16 typedef void (*rcu_tasks_gp_func_t)(struct rcu_tasks *rtp);
21 typedef void (*postgp_func_t)(struct rcu_tasks *rtp);
204 static void set_tasks_gp_state(struct rcu_tasks *rtp, int newstate)  in set_tasks_gp_state()  argument
206 	rtp->gp_state = newstate;  in set_tasks_gp_state()
207 	rtp->gp_jiffies = jiffies;  in set_tasks_gp_state()
212 static const char *tasks_gp_state_getname(struct rcu_tasks *rtp)  in tasks_gp_state_getname()  argument
214 	int i = data_race(rtp->gp_state); // Let KCSAN detect update races  in tasks_gp_state_getname()
225 static void cblist_init_generic(struct rcu_tasks *rtp)  in cblist_init_generic()  argument
232 	raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in cblist_init_generic()
247 	WRITE_ONCE(rtp->percpu_enqueue_shift, shift);  in cblist_init_generic()
248 	WRITE_ONCE(rtp->percpu_dequeue_lim, lim);  in cblist_init_generic()
249 	smp_store_release(&rtp->percpu_enqueue_lim, lim);  in cblist_init_generic()
251 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in cblist_init_generic()
261 		rtpcp->rtpp = rtp;  in cblist_init_generic()
266 	raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in cblist_init_generic()
267 …ting shift to %d and lim to %d.\n", __func__, data_race(rtp->percpu_enqueue_shift), data_race(rtp-…  in cblist_init_generic()
273 	struct rcu_tasks *rtp;  in call_rcu_tasks_iw_wakeup()  local
276 	rtp = rtpcp->rtpp;  in call_rcu_tasks_iw_wakeup()
277 	rcuwait_wake_up(&rtp->cbs_wait);  in call_rcu_tasks_iw_wakeup()
282 				   struct rcu_tasks *rtp)  in call_rcu_tasks_generic()  argument
296 	ideal_cpu = smp_processor_id() >> READ_ONCE(rtp->percpu_enqueue_shift);  in call_rcu_tasks_generic()
298 	rtpcp = per_cpu_ptr(rtp->rtpcpu, chosen_cpu);  in call_rcu_tasks_generic()
307 		    READ_ONCE(rtp->percpu_enqueue_lim) != nr_cpu_ids)  in call_rcu_tasks_generic()
312 		cblist_init_generic(rtp);  in call_rcu_tasks_generic()
319 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in call_rcu_tasks_generic()
320 		if (rtp->percpu_enqueue_lim != nr_cpu_ids) {  in call_rcu_tasks_generic()
321 			WRITE_ONCE(rtp->percpu_enqueue_shift, 0);  in call_rcu_tasks_generic()
322 			WRITE_ONCE(rtp->percpu_dequeue_lim, nr_cpu_ids);  in call_rcu_tasks_generic()
323 			smp_store_release(&rtp->percpu_enqueue_lim, nr_cpu_ids);  in call_rcu_tasks_generic()
324 			pr_info("Switching %s to per-CPU callback queuing.\n", rtp->name);  in call_rcu_tasks_generic()
326 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in call_rcu_tasks_generic()
330 	if (needwake && READ_ONCE(rtp->kthread_ptr))  in call_rcu_tasks_generic()
337 	struct rcu_tasks *rtp;  in rcu_barrier_tasks_generic_cb()  local
341 	rtp = rtpcp->rtpp;  in rcu_barrier_tasks_generic_cb()
342 	if (atomic_dec_and_test(&rtp->barrier_q_count))  in rcu_barrier_tasks_generic_cb()
343 		complete(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic_cb()
348 static void rcu_barrier_tasks_generic(struct rcu_tasks *rtp)  in rcu_barrier_tasks_generic()  argument
353 	unsigned long s = rcu_seq_snap(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
355 	mutex_lock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
356 	if (rcu_seq_done(&rtp->barrier_q_seq, s)) {  in rcu_barrier_tasks_generic()
358 		mutex_unlock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
361 	rcu_seq_start(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
362 	init_completion(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
363 	atomic_set(&rtp->barrier_q_count, 2);  in rcu_barrier_tasks_generic()
365 		if (cpu >= smp_load_acquire(&rtp->percpu_dequeue_lim))  in rcu_barrier_tasks_generic()
