xref: /linux/mm/damon/sysfs.c (revision da939ef4c494246bc2102ecb628bbcc71d650410)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * DAMON sysfs Interface
4  *
5  * Copyright (c) 2022 SeongJae Park <sj@kernel.org>
6  */
7 
8 #include <linux/pid.h>
9 #include <linux/sched.h>
10 #include <linux/slab.h>
11 
12 #include "sysfs-common.h"
13 
14 /*
15  * init region directory
16  */
17 
18 struct damon_sysfs_region {
19 	struct kobject kobj;
20 	struct damon_addr_range ar;
21 };
22 
23 static struct damon_sysfs_region *damon_sysfs_region_alloc(void)
24 {
25 	return kzalloc(sizeof(struct damon_sysfs_region), GFP_KERNEL);
26 }
27 
28 static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
29 		char *buf)
30 {
31 	struct damon_sysfs_region *region = container_of(kobj,
32 			struct damon_sysfs_region, kobj);
33 
34 	return sysfs_emit(buf, "%lu\n", region->ar.start);
35 }
36 
37 static ssize_t start_store(struct kobject *kobj, struct kobj_attribute *attr,
38 		const char *buf, size_t count)
39 {
40 	struct damon_sysfs_region *region = container_of(kobj,
41 			struct damon_sysfs_region, kobj);
42 	int err = kstrtoul(buf, 0, &region->ar.start);
43 
44 	return err ? err : count;
45 }
46 
47 static ssize_t end_show(struct kobject *kobj, struct kobj_attribute *attr,
48 		char *buf)
49 {
50 	struct damon_sysfs_region *region = container_of(kobj,
51 			struct damon_sysfs_region, kobj);
52 
53 	return sysfs_emit(buf, "%lu\n", region->ar.end);
54 }
55 
56 static ssize_t end_store(struct kobject *kobj, struct kobj_attribute *attr,
57 		const char *buf, size_t count)
58 {
59 	struct damon_sysfs_region *region = container_of(kobj,
60 			struct damon_sysfs_region, kobj);
61 	int err = kstrtoul(buf, 0, &region->ar.end);
62 
63 	return err ? err : count;
64 }
65 
66 static void damon_sysfs_region_release(struct kobject *kobj)
67 {
68 	kfree(container_of(kobj, struct damon_sysfs_region, kobj));
69 }
70 
71 static struct kobj_attribute damon_sysfs_region_start_attr =
72 		__ATTR_RW_MODE(start, 0600);
73 
74 static struct kobj_attribute damon_sysfs_region_end_attr =
75 		__ATTR_RW_MODE(end, 0600);
76 
77 static struct attribute *damon_sysfs_region_attrs[] = {
78 	&damon_sysfs_region_start_attr.attr,
79 	&damon_sysfs_region_end_attr.attr,
80 	NULL,
81 };
82 ATTRIBUTE_GROUPS(damon_sysfs_region);
83 
84 static const struct kobj_type damon_sysfs_region_ktype = {
85 	.release = damon_sysfs_region_release,
86 	.sysfs_ops = &kobj_sysfs_ops,
87 	.default_groups = damon_sysfs_region_groups,
88 };
89 
90 /*
91  * init_regions directory
92  */
93 
94 struct damon_sysfs_regions {
95 	struct kobject kobj;
96 	struct damon_sysfs_region **regions_arr;
97 	int nr;
98 };
99 
100 static struct damon_sysfs_regions *damon_sysfs_regions_alloc(void)
101 {
102 	return kzalloc(sizeof(struct damon_sysfs_regions), GFP_KERNEL);
103 }
104 
105 static void damon_sysfs_regions_rm_dirs(struct damon_sysfs_regions *regions)
106 {
107 	struct damon_sysfs_region **regions_arr = regions->regions_arr;
108 	int i;
109 
110 	for (i = 0; i < regions->nr; i++)
111 		kobject_put(&regions_arr[i]->kobj);
112 	regions->nr = 0;
113 	kfree(regions_arr);
114 	regions->regions_arr = NULL;
115 }
116 
117 static int damon_sysfs_regions_add_dirs(struct damon_sysfs_regions *regions,
118 		int nr_regions)
119 {
120 	struct damon_sysfs_region **regions_arr, *region;
121 	int err, i;
122 
123 	damon_sysfs_regions_rm_dirs(regions);
124 	if (!nr_regions)
125 		return 0;
126 
127 	regions_arr = kmalloc_array(nr_regions, sizeof(*regions_arr),
128 			GFP_KERNEL | __GFP_NOWARN);
129 	if (!regions_arr)
130 		return -ENOMEM;
131 	regions->regions_arr = regions_arr;
132 
133 	for (i = 0; i < nr_regions; i++) {
134 		region = damon_sysfs_region_alloc();
135 		if (!region) {
136 			damon_sysfs_regions_rm_dirs(regions);
137 			return -ENOMEM;
138 		}
139 
140 		err = kobject_init_and_add(&region->kobj,
141 				&damon_sysfs_region_ktype, &regions->kobj,
142 				"%d", i);
143 		if (err) {
144 			kobject_put(&region->kobj);
145 			damon_sysfs_regions_rm_dirs(regions);
146 			return err;
147 		}
148 
149 		regions_arr[i] = region;
150 		regions->nr++;
151 	}
152 	return 0;
153 }
154 
155 static ssize_t nr_regions_show(struct kobject *kobj,
156 		struct kobj_attribute *attr, char *buf)
157 {
158 	struct damon_sysfs_regions *regions = container_of(kobj,
159 			struct damon_sysfs_regions, kobj);
160 
161 	return sysfs_emit(buf, "%d\n", regions->nr);
162 }
163 
164 static ssize_t nr_regions_store(struct kobject *kobj,
165 		struct kobj_attribute *attr, const char *buf, size_t count)
166 {
167 	struct damon_sysfs_regions *regions;
168 	int nr, err = kstrtoint(buf, 0, &nr);
169 
170 	if (err)
171 		return err;
172 	if (nr < 0)
173 		return -EINVAL;
174 
175 	regions = container_of(kobj, struct damon_sysfs_regions, kobj);
176 
177 	if (!mutex_trylock(&damon_sysfs_lock))
178 		return -EBUSY;
179 	err = damon_sysfs_regions_add_dirs(regions, nr);
180 	mutex_unlock(&damon_sysfs_lock);
181 	if (err)
182 		return err;
183 
184 	return count;
185 }
186 
187 static void damon_sysfs_regions_release(struct kobject *kobj)
188 {
189 	kfree(container_of(kobj, struct damon_sysfs_regions, kobj));
190 }
191 
192 static struct kobj_attribute damon_sysfs_regions_nr_attr =
193 		__ATTR_RW_MODE(nr_regions, 0600);
194 
195 static struct attribute *damon_sysfs_regions_attrs[] = {
196 	&damon_sysfs_regions_nr_attr.attr,
197 	NULL,
198 };
199 ATTRIBUTE_GROUPS(damon_sysfs_regions);
200 
201 static const struct kobj_type damon_sysfs_regions_ktype = {
202 	.release = damon_sysfs_regions_release,
203 	.sysfs_ops = &kobj_sysfs_ops,
204 	.default_groups = damon_sysfs_regions_groups,
205 };
206 
207 /*
208  * target directory
209  */
210 
211 struct damon_sysfs_target {
212 	struct kobject kobj;
213 	struct damon_sysfs_regions *regions;
214 	int pid;
215 };
216 
217 static struct damon_sysfs_target *damon_sysfs_target_alloc(void)
218 {
219 	return kzalloc(sizeof(struct damon_sysfs_target), GFP_KERNEL);
220 }
221 
222 static int damon_sysfs_target_add_dirs(struct damon_sysfs_target *target)
223 {
224 	struct damon_sysfs_regions *regions = damon_sysfs_regions_alloc();
225 	int err;
226 
227 	if (!regions)
228 		return -ENOMEM;
229 
230 	err = kobject_init_and_add(&regions->kobj, &damon_sysfs_regions_ktype,
231 			&target->kobj, "regions");
232 	if (err)
233 		kobject_put(&regions->kobj);
234 	else
235 		target->regions = regions;
236 	return err;
237 }
238 
239 static void damon_sysfs_target_rm_dirs(struct damon_sysfs_target *target)
240 {
241 	damon_sysfs_regions_rm_dirs(target->regions);
242 	kobject_put(&target->regions->kobj);
243 }
244 
245 static ssize_t pid_target_show(struct kobject *kobj,
246 		struct kobj_attribute *attr, char *buf)
247 {
248 	struct damon_sysfs_target *target = container_of(kobj,
249 			struct damon_sysfs_target, kobj);
250 
251 	return sysfs_emit(buf, "%d\n", target->pid);
252 }
253 
254 static ssize_t pid_target_store(struct kobject *kobj,
255 		struct kobj_attribute *attr, const char *buf, size_t count)
256 {
257 	struct damon_sysfs_target *target = container_of(kobj,
258 			struct damon_sysfs_target, kobj);
259 	int err = kstrtoint(buf, 0, &target->pid);
260 
261 	if (err)
262 		return -EINVAL;
263 	return count;
264 }
265 
266 static void damon_sysfs_target_release(struct kobject *kobj)
267 {
268 	kfree(container_of(kobj, struct damon_sysfs_target, kobj));
269 }
270 
271 static struct kobj_attribute damon_sysfs_target_pid_attr =
