[Xen-devel] [PATCH v2 0/6] xen: sched: fix locking of {insert, remove}_vcpu()

[Dario Faggioli <dario.faggioli@xxxxxxxxxx>]

Hey,

Here it comes v2 of this series. It took a bit more than how I wanted, mostly
because of the cpufreq issue I found while testing (as I though I was causing
it! :-/).

Version 1 is here:

 http://www.gossamer-threads.com/lists/xen/devel/401619?page=last

I think I've addressed all the review comments, but the series also changed a
little bit. Because of that, most of the patches don't carry the
Reviewed-/Acked-by tags they were given during v1's review.

More specifically:
 
 * patch 2 needed adjustments as, in case only patches 1 and 2 are applied
   (i.e., if what was patch 3 in v1, which is now patch 4, is _not_applied)
   the runqueue lock in Credit1's implementation of insert_vcpu() needs to
   be an _irqsave() one. In fact, it is acquired with interrupt disabled
   during boot (when initializing idle vCPUs). Since Credit2 and RTDS bail
   out before even trying taking the lock, for idle vCPUs, they're fine with
   just _irq(). Also, it can be turned into an _irq() one in patch 4, when we
   kill the need of calling that hook altogether, for idle vCPUs.  This is
   done like this because I think it is worth considering backporting patches
   1 and 2, so I think it's important that they work well, independently from
   the rest of the series (which is mostly improvements, so backporting is
   out of question)

 * patch 3 is new. It's "just" comments and ASSERT()-s about something
   discussed already with both Jan and George.

The rest, really should be no more than v1 with review comments addressed
(except, of course, patches 6 and 7 from v1, which are in already :-D).

Git branch available here:

 git://xenbits.xen.org/people/dariof/xen.git  rel/sched/fix-vcpu-ins-rem-v2

Thanks and Regards,
Dario
---
Dario Faggioli (6):
      xen: sched: fix locking of remove_vcpu() in credit1
      xen: sched: fix locking for insert_vcpu() in credit1 and RTDS
      xen: sched: clarify use cases of schedule_cpu_switch()
      xen: sched: better handle (not) inserting idle vCPUs in runqueues
      xen: sched: get rid of the per domain vCPU list in RTDS
      xen: sched: get rid of the per domain vCPU list in Credit2

 xen/common/sched_credit.c  |   17 ++++++++++--
 xen/common/sched_credit2.c |   55 ++++++++++++++--------------------------
 xen/common/sched_rt.c      |   61 ++++++++++++++++++++++----------------------
 xen/common/schedule.c      |   55 ++++++++++++++++++++++++++++------------
 4 files changed, 102 insertions(+), 86 deletions(-)
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

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