diff options
| -rw-r--r-- | include/linux/rcupdate.h | 2 | ||||
| -rw-r--r-- | kernel/rcutree.c | 43 |
2 files changed, 45 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index d8b20bfd4795..f818dd165b44 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -193,6 +193,8 @@ extern void rcu_irq_enter(void); extern void rcu_irq_exit(void); extern void rcu_user_enter(void); extern void rcu_user_exit(void); +extern void rcu_user_enter_after_irq(void); +extern void rcu_user_exit_after_irq(void); extern void exit_rcu(void); /** diff --git a/kernel/rcutree.c b/kernel/rcutree.c index af0dc3472a4b..4138f59fa2f4 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -426,6 +426,27 @@ void rcu_user_enter(void) /** + * rcu_user_enter_after_irq - inform RCU that we are going to resume userspace + * after the current irq returns. + * + * This is similar to rcu_user_enter() but in the context of a non-nesting + * irq. After this call, RCU enters into idle mode when the interrupt + * returns. + */ +void rcu_user_enter_after_irq(void) +{ + unsigned long flags; + struct rcu_dynticks *rdtp; + + local_irq_save(flags); + rdtp = &__get_cpu_var(rcu_dynticks); + /* Ensure this irq is interrupting a non-idle RCU state. */ + WARN_ON_ONCE(!(rdtp->dynticks_nesting & DYNTICK_TASK_MASK)); + rdtp->dynticks_nesting = 1; + local_irq_restore(flags); +} + +/** * rcu_irq_exit - inform RCU that current CPU is exiting irq towards idle * * Exit from an interrupt handler, which might possibly result in entering @@ -550,6 +571,28 @@ void rcu_user_exit(void) } /** + * rcu_user_exit_after_irq - inform RCU that we won't resume to userspace + * idle mode after the current non-nesting irq returns. + * + * This is similar to rcu_user_exit() but in the context of an irq. + * This is called when the irq has interrupted a userspace RCU idle mode + * context. When the current non-nesting interrupt returns after this call, + * the CPU won't restore the RCU idle mode. + */ +void rcu_user_exit_after_irq(void) +{ + unsigned long flags; + struct rcu_dynticks *rdtp; + + local_irq_save(flags); + rdtp = &__get_cpu_var(rcu_dynticks); + /* Ensure we are interrupting an RCU idle mode. */ + WARN_ON_ONCE(rdtp->dynticks_nesting & DYNTICK_TASK_NEST_MASK); + rdtp->dynticks_nesting += DYNTICK_TASK_EXIT_IDLE; + local_irq_restore(flags); +} + +/** * rcu_irq_enter - inform RCU that current CPU is entering irq away from idle * * Enter an interrupt handler, which might possibly result in exiting |