272 		__ATTR_RW_MODE(pid_target, 0600);
273 
274 static struct attribute *damon_sysfs_target_attrs[] = {
275 	&damon_sysfs_target_pid_attr.attr,
276 	NULL,
277 };
278 ATTRIBUTE_GROUPS(damon_sysfs_target);
279 
280 static const struct kobj_type damon_sysfs_target_ktype = {
281 	.release = damon_sysfs_target_release,
282 	.sysfs_ops = &kobj_sysfs_ops,
283 	.default_groups = damon_sysfs_target_groups,
284 };
285 
286 /*
287  * targets directory
288  */
289 
290 struct damon_sysfs_targets {
291 	struct kobject kobj;
292 	struct damon_sysfs_target **targets_arr;
293 	int nr;
294 };
295 
296 static struct damon_sysfs_targets *damon_sysfs_targets_alloc(void)
297 {
298 	return kzalloc(sizeof(struct damon_sysfs_targets), GFP_KERNEL);
299 }
300 
301 static void damon_sysfs_targets_rm_dirs(struct damon_sysfs_targets *targets)
302 {
303 	struct damon_sysfs_target **targets_arr = targets->targets_arr;
304 	int i;
305 
306 	for (i = 0; i < targets->nr; i++) {
307 		damon_sysfs_target_rm_dirs(targets_arr[i]);
308 		kobject_put(&targets_arr[i]->kobj);
309 	}
310 	targets->nr = 0;
311 	kfree(targets_arr);
312 	targets->targets_arr = NULL;
313 }
314 
315 static int damon_sysfs_targets_add_dirs(struct damon_sysfs_targets *targets,
316 		int nr_targets)
317 {
318 	struct damon_sysfs_target **targets_arr, *target;
319 	int err, i;
320 
321 	damon_sysfs_targets_rm_dirs(targets);
322 	if (!nr_targets)
323 		return 0;
324 
325 	targets_arr = kmalloc_array(nr_targets, sizeof(*targets_arr),
326 			GFP_KERNEL | __GFP_NOWARN);
327 	if (!targets_arr)
328 		return -ENOMEM;
329 	targets->targets_arr = targets_arr;
330 
331 	for (i = 0; i < nr_targets; i++) {
332 		target = damon_sysfs_target_alloc();
333 		if (!target) {
334 			damon_sysfs_targets_rm_dirs(targets);
335 			return -ENOMEM;
336 		}
337 
338 		err = kobject_init_and_add(&target->kobj,
339 				&damon_sysfs_target_ktype, &targets->kobj,
340 				"%d", i);
341 		if (err)
342 			goto out;
343 
344 		err = damon_sysfs_target_add_dirs(target);
345 		if (err)
346 			goto out;
347 
348 		targets_arr[i] = target;
349 		targets->nr++;
350 	}
351 	return 0;
352 
353 out:
354 	damon_sysfs_targets_rm_dirs(targets);
355 	kobject_put(&target->kobj);
356 	return err;
357 }
358 
359 static ssize_t nr_targets_show(struct kobject *kobj,
360 		struct kobj_attribute *attr, char *buf)
361 {
362 	struct damon_sysfs_targets *targets = container_of(kobj,
363 			struct damon_sysfs_targets, kobj);
364 
365 	return sysfs_emit(buf, "%d\n", targets->nr);
366 }
367 
368 static ssize_t nr_targets_store(struct kobject *kobj,
369 		struct kobj_attribute *attr, const char *buf, size_t count)
370 {
371 	struct damon_sysfs_targets *targets;
372 	int nr, err = kstrtoint(buf, 0, &nr);
373 
374 	if (err)
375 		return err;
376 	if (nr < 0)
377 		return -EINVAL;
378 
379 	targets = container_of(kobj, struct damon_sysfs_targets, kobj);
380 
381 	if (!mutex_trylock(&damon_sysfs_lock))
382 		return -EBUSY;
383 	err = damon_sysfs_targets_add_dirs(targets, nr);
384 	mutex_unlock(&damon_sysfs_lock);
385 	if (err)
386 		return err;
387 
388 	return count;
389 }
390 
391 static void damon_sysfs_targets_release(struct kobject *kobj)
392 {
393 	kfree(container_of(kobj, struct damon_sysfs_targets, kobj));
394 }
395 
396 static struct kobj_attribute damon_sysfs_targets_nr_attr =
397 		__ATTR_RW_MODE(nr_targets, 0600);
398 
399 static struct attribute *damon_sysfs_targets_attrs[] = {
400 	&damon_sysfs_targets_nr_attr.attr,
401 	NULL,
402 };
403 ATTRIBUTE_GROUPS(damon_sysfs_targets);
404 
405 static const struct kobj_type damon_sysfs_targets_ktype = {
406 	.release = damon_sysfs_targets_release,
407 	.sysfs_ops = &kobj_sysfs_ops,
408 	.default_groups = damon_sysfs_targets_groups,
409 };
410 
411 /*
412  * intervals goal directory
413  */
414 
415 struct damon_sysfs_intervals_goal {
416 	struct kobject kobj;
417 	unsigned long access_bp;
418 	unsigned long aggrs;
419 	unsigned long min_sample_us;
420 	unsigned long max_sample_us;
421 };
422 
423 static struct damon_sysfs_intervals_goal *damon_sysfs_intervals_goal_alloc(
424 		unsigned long access_bp, unsigned long aggrs,
425 		unsigned long min_sample_us, unsigned long max_sample_us)
426 {
427 	struct damon_sysfs_intervals_goal *goal = kmalloc(sizeof(*goal),
428 			GFP_KERNEL);
429 
430 	if (!goal)
431 		return NULL;
432 
433 	goal->kobj = (struct kobject){};
434 	goal->access_bp = access_bp;
435 	goal->aggrs = aggrs;
436 	goal->min_sample_us = min_sample_us;
437 	goal->max_sample_us = max_sample_us;
438 	return goal;
439 }
440 
441 static ssize_t access_bp_show(struct kobject *kobj,
442 		struct kobj_attribute *attr, char *buf)
443 {
444 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
445 			struct damon_sysfs_intervals_goal, kobj);
446 
447 	return sysfs_emit(buf, "%lu\n", goal->access_bp);
448 }
449 
450 static ssize_t access_bp_store(struct kobject *kobj,
451 		struct kobj_attribute *attr, const char *buf, size_t count)
452 {
453 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
454 			struct damon_sysfs_intervals_goal, kobj);
455 	unsigned long nr;
456 	int err = kstrtoul(buf, 0, &nr);
457 
458 	if (err)
459 		return err;
460 
461 	goal->access_bp = nr;
462 	return count;
463 }
464 
465 static ssize_t aggrs_show(struct kobject *kobj,
466 		struct kobj_attribute *attr, char *buf)
467 {
468 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
469 			struct damon_sysfs_intervals_goal, kobj);
470 
471 	return sysfs_emit(buf, "%lu\n", goal->aggrs);
472 }
473 
474 static ssize_t aggrs_store(struct kobject *kobj,
475 		struct kobj_attribute *attr, const char *buf, size_t count)
476 {
477 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
478 			struct damon_sysfs_intervals_goal, kobj);
479 	unsigned long nr;
480 	int err = kstrtoul(buf, 0, &nr);
481 
482 	if (err)
483 		return err;
484 
485 	goal->aggrs = nr;
486 	return count;
487 }
488 
489 static ssize_t min_sample_us_show(struct kobject *kobj,
490 		struct kobj_attribute *attr, char *buf)
491 {
492 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
493 			struct damon_sysfs_intervals_goal, kobj);
494 
495 	return sysfs_emit(buf, "%lu\n", goal->min_sample_us);
496 }
497 
498 static ssize_t min_sample_us_store(struct kobject *kobj,
499 		struct kobj_attribute *attr, const char *buf, size_t count)
500 {
501 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
502 			struct damon_sysfs_intervals_goal, kobj);
503 	unsigned long nr;
504 	int err = kstrtoul(buf, 0, &nr);
505 
506 	if (err)
507 		return err;
508 
509 	goal->min_sample_us = nr;
510 	return count;
511 }
512 
513 static ssize_t max_sample_us_show(struct kobject *kobj,
514 		struct kobj_attribute *attr, char *buf)
515 {
516 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
517 			struct damon_sysfs_intervals_goal, kobj);
518 
519 	return sysfs_emit(buf, "%lu\n", goal->max_sample_us);
520 }
521 
522 static ssize_t max_sample_us_store(struct kobject *kobj,
523 		struct kobj_attribute *attr, const char *buf, size_t count)
524 {
525 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
526 			struct damon_sysfs_intervals_goal, kobj);
527 	unsigned long nr;
528 	int err = kstrtoul(buf, 0, &nr);
529 
530 	if (err)
531 		return err;
532 
533 	goal->max_sample_us = nr;
534 	return count;
535 }
536 
537 static void damon_sysfs_intervals_goal_release(struct kobject *kobj)
538 {
539 	kfree(container_of(kobj, struct damon_sysfs_intervals_goal, kobj));
540 }
541 
