[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [PATCH][RESEND]RE: [Xen-devel] [PATCH] Fix softlockup issue aftervcpu hotplug

  • To: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
  • Date: Sun, 4 Feb 2007 20:30:53 +0800
  • Delivery-date: Sun, 04 Feb 2007 04:30:33 -0800
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-topic: [PATCH][RESEND]RE: [Xen-devel] [PATCH] Fix softlockup issue aftervcpu hotplug

Keir, how about your opinion about this version? Maybe I missed
your reply...


>-----Original Message-----
>From: Tian, Kevin 
>Sent: 2007年2月2日 21:57
>To: Tian, Kevin; Keir Fraser; xen-devel@xxxxxxxxxxxxxxxxxxx
>Subject: RE: [PATCH][RESEND]RE: [Xen-devel] [PATCH] Fix 
>softlockup issue aftervcpu hotplug
>Hi, Keir,
>       Please check whether attached patch matches 
>your suggestion. Test OK with vcpu hotplug and save/restore.
>>From: Tian, Kevin
>>Sent: 2007年2月2日 10:49
>>>Okay, I now see how this works -- the thread is kicked from
>>>softlockup_tick(), from the timer ISR. So this wakeup event is hidden
>>>next_timer_interrupt(), which only searches timer wheels and 
>>>The strictly correct fix here is to make next_timer_interrupt()
>>>softlockup-aware. I would say it is currently incorrect in 
>>the presence of
>>>softlockup since it is not doing its job (telling an idle 
>>process what the
>>>next time-based event is that it must wake up for).
>>>We can do this by adding a softlockup_get_next_event(), 
>>called from the
>>>bottom of next_timer_interrupt(). I would pass it the current 
>>return value
>>>and have it return an adjusted value: so in the absence of 
>>softlockup it
>>>would simply return its argument unmodified. In the presence of
>>>it would return a sooner value if softlockup is the next 
>>event to fire.
>>>Do you want to try coding this up?
>>> -- Keir

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.