xref: /linux/mm/damon/sysfs.c (revision 60bee40e30d047356a118bd637ba4960baadcd46)
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_obj(struct damon_sysfs_region);
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_obj(struct damon_sysfs_regions);
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_objs(*regions_arr, nr_regions,
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 	bool obsolete;
216 };
217 
218 static struct damon_sysfs_target *damon_sysfs_target_alloc(void)
219 {
220 	return kzalloc_obj(struct damon_sysfs_target);
221 }
222 
223 static int damon_sysfs_target_add_dirs(struct damon_sysfs_target *target)
224 {
225 	struct damon_sysfs_regions *regions = damon_sysfs_regions_alloc();
226 	int err;
227 
228 	if (!regions)
229 		return -ENOMEM;
230 
231 	err = kobject_init_and_add(&regions->kobj, &damon_sysfs_regions_ktype,
232 			&target->kobj, "regions");
233 	if (err)
234 		kobject_put(&regions->kobj);
235 	else
236 		target->regions = regions;
237 	return err;
238 }
239 
240 static void damon_sysfs_target_rm_dirs(struct damon_sysfs_target *target)
241 {
242 	damon_sysfs_regions_rm_dirs(target->regions);
243 	kobject_put(&target->regions->kobj);
244 }
245 
246 static ssize_t pid_target_show(struct kobject *kobj,
247 		struct kobj_attribute *attr, char *buf)
248 {
249 	struct damon_sysfs_target *target = container_of(kobj,
250 			struct damon_sysfs_target, kobj);
251 
252 	return sysfs_emit(buf, "%d\n", target->pid);
253 }
254 
255 static ssize_t pid_target_store(struct kobject *kobj,
256 		struct kobj_attribute *attr, const char *buf, size_t count)
257 {
258 	struct damon_sysfs_target *target = container_of(kobj,
259 			struct damon_sysfs_target, kobj);
260 	int err = kstrtoint(buf, 0, &target->pid);
261 
262 	if (err)
263 		return -EINVAL;
264 	return count;
265 }
266 
267 static ssize_t obsolete_target_show(struct kobject *kobj,
268 		struct kobj_attribute *attr, char *buf)
269 {
270 	struct damon_sysfs_target *target = container_of(kobj,
271 			struct damon_sysfs_target, kobj);
272 
273 	return sysfs_emit(buf, "%c\n", target->obsolete ? 'Y' : 'N');
274 }
275 
276 static ssize_t obsolete_target_store(struct kobject *kobj,
277 		struct kobj_attribute *attr, const char *buf, size_t count)
278 {
279 	struct damon_sysfs_target *target = container_of(kobj,
280 			struct damon_sysfs_target, kobj);
281 	bool obsolete;
282 	int err = kstrtobool(buf, &obsolete);
283 
284 	if (err)
285 		return err;
286 	target->obsolete = obsolete;
287 	return count;
288 }
289 
290 static void damon_sysfs_target_release(struct kobject *kobj)
291 {
292 	kfree(container_of(kobj, struct damon_sysfs_target, kobj));
293 }
294 
295 static struct kobj_attribute damon_sysfs_target_pid_attr =
296 		__ATTR_RW_MODE(pid_target, 0600);
297 
298 static struct kobj_attribute damon_sysfs_target_obsolete_attr =
299 		__ATTR_RW_MODE(obsolete_target, 0600);
300 
301 static struct attribute *damon_sysfs_target_attrs[] = {
302 	&damon_sysfs_target_pid_attr.attr,
303 	&damon_sysfs_target_obsolete_attr.attr,
304 	NULL,
305 };
306 ATTRIBUTE_GROUPS(damon_sysfs_target);
307 
308 static const struct kobj_type damon_sysfs_target_ktype = {
309 	.release = damon_sysfs_target_release,
310 	.sysfs_ops = &kobj_sysfs_ops,
311 	.default_groups = damon_sysfs_target_groups,
312 };
313 
314 /*
315  * targets directory
316  */
317 
318 struct damon_sysfs_targets {
319 	struct kobject kobj;
320 	struct damon_sysfs_target **targets_arr;
321 	int nr;
322 };
323 
324 static struct damon_sysfs_targets *damon_sysfs_targets_alloc(void)
325 {
326 	return kzalloc_obj(struct damon_sysfs_targets);
327 }
328 
329 static void damon_sysfs_targets_rm_dirs(struct damon_sysfs_targets *targets)
330 {
