guest_enter() doesn't call context_tracking_enabled() before calling context_tracking_enabled_this_cpu(). Therefore the guest code doesn't benefit from the static key on the fast path.
Just make sure that context_tracking_enabled_*cpu() functions check the static key by themselves to propagate the optimization. Reported-by: Peter Zijlstra <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Yauheni Kaliuta <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Wanpeng Li <[email protected]> Cc: Ingo Molnar <[email protected]> --- include/linux/context_tracking_state.h | 4 ++-- include/linux/vtime.h | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h index 587717705727..e7fe6678b7ad 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -33,12 +33,12 @@ static inline bool context_tracking_enabled(void) static inline bool context_tracking_enabled_cpu(int cpu) { - return per_cpu(context_tracking.active, cpu); + return context_tracking_enabled() && per_cpu(context_tracking.active, cpu); } static inline bool context_tracking_enabled_this_cpu(void) { - return __this_cpu_read(context_tracking.active); + return context_tracking_enabled() && __this_cpu_read(context_tracking.active); } static inline bool context_tracking_in_user(void) diff --git a/include/linux/vtime.h b/include/linux/vtime.h index e2733bf33541..2cdeca062db3 100644 --- a/include/linux/vtime.h +++ b/include/linux/vtime.h @@ -33,12 +33,12 @@ static inline bool vtime_accounting_enabled(void) static inline bool vtime_accounting_enabled_cpu(int cpu) { - return (vtime_accounting_enabled() && context_tracking_enabled_cpu(cpu)); + return context_tracking_enabled_cpu(cpu); } static inline bool vtime_accounting_enabled_this_cpu(void) { - return (vtime_accounting_enabled() && context_tracking_enabled_this_cpu()); + return context_tracking_enabled_this_cpu(); } extern void vtime_task_switch_generic(struct task_struct *prev); -- 2.23.0
