diff options
Diffstat (limited to 'kernel/rcu/tree_plugin.h')
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 98 |
1 files changed, 58 insertions, 40 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 84fbee4686d3..7fd12039e512 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -182,7 +182,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) raw_lockdep_assert_held_rcu_node(rnp); WARN_ON_ONCE(rdp->mynode != rnp); - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); + WARN_ON_ONCE(!rcu_is_leaf_node(rnp)); /* * Decide where to queue the newly blocked task. In theory, @@ -384,6 +384,50 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp) } /* + * Preemptible RCU implementation for rcu_read_lock(). + * Just increment ->rcu_read_lock_nesting, shared state will be updated + * if we block. + */ +void __rcu_read_lock(void) +{ + current->rcu_read_lock_nesting++; + barrier(); /* critical section after entry code. */ +} +EXPORT_SYMBOL_GPL(__rcu_read_lock); + +/* + * Preemptible RCU implementation for rcu_read_unlock(). + * Decrement ->rcu_read_lock_nesting. If the result is zero (outermost + * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then + * invoke rcu_read_unlock_special() to clean up after a context switch + * in an RCU read-side critical section and other special cases. + */ +void __rcu_read_unlock(void) +{ + struct task_struct *t = current; + + if (t->rcu_read_lock_nesting != 1) { + --t->rcu_read_lock_nesting; + } else { + barrier(); /* critical section before exit code. */ + t->rcu_read_lock_nesting = INT_MIN; + barrier(); /* assign before ->rcu_read_unlock_special load */ + if (unlikely(READ_ONCE(t->rcu_read_unlock_special.s))) + rcu_read_unlock_special(t); + barrier(); /* ->rcu_read_unlock_special load before assign */ + t->rcu_read_lock_nesting = 0; + } +#ifdef CONFIG_PROVE_LOCKING + { + int rrln = READ_ONCE(t->rcu_read_lock_nesting); + + WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2); + } +#endif /* #ifdef CONFIG_PROVE_LOCKING */ +} +EXPORT_SYMBOL_GPL(__rcu_read_unlock); + +/* * Advance a ->blkd_tasks-list pointer to the next entry, instead * returning NULL if at the end of the list. */ @@ -489,7 +533,7 @@ void rcu_read_unlock_special(struct task_struct *t) rnp = t->rcu_blocked_node; raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ WARN_ON_ONCE(rnp != t->rcu_blocked_node); - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); + WARN_ON_ONCE(!rcu_is_leaf_node(rnp)); empty_norm = !rcu_preempt_blocked_readers_cgp(rnp); empty_exp = sync_rcu_preempt_exp_done(rnp); smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ @@ -685,15 +729,6 @@ static void rcu_preempt_check_callbacks(void) t->rcu_read_unlock_special.b.need_qs = true; } -#ifdef CONFIG_RCU_BOOST - -static void rcu_preempt_do_callbacks(void) -{ - rcu_do_batch(rcu_state_p, this_cpu_ptr(rcu_data_p)); -} - -#endif /* #ifdef CONFIG_RCU_BOOST */ - /** * call_rcu() - Queue an RCU callback for invocation after a grace period. * @head: structure to be used for queueing the RCU updates. @@ -1140,7 +1175,7 @@ static void rcu_kthread_do_work(void) { rcu_do_batch(&rcu_sched_state, this_cpu_ptr(&rcu_sched_data)); rcu_do_batch(&rcu_bh_state, this_cpu_ptr(&rcu_bh_data)); - rcu_preempt_do_callbacks(); + rcu_do_batch(&rcu_preempt_state, this_cpu_ptr(&rcu_preempt_data)); } static void rcu_cpu_kthread_setup(unsigned int cpu) @@ -1607,7 +1642,7 @@ static int rcu_oom_notify(struct notifier_block *self, for_each_online_cpu(cpu) { smp_call_function_single(cpu, rcu_oom_notify_cpu, NULL, 1); - cond_resched_rcu_qs(); + cond_resched_tasks_rcu_qs(); } /* Unconditionally