Re: [PATCH v6 01/24] tick/nohz: Move tick_nohz_full_mask declaration outside the #ifdef

Reinette Chatre
2023-10-03T21:11:32Z

On 9/14/2023 10:21 AM, James Morse wrote:
> tick_nohz_full_mask lists the CPUs that are nohz_full. This is only
> needed when CONFIG_NO_HZ_FULL is defined. tick_nohz_full_cpu() allows
> a specific CPU to be tested against the mask, and evaluates to false
> when CONFIG_NO_HZ_FULL is not defined.
>
> The resctrl code needs to pick a CPU to run some work on, a new helper
> prefers housekeeping CPUs by examining the tick_nohz_full_mask. Hiding
> the declaration behind #ifdef CONFIG_NO_HZ_FULL forces all the users to
> be behind an ifdef too.
>
> Move the tick_nohz_full_mask declaration, this lets callers drop the
> ifdef, and guard access to tick_nohz_full_mask with IS_ENABLED() or
> something like tick_nohz_full_cpu().
>
> The definition does not need to be moved as any callers should be
> removed at compile time unless CONFIG_NO_HZ_FULL is defined.
>
> CC: Frederic Weisbecker <frederic@kernel.org>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
> Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
> Tested-By: Peter Newman <peternewman@google.com>
> Signed-off-by: James Morse <james.morse@arm.com>

Acked-by: Reinette Chatre <reinette.chatre@intel.com> # for resctrl dependency

Reinette