16 typedef void (*rcu_tasks_gp_func_t)(struct rcu_tasks *rtp);
21 typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
225 static void set_tasks_gp_state(struct rcu_tasks *rtp, int newstate)  in set_tasks_gp_state()  argument
227 	rtp->gp_state = newstate;  in set_tasks_gp_state()
228 	rtp->gp_jiffies = jiffies;  in set_tasks_gp_state()
233 static const char *tasks_gp_state_getname(struct rcu_tasks *rtp)  in tasks_gp_state_getname()  argument
235 	int i = data_race(rtp->gp_state); // Let KCSAN detect update races  in tasks_gp_state_getname()
246 static void cblist_init_generic(struct rcu_tasks *rtp)  in cblist_init_generic()  argument
262 	rtp->rtpcp_array = kzalloc_objs(struct rcu_tasks_percpu *,  in cblist_init_generic()
264 	BUG_ON(!rtp->rtpcp_array);  in cblist_init_generic()
267 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in cblist_init_generic()
276 		rtpcp->rtpp = rtp;  in cblist_init_generic()
278 		rtp->rtpcp_array[index] = rtpcp;  in cblist_init_generic()
294 	WRITE_ONCE(rtp->percpu_enqueue_shift, shift);  in cblist_init_generic()
295 	WRITE_ONCE(rtp->percpu_dequeue_lim, lim);  in cblist_init_generic()
296 	smp_store_release(&rtp->percpu_enqueue_lim, lim);  in cblist_init_generic()
299 			rtp->name, data_race(rtp->percpu_enqueue_shift), data_race(rtp->percpu_enqueue_lim),  in cblist_init_generic()
304 static unsigned long rcu_tasks_lazy_time(struct rcu_tasks *rtp)  in rcu_tasks_lazy_time()  argument
306 	return jiffies + rtp->lazy_jiffies;  in rcu_tasks_lazy_time()
314 	struct rcu_tasks *rtp;  in call_rcu_tasks_generic_timer()  local
318 	rtp = rtpcp->rtpp;  in call_rcu_tasks_generic_timer()
320 	if (!rcu_segcblist_empty(&rtpcp->cblist) && rtp->lazy_jiffies) {  in call_rcu_tasks_generic_timer()
324 		mod_timer(&rtpcp->lazy_timer, rcu_tasks_lazy_time(rtp));  in call_rcu_tasks_generic_timer()
328 		rcuwait_wake_up(&rtp->cbs_wait);  in call_rcu_tasks_generic_timer()
334 	struct rcu_tasks *rtp;  in call_rcu_tasks_iw_wakeup()  local
337 	rtp = rtpcp->rtpp;  in call_rcu_tasks_iw_wakeup()
338 	rcuwait_wake_up(&rtp->cbs_wait);  in call_rcu_tasks_iw_wakeup()
343 				   struct rcu_tasks *rtp)  in call_rcu_tasks_generic()  argument
347 	bool havekthread = smp_load_acquire(&rtp->kthread_ptr);  in call_rcu_tasks_generic()
358 	ideal_cpu = smp_processor_id() >> READ_ONCE(rtp->percpu_enqueue_shift);  in call_rcu_tasks_generic()
361 	rtpcp = per_cpu_ptr(rtp->rtpcpu, chosen_cpu);  in call_rcu_tasks_generic()
370 		    READ_ONCE(rtp->percpu_enqueue_lim) != rcu_task_cpu_ids)  in call_rcu_tasks_generic()
379 		if (rtp->lazy_jiffies)  in call_rcu_tasks_generic()
380 			mod_timer(&rtpcp->lazy_timer, rcu_tasks_lazy_time(rtp));  in call_rcu_tasks_generic()
389 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in call_rcu_tasks_generic()
390 		if (rtp->percpu_enqueue_lim != rcu_task_cpu_ids) {  in call_rcu_tasks_generic()
391 			WRITE_ONCE(rtp->percpu_enqueue_shift, 0);  in call_rcu_tasks_generic()
392 			WRITE_ONCE(rtp->percpu_dequeue_lim, rcu_task_cpu_ids);  in call_rcu_tasks_generic()
393 			smp_store_release(&rtp->percpu_enqueue_lim, rcu_task_cpu_ids);  in call_rcu_tasks_generic()
394 			pr_info("Switching %s to per-CPU callback queuing.\n", rtp->name);  in call_rcu_tasks_generic()
