1 // SPDX-License-Identifier: GPL-2.0-or-later
3 #include "cgroup-internal.h"
4 #include "cpuset-internal.h"
15  * Frequency meter - How fast is some event occurring?
17  * These routines manage a digitally filtered, constant time based,
19  *   fmeter_init() - initialize a frequency meter.
20  *   fmeter_markevent() - called each time the event happens.
21  *   fmeter_getrate() - returns the recent rate of such events.
22  *   fmeter_update() - internal routine used to update fmeter.
28  * The filter works on the number of events marked per unit time.
29  * The filter is single-pole low-pass recursive (IIR).  The time unit
30  * is 1 second.  Arithmetic is done using 32-bit integers scaled to
33  * With an FM_COEF of 933, and a time base of 1 second, the filter
34  * has a half-life of 10 seconds, meaning that if the events quit
48  * one per 32 (approx) seconds.  At constant rates faster than one
49  * per msec it maxes out at values just under 1,000,000.  At constant
52  * At constant rates between one per second and one per 32 seconds,
53  * it will be choppy, moving up on the seconds that have an event,
59 #define FM_COEF 933		/* coefficient for half-life of 10 secs */
67 	fmp->cnt = 0;  in fmeter_init()
68 	fmp->val = 0;  in fmeter_init()
69 	fmp->time = 0;  in fmeter_init()
70 	spin_lock_init(&fmp->lock);  in fmeter_init()
73 /* Internal meter update - process cnt events and update value */
80 	ticks = now - fmp->time;  in fmeter_update()
86 	while (ticks-- > 0)  in fmeter_update()
87 		fmp->val = (FM_COEF * fmp->val) / FM_SCALE;  in fmeter_update()
88 	fmp->time = now;  in fmeter_update()
90 	fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;  in fmeter_update()
91 	fmp->cnt = 0;  in fmeter_update()
97 	spin_lock(&fmp->lock);  in fmeter_markevent()
99 	fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);  in fmeter_markevent()
100 	spin_unlock(&fmp->lock);  in fmeter_markevent()
108 	spin_lock(&fmp->lock);  in fmeter_getrate()
110 	val = fmp->val;  in fmeter_getrate()
111 	spin_unlock(&fmp->lock);  in fmeter_getrate()
124  * __cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
130  * ran low on memory on all nodes it was allowed to use, and
135  * Display to user space in the per-cpuset read-only file
144 	fmeter_markevent(&task_cs(current)->fmeter);  in __cpuset_memory_pressure_bump()
151 	if (val < -1 || val > sched_domain_level_max + 1)  in update_relax_domain_level()
152 		return -EINVAL;  in update_relax_domain_level()
155 	if (val != cs->relax_domain_level) {  in update_relax_domain_level()
156 		cs->relax_domain_level = val;  in update_relax_domain_level()
157 		if (!cpumask_empty(cs->cpus_allowed) &&  in update_relax_domain_level()
169 	cpuset_filetype_t type = cft->private;  in cpuset_write_s64()
170 	int retval = -ENODEV;  in cpuset_write_s64()
178 		pr_info_once("cpuset.%s is deprecated\n", cft->name);  in cpuset_write_s64()
182 		retval = -EINVAL;  in cpuset_write_s64()
193 	cpuset_filetype_t type = cft->private;  in cpuset_read_s64()
197 		return cs->relax_domain_level;  in cpuset_read_s64()
210  * if on default hierarchy.
230  * cpuset1_update_tasks_flags - update the spread flags of tasks in the cpuset.
242 	css_task_iter_start(&cs->css, 0, &it);  in cpuset1_update_tasks_flags()
253  * cpuset to its next-highest non-empty parent.