decrement: no need to wake ourselves up. */ @@ -1780,19 +1815,6 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq) swake_up_all(sq); } -/* - * Set the root rcu_node structure's ->need_future_gp field - * based on the sum of those of all rcu_node structures. This does - * double-count the root rcu_node structure's requests, but this - * is necessary to handle the possibility of a rcu_nocb_kthread() - * having awakened during the time that the rcu_node structures - * were being updated for the end of the previous grace period. - */ -static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq) -{ - rnp->need_future_gp[(rnp->completed + 1) & 0x1] += nrq; -} - static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp) { return &rnp->nocb_gp_wq[rnp->completed & 0x1]; @@ -1966,7 +1988,7 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp, trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeOvf")); } else { - wake_nocb_leader_defer(rdp, RCU_NOCB_WAKE, + wake_nocb_leader_defer(rdp, RCU_NOCB_WAKE_FORCE, TPS("WakeOvfIsDeferred")); } rdp->qlen_last_fqs_check = LONG_MAX / 2; @@ -2048,7 +2070,8 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) struct rcu_node *rnp = rdp->mynode; raw_spin_lock_irqsave_rcu_node(rnp, flags); - needwake = rcu_start_future_gp(rnp, rdp, &c); + c = rcu_cbs_completed(rdp->rsp, rnp); + needwake = rcu_start_this_gp(rnp, rdp, c); raw_spin_unlock_irqrestore_rcu_node(rnp, flags); if (needwake) rcu_gp_kthread_wake(rdp->rsp); @@ -2057,7 +2080,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) * Wait for the grace period. Do so interruptibly to avoid messing * up the load average. */ - trace_rcu_future_gp(rnp, rdp, c, TPS("StartWait")); + trace_rcu_this_gp(rnp, rdp, c, TPS("StartWait")); for (;;) { swait_event_interruptible( rnp->nocb_gp_wq[c & 0x1], @@ -2065,9 +2088,9 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) if (likely(d)) break; WARN_ON(signal_pending(current)); - trace_rcu_future_gp(rnp, rdp, c, TPS("ResumeWait")); + trace_rcu_this_gp(rnp, rdp, c, TPS("ResumeWait")); } - trace_rcu_future_gp(rnp, rdp, c, TPS("EndWait")); + trace_rcu_this_gp(rnp, rdp, c, TPS("EndWait")); smp_mb(); /* Ensure that CB invocation happens after GP end. */ } @@ -2236,7 +2259,7 @@ static int rcu_nocb_kthread(void *arg) cl++; c++; local_bh_enable(); - cond_resched_rcu_qs(); + cond_resched_tasks_rcu_qs(); list = next; } trace_rcu_batch_end(rdp->rsp->name, c, !!list, 0, 0, 1); @@ -2292,7 +2315,7 @@ static void do_nocb_deferred_wakeup(struct rcu_data *rdp) void __init rcu_init_nohz(void) { int cpu; - bool need_rcu_nocb_mask = true; + bool need_rcu_nocb_mask = false; struct rcu_state *rsp; #if defined(CONFIG_NO_HZ_FULL) @@ -2315,7 +2338,7 @@ void __init rcu_init_nohz(void) #endif /* #if defined(CONFIG_NO_HZ_FULL) */ if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) { - pr_info("\tNote: kernel parameter 'rcu_nocbs=' contains nonexistent CPUs.\n"); + pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n"); cpumask_and(rcu_nocb_mask, cpu_possible_mask, rcu_nocb_mask); } @@ -2495,10 +2518,6 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq) { } -static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq) -{ -} - static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp) { return NULL; @@ -2587,8 +2606,7 @@ static bool rcu_nohz_full_cpu(struct rcu_state *rsp) } /* - * Bind the grace-period kthread for the sysidle flavor of RCU to the - * timekeeping CPU. + * Bind the RCU grace-period kthreads to the housekeeping CPU. */ static void rcu_bind_gp_kthread(void) { |