From: Paolo Bonzini <pbonzini@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Umesh Deshpande <udeshpan@redhat.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] [PATCH 1/5] Support for vm_stop from the migration thread
Date: Tue, 30 Aug 2011 10:40:41 +0200 [thread overview]
Message-ID: <4E5CA209.7080506@redhat.com> (raw)
In-Reply-To: <20110829165624.GA3003@amt.cnet>
On 08/29/2011 06:56 PM, Marcelo Tosatti wrote:
>> > diff --git a/cpus.c b/cpus.c
>> > index de70e02..f35f683 100644
>> > --- a/cpus.c
>> > +++ b/cpus.c
>> > @@ -122,8 +122,8 @@ static void do_vm_stop(int reason)
>> > {
>> > if (vm_running) {
>> > cpu_disable_ticks();
>> > - vm_running = 0;
>> > pause_all_vcpus();
>> > + vm_running = 0;
>> > vm_state_notify(0, reason);
>> > qemu_aio_flush();
>> > bdrv_flush_all();
> Why this change?
Without it, you could have two threads calling into do_vm_stop and the
second would not wait for all CPUs to be paused. Still not perfect as
you'd get double notifications, you would need a condition variable or
QemuEvent (from the RCU series) for that.
Paolo
next prev parent reply other threads:[~2011-08-30 8:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-27 18:09 [Qemu-devel] [PATCH 0/5] Separate thread for VM migration Umesh Deshpande
2011-08-27 18:09 ` [Qemu-devel] [PATCH 1/5] Support for vm_stop from the migration thread Umesh Deshpande
2011-08-29 16:56 ` Marcelo Tosatti
2011-08-30 8:40 ` Paolo Bonzini [this message]
2011-08-27 18:09 ` [Qemu-devel] [PATCH 2/5] MRU ram block list Umesh Deshpande
2011-08-27 18:09 ` [Qemu-devel] [PATCH 3/5] Migration thread mutex Umesh Deshpande
2011-08-29 9:04 ` Stefan Hajnoczi
2011-08-29 13:49 ` Umesh Deshpande
2011-08-29 18:40 ` Marcelo Tosatti
2011-08-27 18:09 ` [Qemu-devel] [PATCH 4/5] Separate migration dirty bitmap Umesh Deshpande
2011-08-27 18:09 ` [Qemu-devel] [PATCH 5/5] Separate migration thread Umesh Deshpande
2011-08-29 9:09 ` Stefan Hajnoczi
2011-08-29 13:49 ` Umesh Deshpande
2011-08-29 18:49 ` Marcelo Tosatti
2011-08-30 8:48 ` Paolo Bonzini
2011-08-30 12:31 ` Marcelo Tosatti
2011-08-29 10:20 ` [Qemu-devel] [PATCH 0/5] Separate thread for VM migration Paolo Bonzini
2011-08-31 3:53 ` Umesh Deshpande
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