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From: "Zhang, Xiantao" <xiantao.zhang@intel.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: Avi Kivity <avi@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Ingo Molnar <mingo@elte.hu>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Peter Zijlstra <peter@programming.kicks-ass.net>
Subject: RE: x86: use smp_send_reschedule in kvm_vcpu_kick
Date: Fri, 13 Mar 2009 10:15:22 +0800	[thread overview]
Message-ID: <706158FABBBA044BAD4FE898A02E4BC224452426@pdsmsx503.ccr.corp.intel.com> (raw)
In-Reply-To: <20090312110422.GB10892@redhat.com>

We also hacked the source like the patch. But the issue is not caused by it. We are still trying to figure the reason out. Thanks!  
Xiantao

-----Original Message-----
From: Gleb Natapov [mailto:gleb@redhat.com] 
Sent: Thursday, March 12, 2009 7:04 PM
To: Zhang, Xiantao
Cc: Avi Kivity; Marcelo Tosatti; Ingo Molnar; kvm@vger.kernel.org; Peter Zijlstra
Subject: Re: x86: use smp_send_reschedule in kvm_vcpu_kick

On Thu, Mar 12, 2009 at 10:31:47AM +0800, Zhang, Xiantao wrote:
> Avi Kivity wrote:
> > Marcelo Tosatti wrote:
> >> OK, reworked patch:
> >> - change ia64 in addition to x86
> >> - add comment on smp send reschedule handlers about KVM's usage
> >> 
> >> Untested on IA64.
> >> 
> >> KVM: use smp_send_reschedule in kvm_vcpu_kick
> >> 
> >> KVM uses a function call IPI to cause the exit of a guest running on
> >> a physical cpu. For virtual interrupt notification there is no need
> >> to wait on IPI receival, or to execute any function.
> >> 
> >> This is exactly what the reschedule IPI does, without the overhead
> >> of function IPI. So use it instead of smp_call_function_single in
> >> kvm_vcpu_kick. 
> >> 
> >> Also change the "guest_mode" variable to a bit in vcpu->requests, and
> >> use that to collapse multiple IPI's that would be issued between the
> >> first one and zeroing of guest mode.
> >> 
> >> This allows kvm_vcpu_kick to called with interrupts disabled.
> >> 
> > 
> > Looks good. Will wait for Xiantao's test-n-ack before applying.
> 
> kvm-ia64 is broken due to recent check-ins about irq-bits, and we are trying to fix it. For this patch, ia64 has to export the symbol smp_send_reschedule before applying the patch.
Can you try this patch please: http://patchwork.kernel.org/patch/11103/

--
			Gleb.

  reply	other threads:[~2009-03-13  2:16 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-03  0:14 KVM: x86: use smp_send_reschedule in kvm_vcpu_kick Marcelo Tosatti
2009-03-03  7:53 ` Zhang, Xiantao
2009-03-03 13:25   ` Marcelo Tosatti
2009-03-03 13:25     ` Gleb Natapov
2009-03-03 13:56       ` Marcelo Tosatti
2009-03-09 10:17 ` KVM: " Avi Kivity
2009-03-09 10:58   ` Ingo Molnar
2009-03-09 11:09     ` Peter Zijlstra
2009-03-09 23:23       ` Marcelo Tosatti
2009-03-10  8:01         ` Avi Kivity
2009-03-12  2:31           ` Zhang, Xiantao
2009-03-12  7:06             ` Avi Kivity
2009-03-12 11:04             ` Gleb Natapov
2009-03-13  2:15               ` Zhang, Xiantao [this message]
2009-03-19  7:38                 ` Gleb Natapov
2009-03-19  7:56                   ` Zhang, Xiantao
2009-03-19  8:11                     ` Gleb Natapov

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