Re: cpu/hotplug: broken sibling thread hotplug

From: Josh Poimboeuf
Date: Mon Jan 28 2019 - 07:53:02 EST


On Mon, Jan 28, 2019 at 11:13:04AM +0100, Igor Mammedov wrote:
> On Fri, 25 Jan 2019 11:02:03 -0600
> Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
>
> > On Fri, Jan 25, 2019 at 10:36:57AM -0600, Josh Poimboeuf wrote:
> > > How about this patch? It's just a revert of 73d5e2b47264 and
> > > bc2d8d262cba, plus the 1-line vmx_vm_init() change. If it looks ok to
> > > you, I can clean it up and submit an official version.
> >
> > This one actually compiles...
>
> Looks good to me,
> (one small question below)
>
>
> [...]
> > static inline bool cpu_smt_allowed(unsigned int cpu)
> > {
> > - if (topology_is_primary_thread(cpu))
> > + if (cpu_smt_control == CPU_SMT_ENABLED)
> > return true;
> >
> > - /*
> > - * If the CPU is not a 'primary' thread and the booted_once bit is
> > - * set then the processor has SMT support. Store this information
> > - * for the late check of SMT support in cpu_smt_check_topology().
> > - */
> > - if (per_cpu(cpuhp_state, cpu).booted_once)
> > - cpu_smt_available = true;
> > -
> > - if (cpu_smt_control == CPU_SMT_ENABLED)
> > + if (topology_is_primary_thread(cpu))
> > return true;
> why did you swap cpu_smt_control and topology_is_primary_thread checks?

That's just the revert of bc2d8d262cba5.

--
Josh