From 31a5c0b7c674977889ce721d69101bc35f25e041 Mon Sep 17 00:00:00 2001 From: James Morse Date: Tue, 13 Feb 2024 18:44:15 +0000 Subject: tick/nohz: Move tick_nohz_full_mask declaration outside the #ifdef 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. Signed-off-by: James Morse Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Shaopeng Tan Reviewed-by: Thomas Gleixner Acked-by: Reinette Chatre # for resctrl dependency Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Carl Worth # arm64 Link: https://lore.kernel.org/r/20240213184438.16675-2-james.morse@arm.com Signed-off-by: Borislav Petkov (AMD) --- include/linux/tick.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'include/linux/tick.h') diff --git a/include/linux/tick.h b/include/linux/tick.h index 716d17f31c45..0fb903838dfb 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -164,9 +164,16 @@ static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; } static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; } #endif /* !CONFIG_NO_HZ_COMMON */ +/* + * Mask of CPUs that are nohz_full. + * + * Users should be guarded by CONFIG_NO_HZ_FULL or a tick_nohz_full_cpu() + * check. + */ +extern cpumask_var_t tick_nohz_full_mask; + #ifdef CONFIG_NO_HZ_FULL extern bool tick_nohz_full_running; -extern cpumask_var_t tick_nohz_full_mask; static inline bool tick_nohz_full_enabled(void) { -- cgit v1.2.3-59-g8ed1b