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
235  * only in-kernel users are notified.
257 	 * Indirect reclaim (kswapd) sets sc->gfp_mask to GFP_KERNEL, so  in vmpressure()
275 		spin_lock(&vmpr->sr_lock);  in vmpressure()
276 		scanned = vmpr->tree_scanned += scanned;  in vmpressure()
277 		vmpr->tree_reclaimed += reclaimed;  in vmpressure()
278 		spin_unlock(&vmpr->sr_lock);  in vmpressure()
282 		schedule_work(&vmpr->work);  in vmpressure()
286 		/* For now, no users for root-level efficiency */  in vmpressure()
290 		spin_lock(&vmpr->sr_lock);  in vmpressure()
291 		scanned = vmpr->scanned += scanned;  in vmpressure()
292 		reclaimed = vmpr->reclaimed += reclaimed;  in vmpressure()
294 			spin_unlock(&vmpr->sr_lock);  in vmpressure()
297 		vmpr->scanned = vmpr->reclaimed = 0;  in vmpressure()
298 		spin_unlock(&vmpr->sr_lock);  in vmpressure()
311 			WRITE_ONCE(memcg->socket_pressure, jiffies + HZ);  in vmpressure()
317  * vmpressure_prio() - Account memory pressure through reclaimer priority level
349  * vmpressure_register_event() - Bind vmpressure notifications to an eventfd
356  * @eventfd. The @args parameter is a comma-delimited string that denotes a
363  * Return: 0 on success, -ENOMEM on memory failure or -EINVAL if @args could
374 	char *token;  in vmpressure_register_event()  local
379 		return -ENOMEM;  in vmpressure_register_event()
382 	token = strsep(&spec, ",");  in vmpressure_register_event()
383 	ret = match_string(vmpressure_str_levels, VMPRESSURE_NUM_LEVELS, token);  in vmpressure_register_event()
389 	token = strsep(&spec, ",");  in vmpressure_register_event()
390 	if (token) {  in vmpressure_register_event()
391 		ret = match_string(vmpressure_str_modes, VMPRESSURE_NUM_MODES, token);  in vmpressure_register_event()
399 		ret = -ENOMEM;  in vmpressure_register_event()
403 	ev->efd = eventfd;  in vmpressure_register_event()
404 	ev->level = level;  in vmpressure_register_event()
405 	ev->mode = mode;  in vmpressure_register_event()
407 	mutex_lock(&vmpr->events_lock);  in vmpressure_register_event()
408 	list_add(&ev->node, &vmpr->events);  in vmpressure_register_event()
409 	mutex_unlock(&vmpr->events_lock);  in vmpressure_register_event()
417  * vmpressure_unregister_event() - Unbind eventfd from vmpressure
433 	mutex_lock(&vmpr->events_lock);  in vmpressure_unregister_event()
434 	list_for_each_entry(ev, &vmpr->events, node) {  in vmpressure_unregister_event()
435 		if (ev->efd != eventfd)  in vmpressure_unregister_event()
437 		list_del(&ev->node);  in vmpressure_unregister_event()
441 	mutex_unlock(&vmpr->events_lock);  in vmpressure_unregister_event()
445  * vmpressure_init() - Initialize vmpressure control structure
453 	spin_lock_init(&vmpr->sr_lock);  in vmpressure_init()
454 	mutex_init(&vmpr->events_lock);  in vmpressure_init()
455 	INIT_LIST_HEAD(&vmpr->events);  in vmpressure_init()
456 	INIT_WORK(&vmpr->work, vmpressure_work_fn);  in vmpressure_init()
460  * vmpressure_cleanup() - shuts down vmpressure control structure
472 	flush_work(&vmpr->work);  in vmpressure_cleanup()