diff options
| -rw-r--r-- | include/linux/context_tracking.h | 10 | ||||
| -rw-r--r-- | init/main.c | 2 | ||||
| -rw-r--r-- | kernel/context_tracking.c | 23 |
3 files changed, 29 insertions, 6 deletions
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 1ae37c708c6..c138c24bad1 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -4,6 +4,7 @@ #include <linux/sched.h> #include <linux/percpu.h> #include <linux/vtime.h> +#include <linux/static_key.h> #include <asm/ptrace.h> struct context_tracking { @@ -22,6 +23,7 @@ struct context_tracking { #ifdef CONFIG_CONTEXT_TRACKING +extern struct static_key context_tracking_enabled; DECLARE_PER_CPU(struct context_tracking, context_tracking); static inline bool context_tracking_in_user(void) @@ -67,6 +69,14 @@ static inline void context_tracking_task_switch(struct task_struct *prev, struct task_struct *next) { } #endif /* !CONFIG_CONTEXT_TRACKING */ + +#ifdef CONFIG_CONTEXT_TRACKING_FORCE +extern void context_tracking_init(void); +#else +static inline void context_tracking_init(void) { } +#endif /* CONFIG_CONTEXT_TRACKING_FORCE */ + + #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN extern void guest_enter(void); extern void guest_exit(void); diff --git a/init/main.c b/init/main.c index d03d2ec2eac..af310afbef2 100644 --- a/init/main.c +++ b/init/main.c @@ -75,6 +75,7 @@ #include <linux/blkdev.h> #include <linux/elevator.h> #include <linux/sched_clock.h> +#include <linux/context_tracking.h> #include <asm/io.h> #include <asm/bugs.h> @@ -545,6 +546,7 @@ asmlinkage void __init start_kernel(void) idr_init_cache(); rcu_init(); tick_nohz_init(); + context_tracking_init(); radix_tree_init(); /* init some links before init_ISA_irqs() */ early_irq_init(); diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 72bcb2570d3..839d377d0da 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -20,15 +20,16 @@ #include <linux/hardirq.h> #include <linux/export.h> -DEFINE_PER_CPU(struct context_tracking, context_tracking) = { -#ifdef CONFIG_CONTEXT_TRACKING_FORCE - .active = true, -#endif -}; +struct static_key context_tracking_enabled = STATIC_KEY_INIT_FALSE; + +DEFINE_PER_CPU(struct context_tracking, context_tracking); void context_tracking_cpu_set(int cpu) { - per_cpu(context_tracking.active, cpu) = true; + if (!per_cpu(context_tracking.active, cpu)) { + per_cpu(context_tracking.active, cpu) = true; + static_key_slow_inc(&context_tracking_enabled); + } } /** @@ -202,3 +203,13 @@ void context_tracking_task_switch(struct task_struct *prev, clear_tsk_thread_flag(prev, TIF_NOHZ); set_tsk_thread_flag(next, TIF_NOHZ); } + +#ifdef CONFIG_CONTEXT_TRACKING_FORCE +void __init context_tracking_init(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + context_tracking_cpu_set(cpu); +} +#endif |