542 static struct kobj_attribute damon_sysfs_intervals_goal_access_bp_attr =
543 		__ATTR_RW_MODE(access_bp, 0600);
544 
545 static struct kobj_attribute damon_sysfs_intervals_goal_aggrs_attr =
546 		__ATTR_RW_MODE(aggrs, 0600);
547 
548 static struct kobj_attribute damon_sysfs_intervals_goal_min_sample_us_attr =
549 		__ATTR_RW_MODE(min_sample_us, 0600);
550 
551 static struct kobj_attribute damon_sysfs_intervals_goal_max_sample_us_attr =
552 		__ATTR_RW_MODE(max_sample_us, 0600);
553 
554 static struct attribute *damon_sysfs_intervals_goal_attrs[] = {
555 	&damon_sysfs_intervals_goal_access_bp_attr.attr,
556 	&damon_sysfs_intervals_goal_aggrs_attr.attr,
557 	&damon_sysfs_intervals_goal_min_sample_us_attr.attr,
558 	&damon_sysfs_intervals_goal_max_sample_us_attr.attr,
559 	NULL,
560 };
561 ATTRIBUTE_GROUPS(damon_sysfs_intervals_goal);
562 
563 static const struct kobj_type damon_sysfs_intervals_goal_ktype = {
564 	.release = damon_sysfs_intervals_goal_release,
565 	.sysfs_ops = &kobj_sysfs_ops,
566 	.default_groups = damon_sysfs_intervals_goal_groups,
567 };
568 
569 /*
570  * intervals directory
571  */
572 
573 struct damon_sysfs_intervals {
574 	struct kobject kobj;
575 	unsigned long sample_us;
576 	unsigned long aggr_us;
577 	unsigned long update_us;
578 	struct damon_sysfs_intervals_goal *intervals_goal;
579 };
580 
581 static struct damon_sysfs_intervals *damon_sysfs_intervals_alloc(
582 		unsigned long sample_us, unsigned long aggr_us,
583 		unsigned long update_us)
584 {
585 	struct damon_sysfs_intervals *intervals = kmalloc(sizeof(*intervals),
586 			GFP_KERNEL);
587 
588 	if (!intervals)
589 		return NULL;
590 
591 	intervals->kobj = (struct kobject){};
592 	intervals->sample_us = sample_us;
593 	intervals->aggr_us = aggr_us;
594 	intervals->update_us = update_us;
595 	return intervals;
596 }
597 
598 static int damon_sysfs_intervals_add_dirs(struct damon_sysfs_intervals *intervals)
599 {
600 	struct damon_sysfs_intervals_goal *goal;
601 	int err;
602 
603 	goal = damon_sysfs_intervals_goal_alloc(0, 0, 0, 0);
604 	if (!goal)
605 		return -ENOMEM;
606 
607 	err = kobject_init_and_add(&goal->kobj,
608 			&damon_sysfs_intervals_goal_ktype, &intervals->kobj,
609 			"intervals_goal");
610 	if (err) {
611 		kobject_put(&goal->kobj);
612 		intervals->intervals_goal = NULL;
613 		return err;
614 	}
615 	intervals->intervals_goal = goal;
616 	return 0;
617 }
618 
619 static void damon_sysfs_intervals_rm_dirs(struct damon_sysfs_intervals *intervals)
620 {
621 	kobject_put(&intervals->intervals_goal->kobj);
622 }
623 
624 static ssize_t sample_us_show(struct kobject *kobj,
625 		struct kobj_attribute *attr, char *buf)
626 {
627 	struct damon_sysfs_intervals *intervals = container_of(kobj,
628 			struct damon_sysfs_intervals, kobj);
629 
630 	return sysfs_emit(buf, "%lu\n", intervals->sample_us);
631 }
632 
633 static ssize_t sample_us_store(struct kobject *kobj,
634 		struct kobj_attribute *attr, const char *buf, size_t count)
635 {
636 	struct damon_sysfs_intervals *intervals = container_of(kobj,
637 			struct damon_sysfs_intervals, kobj);
638 	unsigned long us;
639 	int err = kstrtoul(buf, 0, &us);
640 
641 	if (err)
642 		return err;
643 
644 	intervals->sample_us = us;
645 	return count;
646 }
647 
648 static ssize_t aggr_us_show(struct kobject *kobj, struct kobj_attribute *attr,
649 		char *buf)
650 {
651 	struct damon_sysfs_intervals *intervals = container_of(kobj,
652 			struct damon_sysfs_intervals, kobj);
653 
654 	return sysfs_emit(buf, "%lu\n", intervals->aggr_us);
655 }
656 
657 static ssize_t aggr_us_store(struct kobject *kobj, struct kobj_attribute *attr,
658 		const char *buf, size_t count)
659 {
660 	struct damon_sysfs_intervals *intervals = container_of(kobj,
661 			struct damon_sysfs_intervals, kobj);
662 	unsigned long us;
663 	int err = kstrtoul(buf, 0, &us);
664 
665 	if (err)
666 		return err;
667 
668 	intervals->aggr_us = us;
669 	return count;
670 }
671 
672 static ssize_t update_us_show(struct kobject *kobj,
673 		struct kobj_attribute *attr, char *buf)
674 {
675 	struct damon_sysfs_intervals *intervals = container_of(kobj,
676 			struct damon_sysfs_intervals, kobj);
677 
678 	return sysfs_emit(buf, "%lu\n", intervals->update_us);
679 }
680 
681 static ssize_t update_us_store(struct kobject *kobj,
682 		struct kobj_attribute *attr, const char *buf, size_t count)
683 {
684 	struct damon_sysfs_intervals *intervals = container_of(kobj,
685 			struct damon_sysfs_intervals, kobj);
686 	unsigned long us;
687 	int err = kstrtoul(buf, 0, &us);
688 
689 	if (err)
690 		return err;
691 
692 	intervals->update_us = us;
693 	return count;
694 }
695 
696 static void damon_sysfs_intervals_release(struct kobject *kobj)
697 {
698 	kfree(container_of(kobj, struct damon_sysfs_intervals, kobj));
699 }
700 
701 static struct kobj_attribute damon_sysfs_intervals_sample_us_attr =
702 		__ATTR_RW_MODE(sample_us, 0600);
703 
704 static struct kobj_attribute damon_sysfs_intervals_aggr_us_attr =
705 		__ATTR_RW_MODE(aggr_us, 0600);
706 
707 static struct kobj_attribute damon_sysfs_intervals_update_us_attr =
708 		__ATTR_RW_MODE(update_us, 0600);
709 
710 static struct attribute *damon_sysfs_intervals_attrs[] = {
711 	&damon_sysfs_intervals_sample_us_attr.attr,
712 	&damon_sysfs_intervals_aggr_us_attr.attr,
713 	&damon_sysfs_intervals_update_us_attr.attr,
714 	NULL,
715 };
716 ATTRIBUTE_GROUPS(damon_sysfs_intervals);
717 
718 static const struct kobj_type damon_sysfs_intervals_ktype = {
719 	.release = damon_sysfs_intervals_release,
720 	.sysfs_ops = &kobj_sysfs_ops,
721 	.default_groups = damon_sysfs_intervals_groups,
722 };
723 
724 /*
725  * monitoring_attrs directory
726  */
727 
728 struct damon_sysfs_attrs {
729 	struct kobject kobj;
730 	struct damon_sysfs_intervals *intervals;
731 	struct damon_sysfs_ul_range *nr_regions_range;
732 };
733 
734 static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
735 {
736 	struct damon_sysfs_attrs *attrs = kmalloc(sizeof(*attrs), GFP_KERNEL);
737 
738 	if (!attrs)
739 		return NULL;
740 	attrs->kobj = (struct kobject){};
741 	return attrs;
742 }
743 
744 static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
745 {
746 	struct damon_sysfs_intervals *intervals;
747 	struct damon_sysfs_ul_range *nr_regions_range;
748 	int err;
749 
750 	intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
751 	if (!intervals)
752 		return -ENOMEM;
753 
754 	err = kobject_init_and_add(&intervals->kobj,
755 			&damon_sysfs_intervals_ktype, &attrs->kobj,
756 			"intervals");
757 	if (err)
758 		goto put_intervals_out;
759 	err = damon_sysfs_intervals_add_dirs(intervals);
760 	if (err)
761 		goto put_intervals_out;
762 	attrs->intervals = intervals;
763 
764 	nr_regions_range = damon_sysfs_ul_range_alloc(10, 1000);
765 	if (!nr_regions_range) {
766 		err = -ENOMEM;
767 		goto put_intervals_out;
768 	}
769 
770 	err = kobject_init_and_add(&nr_regions_range->kobj,
771 			&damon_sysfs_ul_range_ktype, &attrs->kobj,
772 			"nr_regions");
773 	if (err)
774 		goto put_nr_regions_intervals_out;
775 	attrs->nr_regions_range = nr_regions_range;
776 	return 0;
777 
778 put_nr_regions_intervals_out:
779 	kobject_put(&nr_regions_range->kobj);
780 	attrs->nr_regions_range = NULL;
781 put_intervals_out:
782 	kobject_put(&intervals->kobj);
783 	attrs->intervals = NULL;
784 	return err;
785 }
786 
787 static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
788 {
789 	kobject_put(&attrs->nr_regions_range->kobj);
790 	damon_sysfs_intervals_rm_dirs(attrs->intervals);
