diff options
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 42a0032dd99f..381ebd3ae26c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -252,6 +252,15 @@ void rcu_softirq_qs(void) } /* + * Increment the current CPU's rcu_data structure's ->dynticks field + * with ordering. Return the new value. + */ +static noinline noinstr unsigned long rcu_dynticks_inc(int incby) +{ + return arch_atomic_add_return(incby, this_cpu_ptr(&rcu_data.dynticks)); +} + +/* * Record entry into an extended quiescent state. This is only to be * called when not already in an extended quiescent state, that is, * RCU is watching prior to the call to this function and is no longer @@ -267,7 +276,7 @@ static noinstr void rcu_dynticks_eqs_enter(void) * next idle sojourn. */ rcu_dynticks_task_trace_enter(); // Before ->dynticks update! - seq = arch_atomic_inc_return(&this_cpu_ptr(&rcu_data)->dynticks); + seq = rcu_dynticks_inc(1); // RCU is no longer watching. Better be in extended quiescent state! WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && (seq & 0x1)); } @@ -286,7 +295,7 @@ static noinstr void rcu_dynticks_eqs_exit(void) * and we also must force ordering with the next RCU read-side * critical section. */ - seq = arch_atomic_inc_return(&this_cpu_ptr(&rcu_data)->dynticks); + seq = rcu_dynticks_inc(1); // RCU is now watching. Better not be in an extended quiescent state! rcu_dynticks_task_trace_exit(); // After ->dynticks update! WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !(seq & 0x1)); @@ -308,7 +317,7 @@ static void rcu_dynticks_eqs_online(void) if (atomic_read(&rdp->dynticks) & 0x1) return; - atomic_inc(&rdp->dynticks); + rcu_dynticks_inc(1); } /* @@ -318,7 +327,7 @@ static void rcu_dynticks_eqs_online(void) */ static __always_inline bool rcu_dynticks_curr_cpu_in_eqs(void) { - return !(arch_atomic_read(&this_cpu_ptr(&rcu_data)->dynticks) & 0x1); + return !(atomic_read(this_cpu_ptr(&rcu_data.dynticks)) & 0x1); } /* @@ -327,7 +336,8 @@ static __always_inline bool rcu_dynticks_curr_cpu_in_eqs(void) */ static int rcu_dynticks_snap(struct rcu_data *rdp) { - return atomic_add_return(0, &rdp->dynticks); + smp_mb(); // Fundamental RCU ordering guarantee. + return atomic_read_acquire(&rdp->dynticks); } /* @@ -391,12 +401,12 @@ bool rcu_dynticks_zero_in_eqs(int cpu, int *vp) */ notrace void rcu_momentary_dyntick_idle(void) { - int special; + int seq; raw_cpu_write(rcu_data.rcu_need_heavy_qs, false); - special = atomic_add_return(2, &this_cpu_ptr(&rcu_data)->dynticks); + seq = rcu_dynticks_inc(2); /* It is illegal to call this from idle state. */ - WARN_ON_ONCE(!(special & 0x1)); + WARN_ON_ONCE(!(seq & 0x1)); rcu_preempt_deferred_qs(current); } EXPORT_SYMBOL_GPL(rcu_momentary_dyntick_idle); |