16 typedef void (*rcu_tasks_gp_func_t)(struct rcu_tasks *rtp);
21 typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
230 static void set_tasks_gp_state(struct rcu_tasks *rtp, int newstate)  in set_tasks_gp_state()  argument
232 	rtp->gp_state = newstate;  in set_tasks_gp_state()
233 	rtp->gp_jiffies = jiffies;  in set_tasks_gp_state()
238 static const char *tasks_gp_state_getname(struct rcu_tasks *rtp)  in tasks_gp_state_getname()  argument
240 	int i = data_race(rtp->gp_state); // Let KCSAN detect update races  in tasks_gp_state_getname()
251 static void cblist_init_generic(struct rcu_tasks *rtp)  in cblist_init_generic()  argument
267 	rtp->rtpcp_array = kcalloc(num_possible_cpus(), sizeof(struct rcu_tasks_percpu *), GFP_KERNEL);  in cblist_init_generic()
268 	BUG_ON(!rtp->rtpcp_array);  in cblist_init_generic()
271 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in cblist_init_generic()
280 		rtpcp->rtpp = rtp;  in cblist_init_generic()
282 		rtp->rtpcp_array[index] = rtpcp;  in cblist_init_generic()
298 	WRITE_ONCE(rtp->percpu_enqueue_shift, shift);  in cblist_init_generic()
299 	WRITE_ONCE(rtp->percpu_dequeue_lim, lim);  in cblist_init_generic()
300 	smp_store_release(&rtp->percpu_enqueue_lim, lim);  in cblist_init_generic()
303 			rtp->name, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim),  in cblist_init_generic()
308 static unsigned long rcu_tasks_lazy_time(struct rcu_tasks *rtp)  in rcu_tasks_lazy_time()  argument
310 	return jiffies + rtp->lazy_jiffies;  in rcu_tasks_lazy_time()
318 	struct rcu_tasks *rtp;  in call_rcu_tasks_generic_timer()  local
321 	rtp = rtpcp->rtpp;  in call_rcu_tasks_generic_timer()
323 	if (!rcu_segcblist_empty(&rtpcp->cblist) && rtp->lazy_jiffies) {  in call_rcu_tasks_generic_timer()
327 		mod_timer(&rtpcp->lazy_timer, rcu_tasks_lazy_time(rtp));  in call_rcu_tasks_generic_timer()
331 		rcuwait_wake_up(&rtp->cbs_wait);  in call_rcu_tasks_generic_timer()
337 	struct rcu_tasks *rtp;  in call_rcu_tasks_iw_wakeup()  local
340 	rtp = rtpcp->rtpp;  in call_rcu_tasks_iw_wakeup()
341 	rcuwait_wake_up(&rtp->cbs_wait);  in call_rcu_tasks_iw_wakeup()
346 				   struct rcu_tasks *rtp)  in call_rcu_tasks_generic()  argument
350 	bool havekthread = smp_load_acquire(&rtp->kthread_ptr);  in call_rcu_tasks_generic()
361 	ideal_cpu = smp_processor_id() >> READ_ONCE(rtp->percpu_enqueue_shift);  in call_rcu_tasks_generic()
364 	rtpcp = per_cpu_ptr(rtp->rtpcpu, chosen_cpu);  in call_rcu_tasks_generic()
373 		    READ_ONCE(rtp->percpu_enqueue_lim) != rcu_task_cpu_ids)  in call_rcu_tasks_generic()
382 		if (rtp->lazy_jiffies)  in call_rcu_tasks_generic()
383 			mod_timer(&rtpcp->lazy_timer, rcu_tasks_lazy_time(rtp));  in call_rcu_tasks_generic()
392 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in call_rcu_tasks_generic()
393 		if (rtp->percpu_enqueue_lim != rcu_task_cpu_ids) {  in call_rcu_tasks_generic()
394 			WRITE_ONCE(rtp->percpu_enqueue_shift, 0);  in call_rcu_tasks_generic()
395 			WRITE_ONCE(rtp->percpu_dequeue_lim, rcu_task_cpu_ids);  in call_rcu_tasks_generic()
396 			smp_store_release(&rtp->percpu_enqueue_lim, rcu_task_cpu_ids);  in call_rcu_tasks_generic()
397 			pr_info("Switching %s to per-CPU callback queuing.\n", rtp->name);  in call_rcu_tasks_generic()
399 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in call_rcu_tasks_generic()
