Re: [patch 10/24] sched/smt: Expose sched_smt_present static key

[Thomas Gleixner]

On Wed, 21 Nov 2018, Thomas Gleixner wrote:

> Make the scheduler's 'sched_smt_present' static key globaly available, so
> it can be used in the x86 speculation control code.
> 
> Provide a query function and a stub for the CONFIG_SMP=n case.
> 
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
>  include/linux/sched/topology.h |    9 +++++++++
>  kernel/sched/sched.h           |    3 ---
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> --- a/include/linux/sched/topology.h
> +++ b/include/linux/sched/topology.h
> @@ -34,10 +34,19 @@
>  #define SD_NUMA			0x4000	/* cross-node balancing */
>  
>  #ifdef CONFIG_SCHED_SMT
> +extern struct static_key_false sched_smt_present;
> +
> +static __always_inline bool sched_smt_active(void)
> +{
> +	return static_branch_likely(&sched_smt_present);

0day just told me that this breaks ia64.

/me goes to fix