On Mon, Feb 8, 2016 at 5:07 AM, Wei Liu <wei.l...@citrix.com> wrote: > > > [...] > > >> + num_vcpus = max_vcpuid + 1; > > >> + GCNEW_ARRAY(vcpus, num_vcpus); > > >> + if (sched_rtds_validate_params(gc, scinfo->vcpus[0].period, > > >> + scinfo->vcpus[0].budget, > > > > > > This doesn't make sense. You take this path because scinfo->num_vcpus is > > > 0 but now you're dereferencing scinfo->vcpus[0]. Do I miss anything? > > For commands like " xl sched-rtds -d vm1 -v all -p 1000 -b 1000" > > (which sets all vcpus with > > the same scheduling parameters), we pass the budget and period via > > scinfo->vcpus[0]. > > > > I'll add more explanation here. > > No, adding more explanation won't help. > > Let me explain a bit. Libxl is the library that can be used by multiple > applications. Xl is just one of the applications. The other application > that I know of is libvirt. > > So, the incarnation of a particular xl command is of no concern how we > define the semantics of a libxl API. That is, you can come up with an > unambiguous API but still support the same xl command. > > Currently the semantics of this (new?) libxl API seems to be broken, > because you're (ab)using num_vcpus to represent a special case. In > effect you can't really whether the array is empty. When num_vcpus is 0, > you shouldn't dereference vcpus array, at all, because the semantics of > num_vcpus == 0 is that the array is empty. > > Wei.
I see. I'll think about re-designing the data structure of libxl_vcpu_sched_params. Chong > > > > > > >> + &vcpus[0].s.rtds.period, > > >> + &vcpus[0].s.rtds.budget)) > > > > > > > -- > > Chong Li > > Department of Computer Science and Engineering > > Washington University in St.louis -- Chong Li Department of Computer Science and Engineering Washington University in St.louis _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