331 	struct damon_sysfs_target **targets_arr = targets->targets_arr;
332 	int i;
333 
334 	for (i = 0; i < targets->nr; i++) {
335 		damon_sysfs_target_rm_dirs(targets_arr[i]);
336 		kobject_put(&targets_arr[i]->kobj);
337 	}
338 	targets->nr = 0;
339 	kfree(targets_arr);
340 	targets->targets_arr = NULL;
341 }
342 
343 static int damon_sysfs_targets_add_dirs(struct damon_sysfs_targets *targets,
344 		int nr_targets)
345 {
346 	struct damon_sysfs_target **targets_arr, *target;
347 	int err, i;
348 
349 	damon_sysfs_targets_rm_dirs(targets);
350 	if (!nr_targets)
351 		return 0;
352 
353 	targets_arr = kmalloc_objs(*targets_arr, nr_targets,
354 				   GFP_KERNEL | __GFP_NOWARN);
355 	if (!targets_arr)
356 		return -ENOMEM;
357 	targets->targets_arr = targets_arr;
358 
359 	for (i = 0; i < nr_targets; i++) {
360 		target = damon_sysfs_target_alloc();
361 		if (!target) {
362 			damon_sysfs_targets_rm_dirs(targets);
363 			return -ENOMEM;
364 		}
365 
366 		err = kobject_init_and_add(&target->kobj,
367 				&damon_sysfs_target_ktype, &targets->kobj,
368 				"%d", i);
369 		if (err)
370 			goto out;
371 
372 		err = damon_sysfs_target_add_dirs(target);
373 		if (err)
374 			goto out;
375 
376 		targets_arr[i] = target;
377 		targets->nr++;
378 	}
379 	return 0;
380 
381 out:
382 	damon_sysfs_targets_rm_dirs(targets);
383 	kobject_put(&target->kobj);
384 	return err;
385 }
386 
387 static ssize_t nr_targets_show(struct kobject *kobj,
388 		struct kobj_attribute *attr, char *buf)
389 {
390 	struct damon_sysfs_targets *targets = container_of(kobj,
391 			struct damon_sysfs_targets, kobj);
392 
393 	return sysfs_emit(buf, "%d\n", targets->nr);
394 }
395 
396 static ssize_t nr_targets_store(struct kobject *kobj,
397 		struct kobj_attribute *attr, const char *buf, size_t count)
398 {
399 	struct damon_sysfs_targets *targets;
400 	int nr, err = kstrtoint(buf, 0, &nr);
401 
402 	if (err)
403 		return err;
404 	if (nr < 0)
405 		return -EINVAL;
406 
407 	targets = container_of(kobj, struct damon_sysfs_targets, kobj);
408 
409 	if (!mutex_trylock(&damon_sysfs_lock))
410 		return -EBUSY;
411 	err = damon_sysfs_targets_add_dirs(targets, nr);
412 	mutex_unlock(&damon_sysfs_lock);
413 	if (err)
414 		return err;
415 
416 	return count;
417 }
418 
419 static void damon_sysfs_targets_release(struct kobject *kobj)
420 {
421 	kfree(container_of(kobj, struct damon_sysfs_targets, kobj));
422 }
423 
424 static struct kobj_attribute damon_sysfs_targets_nr_attr =
425 		__ATTR_RW_MODE(nr_targets, 0600);
426 
427 static struct attribute *damon_sysfs_targets_attrs[] = {
428 	&damon_sysfs_targets_nr_attr.attr,
429 	NULL,
430 };
431 ATTRIBUTE_GROUPS(damon_sysfs_targets);
432 
433 static const struct kobj_type damon_sysfs_targets_ktype = {
434 	.release = damon_sysfs_targets_release,
435 	.sysfs_ops = &kobj_sysfs_ops,
436 	.default_groups = damon_sysfs_targets_groups,
437 };
438 
439 /*
440  * intervals goal directory
441  */
442 
443 struct damon_sysfs_intervals_goal {
444 	struct kobject kobj;
445 	unsigned long access_bp;
446 	unsigned long aggrs;
447 	unsigned long min_sample_us;
448 	unsigned long max_sample_us;
449 };
450 
451 static struct damon_sysfs_intervals_goal *damon_sysfs_intervals_goal_alloc(
452 		unsigned long access_bp, unsigned long aggrs,
453 		unsigned long min_sample_us, unsigned long max_sample_us)
454 {
455 	struct damon_sysfs_intervals_goal *goal = kmalloc_obj(*goal);
456 
457 	if (!goal)
458 		return NULL;
459 
460 	goal->kobj = (struct kobject){};
461 	goal->access_bp = access_bp;
462 	goal->aggrs = aggrs;
463 	goal->min_sample_us = min_sample_us;
464 	goal->max_sample_us = max_sample_us;
465 	return goal;
466 }
467 
468 static ssize_t access_bp_show(struct kobject *kobj,