791 	kobject_put(&attrs->intervals->kobj);
792 }
793 
794 static void damon_sysfs_attrs_release(struct kobject *kobj)
795 {
796 	kfree(container_of(kobj, struct damon_sysfs_attrs, kobj));
797 }
798 
799 static struct attribute *damon_sysfs_attrs_attrs[] = {
800 	NULL,
801 };
802 ATTRIBUTE_GROUPS(damon_sysfs_attrs);
803 
804 static const struct kobj_type damon_sysfs_attrs_ktype = {
805 	.release = damon_sysfs_attrs_release,
806 	.sysfs_ops = &kobj_sysfs_ops,
807 	.default_groups = damon_sysfs_attrs_groups,
808 };
809 
810 /*
811  * context directory
812  */
813 
814 struct damon_sysfs_ops_name {
815 	enum damon_ops_id ops_id;
816 	char *name;
817 };
818 
819 static const struct damon_sysfs_ops_name damon_sysfs_ops_names[] = {
820 	{
821 		.ops_id = DAMON_OPS_VADDR,
822 		.name = "vaddr",
823 	},
824 	{
825 		.ops_id = DAMON_OPS_FVADDR,
826 		.name = "fvaddr",
827 	},
828 	{
829 		.ops_id = DAMON_OPS_PADDR,
830 		.name = "paddr",
831 	},
832 };
833 
834 struct damon_sysfs_context {
835 	struct kobject kobj;
836 	enum damon_ops_id ops_id;
837 	unsigned long addr_unit;
838 	struct damon_sysfs_attrs *attrs;
839 	struct damon_sysfs_targets *targets;
840 	struct damon_sysfs_schemes *schemes;
841 };
842 
843 static struct damon_sysfs_context *damon_sysfs_context_alloc(
844 		enum damon_ops_id ops_id)
845 {
846 	struct damon_sysfs_context *context = kmalloc(sizeof(*context),
847 				GFP_KERNEL);
848 
849 	if (!context)
850 		return NULL;
851 	context->kobj = (struct kobject){};
852 	context->ops_id = ops_id;
853 	context->addr_unit = 1;
854 	return context;
855 }
856 
857 static int damon_sysfs_context_set_attrs(struct damon_sysfs_context *context)
858 {
859 	struct damon_sysfs_attrs *attrs = damon_sysfs_attrs_alloc();
860 	int err;
861 
862 	if (!attrs)
863 		return -ENOMEM;
864 	err = kobject_init_and_add(&attrs->kobj, &damon_sysfs_attrs_ktype,
865 			&context->kobj, "monitoring_attrs");
866 	if (err)
867 		goto out;
868 	err = damon_sysfs_attrs_add_dirs(attrs);
869 	if (err)
870 		goto out;
871 	context->attrs = attrs;
872 	return 0;
873 
874 out:
875 	kobject_put(&attrs->kobj);
876 	return err;
877 }
878 
879 static int damon_sysfs_context_set_targets(struct damon_sysfs_context *context)
880 {
881 	struct damon_sysfs_targets *targets = damon_sysfs_targets_alloc();
882 	int err;
883 
884 	if (!targets)
885 		return -ENOMEM;
886 	err = kobject_init_and_add(&targets->kobj, &damon_sysfs_targets_ktype,
887 			&context->kobj, "targets");
888 	if (err) {
889 		kobject_put(&targets->kobj);
890 		return err;
891 	}
892 	context->targets = targets;
893 	return 0;
894 }
895 
896 static int damon_sysfs_context_set_schemes(struct damon_sysfs_context *context)
897 {
898 	struct damon_sysfs_schemes *schemes = damon_sysfs_schemes_alloc();
899 	int err;
900 
901 	if (!schemes)
902 		return -ENOMEM;
903 	err = kobject_init_and_add(&schemes->kobj, &damon_sysfs_schemes_ktype,
904 			&context->kobj, "schemes");
905 	if (err) {
906 		kobject_put(&schemes->kobj);
907 		return err;
908 	}
909 	context->schemes = schemes;
910 	return 0;
911 }
912 
913 static int damon_sysfs_context_add_dirs(struct damon_sysfs_context *context)
914 {
915 	int err;
916 
917 	err = damon_sysfs_context_set_attrs(context);
918 	if (err)
919 		return err;
920 
921 	err = damon_sysfs_context_set_targets(context);
922 	if (err)
923 		goto put_attrs_out;
924 
925 	err = damon_sysfs_context_set_schemes(context);
926 	if (err)
927 		goto put_targets_attrs_out;
928 	return 0;
929 
930 put_targets_attrs_out:
931 	kobject_put(&context->targets->kobj);
932 	context->targets = NULL;
933 put_attrs_out:
934 	kobject_put(&context->attrs->kobj);
935 	context->attrs = NULL;
936 	return err;
937 }
938 
939 static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context)
940 {
941 	damon_sysfs_attrs_rm_dirs(context->attrs);
942 	kobject_put(&context->attrs->kobj);
943 	damon_sysfs_targets_rm_dirs(context->targets);
944 	kobject_put(&context->targets->kobj);
945 	damon_sysfs_schemes_rm_dirs(context->schemes);
946 	kobject_put(&context->schemes->kobj);
947 }
948 
949 static ssize_t avail_operations_show(struct kobject *kobj,
950 		struct kobj_attribute *attr, char *buf)
951 {
952 	int len = 0;
953 	int i;
954 
955 	for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
956 		const struct damon_sysfs_ops_name *ops_name;
957 
958 		ops_name = &damon_sysfs_ops_names[i];
959 		if (!damon_is_registered_ops(ops_name->ops_id))
960 			continue;
961 		len += sysfs_emit_at(buf, len, "%s\n", ops_name->name);
962 	}
963 	return len;
964 }
965 
966 static ssize_t operations_show(struct kobject *kobj,
967 		struct kobj_attribute *attr, char *buf)
968 {
969 	struct damon_sysfs_context *context = container_of(kobj,
970 			struct damon_sysfs_context, kobj);
971 	int i;
972 
973 	for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
974 		const struct damon_sysfs_ops_name *ops_name;
975 
976 		ops_name = &damon_sysfs_ops_names[i];
977 		if (ops_name->ops_id == context->ops_id)
978 			return sysfs_emit(buf, "%s\n", ops_name->name);
979 	}
980 	return -EINVAL;
981 }
982 
983 static ssize_t operations_store(struct kobject *kobj,
984 		struct kobj_attribute *attr, const char *buf, size_t count)
985 {
986 	struct damon_sysfs_context *context = container_of(kobj,
987 			struct damon_sysfs_context, kobj);
988 	int i;
989 
990 	for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
991 		const struct damon_sysfs_ops_name *ops_name;
992 
993 		ops_name = &damon_sysfs_ops_names[i];
994 		if (sysfs_streq(buf, ops_name->name)) {
995 			context->ops_id = ops_name->ops_id;
996 			return count;
997 		}
998 	}
999 	return -EINVAL;
1000 }
1001 
1002 static ssize_t addr_unit_show(struct kobject *kobj,
1003 		struct kobj_attribute *attr, char *buf)
1004 {
1005 	struct damon_sysfs_context *context = container_of(kobj,
1006 			struct damon_sysfs_context, kobj);
1007 
1008 	return sysfs_emit(buf, "%lu\n", context->addr_unit);
1009 }
1010 
1011 static ssize_t addr_unit_store(struct kobject *kobj,
1012 		struct kobj_attribute *attr, const char *buf, size_t count)
1013 {
1014 	struct damon_sysfs_context *context = container_of(kobj,
1015 			struct damon_sysfs_context, kobj);
1016 	unsigned long input_addr_unit;
1017 	int err = kstrtoul(buf, 0, &input_addr_unit);
1018 
1019 	if (err)
1020 		return err;
1021 	if (!input_addr_unit)
1022 		return -EINVAL;
1023 
1024 	context->addr_unit = input_addr_unit;
1025 	return count;
1026 }
1027 
1028 static void damon_sysfs_context_release(struct kobject *kobj)
1029 {
1030 	kfree(container_of(kobj, struct damon_sysfs_context, kobj));
1031 }
1032 
1033 static struct kobj_attribute damon_sysfs_context_avail_operations_attr =
1034 		__ATTR_RO_MODE(avail_operations, 0400);
1035 
1036 static struct kobj_attribute damon_sysfs_context_operations_attr =
1037 		__ATTR_RW_MODE(operations, 0600);
1038 
1039 static struct kobj_attribute damon_sysfs_context_addr_unit_attr =
1040 		__ATTR_RW_MODE(addr_unit, 0600);
1041 
1042 static struct attribute *damon_sysfs_context_attrs[] = {
1043 	&damon_sysfs_context_avail_operations_attr.attr,
1044 	&damon_sysfs_context_operations_attr.attr,
1045 	&damon_sysfs_context_addr_unit_attr.attr,
1046 	NULL,
1047 };
1048 ATTRIBUTE_GROUPS(damon_sysfs_context);
1049 
1050 static const struct kobj_type damon_sysfs_context_ktype = {
1051 	.release = damon_sysfs_context_release,
1052 	.sysfs_ops = &kobj_sysfs_ops,
1053 	.default_groups = damon_sysfs_context_groups,