367 		rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_barrier_tasks_generic()
371 			atomic_inc(&rtp->barrier_q_count);  in rcu_barrier_tasks_generic()
374 	if (atomic_sub_and_test(2, &rtp->barrier_q_count))  in rcu_barrier_tasks_generic()
375 		complete(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
376 	wait_for_completion(&rtp->barrier_q_completion);  in rcu_barrier_tasks_generic()
377 	rcu_seq_end(&rtp->barrier_q_seq);  in rcu_barrier_tasks_generic()
378 	mutex_unlock(&rtp->barrier_q_mutex);  in rcu_barrier_tasks_generic()
383 static int rcu_tasks_need_gpcb(struct rcu_tasks *rtp)  in rcu_tasks_need_gpcb()  argument
392 	for (cpu = 0; cpu < smp_load_acquire(&rtp->percpu_dequeue_lim); cpu++) {  in rcu_tasks_need_gpcb()
393 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_need_gpcb()
406 		rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));  in rcu_tasks_need_gpcb()
407 		(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));  in rcu_tasks_need_gpcb()
423 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
424 		if (rtp->percpu_enqueue_lim > 1) {  in rcu_tasks_need_gpcb()
425 			WRITE_ONCE(rtp->percpu_enqueue_shift, order_base_2(nr_cpu_ids));  in rcu_tasks_need_gpcb()
426 			smp_store_release(&rtp->percpu_enqueue_lim, 1);  in rcu_tasks_need_gpcb()
427 			rtp->percpu_dequeue_gpseq = get_state_synchronize_rcu();  in rcu_tasks_need_gpcb()
428 			pr_info("Starting switch %s to CPU-0 callback queuing.\n", rtp->name);  in rcu_tasks_need_gpcb()
430 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
433 	    poll_state_synchronize_rcu(rtp->percpu_dequeue_gpseq)) {  in rcu_tasks_need_gpcb()
434 		raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
435 		if (rtp->percpu_enqueue_lim < rtp->percpu_dequeue_lim) {  in rcu_tasks_need_gpcb()
436 			WRITE_ONCE(rtp->percpu_dequeue_lim, 1);  in rcu_tasks_need_gpcb()
437 			pr_info("Completing switch %s to CPU-0 callback queuing.\n", rtp->name);  in rcu_tasks_need_gpcb()
439 		for (cpu = rtp->percpu_dequeue_lim; cpu < nr_cpu_ids; cpu++) {  in rcu_tasks_need_gpcb()
440 			struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in rcu_tasks_need_gpcb()
444 		raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags);  in rcu_tasks_need_gpcb()
451 static void rcu_tasks_invoke_cbs(struct rcu_tasks *rtp, struct rcu_tasks_percpu *rtpcp)  in rcu_tasks_invoke_cbs()  argument
463 	if (cpunext < smp_load_acquire(&rtp->percpu_dequeue_lim)) {  in rcu_tasks_invoke_cbs()
464 		rtpcp_next = per_cpu_ptr(rtp->rtpcpu, cpunext);  in rcu_tasks_invoke_cbs()
467 		if (cpunext < smp_load_acquire(&rtp->percpu_dequeue_lim)) {  in rcu_tasks_invoke_cbs()
468 			rtpcp_next = per_cpu_ptr(rtp->rtpcpu, cpunext);  in rcu_tasks_invoke_cbs()
476 	rcu_segcblist_advance(&rtpcp->cblist, rcu_seq_current(&rtp->tasks_gp_seq));  in rcu_tasks_invoke_cbs()
488 	(void)rcu_segcblist_accelerate(&rtpcp->cblist, rcu_seq_snap(&rtp->tasks_gp_seq));  in rcu_tasks_invoke_cbs()
495 	struct rcu_tasks *rtp;  in rcu_tasks_invoke_cbs_wq()  local
498 	rtp = rtpcp->rtpp;  in rcu_tasks_invoke_cbs_wq()
499 	rcu_tasks_invoke_cbs(rtp, rtpcp);  in rcu_tasks_invoke_cbs_wq()
503 static void rcu_tasks_one_gp(struct rcu_tasks *rtp, bool midboot)  in rcu_tasks_one_gp()  argument
507 	mutex_lock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
513 		set_tasks_gp_state(rtp, RTGS_WAIT_CBS);  in rcu_tasks_one_gp()
514 		rcuwait_wait_event(&rtp->cbs_wait,  in rcu_tasks_one_gp()
515 				   (needgpcb = rcu_tasks_need_gpcb(rtp)),  in rcu_tasks_one_gp()
521 		set_tasks_gp_state(rtp, RTGS_WAIT_GP);  in rcu_tasks_one_gp()
