1 // SPDX-License-Identifier: GPL-2.0-only
27  * rate-limit tunable for the "low" level notification, and also for
58  * prio <= DEF_PRIORITY - 2 : kswapd becomes somewhat overwhelmed
140 	pressure = scale - (reclaimed * scale / scanned);  in vmpressure_calc_level()
164 	mutex_lock(&vmpr->events_lock);  in vmpressure_event()
165 	list_for_each_entry(ev, &vmpr->events, node) {  in vmpressure_event()
166 		if (ancestor && ev->mode == VMPRESSURE_LOCAL)  in vmpressure_event()
168 		if (signalled && ev->mode == VMPRESSURE_NO_PASSTHROUGH)  in vmpressure_event()
170 		if (level < ev->level)  in vmpressure_event()
172 		eventfd_signal(ev->efd, 1);  in vmpressure_event()
175 	mutex_unlock(&vmpr->events_lock);  in vmpressure_event()
189 	spin_lock(&vmpr->sr_lock);  in vmpressure_work_fn()
196 	 * vmpr->reclaimed is in sync.  in vmpressure_work_fn()
198 	scanned = vmpr->tree_scanned;  in vmpressure_work_fn()
200 		spin_unlock(&vmpr->sr_lock);  in vmpressure_work_fn()
204 	reclaimed = vmpr->tree_reclaimed;  in vmpressure_work_fn()
205 	vmpr->tree_scanned = 0;  in vmpressure_work_fn()
206 	vmpr->tree_reclaimed = 0;  in vmpressure_work_fn()
207 	spin_unlock(&vmpr->sr_lock);  in vmpressure_work_fn()
219  * vmpressure() - Account memory pressure through scanned/reclaimed ratio
232  * notified of the entire subtree's reclaim efficiency.
234  * If @tree is not set, reclaim efficiency is recorded for @memcg, and
235  * only in-kernel users are notified.
248 	 * The in-kernel users only care about the reclaim efficiency  in vmpressure()
250 	 * isn't and won't be any in-kernel user in a legacy cgroup.  in vmpressure()
265 	 * Indirect reclaim (kswapd) sets sc->gfp_mask to GFP_KERNEL, so  in vmpressure()
276 	 * (scanning depth) goes too high (deep), we will be notified  in vmpressure()
283 		spin_lock(&vmpr->sr_lock);  in vmpressure()
284 		scanned = vmpr->tree_scanned += scanned;  in vmpressure()
285 		vmpr->tree_reclaimed += reclaimed;  in vmpressure()
286 		spin_unlock(&vmpr->sr_lock);  in vmpressure()
290 		schedule_work(&vmpr->work);  in vmpressure()
294 		/* For now, no users for root-level efficiency */  in vmpressure()
298 		spin_lock(&vmpr->sr_lock);  in vmpressure()
299 		scanned = vmpr->scanned += scanned;  in vmpressure()
300 		reclaimed = vmpr->reclaimed += reclaimed;  in vmpressure()
302 			spin_unlock(&vmpr->sr_lock);  in vmpressure()
305 		vmpr->scanned = vmpr->reclaimed = 0;  in vmpressure()
306 		spin_unlock(&vmpr->sr_lock);  in vmpressure()
319 			WRITE_ONCE(memcg->socket_pressure, jiffies + HZ);  in vmpressure()
325  * vmpressure_prio() - Account memory pressure through reclaimer priority level
357  * vmpressure_register_event() - Bind vmpressure notifications to an eventfd
364  * @eventfd. The @args parameter is a comma-delimited string that denotes a
371  * Return: 0 on success, -ENOMEM on memory failure or -EINVAL if @args could
387 		return -ENOMEM;  in vmpressure_register_event()
407 		ret = -ENOMEM;  in vmpressure_register_event()
411 	ev->efd = eventfd;  in vmpressure_register_event()
412 	ev->level = level;  in vmpressure_register_event()
413 	ev->mode = mode;  in vmpressure_register_event()
415 	mutex_lock(&vmpr->events_lock);  in vmpressure_register_event()
416 	list_add(&ev->node, &vmpr->events);  in vmpressure_register_event()
417 	mutex_unlock(&vmpr->events_lock);  in vmpressure_register_event()
425  * vmpressure_unregister_event() - Unbind eventfd from vmpressure
441 	mutex_lock(&vmpr->events_lock);  in vmpressure_unregister_event()
442 	list_for_each_entry(ev, &vmpr->events, node) {  in vmpressure_unregister_event()
443 		if (ev->efd != eventfd)  in vmpressure_unregister_event()
445 		list_del(&ev->node);  in vmpressure_unregister_event()
449 	mutex_unlock(&vmpr->events_lock);  in vmpressure_unregister_event()
453  * vmpressure_init() - Initialize vmpressure control structure
461 	spin_lock_init(&vmpr->sr_lock);  in vmpressure_init()
462 	mutex_init(&vmpr->events_lock);  in vmpressure_init()
463 	INIT_LIST_HEAD(&vmpr->events);  in vmpressure_init()
464 	INIT_WORK(&vmpr->work, vmpressure_work_fn);  in vmpressure_init()
468  * vmpressure_cleanup() - shuts down vmpressure control structure
480 	flush_work(&vmpr->work);  in vmpressure_cleanup()