1054 };
1055 
1056 /*
1057  * contexts directory
1058  */
1059 
1060 struct damon_sysfs_contexts {
1061 	struct kobject kobj;
1062 	struct damon_sysfs_context **contexts_arr;
1063 	int nr;
1064 };
1065 
1066 static struct damon_sysfs_contexts *damon_sysfs_contexts_alloc(void)
1067 {
1068 	return kzalloc(sizeof(struct damon_sysfs_contexts), GFP_KERNEL);
1069 }
1070 
1071 static void damon_sysfs_contexts_rm_dirs(struct damon_sysfs_contexts *contexts)
1072 {
1073 	struct damon_sysfs_context **contexts_arr = contexts->contexts_arr;
1074 	int i;
1075 
1076 	for (i = 0; i < contexts->nr; i++) {
1077 		damon_sysfs_context_rm_dirs(contexts_arr[i]);
1078 		kobject_put(&contexts_arr[i]->kobj);
1079 	}
1080 	contexts->nr = 0;
1081 	kfree(contexts_arr);
1082 	contexts->contexts_arr = NULL;
1083 }
1084 
1085 static int damon_sysfs_contexts_add_dirs(struct damon_sysfs_contexts *contexts,
1086 		int nr_contexts)
1087 {
1088 	struct damon_sysfs_context **contexts_arr, *context;
1089 	int err, i;
1090 
1091 	damon_sysfs_contexts_rm_dirs(contexts);
1092 	if (!nr_contexts)
1093 		return 0;
1094 
1095 	contexts_arr = kmalloc_array(nr_contexts, sizeof(*contexts_arr),
1096 			GFP_KERNEL | __GFP_NOWARN);
1097 	if (!contexts_arr)
1098 		return -ENOMEM;
1099 	contexts->contexts_arr = contexts_arr;
1100 
1101 	for (i = 0; i < nr_contexts; i++) {
1102 		context = damon_sysfs_context_alloc(DAMON_OPS_VADDR);
1103 		if (!context) {
1104 			damon_sysfs_contexts_rm_dirs(contexts);
1105 			return -ENOMEM;
1106 		}
1107 
1108 		err = kobject_init_and_add(&context->kobj,
1109 				&damon_sysfs_context_ktype, &contexts->kobj,
1110 				"%d", i);
1111 		if (err)
1112 			goto out;
1113 
1114 		err = damon_sysfs_context_add_dirs(context);
1115 		if (err)
1116 			goto out;
1117 
1118 		contexts_arr[i] = context;
1119 		contexts->nr++;
1120 	}
1121 	return 0;
1122 
1123 out:
1124 	damon_sysfs_contexts_rm_dirs(contexts);
1125 	kobject_put(&context->kobj);
1126 	return err;
1127 }
1128 
1129 static ssize_t nr_contexts_show(struct kobject *kobj,
1130 		struct kobj_attribute *attr, char *buf)
1131 {
1132 	struct damon_sysfs_contexts *contexts = container_of(kobj,
1133 			struct damon_sysfs_contexts, kobj);
1134 
1135 	return sysfs_emit(buf, "%d\n", contexts->nr);
1136 }
1137 
1138 static ssize_t nr_contexts_store(struct kobject *kobj,
1139 		struct kobj_attribute *attr, const char *buf, size_t count)
1140 {
1141 	struct damon_sysfs_contexts *contexts;
1142 	int nr, err;
1143 
1144 	err = kstrtoint(buf, 0, &nr);
1145 	if (err)
1146 		return err;
1147 	/* TODO: support multiple contexts per kdamond */
1148 	if (nr < 0 || 1 < nr)
1149 		return -EINVAL;
1150 
1151 	contexts = container_of(kobj, struct damon_sysfs_contexts, kobj);
1152 	if (!mutex_trylock(&damon_sysfs_lock))
1153 		return -EBUSY;
1154 	err = damon_sysfs_contexts_add_dirs(contexts, nr);
1155 	mutex_unlock(&damon_sysfs_lock);
1156 	if (err)
1157 		return err;
1158 
1159 	return count;
1160 }
1161 
1162 static void damon_sysfs_contexts_release(struct kobject *kobj)
1163 {
1164 	kfree(container_of(kobj, struct damon_sysfs_contexts, kobj));
1165 }
1166 
1167 static struct kobj_attribute damon_sysfs_contexts_nr_attr
1168 		= __ATTR_RW_MODE(nr_contexts, 0600);
1169 
1170 static struct attribute *damon_sysfs_contexts_attrs[] = {
1171 	&damon_sysfs_contexts_nr_attr.attr,
1172 	NULL,
1173 };
1174 ATTRIBUTE_GROUPS(damon_sysfs_contexts);
1175 
1176 static const struct kobj_type damon_sysfs_contexts_ktype = {
1177 	.release = damon_sysfs_contexts_release,
1178 	.sysfs_ops = &kobj_sysfs_ops,
1179 	.default_groups = damon_sysfs_contexts_groups,
1180 };
1181 
1182 /*
1183  * kdamond directory
1184  */
1185 
1186 struct damon_sysfs_kdamond {
1187 	struct kobject kobj;
1188 	struct damon_sysfs_contexts *contexts;
1189 	struct damon_ctx *damon_ctx;
1190 	unsigned int refresh_ms;
1191 };
1192 
1193 static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void)
1194 {
1195 	return kzalloc(sizeof(struct damon_sysfs_kdamond), GFP_KERNEL);
1196 }
1197 
1198 static int damon_sysfs_kdamond_add_dirs(struct damon_sysfs_kdamond *kdamond)
1199 {
1200 	struct damon_sysfs_contexts *contexts;
1201 	int err;
1202 
1203 	contexts = damon_sysfs_contexts_alloc();
1204 	if (!contexts)
1205 		return -ENOMEM;
1206 
1207 	err = kobject_init_and_add(&contexts->kobj,
1208 			&damon_sysfs_contexts_ktype, &kdamond->kobj,
1209 			"contexts");
1210 	if (err) {
1211 		kobject_put(&contexts->kobj);
1212 		return err;
1213 	}
1214 	kdamond->contexts = contexts;
1215 
1216 	return err;
1217 }
1218 
1219 static void damon_sysfs_kdamond_rm_dirs(struct damon_sysfs_kdamond *kdamond)
1220 {
1221 	damon_sysfs_contexts_rm_dirs(kdamond->contexts);
1222 	kobject_put(&kdamond->contexts->kobj);
1223 }
1224 
1225 /*
1226  * enum damon_sysfs_cmd - Commands for a specific kdamond.
1227  */
1228 enum damon_sysfs_cmd {
1229 	/* @DAMON_SYSFS_CMD_ON: Turn the kdamond on. */
1230 	DAMON_SYSFS_CMD_ON,
1231 	/* @DAMON_SYSFS_CMD_OFF: Turn the kdamond off. */
1232 	DAMON_SYSFS_CMD_OFF,
1233 	/* @DAMON_SYSFS_CMD_COMMIT: Update kdamond inputs. */
1234 	DAMON_SYSFS_CMD_COMMIT,
1235 	/*
1236 	 * @DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS: Commit the quota goals
1237 	 * to DAMON.
1238 	 */
1239 	DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS,
1240 	/*
1241 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS: Update scheme stats sysfs
1242 	 * files.
1243 	 */
1244 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,
1245 	/*
1246 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES: Update
1247 	 * tried_regions/total_bytes sysfs files for each scheme.
1248 	 */
1249 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES,
1250 	/*
1251 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS: Update schemes tried
1252 	 * regions
1253 	 */
1254 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS,
1255 	/*
1256 	 * @DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS: Clear schemes tried
1257 	 * regions
1258 	 */
1259 	DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS,
1260 	/*
1261 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS: Update the
1262 	 * effective size quota of the scheme in bytes.
1263 	 */
1264 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS,
1265 	/*
1266 	 * @DAMON_SYSFS_CMD_UPDATE_TUNED_INTERVALS: Update the tuned monitoring
1267 	 * intevals.
1268 	 */
1269 	DAMON_SYSFS_CMD_UPDATE_TUNED_INTERVALS,
1270 	/*
1271 	 * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
1272 	 */
1273 	NR_DAMON_SYSFS_CMDS,
1274 };
1275 
1276 /* Should match with enum damon_sysfs_cmd */
1277 static const char * const damon_sysfs_cmd_strs[] = {
1278 	"on",
1279 	"off",
1280 	"commit",
1281 	"commit_schemes_quota_goals",
1282 	"update_schemes_stats",
1283 	"update_schemes_tried_bytes",
1284 	"update_schemes_tried_regions",
1285 	"clear_schemes_tried_regions",
1286 	"update_schemes_effective_quotas",
1287 	"update_tuned_intervals",
1288 };
1289 
1290 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
1291 		char *buf)
1292 {
1293 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1294 			struct damon_sysfs_kdamond, kobj);
1295 	struct damon_ctx *ctx;
1296 	bool running = false;
1297 
1298 	if (!mutex_trylock(&damon_sysfs_lock))
1299 		return -EBUSY;
1300 
1301 	ctx = kdamond->damon_ctx;
1302 	if (ctx)
1303 		running = damon_is_running(ctx);
1304 
1305 	mutex_unlock(&damon_sysfs_lock);
1306 
1307 	return sysfs_emit(buf, "%s\n", running ?