396 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in call_rcu_tasks_generic()
400 	if (needwake && READ_ONCE(rtp->kthread_ptr))  in call_rcu_tasks_generic()
407 	struct rcu_tasks *rtp;  in rcu_barrier_tasks_generic_cb()  local
412 	rtp = rtpcp->rtpp;  in rcu_barrier_tasks_generic_cb()
413 	if (atomic_dec_and_test(&rtp->barrier_q_count))  in rcu_barrier_tasks_generic_cb()
414 		complete(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic_cb()
419 static void __maybe_unused rcu_barrier_tasks_generic(struct rcu_tasks *rtp)  in rcu_barrier_tasks_generic()  argument
424 	unsigned long s = rcu_seq_snap(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
426 	mutex_lock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
427 	if (rcu_seq_done(&rtp->barrier_q_seq, s)) {  in rcu_barrier_tasks_generic()
429 		mutex_unlock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
432 	rtp->barrier_q_start = jiffies;  in rcu_barrier_tasks_generic()
433 	rcu_seq_start(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
434 	init_completion(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
435 	atomic_set(&rtp->barrier_q_count, 2);  in rcu_barrier_tasks_generic()
437 		if (cpu >= smp_load_acquire(&rtp->percpu_dequeue_lim))  in rcu_barrier_tasks_generic()
439 		rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_barrier_tasks_generic()
443 			atomic_inc(&rtp->barrier_q_count);  in rcu_barrier_tasks_generic()
446 	if (atomic_sub_and_test(2, &rtp->barrier_q_count))  in rcu_barrier_tasks_generic()
447 		complete(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
448 	wait_for_completion(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
449 	rcu_seq_end(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
450 	mutex_unlock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
455 static int rcu_tasks_need_gpcb(struct rcu_tasks *rtp)  in rcu_tasks_need_gpcb()  argument
460 	bool gpdone = poll_state_synchronize_rcu(rtp->percpu_dequeue_gpseq);  in rcu_tasks_need_gpcb()
466 	dequeue_limit = smp_load_acquire(&rtp->percpu_dequeue_lim);  in rcu_tasks_need_gpcb()
470 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_need_gpcb()
483 		rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));  in rcu_tasks_need_gpcb()
484 		(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));  in rcu_tasks_need_gpcb()
486 			if (rtp->lazy_jiffies)  in rcu_tasks_need_gpcb()
505 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
506 		if (rtp->percpu_enqueue_lim > 1) {  in rcu_tasks_need_gpcb()
507 			WRITE_ONCE(rtp->percpu_enqueue_shift, order_base_2(rcu_task_cpu_ids));  in rcu_tasks_need_gpcb()
508 			smp_store_release(&rtp->percpu_enqueue_lim, 1);  in rcu_tasks_need_gpcb()
509 			rtp->percpu_dequeue_gpseq = get_state_synchronize_rcu();  in rcu_tasks_need_gpcb()
511 			pr_info("Starting switch %s to CPU-0 callback queuing.\n", rtp->name);  in rcu_tasks_need_gpcb()
513 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
516 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
517 		if (rtp->percpu_enqueue_lim < rtp->percpu_dequeue_lim) {  in rcu_tasks_need_gpcb()
518 			WRITE_ONCE(rtp->percpu_dequeue_lim, 1);  in rcu_tasks_need_gpcb()
519 			pr_info("Completing switch %s to CPU-0 callback queuing.\n", rtp->name);  in rcu_tasks_need_gpcb()
