On Mon, Jul 25, 2016 at 7:17 AM, George Dunlap <george.dun...@citrix.com> wrote: > On 18/07/16 11:28, Dario Faggioli wrote: >> On Fri, 2016-07-15 at 19:02 +0100, George Dunlap wrote: >>> The generic domain creation logic in >>> xen/common/domctl.c:default_vcpu0_location() attempts to try to do >>> initial placement load-balancing by placing vcpu 0 on the least-busy >>> non-primary hyperthread available. Unfortunately, the logic can end >>> up picking a pcpu that's not in the online mask. When this is passed >>> to a scheduler such which assumes that the initial assignment is >>> valid, it causes a null pointer dereference looking up the runqueue. >>> >>> Furthermore, this initial placement doesn't take into account hard or >>> soft affinity, or any scheduler-specific knowledge (such as historic >>> runqueue load, as in credit2). >>> >>> To solve this, when inserting a vcpu, always call the per-scheduler >>> "pick" function to revise the initial placement. This will >>> automatically take all knowledge the scheduler has into account. >>> >>> Signed-off-by: George Dunlap <george.dun...@citrix.com> >>> --- >>> CC: Dario Faggioli <dario.faggi...@citrix.com> >>> CC: Anshul Makkar <anshul.mak...@citrix.com> >>> CC: Meng Xu <men...@cis.upenn.edu> >>> CC: Jan Beulich <jbeul...@suse.com> >>> >> Reviewed-by: Dario Faggioli <dario.faggi...@citrix.com> > > Just to clarify - does this cover the sched_rt.c changes as well?
Hi George, I had a look at the sched_rt.c, it looks good to me. I sent out my review tag for the sched_rt.c, just now. Meng ----------- Meng Xu PhD Student in Computer and Information Science University of Pennsylvania http://www.cis.upenn.edu/~mengxu/ _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