403 	if (needwake && READ_ONCE(rtp->kthread_ptr))  in call_rcu_tasks_generic()
410 	struct rcu_tasks *rtp;  in rcu_barrier_tasks_generic_cb()  local
415 	rtp = rtpcp->rtpp;  in rcu_barrier_tasks_generic_cb()
416 	if (atomic_dec_and_test(&rtp->barrier_q_count))  in rcu_barrier_tasks_generic_cb()
417 		complete(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic_cb()
422 static void __maybe_unused rcu_barrier_tasks_generic(struct rcu_tasks *rtp)  in rcu_barrier_tasks_generic()  argument
427 	unsigned long s = rcu_seq_snap(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
429 	mutex_lock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
430 	if (rcu_seq_done(&rtp->barrier_q_seq, s)) {  in rcu_barrier_tasks_generic()
432 		mutex_unlock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
435 	rtp->barrier_q_start = jiffies;  in rcu_barrier_tasks_generic()
436 	rcu_seq_start(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
437 	init_completion(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
438 	atomic_set(&rtp->barrier_q_count, 2);  in rcu_barrier_tasks_generic()
440 		if (cpu >= smp_load_acquire(&rtp->percpu_dequeue_lim))  in rcu_barrier_tasks_generic()
442 		rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_barrier_tasks_generic()
446 			atomic_inc(&rtp->barrier_q_count);  in rcu_barrier_tasks_generic()
449 	if (atomic_sub_and_test(2, &rtp->barrier_q_count))  in rcu_barrier_tasks_generic()
450 		complete(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
451 	wait_for_completion(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
452 	rcu_seq_end(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
453 	mutex_unlock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
458 static int rcu_tasks_need_gpcb(struct rcu_tasks *rtp)  in rcu_tasks_need_gpcb()  argument
463 	bool gpdone = poll_state_synchronize_rcu(rtp->percpu_dequeue_gpseq);  in rcu_tasks_need_gpcb()
469 	dequeue_limit = smp_load_acquire(&rtp->percpu_dequeue_lim);  in rcu_tasks_need_gpcb()
473 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_need_gpcb()
486 		rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));  in rcu_tasks_need_gpcb()
487 		(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));  in rcu_tasks_need_gpcb()
489 			if (rtp->lazy_jiffies)  in rcu_tasks_need_gpcb()
508 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
509 		if (rtp->percpu_enqueue_lim > 1) {  in rcu_tasks_need_gpcb()
510 			WRITE_ONCE(rtp->percpu_enqueue_shift, order_base_2(rcu_task_cpu_ids));  in rcu_tasks_need_gpcb()
511 			smp_store_release(&rtp->percpu_enqueue_lim, 1);  in rcu_tasks_need_gpcb()
512 			rtp->percpu_dequeue_gpseq = get_state_synchronize_rcu();  in rcu_tasks_need_gpcb()
514 			pr_info("Starting switch %s to CPU-0 callback queuing.\n", rtp->name);  in rcu_tasks_need_gpcb()
516 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
519 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
520 		if (rtp->percpu_enqueue_lim < rtp->percpu_dequeue_lim) {  in rcu_tasks_need_gpcb()
521 			WRITE_ONCE(rtp->percpu_dequeue_lim, 1);  in rcu_tasks_need_gpcb()
522 			pr_info("Completing switch %s to CPU-0 callback queuing.\n", rtp->name);  in rcu_tasks_need_gpcb()
524 		if (rtp->percpu_dequeue_lim == 1) {  in rcu_tasks_need_gpcb()
