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From: Peter Zijlstra <peterz@infradead.org>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>,
	linux-s390 <linux-s390@vger.kernel.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	mpe@ellerman.id.au, boqun.feng@gmail.com, will.deacon@arm.com,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Waiman Long <waiman.long@hpe.com>,
	virtualization@lists.linux-foundation.org,
	Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
	benh@kernel.crashing.org, schwidefsky@de.ibm.com,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, kvm <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 0/4] implement vcpu preempted check
Date: Thu, 7 Jul 2016 13:21:21 +0200	[thread overview]
Message-ID: <20160707112121.GJ30927@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160707094215.GT30921@twins.programming.kicks-ass.net>

On Thu, Jul 07, 2016 at 11:42:15AM +0200, Peter Zijlstra wrote:
> +static void update_steal_time_preempt(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_steal_time *st;
> +
> +	if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
> +		return;
> +
> +	if (unlikely(kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
> +		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
> +		return;
> +
> +	st = &vcpu->arch.st.steal;
> +
> +	st->pad[KVM_ST_PAD_PREEMPT] = 1; /* we've stopped running */

So maybe have this be:

	... = kvm_vcpu_running();

That avoids marking the vcpu preempted when we do hlt and such.

> +	kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
> +		st, sizeof(struct kvm_steal_time));
> +}

WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: linux-s390 <linux-s390@vger.kernel.org>,
	Davidlohr Bueso <dave@stgolabs.net>,
	benh@kernel.crashing.org, kvm <kvm@vger.kernel.org>,
	mpe@ellerman.id.au, boqun.feng@gmail.com, will.deacon@arm.com,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Waiman Long <waiman.long@hpe.com>,
	virtualization@lists.linux-foundation.org,
	Ingo Molnar <mingo@redhat.com>, Paul Mackerras <paulus@samba.org>,
	Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>,
	schwidefsky@de.ibm.com, Paolo Bonzini <pbonzini@redhat.com>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 0/4] implement vcpu preempted check
Date: Thu, 7 Jul 2016 13:21:21 +0200	[thread overview]
Message-ID: <20160707112121.GJ30927@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160707094215.GT30921@twins.programming.kicks-ass.net>

On Thu, Jul 07, 2016 at 11:42:15AM +0200, Peter Zijlstra wrote:
> +static void update_steal_time_preempt(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_steal_time *st;
> +
> +	if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
> +		return;
> +
> +	if (unlikely(kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
> +		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
> +		return;
> +
> +	st = &vcpu->arch.st.steal;
> +
> +	st->pad[KVM_ST_PAD_PREEMPT] = 1; /* we've stopped running */

So maybe have this be:

	... = kvm_vcpu_running();

That avoids marking the vcpu preempted when we do hlt and such.

> +	kvm_write_guest_cached(vcpu->kvm, &vcpu->arch.st.stime,
> +		st, sizeof(struct kvm_steal_time));
> +}

  parent reply	other threads:[~2016-07-07 11:21 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-28 14:43 [PATCH v2 0/4] implement vcpu preempted check Pan Xinhui
2016-06-28 14:43 ` Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 1/4] kernel/sched: introduce vcpu preempted check interface Pan Xinhui
2016-06-28 14:43   ` Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Pan Xinhui
2016-06-28 14:43   ` Pan Xinhui
2016-07-05  9:57   ` Wanpeng Li
2016-07-05  9:57   ` Wanpeng Li
2016-07-06  4:58     ` xinhui
2016-07-06  4:58       ` xinhui
2016-07-06  6:46       ` Wanpeng Li
2016-07-06  6:46         ` Wanpeng Li
2016-07-06  6:46         ` Wanpeng Li
2016-07-06  7:58         ` Peter Zijlstra
2016-07-06  7:58           ` Peter Zijlstra
2016-07-06  8:32           ` Wanpeng Li
2016-07-06  8:32             ` Wanpeng Li
2016-07-06 10:18             ` xinhui
2016-07-06 10:18               ` xinhui
2016-07-06 10:54   ` Balbir Singh
2016-07-06 10:54     ` Balbir Singh
2016-07-06 10:54     ` Balbir Singh
2016-07-15 15:35     ` Pan Xinhui
2016-07-15 15:35     ` Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 3/4] locking/osq: Drop the overload of osq_lock() Pan Xinhui
2016-06-28 14:43 ` Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 4/4] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner Pan Xinhui
2016-06-28 14:43   ` [PATCH v2 4/4] kernel/locking: Drop the overload of {mutex, rwsem}_spin_on_owner Pan Xinhui
2016-06-28 14:43   ` Pan Xinhui
2016-07-06  6:52 ` [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra
2016-07-06  6:52   ` Peter Zijlstra
2016-07-06  7:47   ` Juergen Gross
2016-07-06  7:47     ` Juergen Gross
2016-07-06  8:19     ` Peter Zijlstra
2016-07-06  8:19       ` Peter Zijlstra
2016-07-06  8:38       ` Juergen Gross
2016-07-06  8:38         ` Juergen Gross
2016-07-06 12:44       ` Paolo Bonzini
2016-07-06 12:44         ` Paolo Bonzini
2016-07-06 16:56       ` Christian Borntraeger
2016-07-06 16:56         ` Christian Borntraeger
2016-07-06 16:56         ` Christian Borntraeger
2016-07-06 10:05   ` xinhui
2016-07-06 10:05     ` xinhui
2016-07-06 10:44   ` Paolo Bonzini
2016-07-06 11:59     ` Peter Zijlstra
2016-07-06 11:59     ` Peter Zijlstra
2016-07-06 12:08     ` Wanpeng Li
2016-07-06 12:08       ` Wanpeng Li
2016-07-06 12:28       ` Paolo Bonzini
2016-07-06 12:28         ` Paolo Bonzini
2016-07-06 13:03         ` Wanpeng Li
2016-07-06 13:03           ` Wanpeng Li
2016-07-07  8:48         ` Wanpeng Li
2016-07-07  8:48           ` Wanpeng Li
2016-07-07  9:42           ` Peter Zijlstra
2016-07-07  9:42             ` Peter Zijlstra
2016-07-07 10:12             ` Wanpeng Li
2016-07-07 10:12               ` Wanpeng Li
2016-07-07 10:27               ` Wanpeng Li
2016-07-07 10:27                 ` Wanpeng Li
2016-07-07 11:15                 ` Peter Zijlstra
2016-07-07 11:15                   ` Peter Zijlstra
2016-07-07 11:08               ` Peter Zijlstra
2016-07-07 11:08                 ` Peter Zijlstra
2016-07-07 11:09             ` Peter Zijlstra
2016-07-07 11:09               ` Peter Zijlstra
2016-07-07 11:21             ` Peter Zijlstra [this message]
2016-07-07 11:21               ` Peter Zijlstra
2016-07-11 15:10   ` Waiman Long
2016-07-11 15:10     ` Waiman Long
2016-07-11 15:10     ` Waiman Long
2016-07-12  4:16     ` Juergen Gross
2016-07-12  4:16     ` Juergen Gross
2016-07-12 18:16       ` Waiman Long
2016-07-12 18:16         ` Waiman Long
2016-07-12 18:16         ` Waiman Long

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