1308 			damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_ON] :
1309 			damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_OFF]);
1310 }
1311 
1312 static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
1313 		struct damon_sysfs_attrs *sys_attrs)
1314 {
1315 	struct damon_sysfs_intervals *sys_intervals = sys_attrs->intervals;
1316 	struct damon_sysfs_intervals_goal *sys_goal =
1317 		sys_intervals->intervals_goal;
1318 	struct damon_sysfs_ul_range *sys_nr_regions =
1319 		sys_attrs->nr_regions_range;
1320 	struct damon_attrs attrs = {
1321 		.sample_interval = sys_intervals->sample_us,
1322 		.aggr_interval = sys_intervals->aggr_us,
1323 		.intervals_goal = {
1324 			.access_bp = sys_goal->access_bp,
1325 			.aggrs = sys_goal->aggrs,
1326 			.min_sample_us = sys_goal->min_sample_us,
1327 			.max_sample_us = sys_goal->max_sample_us},
1328 		.ops_update_interval = sys_intervals->update_us,
1329 		.min_nr_regions = sys_nr_regions->min,
1330 		.max_nr_regions = sys_nr_regions->max,
1331 	};
1332 	return damon_set_attrs(ctx, &attrs);
1333 }
1334 
1335 static int damon_sysfs_set_regions(struct damon_target *t,
1336 		struct damon_sysfs_regions *sysfs_regions,
1337 		unsigned long min_sz_region)
1338 {
1339 	struct damon_addr_range *ranges = kmalloc_array(sysfs_regions->nr,
1340 			sizeof(*ranges), GFP_KERNEL | __GFP_NOWARN);
1341 	int i, err = -EINVAL;
1342 
1343 	if (!ranges)
1344 		return -ENOMEM;
1345 	for (i = 0; i < sysfs_regions->nr; i++) {
1346 		struct damon_sysfs_region *sys_region =
1347 			sysfs_regions->regions_arr[i];
1348 
1349 		if (sys_region->ar.start > sys_region->ar.end)
1350 			goto out;
1351 
1352 		ranges[i].start = sys_region->ar.start;
1353 		ranges[i].end = sys_region->ar.end;
1354 		if (i == 0)
1355 			continue;
1356 		if (ranges[i - 1].end > ranges[i].start)
1357 			goto out;
1358 	}
1359 	err = damon_set_regions(t, ranges, sysfs_regions->nr, min_sz_region);
1360 out:
1361 	kfree(ranges);
1362 	return err;
1363 
1364 }
1365 
1366 static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
1367 		struct damon_ctx *ctx)
1368 {
1369 	struct damon_target *t = damon_new_target();
1370 
1371 	if (!t)
1372 		return -ENOMEM;
1373 	damon_add_target(ctx, t);
1374 	if (damon_target_has_pid(ctx)) {
1375 		t->pid = find_get_pid(sys_target->pid);
1376 		if (!t->pid)
1377 			/* caller will destroy targets */
1378 			return -EINVAL;
1379 	}
1380 	return damon_sysfs_set_regions(t, sys_target->regions, ctx->min_sz_region);
1381 }
1382 
1383 static int damon_sysfs_add_targets(struct damon_ctx *ctx,
1384 		struct damon_sysfs_targets *sysfs_targets)
1385 {
1386 	int i, err;
1387 
1388 	/* Multiple physical address space monitoring targets makes no sense */
1389 	if (ctx->ops.id == DAMON_OPS_PADDR && sysfs_targets->nr > 1)
1390 		return -EINVAL;
1391 
1392 	for (i = 0; i < sysfs_targets->nr; i++) {
1393 		struct damon_sysfs_target *st = sysfs_targets->targets_arr[i];
1394 
1395 		err = damon_sysfs_add_target(st, ctx);
1396 		if (err)
1397 			return err;
1398 	}
1399 	return 0;
1400 }
1401 
1402 /*
1403  * damon_sysfs_upd_schemes_stats() - Update schemes stats sysfs files.
1404  * @data:	The kobject wrapper that associated to the kdamond thread.
1405  *
1406  * This function reads the schemes stats of specific kdamond and update the
1407  * related values for sysfs files.  This function should be called from DAMON
1408  * worker thread,to safely access the DAMON contexts-internal data.  Caller
1409  * should also ensure holding ``damon_syfs_lock``, and ->damon_ctx of @data is
1410  * not NULL but a valid pointer, to safely access DAMON sysfs variables.
1411  */
1412 static int damon_sysfs_upd_schemes_stats(void *data)
1413 {
1414 	struct damon_sysfs_kdamond *kdamond = data;
1415 	struct damon_ctx *ctx = kdamond->damon_ctx;
1416 
1417 	damon_sysfs_schemes_update_stats(
1418 			kdamond->contexts->contexts_arr[0]->schemes, ctx);
1419 	return 0;
1420 }
1421 
1422 static inline bool damon_sysfs_kdamond_running(
1423 		struct damon_sysfs_kdamond *kdamond)
1424 {
1425 	return kdamond->damon_ctx &&
1426 		damon_is_running(kdamond->damon_ctx);
1427 }
1428 
1429 static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
1430 		struct damon_sysfs_context *sys_ctx)
1431 {
1432 	int err;
1433 
1434 	err = damon_select_ops(ctx, sys_ctx->ops_id);
1435 	if (err)
1436 		return err;
1437 	ctx->addr_unit = sys_ctx->addr_unit;
1438 	ctx->min_sz_region = max(DAMON_MIN_REGION / sys_ctx->addr_unit, 1);
1439 	err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
1440 	if (err)
1441 		return err;
1442 	err = damon_sysfs_add_targets(ctx, sys_ctx->targets);
1443 	if (err)
1444 		return err;
1445 	return damon_sysfs_add_schemes(ctx, sys_ctx->schemes);
1446 }
1447 
1448 static struct damon_ctx *damon_sysfs_build_ctx(
1449 		struct damon_sysfs_context *sys_ctx);
1450 
1451 /*
1452  * damon_sysfs_commit_input() - Commit user inputs to a running kdamond.
1453  * @kdamond:	The kobject wrapper for the associated kdamond.
1454  *
1455  * Returns error if the sysfs input is wrong.
1456  */
1457 static int damon_sysfs_commit_input(void *data)
1458 {
1459 	struct damon_sysfs_kdamond *kdamond = data;
1460 	struct damon_ctx *param_ctx, *test_ctx;
1461 	int err;
1462 
1463 	if (!damon_sysfs_kdamond_running(kdamond))
1464 		return -EINVAL;
1465 	/* TODO: Support multiple contexts per kdamond */
1466 	if (kdamond->contexts->nr != 1)
1467 		return -EINVAL;
1468 
1469 	param_ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
1470 	if (IS_ERR(param_ctx))
1471 		return PTR_ERR(param_ctx);
1472 	test_ctx = damon_new_ctx();
1473 	err = damon_commit_ctx(test_ctx, param_ctx);
1474 	if (err) {
1475 		damon_destroy_ctx(test_ctx);
1476 		goto out;
1477 	}
1478 	err = damon_commit_ctx(kdamond->damon_ctx, param_ctx);
1479 out:
1480 	damon_destroy_ctx(param_ctx);
1481 	return err;
1482 }
1483 
1484 static int damon_sysfs_commit_schemes_quota_goals(void *data)
1485 {
1486 	struct damon_sysfs_kdamond *sysfs_kdamond = data;
1487 	struct damon_ctx *ctx;
1488 	struct damon_sysfs_context *sysfs_ctx;
1489 
1490 	if (!damon_sysfs_kdamond_running(sysfs_kdamond))
1491 		return -EINVAL;
1492 	/* TODO: Support multiple contexts per kdamond */
1493 	if (sysfs_kdamond->contexts->nr != 1)
1494 		return -EINVAL;
1495 
1496 	ctx = sysfs_kdamond->damon_ctx;
1497 	sysfs_ctx = sysfs_kdamond->contexts->contexts_arr[0];
1498 	return damos_sysfs_set_quota_scores(sysfs_ctx->schemes, ctx);
1499 }
1500 
1501 /*
1502  * damon_sysfs_upd_schemes_effective_quotas() - Update schemes effective quotas
1503  * sysfs files.
1504  * @data:	The kobject wrapper that associated to the kdamond thread.
1505  *
1506  * This function reads the schemes' effective quotas of specific kdamond and
1507  * update the related values for sysfs files.  This function should be called
1508  * from DAMON callbacks while holding ``damon_syfs_lock``, to safely access the
1509  * DAMON contexts-internal data and DAMON sysfs variables.
