On Fri, Apr 26, 2019 at 04:13:07PM +0200 Peter Zijlstra wrote: > On Thu, Apr 25, 2019 at 10:26:53AM -0400, Phil Auld wrote: > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index e8e5f26db052..b312ea1e28a4 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -7541,6 +7541,9 @@ static int cpu_core_tag_write_u64(struct > > cgroup_subsys_state *css, struct cftype > > if (val > 1) > > return -ERANGE; > > > > + if (num_online_cpus() <= 1) > > + return -EINVAL; > > We actually know if there SMT on the system or not, which is much better > indication still: > > if (!static_branch_likely(&sched_smt_present)) > return -EINVAL; > > > if (tg->tagged == !!val) > > return 0; > > > > > > > > > > --
Yeah, I thought there was probably a better check. Thanks! --
