Messages in this thread | | | Date | Mon, 19 Nov 2018 20:03:02 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [Patch v5 08/16] smt: Create cpu_smt_enabled static key for SMT specific code |
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Tim,
On Mon, 19 Nov 2018, Tim Chen wrote: > On 11/19/2018 06:57 AM, Peter Zijlstra wrote: > > In particular, the SMT topology bits are set before we enable > > interrrupts and similarly, are cleared after we disable interrupts for > > the last time and die. > > > Peter & Thomas, > > Any objection if I export sched_smt_present after including > Peter's patch and use it in spec_ctrl_update_msr instead. > > Something like this?
> > +#ifdef CONFIG_SCHED_SMT > + > +extern struct static_key_false sched_smt_present; > + > +static inline bool cpu_smt_present(void) > +{ > + if (static_branch_unlikely(&sched_smt_present)) > + return true; > + else > + return false;
What's wrong with
return static_branch_unlikely(&sched_smt_present);
???
But that's just a stylistic nitpick. The real issue is that you prevent the mitigation when CONFIG_SCHED_SMT=n.
Thanks,
tglx
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