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From: Gleb Natapov <gleb@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: avi@redhat.com, kvm@vger.kernel.org
Subject: Re: [PATCH v3 7/8] Move IO APIC to its own lock.
Date: Thu, 13 Aug 2009 12:48:10 +0300	[thread overview]
Message-ID: <20090813094810.GB23736@redhat.com> (raw)
In-Reply-To: <20090813091330.GB17022@amt.cnet>

On Thu, Aug 13, 2009 at 06:13:30AM -0300, Marcelo Tosatti wrote:
> > +++ b/virt/kvm/ioapic.c
> > @@ -182,6 +182,7 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
> >  	union kvm_ioapic_redirect_entry entry;
> >  	int ret = 1;
> >  
> > +	mutex_lock(&ioapic->lock);
> >  	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
> >  		entry = ioapic->redirtbl[irq];
> >  		level ^= entry.fields.polarity;
> 
> But this is an RCU critical section now, right? 
> 
Correct! Forget about that. It was spinlock, but Avi prefers mutexes.

> If so, you can't sleep, must use a spinlock.
Either that or I can collect callbacks in critical section and call them
afterwords.

--
			Gleb.

  reply	other threads:[~2009-08-13  9:48 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-12 12:17 [PATCH v3 0/8] make interrupt injection lockless (almost) Gleb Natapov
2009-08-12 12:17 ` [PATCH v3 1/8] Do not call ack notifiers on PIC reset Gleb Natapov
2009-08-13  9:11   ` Marcelo Tosatti
2009-08-13  9:39     ` Gleb Natapov
2009-08-12 12:17 ` [PATCH v3 2/8] Change irq routing table to use gsi indexed array Gleb Natapov
2009-08-12 12:17 ` [PATCH v3 3/8] Maintain back mapping from irqchip/pin to gsi Gleb Natapov
2009-08-17  9:43   ` Avi Kivity
2009-08-12 12:17 ` [PATCH v3 4/8] Move irq routing data structure to rcu locking Gleb Natapov
2009-08-12 12:17 ` [PATCH v3 5/8] Move irq ack notifier list to arch independent code Gleb Natapov
2009-08-12 12:17 ` [PATCH v3 6/8] Convert irq notifiers lists to RCU locking Gleb Natapov
2009-08-12 12:17 ` [PATCH v3 7/8] Move IO APIC to its own lock Gleb Natapov
2009-08-13  9:13   ` Marcelo Tosatti
2009-08-13  9:48     ` Gleb Natapov [this message]
2009-08-13  9:49       ` Avi Kivity
2009-08-13 10:09         ` Gleb Natapov
2009-08-13 10:44           ` Avi Kivity
2009-08-13 15:15             ` Paul E. McKenney
2009-08-12 12:17 ` [PATCH v3 8/8] Drop kvm->irq_lock lock from irq injection path Gleb Natapov
2009-08-17  9:46 ` [PATCH v3 0/8] make interrupt injection lockless (almost) Avi Kivity

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