522 		rtp->gp_start = jiffies;  in rcu_tasks_one_gp()
523 		rcu_seq_start(&rtp->tasks_gp_seq);  in rcu_tasks_one_gp()
524 		rtp->gp_func(rtp);  in rcu_tasks_one_gp()
525 		rcu_seq_end(&rtp->tasks_gp_seq);  in rcu_tasks_one_gp()
529 	set_tasks_gp_state(rtp, RTGS_INVOKE_CBS);  in rcu_tasks_one_gp()
530 	rcu_tasks_invoke_cbs(rtp, per_cpu_ptr(rtp->rtpcpu, 0));  in rcu_tasks_one_gp()
531 	mutex_unlock(&rtp->tasks_gp_mutex);  in rcu_tasks_one_gp()
537 	struct rcu_tasks *rtp = arg;  in rcu_tasks_kthread()  local
541 	WRITE_ONCE(rtp->kthread_ptr, current); // Let GPs start!  in rcu_tasks_kthread()
552 		rcu_tasks_one_gp(rtp, false);  in rcu_tasks_kthread()
555 		schedule_timeout_idle(rtp->gp_sleep);  in rcu_tasks_kthread()
560 static void synchronize_rcu_tasks_generic(struct rcu_tasks *rtp)  in synchronize_rcu_tasks_generic()  argument
567 	if (READ_ONCE(rtp->kthread_ptr)) {  in synchronize_rcu_tasks_generic()
568 		wait_rcu_gp(rtp->call_func);  in synchronize_rcu_tasks_generic()
571 	rcu_tasks_one_gp(rtp, true);  in synchronize_rcu_tasks_generic()
575 static void __init rcu_spawn_tasks_kthread_generic(struct rcu_tasks *rtp)  in rcu_spawn_tasks_kthread_generic()  argument
579 	t = kthread_run(rcu_tasks_kthread, rtp, "%s_kthread", rtp->kname);  in rcu_spawn_tasks_kthread_generic()
580 …%s: Could not start %s grace-period kthread, OOM is now expected behavior\n", __func__, rtp->name))  in rcu_spawn_tasks_kthread_generic()
618 static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)  in show_rcu_tasks_generic_gp_kthread()  argument
624 		struct rcu_tasks_percpu *rtpcp = per_cpu_ptr(rtp->rtpcpu, cpu);  in show_rcu_tasks_generic_gp_kthread()
632 		rtp->kname,  in show_rcu_tasks_generic_gp_kthread()
633 		tasks_gp_state_getname(rtp), data_race(rtp->gp_state),  in show_rcu_tasks_generic_gp_kthread()
634 		jiffies - data_race(rtp->gp_jiffies),  in show_rcu_tasks_generic_gp_kthread()
635 		data_race(rcu_seq_current(&rtp->tasks_gp_seq)),  in show_rcu_tasks_generic_gp_kthread()
636 		data_race(rtp->n_ipis_fails), data_race(rtp->n_ipis),  in show_rcu_tasks_generic_gp_kthread()
637 		".k"[!!data_race(rtp->kthread_ptr)],  in show_rcu_tasks_generic_gp_kthread()
652 static void rcu_tasks_wait_gp(struct rcu_tasks *rtp)  in rcu_tasks_wait_gp()  argument
664 	set_tasks_gp_state(rtp, RTGS_PRE_WAIT_GP);  in rcu_tasks_wait_gp()
665 	rtp->pregp_func(&holdouts);  in rcu_tasks_wait_gp()
673 	set_tasks_gp_state(rtp, RTGS_SCAN_TASKLIST);  in rcu_tasks_wait_gp()
674 	if (rtp->pertask_func) {  in rcu_tasks_wait_gp()
677 			rtp->pertask_func(t, &holdouts);  in rcu_tasks_wait_gp()
681 	set_tasks_gp_state(rtp, RTGS_POST_SCAN_TASKLIST);  in rcu_tasks_wait_gp()
682 	rtp->postscan_func(&holdouts);  in rcu_tasks_wait_gp()
694 	fract = rtp->init_fract;  in rcu_tasks_wait_gp()
703 		set_tasks_gp_state(rtp, RTGS_WAIT_SCAN_HOLDOUTS);  in rcu_tasks_wait_gp()
723 		set_tasks_gp_state(rtp, RTGS_SCAN_HOLDOUTS);  in rcu_tasks_wait_gp()
724 		rtp->holdouts_func(&holdouts, needreport, &firstreport);  in rcu_tasks_wait_gp()
732 				__func__, rtp->kname, rtp->tasks_gp_seq, j - rtp->gp_start);  in rcu_tasks_wait_gp()
736 	set_tasks_gp_state(rtp, RTGS_POST_GP);  in rcu_tasks_wait_gp()
737 	rtp->postgp_func(rtp);  in rcu_tasks_wait_gp()
884 static void rcu_tasks_postgp(struct rcu_tasks *rtp)  in rcu_tasks_postgp()  argument
1037 static void rcu_tasks_rude_wait_gp(struct rcu_tasks *rtp)  in rcu_tasks_rude_wait_gp()  argument
1042 	rtp->n_ipis += cpumask_weight(cpu_online_mask);  in rcu_tasks_rude_wait_gp()
1642 static void rcu_tasks_trace_postgp(struct rcu_tasks *rtp)  in rcu_tasks_trace_postgp()  argument