From: Gleb Natapov <gleb@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] kvm: enable irq injection from interrupt context
Date: Thu, 16 Sep 2010 11:25:53 +0200 [thread overview]
Message-ID: <20100916092553.GV3008@redhat.com> (raw)
In-Reply-To: <20100916091054.GA20864@redhat.com>
On Thu, Sep 16, 2010 at 11:10:55AM +0200, Michael S. Tsirkin wrote:
> On Thu, Sep 16, 2010 at 11:02:56AM +0200, Gleb Natapov wrote:
> > On Wed, Sep 15, 2010 at 08:54:17PM +0200, Michael S. Tsirkin wrote:
> > > To avoid bouncing irqfd injection out to workqueue context,
> > > we must support injecting irqs from local interrupt
> > > context. Doing this seems to only require disabling
> > > irqs locally.
> > >
> > > RFC, completely untested, x86 only.
> > >
> > > Thoughts?
> > >
> > We do not want to disable irqs for a long time and some of code paths
> > under lock involve looping over all cpus. For MSI injection path is
> > lockless and this is the only case that matters,
>
> MSI only appeared in rhel6, older guests still use level interrupts.
So they are already slow for other reasons.
> Which paths require looping over all cpus? Do PCI interrupts
> need this?
>
All interrupts need it. IOAPIC has a loop to find dst cpu for interrupt.
Pic has a loop to find cpu in virtual wire mode.
--
Gleb.
next prev parent reply other threads:[~2010-09-16 9:25 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-15 18:54 [PATCH RFC] kvm: enable irq injection from interrupt context Michael S. Tsirkin
2010-09-16 9:02 ` Gleb Natapov
2010-09-16 9:10 ` Michael S. Tsirkin
2010-09-16 9:25 ` Gleb Natapov [this message]
2010-09-16 9:43 ` Michael S. Tsirkin
2010-09-16 9:46 ` Avi Kivity
2010-09-16 9:53 ` Michael S. Tsirkin
2010-09-16 10:13 ` Gleb Natapov
2010-09-16 10:13 ` Michael S. Tsirkin
2010-09-16 10:20 ` Gleb Natapov
2010-09-16 10:44 ` Michael S. Tsirkin
2010-09-16 10:54 ` Gleb Natapov
2010-09-16 10:53 ` Michael S. Tsirkin
2010-09-16 11:17 ` Gleb Natapov
2010-09-16 12:13 ` Michael S. Tsirkin
2010-09-16 12:33 ` Gleb Natapov
2010-09-16 12:57 ` Michael S. Tsirkin
2010-09-16 13:14 ` Avi Kivity
2010-09-16 13:38 ` Michael S. Tsirkin
2010-09-16 13:50 ` Avi Kivity
2010-09-16 13:55 ` Gleb Natapov
2010-09-16 13:18 ` Gleb Natapov
2010-09-16 13:51 ` Michael S. Tsirkin
2010-09-16 14:06 ` Gleb Natapov
2010-09-16 14:23 ` Michael S. Tsirkin
2010-09-16 14:51 ` Gleb Natapov
2010-09-16 15:24 ` Michael S. Tsirkin
2010-09-16 15:43 ` Gleb Natapov
2010-09-16 22:07 ` Michael S. Tsirkin
2010-09-17 7:59 ` Gleb Natapov
2010-09-19 10:45 ` Michael S. Tsirkin
2010-09-19 10:56 ` Avi Kivity
2010-09-19 10:55 ` Michael S. Tsirkin
2010-09-19 11:05 ` Avi Kivity
2010-09-19 11:23 ` Michael S. Tsirkin
2010-09-19 11:18 ` Gleb Natapov
2010-09-19 11:21 ` Michael S. Tsirkin
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