525 			for (cpu = rtp->percpu_dequeue_lim; cpu < rcu_task_cpu_ids; cpu++) {  in rcu_tasks_need_gpcb()
528 				struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_need_gpcb()
533 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
540 static void rcu_tasks_invoke_cbs(struct rcu_tasks *rtp, struct rcu_tasks_percpu *rtpcp)  in rcu_tasks_invoke_cbs()  argument
552 		rtpcp_next = rtp->rtpcp_array[index];  in rcu_tasks_invoke_cbs()
553 		if (rtpcp_next->cpu < smp_load_acquire(&rtp->percpu_dequeue_lim)) {  in rcu_tasks_invoke_cbs()
558 				rtpcp_next = rtp->rtpcp_array[index];  in rcu_tasks_invoke_cbs()
559 				if (rtpcp_next->cpu < smp_load_acquire(&rtp->percpu_dequeue_lim)) {  in rcu_tasks_invoke_cbs()
570 	rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));  in rcu_tasks_invoke_cbs()
583 	(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));  in rcu_tasks_invoke_cbs()
590 	struct rcu_tasks *rtp;  in rcu_tasks_invoke_cbs_wq()  local
593 	rtp = rtpcp->rtpp;  in rcu_tasks_invoke_cbs_wq()
594 	rcu_tasks_invoke_cbs(rtp, rtpcp);  in rcu_tasks_invoke_cbs_wq()
598 static void rcu_tasks_one_gp(struct rcu_tasks *rtp, bool midboot)  in rcu_tasks_one_gp()  argument
602 	mutex_lock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
608 		mutex_unlock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
609 		set_tasks_gp_state(rtp, RTGS_WAIT_CBS);  in rcu_tasks_one_gp()
610 		rcuwait_wait_event(&rtp->cbs_wait,  in rcu_tasks_one_gp()
611 				   (needgpcb = rcu_tasks_need_gpcb(rtp)),  in rcu_tasks_one_gp()
613 		mutex_lock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
618 		set_tasks_gp_state(rtp, RTGS_WAIT_GP);  in rcu_tasks_one_gp()
619 		rtp->gp_start = jiffies;  in rcu_tasks_one_gp()
620 		rcu_seq_start(&rtp->tasks_gp_seq);  in rcu_tasks_one_gp()
621 		rtp->gp_func(rtp);  in rcu_tasks_one_gp()
622 		rcu_seq_end(&rtp->tasks_gp_seq);  in rcu_tasks_one_gp()
626 	set_tasks_gp_state(rtp, RTGS_INVOKE_CBS);  in rcu_tasks_one_gp()
627 	rcu_tasks_invoke_cbs(rtp, per_cpu_ptr(rtp->rtpcpu, 0));  in rcu_tasks_one_gp()
628 	mutex_unlock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
635 	struct rcu_tasks *rtp = arg;  in rcu_tasks_kthread()  local
638 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_kthread()
646 	smp_store_release(&rtp->kthread_ptr, current); // Let GPs start!  in rcu_tasks_kthread()
657 		rcu_tasks_one_gp(rtp, false);  in rcu_tasks_kthread()
660 		schedule_timeout_idle(rtp->gp_sleep);  in rcu_tasks_kthread()
665 static void synchronize_rcu_tasks_generic(struct rcu_tasks *rtp)  in synchronize_rcu_tasks_generic()  argument
669 			 "synchronize_%s() called too soon", rtp->name))  in synchronize_rcu_tasks_generic()
673 	if (READ_ONCE(rtp->kthread_ptr)) {  in synchronize_rcu_tasks_generic()
674 		wait_rcu_gp_state(rtp->wait_state, rtp->call_func);  in synchronize_rcu_tasks_generic()
677 	rcu_tasks_one_gp(rtp, true);  in synchronize_rcu_tasks_generic()
681 static void __init rcu_spawn_tasks_kthread_generic(struct rcu_tasks *rtp)  in rcu_spawn_tasks_kthread_generic()  argument
685 	t = kthread_run(rcu_tasks_kthread, rtp, "%s_kthread", rtp->kname);  in rcu_spawn_tasks_kthread_generic()
686 …%s: Could not start %s grace-period kthread, OOM is now expected behavior\n", __func__, rtp->name))  in rcu_spawn_tasks_kthread_generic()