1510  */
1511 static int damon_sysfs_upd_schemes_effective_quotas(void *data)
1512 {
1513 	struct damon_sysfs_kdamond *kdamond = data;
1514 	struct damon_ctx *ctx = kdamond->damon_ctx;
1515 
1516 	damos_sysfs_update_effective_quotas(
1517 			kdamond->contexts->contexts_arr[0]->schemes, ctx);
1518 	return 0;
1519 }
1520 
1521 static int damon_sysfs_upd_tuned_intervals(void *data)
1522 {
1523 	struct damon_sysfs_kdamond *kdamond = data;
1524 	struct damon_ctx *ctx = kdamond->damon_ctx;
1525 
1526 	kdamond->contexts->contexts_arr[0]->attrs->intervals->sample_us =
1527 		ctx->attrs.sample_interval;
1528 	kdamond->contexts->contexts_arr[0]->attrs->intervals->aggr_us =
1529 		ctx->attrs.aggr_interval;
1530 	return 0;
1531 }
1532 
1533 static struct damon_ctx *damon_sysfs_build_ctx(
1534 		struct damon_sysfs_context *sys_ctx)
1535 {
1536 	struct damon_ctx *ctx = damon_new_ctx();
1537 	int err;
1538 
1539 	if (!ctx)
1540 		return ERR_PTR(-ENOMEM);
1541 
1542 	err = damon_sysfs_apply_inputs(ctx, sys_ctx);
1543 	if (err) {
1544 		damon_destroy_ctx(ctx);
1545 		return ERR_PTR(err);
1546 	}
1547 
1548 	return ctx;
1549 }
1550 
1551 static int damon_sysfs_repeat_call_fn(void *data)
1552 {
1553 	struct damon_sysfs_kdamond *sysfs_kdamond = data;
1554 	static unsigned long next_update_jiffies;
1555 
1556 	if (!sysfs_kdamond->refresh_ms)
1557 		return 0;
1558 	if (time_before(jiffies, next_update_jiffies))
1559 		return 0;
1560 	next_update_jiffies = jiffies +
1561 		msecs_to_jiffies(sysfs_kdamond->refresh_ms);
1562 
1563 	if (!mutex_trylock(&damon_sysfs_lock))
1564 		return 0;
1565 	damon_sysfs_upd_tuned_intervals(sysfs_kdamond);
1566 	damon_sysfs_upd_schemes_stats(sysfs_kdamond);
1567 	damon_sysfs_upd_schemes_effective_quotas(sysfs_kdamond);
1568 	mutex_unlock(&damon_sysfs_lock);
1569 	return 0;
1570 }
1571 
1572 static int damon_sysfs_turn_damon_on(struct damon_sysfs_kdamond *kdamond)
1573 {
1574 	struct damon_ctx *ctx;
1575 	struct damon_call_control *repeat_call_control;
1576 	int err;
1577 
1578 	if (damon_sysfs_kdamond_running(kdamond))
1579 		return -EBUSY;
1580 	/* TODO: support multiple contexts per kdamond */
1581 	if (kdamond->contexts->nr != 1)
1582 		return -EINVAL;
1583 
1584 	if (kdamond->damon_ctx)
1585 		damon_destroy_ctx(kdamond->damon_ctx);
1586 	kdamond->damon_ctx = NULL;
1587 
1588 	repeat_call_control = kmalloc(sizeof(*repeat_call_control),
1589 			GFP_KERNEL);
1590 	if (!repeat_call_control)
1591 		return -ENOMEM;
1592 
1593 	ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
1594 	if (IS_ERR(ctx)) {
1595 		kfree(repeat_call_control);
1596 		return PTR_ERR(ctx);
1597 	}
1598 	err = damon_start(&ctx, 1, false);
1599 	if (err) {
1600 		kfree(repeat_call_control);
1601 		damon_destroy_ctx(ctx);
1602 		return err;
1603 	}
1604 	kdamond->damon_ctx = ctx;
1605 
1606 	repeat_call_control->fn = damon_sysfs_repeat_call_fn;
1607 	repeat_call_control->data = kdamond;
1608 	repeat_call_control->repeat = true;
1609 	repeat_call_control->dealloc_on_cancel = true;
1610 	damon_call(ctx, repeat_call_control);
1611 	return err;
1612 }
1613 
1614 static int damon_sysfs_turn_damon_off(struct damon_sysfs_kdamond *kdamond)
1615 {
1616 	if (!kdamond->damon_ctx)
1617 		return -EINVAL;
1618 	return damon_stop(&kdamond->damon_ctx, 1);
1619 	/*
1620 	 * To allow users show final monitoring results of already turned-off
1621 	 * DAMON, we free kdamond->damon_ctx in next
1622 	 * damon_sysfs_turn_damon_on(), or kdamonds_nr_store()
1623 	 */
1624 }
1625 
1626 static int damon_sysfs_damon_call(int (*fn)(void *data),
1627 		struct damon_sysfs_kdamond *kdamond)
1628 {
1629 	struct damon_call_control call_control = {};
1630 
1631 	if (!kdamond->damon_ctx)
1632 		return -EINVAL;
1633 	call_control.fn = fn;
1634 	call_control.data = kdamond;
1635 	return damon_call(kdamond->damon_ctx, &call_control);
1636 }
1637 
1638 struct damon_sysfs_schemes_walk_data {
1639 	struct damon_sysfs_kdamond *sysfs_kdamond;
1640 	bool total_bytes_only;
1641 };
1642 
1643 /* populate the region directory */
1644 static void damon_sysfs_schemes_tried_regions_upd_one(void *data, struct damon_ctx *ctx,
1645 		struct damon_target *t, struct damon_region *r,
1646 		struct damos *s, unsigned long sz_filter_passed)
1647 {
1648 	struct damon_sysfs_schemes_walk_data *walk_data = data;
1649 	struct damon_sysfs_kdamond *sysfs_kdamond = walk_data->sysfs_kdamond;
1650 
1651 	damos_sysfs_populate_region_dir(
1652 			sysfs_kdamond->contexts->contexts_arr[0]->schemes,
1653 			ctx, t, r, s, walk_data->total_bytes_only,
1654 			sz_filter_passed);
1655 }
1656 
1657 static int damon_sysfs_update_schemes_tried_regions(
1658 		struct damon_sysfs_kdamond *sysfs_kdamond, bool total_bytes_only)
1659 {
1660 	struct damon_sysfs_schemes_walk_data walk_data = {
1661 		.sysfs_kdamond = sysfs_kdamond,
1662 		.total_bytes_only = total_bytes_only,
1663 	};
1664 	struct damos_walk_control control = {
1665 		.walk_fn = damon_sysfs_schemes_tried_regions_upd_one,
1666 		.data = &walk_data,
1667 	};
1668 	struct damon_ctx *ctx = sysfs_kdamond->damon_ctx;
1669 
1670 	if (!ctx)
1671 		return -EINVAL;
1672 
1673 	damon_sysfs_schemes_clear_regions(
1674 			sysfs_kdamond->contexts->contexts_arr[0]->schemes);
1675 	return damos_walk(ctx, &control);
1676 }
1677 
1678 /*
1679  * damon_sysfs_handle_cmd() - Handle a command for a specific kdamond.
1680  * @cmd:	The command to handle.
1681  * @kdamond:	The kobject wrapper for the associated kdamond.
1682  *
1683  * This function handles a DAMON sysfs command for a kdamond.
1684  *
1685  * Return: 0 on success, negative error code otherwise.
1686  */
1687 static int damon_sysfs_handle_cmd(enum damon_sysfs_cmd cmd,
1688 		struct damon_sysfs_kdamond *kdamond)
1689 {
1690 	switch (cmd) {
1691 	case DAMON_SYSFS_CMD_ON:
1692 		return damon_sysfs_turn_damon_on(kdamond);
1693 	case DAMON_SYSFS_CMD_OFF:
1694 		return damon_sysfs_turn_damon_off(kdamond);
1695 	case DAMON_SYSFS_CMD_COMMIT:
1696 		return damon_sysfs_damon_call(
1697 				damon_sysfs_commit_input, kdamond);
1698 	case DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS:
1699 		return damon_sysfs_damon_call(
1700 				damon_sysfs_commit_schemes_quota_goals,
1701 				kdamond);
1702 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS:
1703 		return damon_sysfs_damon_call(
1704 				damon_sysfs_upd_schemes_stats, kdamond);
1705 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES:
1706 		return damon_sysfs_update_schemes_tried_regions(kdamond, true);
1707 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS:
1708 		return damon_sysfs_update_schemes_tried_regions(kdamond, false);
1709 	case DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS:
1710 		return damon_sysfs_schemes_clear_regions(
1711 			kdamond->contexts->contexts_arr[0]->schemes);
1712 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS:
1713 		return damon_sysfs_damon_call(
1714 				damon_sysfs_upd_schemes_effective_quotas,
1715 				kdamond);
1716 	case DAMON_SYSFS_CMD_UPDATE_TUNED_INTERVALS:
1717 		return damon_sysfs_damon_call(
1718 				damon_sysfs_upd_tuned_intervals, kdamond);
1719 	default:
1720 		return -EINVAL;
1721 	}
1722 }
1723 
1724 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
1725 		const char *buf, size_t count)
1726 {
1727 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1728 			struct damon_sysfs_kdamond, kobj);
1729 	enum damon_sysfs_cmd cmd;
1730 	ssize_t ret = -EINVAL;
1731 
1732 	if (!mutex_trylock(&damon_sysfs_lock))
1733 		return -EBUSY;
1734 	for (cmd = 0; cmd < NR_DAMON_SYSFS_CMDS; cmd++) {
1735 		if (sysfs_streq(buf, damon_sysfs_cmd_strs[cmd])) {
1736 			ret = damon_sysfs_handle_cmd(cmd, kdamond);
1737 			break;
1738 		}
1739 	}
1740 	mutex_unlock(&damon_sysfs_lock);
1741 	if (!ret)
1742 		ret = count;
1743 	return ret;
1744 }
1745 
1746 static ssize_t pid_show(struct kobject *kobj,
1747 		struct kobj_attribute *attr, char *buf)
1748 {
1749 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1750 			struct damon_sysfs_kdamond, kobj);
1751 	struct damon_ctx *ctx;
1752 	int pid = -1;
1753 
1754 	if (!mutex_trylock(&damon_sysfs_lock))
1755 		return -EBUSY;
1756 	ctx = kdamond->damon_ctx;
