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
141 	pressure = scale - (reclaimed * scale / scanned);  in vmpressure_calc_level()
165 	mutex_lock(&vmpr->events_lock);  in vmpressure_event()
166 	list_for_each_entry(ev, &vmpr->events, node) {  in vmpressure_event()
167 		if (ancestor && ev->mode == VMPRESSURE_LOCAL)  in vmpressure_event()
169 		if (signalled && ev->mode == VMPRESSURE_NO_PASSTHROUGH)  in vmpressure_event()
171 		if (level < ev->level)  in vmpressure_event()
173 		eventfd_signal(ev->efd, 1);  in vmpressure_event()
176 	mutex_unlock(&vmpr->events_lock);  in vmpressure_event()
190 	spin_lock(&vmpr->sr_lock);  in vmpressure_work_fn()
197 	 * vmpr->reclaimed is in sync.  in vmpressure_work_fn()
199 	scanned = vmpr->tree_scanned;  in vmpressure_work_fn()
201 		spin_unlock(&vmpr->sr_lock);  in vmpressure_work_fn()
205 	reclaimed = vmpr->tree_reclaimed;  in vmpressure_work_fn()
206 	vmpr->tree_scanned = 0;  in vmpressure_work_fn()
207 	vmpr->tree_reclaimed = 0;  in vmpressure_work_fn()
208 	spin_unlock(&vmpr->sr_lock);  in vmpressure_work_fn()
220  * vmpressure() - Account memory pressure through scanned/reclaimed ratio
236  * only in-kernel users are notified.
253 	 * Indirect reclaim (kswapd) sets sc->gfp_mask to GFP_KERNEL, so  in vmpressure()
271 		spin_lock(&vmpr->sr_lock);  in vmpressure()
272 		scanned = vmpr->tree_scanned += scanned;  in vmpressure()
273 		vmpr->tree_reclaimed += reclaimed;  in vmpressure()
274 		spin_unlock(&vmpr->sr_lock);  in vmpressure()
278 		schedule_work(&vmpr->work);  in vmpressure()
282 		/* For now, no users for root-level efficiency */  in vmpressure()
286 		spin_lock(&vmpr->sr_lock);  in vmpressure()
287 		scanned = vmpr->scanned += scanned;  in vmpressure()
288 		reclaimed = vmpr->reclaimed += reclaimed;  in vmpressure()
290 			spin_unlock(&vmpr->sr_lock);  in vmpressure()
293 		vmpr->scanned = vmpr->reclaimed = 0;  in vmpressure()
294 		spin_unlock(&vmpr->sr_lock);  in vmpressure()
307 			memcg->socket_pressure = jiffies + HZ;  in vmpressure()
313  * vmpressure_prio() - Account memory pressure through reclaimer priority level
345  * vmpressure_register_event() - Bind vmpressure notifications to an eventfd
352  * @eventfd. The @args parameter is a comma-delimited string that denotes a
359  * Return: 0 on success, -ENOMEM on memory failure or -EINVAL if @args could
370 	char *token;  in vmpressure_register_event()  local
375 		return -ENOMEM;  in vmpressure_register_event()
378 	token = strsep(&spec, ",");  in vmpressure_register_event()
379 	ret = match_string(vmpressure_str_levels, VMPRESSURE_NUM_LEVELS, token);  in vmpressure_register_event()
385 	token = strsep(&spec, ",");  in vmpressure_register_event()
386 	if (token) {  in vmpressure_register_event()
387 		ret = match_string(vmpressure_str_modes, VMPRESSURE_NUM_MODES, token);  in vmpressure_register_event()
395 		ret = -ENOMEM;  in vmpressure_register_event()
399 	ev->efd = eventfd;  in vmpressure_register_event()
400 	ev->level = level;  in vmpressure_register_event()
401 	ev->mode = mode;  in vmpressure_register_event()
403 	mutex_lock(&vmpr->events_lock);  in vmpressure_register_event()
404 	list_add(&ev->node, &vmpr->events);  in vmpressure_register_event()
405 	mutex_unlock(&vmpr->events_lock);  in vmpressure_register_event()
413  * vmpressure_unregister_event() - Unbind eventfd from vmpressure
429 	mutex_lock(&vmpr->events_lock);  in vmpressure_unregister_event()
430 	list_for_each_entry(ev, &vmpr->events, node) {  in vmpressure_unregister_event()
431 		if (ev->efd != eventfd)  in vmpressure_unregister_event()
433 		list_del(&ev->node);  in vmpressure_unregister_event()
437 	mutex_unlock(&vmpr->events_lock);  in vmpressure_unregister_event()
441  * vmpressure_init() - Initialize vmpressure control structure
449 	spin_lock_init(&vmpr->sr_lock);  in vmpressure_init()
450 	mutex_init(&vmpr->events_lock);  in vmpressure_init()
451 	INIT_LIST_HEAD(&vmpr->events);  in vmpressure_init()
452 	INIT_WORK(&vmpr->work, vmpressure_work_fn);  in vmpressure_init()
456  * vmpressure_cleanup() - shuts down vmpressure control structure
468 	flush_work(&vmpr->work);  in vmpressure_cleanup()