260 	 * Find its next-highest non-empty parent, (top cpuset  in remove_tasks_in_empty_cpuset()
264 	while (cpumask_empty(parent->cpus_allowed) ||  in remove_tasks_in_empty_cpuset()
265 			nodes_empty(parent->mems_allowed))  in remove_tasks_in_empty_cpuset()
268 	if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {  in remove_tasks_in_empty_cpuset()
270 		pr_cont_cgroup_name(cs->css.cgroup);  in remove_tasks_in_empty_cpuset()
280 	remove_tasks_in_empty_cpuset(s->cs);  in cpuset_migrate_tasks_workfn()
281 	css_put(&s->cs->css);  in cpuset_migrate_tasks_workfn()
292 	cpumask_copy(cs->cpus_allowed, new_cpus);  in cpuset1_hotplug_update_tasks()
293 	cpumask_copy(cs->effective_cpus, new_cpus);  in cpuset1_hotplug_update_tasks()
294 	cs->mems_allowed = *new_mems;  in cpuset1_hotplug_update_tasks()
295 	cs->effective_mems = *new_mems;  in cpuset1_hotplug_update_tasks()
302 	if (cpus_updated && !cpumask_empty(cs->cpus_allowed))  in cpuset1_hotplug_update_tasks()
304 	if (mems_updated && !nodes_empty(cs->mems_allowed))  in cpuset1_hotplug_update_tasks()
307 	is_empty = cpumask_empty(cs->cpus_allowed) ||  in cpuset1_hotplug_update_tasks()
308 		   nodes_empty(cs->mems_allowed);  in cpuset1_hotplug_update_tasks()
315 	if (is_empty && cs->css.cgroup->nr_populated_csets &&  in cpuset1_hotplug_update_tasks()
316 	    css_tryget_online(&cs->css)) {  in cpuset1_hotplug_update_tasks()
321 			css_put(&cs->css);  in cpuset1_hotplug_update_tasks()
325 		s->cs = cs;  in cpuset1_hotplug_update_tasks()
326 		INIT_WORK(&s->work, cpuset_migrate_tasks_workfn);  in cpuset1_hotplug_update_tasks()
327 		schedule_work(&s->work);  in cpuset1_hotplug_update_tasks()
332  * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
341 	return	cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&  in is_cpuset_subset()
342 		nodes_subset(p->mems_allowed, q->mems_allowed) &&  in is_cpuset_subset()
348  * cpuset1_validate_change() - Validate conditions specific to legacy (v1)
360 	ret = -EBUSY;  in cpuset1_validate_change()
365 	/* On legacy hierarchy, we must be a subset of our parent cpuset. */  in cpuset1_validate_change()
366 	ret = -EACCES;  in cpuset1_validate_change()
379  *  - Print tasks cpuset path into seq_file.
380  *  - Used for /proc/<pid>/cpuset.
389 	retval = -ENOMEM;  in proc_cpuset_show()
397 	retval = cgroup_path_ns_locked(css->cgroup, buf, PATH_MAX,  in proc_cpuset_show()
398 				       current->nsproxy->cgroup_ns);  in proc_cpuset_show()
402 	if (retval == -E2BIG)  in proc_cpuset_show()
403 		retval = -ENAMETOOLONG;  in proc_cpuset_show()
419 	cpuset_filetype_t type = cft->private;  in cpuset_read_u64()
435 		return fmeter_getrate(&cs->fmeter);  in cpuset_read_u64()
452 	cpuset_filetype_t type = cft->private;  in cpuset_write_u64()
457 		retval = -ENODEV;  in cpuset_write_u64()
466 		pr_info_once("cpuset.%s is deprecated\n", cft->name);  in cpuset_write_u64()
470 		pr_info_once("cpuset.%s is deprecated\n", cft->name);  in cpuset_write_u64()
474 		pr_info_once("cpuset.%s is deprecated, use cpuset.cpus.partition instead\n", cft->name);  in cpuset_write_u64()
478 		pr_info_once("cpuset.%s is deprecated\n", cft->name);  in cpuset_write_u64()
482 		pr_info_once("cpuset.%s is deprecated, use memory.pressure with CONFIG_PSI instead\n", cft->name);  in cpuset_write_u64()
486 		pr_info_once("cpuset.%s is deprecated\n", cft->name);  in cpuset_write_u64()
490 		pr_warn_once("cpuset.%s is deprecated\n", cft->name);  in cpuset_write_u64()
494 		retval = -EINVAL;  in cpuset_write_u64()