nongnu.org>
Subject: Re: kvm crashes with spice while loading qxl
Date: Tue, 08 Mar 2011 10:28:54 +0100	[thread overview]
Message-ID: <4D75F6D6.1000600@redhat.com> (raw)
In-Reply-To: <4D75F440.6010401@redhat.com>

On 03/08/2011 10:17 AM, Avi Kivity wrote:
>> Memory map can be protected by a read-write lock initially, so that vcpu
>> thread holds it for read. Later can be converted to URCU.
>
> rwlock is insufficient, need a way to force the vcpu off so a writer can
> actually do something.
>
> So we need some kind of priority rwlock where a reader lets the lock
> know how it can force it off in case a writer comes along.

If the reader is the VCPU thread, the VCPU thread can always be bounced 
via qemu_cpu_kick.

Paolo

WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>, xming <xmingske@gmail.com>,
	Jan Kiszka <jan.kiszka@web.de>, Gerd Hoffmann <kraxel@redhat.com>
Subject: [Qemu-devel] Re: kvm crashes with spice while loading qxl
Date: Tue, 08 Mar 2011 10:28:54 +0100	[thread overview]
Message-ID: <4D75F6D6.1000600@redhat.com> (raw)
In-Reply-To: <4D75F440.6010401@redhat.com>

On 03/08/2011 10:17 AM, Avi Kivity wrote:
>> Memory map can be protected by a read-write lock initially, so that vcpu
>> thread holds it for read. Later can be converted to URCU.
>
> rwlock is insufficient, need a way to force the vcpu off so a writer can
> actually do something.
>
> So we need some kind of priority rwlock where a reader lets the lock
> know how it can force it off in case a writer comes along.

If the reader is the VCPU thread, the VCPU thread can always be bounced 
via qemu_cpu_kick.

Paolo

  reply	other threads:[~2011-03-08  9:29 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-26 11:43 kvm crashes with spice while loading qxl xming
2011-02-26 12:29 ` Jan Kiszka
2011-02-26 12:29   ` [Qemu-devel] " Jan Kiszka
2011-02-26 14:44   ` xming
2011-02-26 14:44     ` [Qemu-devel] " xming
2011-02-27 19:03   ` Alon Levy
2011-02-27 19:03     ` Alon Levy
2011-02-27 19:11     ` Jan Kiszka
2011-02-27 19:11       ` Jan Kiszka
2011-02-27 19:16       ` Alon Levy
2011-02-27 19:16         ` Alon Levy
2011-02-27 19:27         ` Jan Kiszka
2011-02-27 19:27           ` Jan Kiszka
2011-02-27 19:29           ` Alon Levy
2011-02-27 19:29             ` Alon Levy
2011-02-27 19:32           ` Alon Levy
2011-02-27 19:32             ` Alon Levy
2011-03-01 12:58       ` Alon Levy
2011-03-01 12:58         ` Alon Levy
2011-03-02  8:22         ` Jan Kiszka
2011-03-02 10:56           ` Alon Levy
2011-03-02 10:56             ` Alon Levy
2011-03-02 11:34             ` Jan Kiszka
2011-03-02 12:32               ` Alon Levy
2011-03-02 12:32                 ` Alon Levy
2011-02-28 12:56     ` xming
2011-03-01  3:56     ` Rick Vernam
2011-03-01  3:56       ` [Qemu-devel] " Rick Vernam
2011-03-05 16:35   ` Marcelo Tosatti
2011-03-05 16:35     ` [Qemu-devel] " Marcelo Tosatti
2011-03-05 17:11     ` Paolo Bonzini
2011-03-05 17:11       ` [Qemu-devel] " Paolo Bonzini
2011-03-06 10:30     ` Alon Levy
2011-03-06 10:30       ` [Qemu-devel] " Alon Levy
2011-03-07 16:02       ` Marcelo Tosatti
2011-03-07 16:02         ` [Qemu-devel] " Marcelo Tosatti
2011-03-06 10:38     ` Avi Kivity
2011-03-06 10:38       ` [Qemu-devel] " Avi Kivity
2011-03-07 16:13       ` Marcelo Tosatti
2011-03-07 16:13         ` [Qemu-devel] " Marcelo Tosatti
2011-03-07 22:27         ` Paolo Bonzini
2011-03-07 22:27           ` [Qemu-devel] " Paolo Bonzini
2011-03-08  9:17         ` Avi Kivity
2011-03-08  9:17           ` [Qemu-devel] " Avi Kivity
2011-03-08  9:28           ` Paolo Bonzini [this message]
2011-03-08  9:28             ` Paolo Bonzini
2011-03-08  9:32             ` Avi Kivity
2011-03-08  9:32               ` [Qemu-devel] " Avi Kivity
2011-04-26  8:53   ` Gerd Hoffmann
2011-04-26  8:53     ` [Qemu-devel] " Gerd Hoffmann
2011-04-26  9:06     ` Jan Kiszka
2011-04-26  9:06       ` [Qemu-devel] " Jan Kiszka
2011-04-26  9:43       ` Gerd Hoffmann
2011-04-26  9:43         ` [Qemu-devel] " Gerd Hoffmann
2011-04-26  9:34     ` Alon Levy
2011-04-26  9:34       ` [Qemu-devel] " Alon Levy

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