diff options
| -rw-r--r-- | include/linux/rcutree.h | 2 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 41 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 39 |
3 files changed, 42 insertions, 40 deletions
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index d09a9abe9440..7f83179177d1 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -66,7 +66,9 @@ void rcu_scheduler_starting(void); extern int rcu_scheduler_active __read_mostly; void rcu_end_inkernel_boot(void); bool rcu_is_watching(void); +#ifndef CONFIG_PREEMPT void rcu_all_qs(void); +#endif /* RCUtree hotplug events */ int rcutree_prepare_cpu(unsigned int cpu); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c8761e7c7c00..e140aaa78527 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -356,7 +356,7 @@ bool rcu_eqs_special_set(int cpu) * * The caller must have disabled interrupts and must not be idle. */ -static void rcu_momentary_dyntick_idle(void) +static void __maybe_unused rcu_momentary_dyntick_idle(void) { struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks); int special; @@ -381,45 +381,6 @@ static int rcu_is_cpu_rrupt_from_idle(void) __this_cpu_read(rcu_dynticks.dynticks_nmi_nesting) <= 1; } -/* - * Register an urgently needed quiescent state. If there is an - * emergency, invoke rcu_momentary_dyntick_idle() to do a heavy-weight - * dyntick-idle quiescent state visible to other CPUs, which will in - * some cases serve for expedited as well as normal grace periods. - * Either way, register a lightweight quiescent state. - * - * The barrier() calls are redundant in the common case when this is - * called externally, but just in case this is called from within this - * file. - * - */ -void rcu_all_qs(void) -{ - unsigned long flags; - - if (!raw_cpu_read(rcu_dynticks.rcu_urgent_qs)) - return; - preempt_disable(); - /* Load rcu_urgent_qs before other flags. */ - if (!smp_load_acquire(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs))) { - preempt_enable(); - return; - } - this_cpu_write(rcu_dynticks.rcu_urgent_qs, false); - barrier(); /* Avoid RCU read-side critical sections leaking down. */ - if (unlikely(raw_cpu_read(rcu_dynticks.rcu_need_heavy_qs))) { - local_irq_save(flags); - rcu_momentary_dyntick_idle(); - local_irq_restore(flags); - } - if (unlikely(raw_cpu_read(rcu_data.cpu_no_qs.b.exp))) - rcu_qs(); - this_cpu_inc(rcu_dynticks.rcu_qs_ctr); - barrier(); /* Avoid RCU read-side critical sections leaking up. */ - preempt_enable(); -} -EXPORT_SYMBOL_GPL(rcu_all_qs); - #define DEFAULT_RCU_BLIMIT 10 /* Maximum callbacks per rcu_do_batch. */ static long blimit = DEFAULT_RCU_BLIMIT; #define DEFAULT_RCU_QHIMARK 10000 /* If this many pending, ignore blimit. */ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index cd4c1b979446..7add1c297500 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -948,6 +948,45 @@ static void rcu_qs(void) } /* + * Register an urgently needed quiescent state. If there is an + * emergency, invoke rcu_momentary_dyntick_idle() to do a heavy-weight + * dyntick-idle quiescent state visible to other CPUs, which will in + * some cases serve for expedited as well as normal grace periods. + * Either way, register a lightweight quiescent state. + * + * The barrier() calls are redundant in the common case when this is + * called externally, but just in case this is called from within this + * file. + * + */ +void rcu_all_qs(void) +{ + unsigned long flags; + + if (!raw_cpu_read(rcu_dynticks.rcu_urgent_qs)) + return; + preempt_disable(); + /* Load rcu_urgent_qs before other flags. */ + if (!smp_load_acquire(this_cpu_ptr(&rcu_dynticks.rcu_urgent_qs))) { + preempt_enable(); + return; + } + this_cpu_write(rcu_dynticks.rcu_urgent_qs, false); + barrier(); /* Avoid RCU read-side critical sections leaking down. */ + if (unlikely(raw_cpu_read(rcu_dynticks.rcu_need_heavy_qs))) { + local_irq_save(flags); + rcu_momentary_dyntick_idle(); + local_irq_restore(flags); + } + if (unlikely(raw_cpu_read(rcu_data.cpu_no_qs.b.exp))) + rcu_qs(); + this_cpu_inc(rcu_dynticks.rcu_qs_ctr); + barrier(); /* Avoid RCU read-side critical sections leaking up. */ + preempt_enable(); +} +EXPORT_SYMBOL_GPL(rcu_all_qs); + +/* * Note a PREEMPT=n context switch. The caller must have disabled interrupts. */ void rcu_note_context_switch(bool preempt) |