521 		if (rtp->percpu_dequeue_lim == 1) {  in rcu_tasks_need_gpcb()
522 			for (cpu = rtp->percpu_dequeue_lim; cpu < rcu_task_cpu_ids; cpu++) {  in rcu_tasks_need_gpcb()
525 				struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_need_gpcb()
530 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
537 static void rcu_tasks_invoke_cbs(struct rcu_tasks *rtp, struct rcu_tasks_percpu *rtpcp)  in rcu_tasks_invoke_cbs()  argument
549 		rtpcp_next = rtp->rtpcp_array[index];  in rcu_tasks_invoke_cbs()
550 		if (rtpcp_next->cpu < smp_load_acquire(&rtp->percpu_dequeue_lim)) {  in rcu_tasks_invoke_cbs()
555 				rtpcp_next = rtp->rtpcp_array[index];  in rcu_tasks_invoke_cbs()
556 				if (rtpcp_next->cpu < smp_load_acquire(&rtp->percpu_dequeue_lim)) {  in rcu_tasks_invoke_cbs()
567 	rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));  in rcu_tasks_invoke_cbs()
580 	(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));  in rcu_tasks_invoke_cbs()
587 	struct rcu_tasks *rtp;  in rcu_tasks_invoke_cbs_wq()  local
590 	rtp = rtpcp->rtpp;  in rcu_tasks_invoke_cbs_wq()
591 	rcu_tasks_invoke_cbs(rtp, rtpcp);  in rcu_tasks_invoke_cbs_wq()
595 static void rcu_tasks_one_gp(struct rcu_tasks *rtp, bool midboot)  in rcu_tasks_one_gp()  argument
599 	mutex_lock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
605 		mutex_unlock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
606 		set_tasks_gp_state(rtp, RTGS_WAIT_CBS);  in rcu_tasks_one_gp()
607 		rcuwait_wait_event(&rtp->cbs_wait,  in rcu_tasks_one_gp()
608 				   (needgpcb = rcu_tasks_need_gpcb(rtp)),  in rcu_tasks_one_gp()
610 		mutex_lock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
615 		set_tasks_gp_state(rtp, RTGS_WAIT_GP);  in rcu_tasks_one_gp()
616 		rtp->gp_start = jiffies;  in rcu_tasks_one_gp()
617 		rcu_seq_start(&rtp->tasks_gp_seq);  in rcu_tasks_one_gp()
618 		rtp->gp_func(rtp);  in rcu_tasks_one_gp()
619 		rcu_seq_end(&rtp->tasks_gp_seq);  in rcu_tasks_one_gp()
623 	set_tasks_gp_state(rtp, RTGS_INVOKE_CBS);  in rcu_tasks_one_gp()
624 	rcu_tasks_invoke_cbs(rtp, per_cpu_ptr(rtp->rtpcpu, 0));  in rcu_tasks_one_gp()
625 	mutex_unlock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
632 	struct rcu_tasks *rtp = arg;  in rcu_tasks_kthread()  local
635 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_kthread()
643 	smp_store_release(&rtp->kthread_ptr, current); // Let GPs start!  in rcu_tasks_kthread()
654 		rcu_tasks_one_gp(rtp, false);  in rcu_tasks_kthread()
657 		schedule_timeout_idle(rtp->gp_sleep);  in rcu_tasks_kthread()
662 static void synchronize_rcu_tasks_generic(struct rcu_tasks *rtp)  in synchronize_rcu_tasks_generic()  argument
666 			 "synchronize_%s() called too soon", rtp->name))  in synchronize_rcu_tasks_generic()
670 	if (READ_ONCE(rtp->kthread_ptr)) {  in synchronize_rcu_tasks_generic()
671 		wait_rcu_gp_state(rtp->wait_state, rtp->call_func);  in synchronize_rcu_tasks_generic()
674 	rcu_tasks_one_gp(rtp, true);  in synchronize_rcu_tasks_generic()
678 static void __init rcu_spawn_tasks_kthread_generic(struct rcu_tasks *rtp)  in rcu_spawn_tasks_kthread_generic()  argument
682 	t = kthread_run(rcu_tasks_kthread, rtp, "%s_kthread", rtp->kname);  in rcu_spawn_tasks_kthread_generic()
683 …%s: Could not start %s grace-period kthread, OOM is now expected behavior\n", __func__, rtp->name))  in rcu_spawn_tasks_kthread_generic()
