From: Avi Kivity <avi@redhat.com>
To: Chris Lalancette <clalance@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, kvm@vger.kernel.org
Subject: Re: [PATCH 5/5] Fix kdump under KVM.
Date: Sun, 01 Nov 2009 17:21:23 +0200 [thread overview]
Message-ID: <4AEDA773.7030906@redhat.com> (raw)
In-Reply-To: <4AEADADD.7070501@redhat.com>
On 10/30/2009 02:23 PM, Chris Lalancette wrote:
> In the meantime, I've gotten the "set_irq from IRQ context" that Avi
> suggested
> working, and the fixing up of this IOAPIC check is the last bit to actually get
> kdump working.
>
There are two problems with that:
- kvm_set_irq() calls some notifiers (irq_mask_notifiers, at least, but
possibly more); need to make sure those are safe from irq context
- kvm_set_irq() will loop on all vcpus, usually incurring a cache miss
or two; with large vcpu counts this can make the irq-off time quite
large, hurting our worst-case latency
we can defer the second problem since it's only a performance issue, but
how did you deal with the first?
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2009-11-01 15:21 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-27 16:41 [PATCH 0/5]: Fix kdump under KVM Chris Lalancette
2009-10-27 16:41 ` [PATCH 1/5] Fix up some comments around the source tree Chris Lalancette
2009-10-27 16:41 ` [PATCH 2/5] Remove KVM_REQ_PENDING_TIMER Chris Lalancette
2009-10-27 16:41 ` [PATCH 3/5] Remove references to VCPU in i8254 Chris Lalancette
2009-10-27 16:41 ` [PATCH 4/5] Remove timer.c Chris Lalancette
2009-10-27 16:41 ` [PATCH 5/5] Fix kdump under KVM Chris Lalancette
2009-10-27 17:42 ` Marcelo Tosatti
2009-10-28 10:21 ` Chris Lalancette
2009-10-28 12:41 ` Marcelo Tosatti
2009-10-30 12:23 ` Chris Lalancette
2009-10-30 13:07 ` Marcelo Tosatti
2009-10-30 15:28 ` Chris Lalancette
2009-10-30 18:03 ` David S. Ahern
2009-10-30 22:21 ` Marcelo Tosatti
2009-10-30 22:19 ` Marcelo Tosatti
2009-11-01 15:21 ` Avi Kivity [this message]
2009-11-02 13:22 ` Chris Lalancette
2009-11-02 13:30 ` Avi Kivity
2009-10-28 9:59 ` [PATCH 0/5]: " Avi Kivity
2009-10-28 10:13 ` Chris Lalancette
2009-10-28 10:31 ` Avi Kivity
2009-10-29 8:34 ` Chris Lalancette
2009-10-29 10:15 ` Avi Kivity
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