Date: Thu, 12 Feb 2015 18:09:12 +0100
From: Frederic Weisbecker <fweisbec@gmail.com>
To: riel@redhat.com
Cc: paulmck@linux.vnet.ibm.com, luto@amacapital.net, will.deacon@arm.com,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mtosatti@redhat.com,
        borntraeger@de.ibm.com, lcapitulino@redhat.com, pbonzini@redhat.com
Subject: Re: [PATCH -v5 0/5] rcu,nohz,kvm: use RCU extended quiescent state
 when running KVM guest
Message-ID: <20150212170909.GI18363@lerouge>
References: <1423600074-2907-1-git-send-email-riel@redhat.com>
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On Tue, Feb 10, 2015 at 03:27:49PM -0500, riel@redhat.com wrote:
> When running a KVM guest on a system with NOHZ_FULL enabled, and the
> KVM guest running with idle=poll mode, we still get wakeups of the
> rcuos/N threads.
> 
> This problem has already been solved for user space by telling the
> RCU subsystem that the CPU is in an extended quiescent state while
> running user space code.
> 
> This patch series extends that code a little bit to make it usable
> to track KVM guest space, too.
> 
> I tested the code by booting a KVM guest with idle=poll, on a system
> with NOHZ_FULL enabled on most CPUs, and a VCPU thread bound to a
> CPU. In a 10 second interval, rcuos/N threads on other CPUs got woken
> up several times, while the rcuos thread on the CPU running the bound
> and alwasy running VCPU thread never got woken up once.
> 
> Thanks to Christian Borntraeger, Paul McKenney, Paulo Bonzini,
> Frederic Weisbecker, and Will Deacon for reviewing and improving
> earlier versions of this patch series.
> 

So the patchset look good, thanks everyone. I'm applying the series
and will see anything explode.

I'll wait until the end of the merge window to push it to Ingo.

Thanks.
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