718 static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)  in show_rcu_tasks_generic_gp_kthread()  argument
726 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in show_rcu_tasks_generic_gp_kthread()
738 		rtp->kname,  in show_rcu_tasks_generic_gp_kthread()
739 		tasks_gp_state_getname(rtp), data_race(rtp->gp_state),  in show_rcu_tasks_generic_gp_kthread()
740 		jiffies - data_race(rtp->gp_jiffies),  in show_rcu_tasks_generic_gp_kthread()
741 		data_race(rcu_seq_current(&rtp->tasks_gp_seq)),  in show_rcu_tasks_generic_gp_kthread()
742 		data_race(rtp->n_ipis_fails), data_race(rtp->n_ipis),  in show_rcu_tasks_generic_gp_kthread()
743 		".k"[!!data_race(rtp->kthread_ptr)],  in show_rcu_tasks_generic_gp_kthread()
747 		rtp->lazy_jiffies,  in show_rcu_tasks_generic_gp_kthread()
752 static void rcu_tasks_torture_stats_print_generic(struct rcu_tasks *rtp, char *tt,  in rcu_tasks_torture_stats_print_generic()  argument
761 		 tt, tf, tst, data_race(rtp->tasks_gp_seq),  in rcu_tasks_torture_stats_print_generic()
762 		 j - data_race(rtp->gp_start), j - data_race(rtp->gp_jiffies),  in rcu_tasks_torture_stats_print_generic()
763 		 data_race(rtp->gp_state), tasks_gp_state_getname(rtp));  in rcu_tasks_torture_stats_print_generic()
765 		 data_race(rtp->percpu_enqueue_shift),  in rcu_tasks_torture_stats_print_generic()
766 		 data_race(rtp->percpu_enqueue_lim),  in rcu_tasks_torture_stats_print_generic()
767 		 data_race(rtp->percpu_dequeue_lim),  in rcu_tasks_torture_stats_print_generic()
768 		 data_race(rtp->percpu_dequeue_gpseq));  in rcu_tasks_torture_stats_print_generic()
773 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_torture_stats_print_generic()
788 		 data_race(rtp->barrier_q_seq), j - data_race(rtp->barrier_q_start),  in rcu_tasks_torture_stats_print_generic()
789 		 atomic_read(&rtp->barrier_q_count));  in rcu_tasks_torture_stats_print_generic()
806 static void rcu_tasks_wait_gp(struct rcu_tasks *rtp)  in rcu_tasks_wait_gp()  argument
818 	set_tasks_gp_state(rtp, RTGS_PRE_WAIT_GP);  in rcu_tasks_wait_gp()
819 	rtp->pregp_func(&holdouts);  in rcu_tasks_wait_gp()
827 	set_tasks_gp_state(rtp, RTGS_SCAN_TASKLIST);  in rcu_tasks_wait_gp()
828 	if (rtp->pertask_func) {  in rcu_tasks_wait_gp()
831 			rtp->pertask_func(t, &holdouts);  in rcu_tasks_wait_gp()
835 	set_tasks_gp_state(rtp, RTGS_POST_SCAN_TASKLIST);  in rcu_tasks_wait_gp()
836 	rtp->postscan_func(&holdouts);  in rcu_tasks_wait_gp()
848 	fract = rtp->init_fract;  in rcu_tasks_wait_gp()
857 		set_tasks_gp_state(rtp, RTGS_WAIT_SCAN_HOLDOUTS);  in rcu_tasks_wait_gp()
877 		set_tasks_gp_state(rtp, RTGS_SCAN_HOLDOUTS);  in rcu_tasks_wait_gp()
878 		rtp->holdouts_func(&holdouts, needreport, &firstreport);  in rcu_tasks_wait_gp()
886 				__func__, rtp->kname, rtp->tasks_gp_seq, j - rtp->gp_start);  in rcu_tasks_wait_gp()
890 	set_tasks_gp_state(rtp, RTGS_POST_GP);  in rcu_tasks_wait_gp()
891 	rtp->postgp_func(rtp);  in rcu_tasks_wait_gp()
1131 static void rcu_tasks_postgp(struct rcu_tasks *rtp)  in rcu_tasks_postgp()  argument
1346 static void rcu_tasks_rude_wait_gp(struct rcu_tasks *rtp)  in rcu_tasks_rude_wait_gp()  argument
1348 	rtp->n_ipis += cpumask_weight(cpu_online_mask);  in rcu_tasks_rude_wait_gp()