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Re: [Xen-devel] Xen4.2 S3 regression?



On 23/08/12 19:03, Ben Guthro wrote:
I did some more bisecting here, and I came up with another changeset
that seems to be problematic, Re: IRQs

After bisecting the problem discussed earlier in this thread to the
changeset below,
http://xenbits.xen.org/hg/xen-unstable.hg/rev/0695a5cdcb42


I worked past that issue by the following hack:

--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -1103,7 +1103,7 @@ void evtchn_destroy_final(struct domain *d)
 void evtchn_move_pirqs(struct vcpu *v)
 {
     struct domain *d = v->domain;
-    const cpumask_t *mask = cpumask_of(v->processor);
+    //const cpumask_t *mask = cpumask_of(v->processor);
     unsigned int port;
     struct evtchn *chn;

@@ -1111,7 +1111,9 @@ void evtchn_move_pirqs(struct vcpu *v)
     for ( port = v->pirq_evtchn_head; port; port = chn->u.pirq.next_port )
     {
         chn = evtchn_from_port(d, port);
+#if 0
         pirq_set_affinity(d, chn->u.pirq.irq, mask);
+#endif
     }
     spin_unlock(&d->event_lock);
 }


This seemed to work for this rather old changeset, but it was not
sufficient to fix it against the 4.1, or unstable trees.

I further bisected, in combination with this hack, and found the
following changeset to also be problematic:

http://xenbits.xen.org/hg/xen-unstable.hg/rev/c2cb776a5365


That is, before this change I could resume reliably (with the hack
above) - and after I could not.
This was surprising to me, as this change also looks rather innocuous.
And by the looks of that changeset, the logic in fixup_irqs() in irq.c
was changed.

Jan: The commit message says "simplify operations [in] a few cases". 
Was the change in fixup_irqs() deliberate?

~Andrew

Ben: Could you test the attached patch?  It is for unstable and undoes the logical change to fixup_irqs()

~Andrew


Naturally, backing out this change seems to be non-trivial against the
tip, since so much around it has changed.

-- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel

-- 
Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer
T: +44 (0)1223 225 900, http://www.citrix.com

Attachment: s3-revert-fixup_irqs.patch
Description: Text Data

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