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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: "Zhang, Yang Z" <yang.z.zhang@intel.com>,
	Jan Kiszka <jan.kiszka@web.de>, kvm <kvm@vger.kernel.org>
Subject: Re: [PATCH] KVM: x86: Avoid busy loops over uninjectable pending APIC timers
Date: Thu, 21 Mar 2013 17:51:50 -0300	[thread overview]
Message-ID: <20130321205150.GA17295@amt.cnet> (raw)
In-Reply-To: <20130321162732.GF9382@redhat.com>

> > > But current PI patches do break them, thats my point. So we either
> > > need to revise them again, or drop LAPIC timer reinjection. Making
> > > apic_accept_irq semantics "it returns coalescing info, but only sometimes"
> > > is dubious though.
> > We may rollback to the initial idea: test both irr and pir to get coalescing info. In this case, inject LAPIC timer always in vcpu context. So apic_accept_irq() will return right coalescing info.
> > Also, we need to add comments to tell caller, apic_accept_irq() can ensure the return value is correct only when caller is in target vcpu context.
> > 
> We cannot touch irr while vcpu is in non-root operation, so we will have
> to pass flag to apic_accept_irq() to let it know that it is called
> synchronously. While all this is possible I want to know which guests
> exactly will we break if we will not track interrupt coalescing for
> lapic timer. If only 2.0 smp kernels will break we can probably drop it.

RHEL4 / RHEL5 guests.


  reply	other threads:[~2013-03-21 20:51 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-16 20:49 [PATCH] KVM: x86: Avoid busy loops over uninjectable pending APIC timers Jan Kiszka
2013-03-17  8:47 ` Gleb Natapov
2013-03-17 10:45   ` Jan Kiszka
2013-03-17 10:47     ` Gleb Natapov
2013-03-20 19:30       ` Marcelo Tosatti
2013-03-20 20:03         ` Marcelo Tosatti
2013-03-20 21:32           ` Gleb Natapov
2013-03-20 23:19             ` Marcelo Tosatti
2013-03-21  4:54               ` Gleb Natapov
2013-03-21 14:02                 ` Marcelo Tosatti
2013-03-21 14:18                   ` Gleb Natapov
2013-03-21 14:27                     ` Zhang, Yang Z
2013-03-21 16:27                       ` Gleb Natapov
2013-03-21 20:51                         ` Marcelo Tosatti [this message]
2013-03-21 21:13                           ` Gleb Natapov
2013-03-21 23:06                             ` Marcelo Tosatti
2013-03-22  1:50                               ` Zhang, Yang Z
2013-03-22  6:53                               ` Gleb Natapov
2013-03-22 10:43                                 ` Marcelo Tosatti
2013-03-22 11:19                                   ` Gleb Natapov
2013-03-24 10:45                                     ` Zhang, Yang Z
2013-03-24 19:03                                       ` Gleb Natapov
2013-04-28 10:15   ` Jan Kiszka
2013-04-28 10:19     ` Gleb Natapov
2013-04-28 10:20       ` Jan Kiszka
2013-04-28 10:23         ` Gleb Natapov

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