722 static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)  in show_rcu_tasks_generic_gp_kthread()  argument
730 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in show_rcu_tasks_generic_gp_kthread()
742 		rtp->kname,  in show_rcu_tasks_generic_gp_kthread()
743 		tasks_gp_state_getname(rtp), data_race(rtp->gp_state),  in show_rcu_tasks_generic_gp_kthread()
744 		jiffies - data_race(rtp->gp_jiffies),  in show_rcu_tasks_generic_gp_kthread()
745 		data_race(rcu_seq_current(&rtp->tasks_gp_seq)),  in show_rcu_tasks_generic_gp_kthread()
746 		data_race(rtp->n_ipis_fails), data_race(rtp->n_ipis),  in show_rcu_tasks_generic_gp_kthread()
747 		".k"[!!data_race(rtp->kthread_ptr)],  in show_rcu_tasks_generic_gp_kthread()
751 		rtp->lazy_jiffies,  in show_rcu_tasks_generic_gp_kthread()
756 static void rcu_tasks_torture_stats_print_generic(struct rcu_tasks *rtp, char *tt,  in rcu_tasks_torture_stats_print_generic()  argument
765 		 tt, tf, tst, data_race(rtp->tasks_gp_seq),  in rcu_tasks_torture_stats_print_generic()
766 		 j - data_race(rtp->gp_start), j - data_race(rtp->gp_jiffies),  in rcu_tasks_torture_stats_print_generic()
767 		 data_race(rtp->gp_state), tasks_gp_state_getname(rtp));  in rcu_tasks_torture_stats_print_generic()
769 		 data_race(rtp->percpu_enqueue_shift),  in rcu_tasks_torture_stats_print_generic()
770 		 data_race(rtp->percpu_enqueue_lim),  in rcu_tasks_torture_stats_print_generic()
771 		 data_race(rtp->percpu_dequeue_lim),  in rcu_tasks_torture_stats_print_generic()
772 		 data_race(rtp->percpu_dequeue_gpseq));  in rcu_tasks_torture_stats_print_generic()
777 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_torture_stats_print_generic()
792 		 data_race(rtp->barrier_q_seq), j - data_race(rtp->barrier_q_start),  in rcu_tasks_torture_stats_print_generic()
793 		 atomic_read(&rtp->barrier_q_count));  in rcu_tasks_torture_stats_print_generic()
812 static void rcu_tasks_wait_gp(struct rcu_tasks *rtp)  in rcu_tasks_wait_gp()  argument
824 	set_tasks_gp_state(rtp, RTGS_PRE_WAIT_GP);  in rcu_tasks_wait_gp()
825 	rtp->pregp_func(&holdouts);  in rcu_tasks_wait_gp()
833 	set_tasks_gp_state(rtp, RTGS_SCAN_TASKLIST);  in rcu_tasks_wait_gp()
834 	if (rtp->pertask_func) {  in rcu_tasks_wait_gp()
837 			rtp->pertask_func(t, &holdouts);  in rcu_tasks_wait_gp()
841 	set_tasks_gp_state(rtp, RTGS_POST_SCAN_TASKLIST);  in rcu_tasks_wait_gp()
842 	rtp->postscan_func(&holdouts);  in rcu_tasks_wait_gp()
854 	fract = rtp->init_fract;  in rcu_tasks_wait_gp()
863 		set_tasks_gp_state(rtp, RTGS_WAIT_SCAN_HOLDOUTS);  in rcu_tasks_wait_gp()
883 		set_tasks_gp_state(rtp, RTGS_SCAN_HOLDOUTS);  in rcu_tasks_wait_gp()
884 		rtp->holdouts_func(&holdouts, needreport, &firstreport);  in rcu_tasks_wait_gp()
892 				__func__, rtp->kname, rtp->tasks_gp_seq, j - rtp->gp_start);  in rcu_tasks_wait_gp()
896 	set_tasks_gp_state(rtp, RTGS_POST_GP);  in rcu_tasks_wait_gp()
897 	rtp->postgp_func(rtp);  in rcu_tasks_wait_gp()
1137 static void rcu_tasks_postgp(struct rcu_tasks *rtp)  in rcu_tasks_postgp()  argument
1354 static void rcu_tasks_rude_wait_gp(struct rcu_tasks *rtp)  in rcu_tasks_rude_wait_gp()  argument
1356 	rtp->n_ipis += cpumask_weight(cpu_online_mask);  in rcu_tasks_rude_wait_gp()
1971 static void rcu_tasks_trace_postgp(struct rcu_tasks *rtp)  in rcu_tasks_trace_postgp()  argument