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From: Davidlohr Bueso <dave@stgolabs.net>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marc Zyngier <maz@kernel.org>,
	tglx@linutronix.de, kvm@vger.kernel.org,
	Davidlohr Bueso <dbueso@suse.de>,
	peterz@infradead.org, torvalds@linux-foundation.org,
	bigeasy@linutronix.de, linux-kernel@vger.kernel.org,
	rostedt@goodmis.org, linux-mips@vger.kernel.org,
	Paul Mackerras <paulus@ozlabs.org>,
	joel@joelfernandes.org, will@kernel.org,
	kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v2] kvm: Replace vcpu->swait with rcuwait
Date: Mon, 20 Apr 2020 14:50:14 -0700	[thread overview]
Message-ID: <20200420215014.sarodevmhphnkkn7@linux-p48b> (raw)
In-Reply-To: <f7cc83fe-3e91-0057-9af2-26c201456689@redhat.com>

On Mon, 20 Apr 2020, Paolo Bonzini wrote:

>On 20/04/20 22:56, Davidlohr Bueso wrote:
>> On Mon, 20 Apr 2020, Marc Zyngier wrote:
>>
>>> This looks like a change in the semantics of the tracepoint. Before this
>>> change, 'waited' would have been true if the vcpu waited at all. Here,
>>> you'd
>>> have false if it has been interrupted by a signal, even if the vcpu
>>> has waited
>>> for a period of time.
>>
>> Hmm but sleeps are now uninterruptible as we're using TASK_IDLE.
>
>Hold on, does that mean that you can't anymore send a signal in order to
>kick a thread out of KVM_RUN?  Or am I just misunderstanding?

Considering that the return value of the interruptible wait is not
checked, I would not think this breaks KVM_RUN.

Thanks,
Davidlohr

  reply	other threads:[~2020-04-20 21:53 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-24  4:44 [PATCH -tip 0/4] kvm: Use rcuwait for vcpu blocking Davidlohr Bueso
2020-03-24  4:44 ` [PATCH 1/4] rcuwait: Fix stale wake call name in comment Davidlohr Bueso
2020-03-24  4:44 ` [PATCH 2/4] rcuwait: Let rcuwait_wake_up() return whether or not a task was awoken Davidlohr Bueso
2020-03-24  4:44 ` [PATCH 3/4] kvm: Replace vcpu->swait with rcuwait Davidlohr Bueso
2020-03-24 12:07   ` kbuild test robot
2020-03-24 16:47   ` kbuild test robot
2020-03-24 17:56     ` Davidlohr Bueso
2020-03-25 17:09   ` Paolo Bonzini
2020-04-14 21:12     ` Davidlohr Bueso
2020-04-15 12:11       ` Paolo Bonzini
2020-04-20 16:41   ` [PATCH v2] " Davidlohr Bueso
2020-04-20 17:12     ` Marc Zyngier
2020-04-20 17:25       ` Paolo Bonzini
2020-04-20 20:56       ` Davidlohr Bueso
2020-04-20 21:04         ` Paolo Bonzini
2020-04-20 21:50           ` Davidlohr Bueso [this message]
2020-04-21  9:43             ` Paolo Bonzini
2020-04-21 18:07               ` Davidlohr Bueso
2020-04-21 19:52                 ` Paolo Bonzini
2020-03-24  4:44 ` [PATCH 4/4] sched/swait: Reword some of the main description Davidlohr Bueso

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