1757 	if (!ctx)
1758 		goto out;
1759 
1760 	mutex_lock(&ctx->kdamond_lock);
1761 	if (ctx->kdamond)
1762 		pid = ctx->kdamond->pid;
1763 	mutex_unlock(&ctx->kdamond_lock);
1764 out:
1765 	mutex_unlock(&damon_sysfs_lock);
1766 	return sysfs_emit(buf, "%d\n", pid);
1767 }
1768 
1769 static ssize_t refresh_ms_show(struct kobject *kobj,
1770 		struct kobj_attribute *attr, char *buf)
1771 {
1772 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1773 			struct damon_sysfs_kdamond, kobj);
1774 
1775 	return sysfs_emit(buf, "%u\n", kdamond->refresh_ms);
1776 }
1777 
1778 static ssize_t refresh_ms_store(struct kobject *kobj,
1779 		struct kobj_attribute *attr, const char *buf, size_t count)
1780 {
1781 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1782 			struct damon_sysfs_kdamond, kobj);
1783 	unsigned int nr;
1784 	int err = kstrtouint(buf, 0, &nr);
1785 
1786 	if (err)
1787 		return err;
1788 
1789 	kdamond->refresh_ms = nr;
1790 	return count;
1791 }
1792 
1793 static void damon_sysfs_kdamond_release(struct kobject *kobj)
1794 {
1795 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1796 			struct damon_sysfs_kdamond, kobj);
1797 
1798 	if (kdamond->damon_ctx)
1799 		damon_destroy_ctx(kdamond->damon_ctx);
1800 	kfree(kdamond);
1801 }
1802 
1803 static struct kobj_attribute damon_sysfs_kdamond_state_attr =
1804 		__ATTR_RW_MODE(state, 0600);
1805 
1806 static struct kobj_attribute damon_sysfs_kdamond_pid_attr =
1807 		__ATTR_RO_MODE(pid, 0400);
1808 
1809 static struct kobj_attribute damon_sysfs_kdamond_refresh_ms_attr =
1810 		__ATTR_RW_MODE(refresh_ms, 0600);
1811 
1812 static struct attribute *damon_sysfs_kdamond_attrs[] = {
1813 	&damon_sysfs_kdamond_state_attr.attr,
1814 	&damon_sysfs_kdamond_pid_attr.attr,
1815 	&damon_sysfs_kdamond_refresh_ms_attr.attr,
1816 	NULL,
1817 };
1818 ATTRIBUTE_GROUPS(damon_sysfs_kdamond);
1819 
1820 static const struct kobj_type damon_sysfs_kdamond_ktype = {
1821 	.release = damon_sysfs_kdamond_release,
1822 	.sysfs_ops = &kobj_sysfs_ops,
1823 	.default_groups = damon_sysfs_kdamond_groups,
1824 };
1825 
1826 /*
1827  * kdamonds directory
1828  */
1829 
1830 struct damon_sysfs_kdamonds {
1831 	struct kobject kobj;
1832 	struct damon_sysfs_kdamond **kdamonds_arr;
1833 	int nr;
1834 };
1835 
1836 static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void)
1837 {
1838 	return kzalloc(sizeof(struct damon_sysfs_kdamonds), GFP_KERNEL);
1839 }
1840 
1841 static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
1842 {
1843 	struct damon_sysfs_kdamond **kdamonds_arr = kdamonds->kdamonds_arr;
1844 	int i;
1845 
1846 	for (i = 0; i < kdamonds->nr; i++) {
1847 		damon_sysfs_kdamond_rm_dirs(kdamonds_arr[i]);
1848 		kobject_put(&kdamonds_arr[i]->kobj);
1849 	}
1850 	kdamonds->nr = 0;
1851 	kfree(kdamonds_arr);
1852 	kdamonds->kdamonds_arr = NULL;
1853 }
1854 
1855 static bool damon_sysfs_kdamonds_busy(struct damon_sysfs_kdamond **kdamonds,
1856 		int nr_kdamonds)
1857 {
1858 	int i;
1859 
1860 	for (i = 0; i < nr_kdamonds; i++) {
1861 		if (damon_sysfs_kdamond_running(kdamonds[i]))
1862 			return true;
1863 	}
1864 
1865 	return false;
1866 }
1867 
1868 static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
1869 		int nr_kdamonds)
1870 {
1871 	struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
1872 	int err, i;
1873 
1874 	if (damon_sysfs_kdamonds_busy(kdamonds->kdamonds_arr, kdamonds->nr))
1875 		return -EBUSY;
1876 
1877 	damon_sysfs_kdamonds_rm_dirs(kdamonds);
1878 	if (!nr_kdamonds)
1879 		return 0;
1880 
1881 	kdamonds_arr = kmalloc_array(nr_kdamonds, sizeof(*kdamonds_arr),
1882 			GFP_KERNEL | __GFP_NOWARN);
1883 	if (!kdamonds_arr)
1884 		return -ENOMEM;
1885 	kdamonds->kdamonds_arr = kdamonds_arr;
1886 
1887 	for (i = 0; i < nr_kdamonds; i++) {
1888 		kdamond = damon_sysfs_kdamond_alloc();
1889 		if (!kdamond) {
1890 			damon_sysfs_kdamonds_rm_dirs(kdamonds);
1891 			return -ENOMEM;
1892 		}
1893 
1894 		err = kobject_init_and_add(&kdamond->kobj,
1895 				&damon_sysfs_kdamond_ktype, &kdamonds->kobj,
1896 				"%d", i);
1897 		if (err)
1898 			goto out;
1899 
1900 		err = damon_sysfs_kdamond_add_dirs(kdamond);
1901 		if (err)
1902 			goto out;
1903 
1904 		kdamonds_arr[i] = kdamond;
1905 		kdamonds->nr++;
1906 	}
1907 	return 0;
1908 
1909 out:
1910 	damon_sysfs_kdamonds_rm_dirs(kdamonds);
1911 	kobject_put(&kdamond->kobj);
1912 	return err;
1913 }
1914 
1915 static ssize_t nr_kdamonds_show(struct kobject *kobj,
1916 		struct kobj_attribute *attr, char *buf)
1917 {
1918 	struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
1919 			struct damon_sysfs_kdamonds, kobj);
1920 
1921 	return sysfs_emit(buf, "%d\n", kdamonds->nr);
1922 }
1923 
1924 static ssize_t nr_kdamonds_store(struct kobject *kobj,
1925 		struct kobj_attribute *attr, const char *buf, size_t count)
1926 {
1927 	struct damon_sysfs_kdamonds *kdamonds;
1928 	int nr, err;
1929 
1930 	err = kstrtoint(buf, 0, &nr);
1931 	if (err)
1932 		return err;
1933 	if (nr < 0)
1934 		return -EINVAL;
1935 
1936 	kdamonds = container_of(kobj, struct damon_sysfs_kdamonds, kobj);
1937 
1938 	if (!mutex_trylock(&damon_sysfs_lock))
1939 		return -EBUSY;
1940 	err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr);
1941 	mutex_unlock(&damon_sysfs_lock);
1942 	if (err)
1943 		return err;
1944 
1945 	return count;
1946 }
1947 
1948 static void damon_sysfs_kdamonds_release(struct kobject *kobj)
1949 {
1950 	kfree(container_of(kobj, struct damon_sysfs_kdamonds, kobj));
1951 }
1952 
1953 static struct kobj_attribute damon_sysfs_kdamonds_nr_attr =
1954 		__ATTR_RW_MODE(nr_kdamonds, 0600);
1955 
1956 static struct attribute *damon_sysfs_kdamonds_attrs[] = {
1957 	&damon_sysfs_kdamonds_nr_attr.attr,
1958 	NULL,
1959 };
1960 ATTRIBUTE_GROUPS(damon_sysfs_kdamonds);
1961 
1962 static const struct kobj_type damon_sysfs_kdamonds_ktype = {
1963 	.release = damon_sysfs_kdamonds_release,
1964 	.sysfs_ops = &kobj_sysfs_ops,
1965 	.default_groups = damon_sysfs_kdamonds_groups,
1966 };
1967 
1968 /*
1969  * damon user interface directory
1970  */
1971 
1972 struct damon_sysfs_ui_dir {
1973 	struct kobject kobj;
1974 	struct damon_sysfs_kdamonds *kdamonds;
1975 };
1976 
1977 static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
1978 {
1979 	return kzalloc(sizeof(struct damon_sysfs_ui_dir), GFP_KERNEL);
1980 }
1981 
1982 static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
1983 {
1984 	struct damon_sysfs_kdamonds *kdamonds;
1985 	int err;
1986 
1987 	kdamonds = damon_sysfs_kdamonds_alloc();
1988 	if (!kdamonds)
1989 		return -ENOMEM;
1990 
1991 	err = kobject_init_and_add(&kdamonds->kobj,
1992 			&damon_sysfs_kdamonds_ktype, &ui_dir->kobj,
1993 			"kdamonds");
1994 	if (err) {
1995 		kobject_put(&kdamonds->kobj);
1996 		return err;
1997 	}
1998 	ui_dir->kdamonds = kdamonds;
1999 	return err;
2000 }
2001 
2002 static void damon_sysfs_ui_dir_release(struct kobject *kobj)
2003 {
2004 	kfree(container_of(kobj, struct damon_sysfs_ui_dir, kobj));
2005 }
2006 
2007 static struct attribute *damon_sysfs_ui_dir_attrs[] = {
2008 	NULL,
2009 };
2010 ATTRIBUTE_GROUPS(damon_sysfs_ui_dir);
2011 
2012 static const struct kobj_type damon_sysfs_ui_dir_ktype = {
2013 	.release = damon_sysfs_ui_dir_release,
2014 	.sysfs_ops = &kobj_sysfs_ops,
2015 	.default_groups = damon_sysfs_ui_dir_groups,
2016 };
2017 
2018 static int __init damon_sysfs_init(void)
2019 {
2020 	struct kobject *damon_sysfs_root;
2021 	struct damon_sysfs_ui_dir *admin;
2022 	int err;
2023 
2024 	damon_sysfs_root = kobject_create_and_add("damon", mm_kobj);
2025 	if (!damon_sysfs_root)
2026 		return -ENOMEM;
2027 
2028 	admin = damon_sysfs_ui_dir_alloc();
2029 	if (!admin) {
2030 		kobject_put(damon_sysfs_root);
2031 		return -ENOMEM;
2032 	}
2033 	err = kobject_init_and_add(&admin->kobj, &damon_sysfs_ui_dir_ktype,
2034 			damon_sysfs_root, "admin");
2035 	if (err)
2036 		goto out;
2037 	err = damon_sysfs_ui_dir_add_dirs(admin);
2038 	if (err)
2039 		goto out;
2040 	return 0;
2041 
2042 out:
2043 	kobject_put(&admin->kobj);
2044 	kobject_put(damon_sysfs_root);
2045 	return err;
2046 }
2047 subsys_initcall(damon_sysfs_init);
2048 
2049 #include "tests/sysfs-kunit.h"
2050