From: Paolo Bonzini <pbonzini@redhat.com>
To: Davidlohr Bueso <dave@stgolabs.net>,
mingo@kernel.org, peterz@infradead.org
Cc: npiggin@gmail.com, paulmck@linux.vnet.ibm.com,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH 3/7] kvm,lapic: Justify use of swait_activate()
Date: Fri, 15 Sep 2017 13:47:10 +0200 [thread overview]
Message-ID: <e2430301-6db2-b50d-a919-ed703f8db367@redhat.com> (raw)
In-Reply-To: <20170913200824.28067-4-dave@stgolabs.net>
On 13/09/2017 22:08, Davidlohr Bueso wrote:
> A comment might serve future readers.
>
> Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> ---
> arch/x86/kvm/lapic.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index aaf10b6f5380..69c5612be786 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1324,6 +1324,10 @@ static void apic_timer_expired(struct kvm_lapic *apic)
> atomic_inc(&apic->lapic_timer.pending);
> kvm_set_pending_timer(vcpu);
>
> + /*
> + * For x86, the atomic_inc() is serialized, thus
> + * using swait_active() is safe.
> + */
> if (swait_active(q))
> swake_up(q);
>
>
Better add an smp_mb__after_atomic() for documentation purposes.
Paolo
next prev parent reply other threads:[~2017-09-15 11:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-13 20:08 [PATCH v2 0/7] swait: Introduce and use swq_has_sleeper() Davidlohr Bueso
2017-09-13 20:08 ` [PATCH 1/7] sched/wait: Add swq_has_sleepers() Davidlohr Bueso
2017-09-13 20:08 ` [PATCH 2/7] kvm,async_pf: Use swq_has_sleepers() Davidlohr Bueso
2017-09-13 20:08 ` [PATCH 3/7] kvm,lapic: Justify use of swait_activate() Davidlohr Bueso
2017-09-15 11:47 ` Paolo Bonzini [this message]
2017-09-13 20:08 ` [PATCH 4/7] kvm,x86: Fix apf_task_wake_one() wq serialization Davidlohr Bueso
2017-09-13 20:08 ` [PATCH 5/7] kvm: Serialize wq active checks in kvm_vcpu_wake_up() Davidlohr Bueso
2017-09-13 20:08 ` [PATCH 6/7] kvm,powerpc: Serialize wq active checks in ops->vcpu_kick Davidlohr Bueso
2017-09-13 20:08 ` [PATCH 7/7] kvm,mips: Fix potential swait_active() races Davidlohr Bueso
2017-09-13 20:35 ` Paolo Bonzini
2017-09-13 22:22 ` Davidlohr Bueso
2017-09-15 11:33 ` Paolo Bonzini
2017-09-15 11:53 ` [PATCH v2 0/7] swait: Introduce and use swq_has_sleeper() Paolo Bonzini
2017-09-19 8:25 ` Christian Borntraeger
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