469 		struct kobj_attribute *attr, char *buf)
470 {
471 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
472 			struct damon_sysfs_intervals_goal, kobj);
473 
474 	return sysfs_emit(buf, "%lu\n", goal->access_bp);
475 }
476 
477 static ssize_t access_bp_store(struct kobject *kobj,
478 		struct kobj_attribute *attr, const char *buf, size_t count)
479 {
480 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
481 			struct damon_sysfs_intervals_goal, kobj);
482 	unsigned long nr;
483 	int err = kstrtoul(buf, 0, &nr);
484 
485 	if (err)
486 		return err;
487 
488 	goal->access_bp = nr;
489 	return count;
490 }
491 
492 static ssize_t aggrs_show(struct kobject *kobj,
493 		struct kobj_attribute *attr, char *buf)
494 {
495 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
496 			struct damon_sysfs_intervals_goal, kobj);
497 
498 	return sysfs_emit(buf, "%lu\n", goal->aggrs);
499 }
500 
501 static ssize_t aggrs_store(struct kobject *kobj,
502 		struct kobj_attribute *attr, const char *buf, size_t count)
503 {
504 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
505 			struct damon_sysfs_intervals_goal, kobj);
506 	unsigned long nr;
507 	int err = kstrtoul(buf, 0, &nr);
508 
509 	if (err)
510 		return err;
511 
512 	goal->aggrs = nr;
513 	return count;
514 }
515 
516 static ssize_t min_sample_us_show(struct kobject *kobj,
517 		struct kobj_attribute *attr, char *buf)
518 {
519 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
520 			struct damon_sysfs_intervals_goal, kobj);
521 
522 	return sysfs_emit(buf, "%lu\n", goal->min_sample_us);
523 }
524 
525 static ssize_t min_sample_us_store(struct kobject *kobj,
526 		struct kobj_attribute *attr, const char *buf, size_t count)
527 {
528 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
529 			struct damon_sysfs_intervals_goal, kobj);
530 	unsigned long nr;
531 	int err = kstrtoul(buf, 0, &nr);
532 
533 	if (err)
534 		return err;
535 
536 	goal->min_sample_us = nr;
537 	return count;
538 }
539 
540 static ssize_t max_sample_us_show(struct kobject *kobj,
541 		struct kobj_attribute *attr, char *buf)
542 {
543 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
544 			struct damon_sysfs_intervals_goal, kobj);
545 
546 	return sysfs_emit(buf, "%lu\n", goal->max_sample_us);
547 }
548 
549 static ssize_t max_sample_us_store(struct kobject *kobj,
550 		struct kobj_attribute *attr, const char *buf, size_t count)
551 {
552 	struct damon_sysfs_intervals_goal *goal = container_of(kobj,
553 			struct damon_sysfs_intervals_goal, kobj);
554 	unsigned long nr;
555 	int err = kstrtoul(buf, 0, &nr);
556 
557 	if (err)
558 		return err;
559 
560 	goal->max_sample_us = nr;
561 	return count;
562 }
563 
564 static void damon_sysfs_intervals_goal_release(struct kobject *kobj)
565 {
566 	kfree(container_of(kobj, struct damon_sysfs_intervals_goal, kobj));
567 }
568 
569 static struct kobj_attribute damon_sysfs_intervals_goal_access_bp_attr =
570 		__ATTR_RW_MODE(access_bp, 0600);
571 
572 static struct kobj_attribute damon_sysfs_intervals_goal_aggrs_attr =
573 		__ATTR_RW_MODE(aggrs, 0600);
574 
575 static struct kobj_attribute damon_sysfs_intervals_goal_min_sample_us_attr =
576 		__ATTR_RW_MODE(min_sample_us, 0600);
577 
578 static struct kobj_attribute damon_sysfs_intervals_goal_max_sample_us_attr =
579 		__ATTR_RW_MODE(max_sample_us, 0600);
580 
581 static struct attribute *damon_sysfs_intervals_goal_attrs[] = {
582 	&damon_sysfs_intervals_goal_access_bp_attr.attr,
583 	&damon_sysfs_intervals_goal_aggrs_attr.attr,
584 	&damon_sysfs_intervals_goal_min_sample_us_attr.attr,
585 	&damon_sysfs_intervals_goal_max_sample_us_attr.attr,
586 	NULL,
587 };
588 ATTRIBUTE_GROUPS(damon_sysfs_intervals_goal);
589 
590 static const struct kobj_type damon_sysfs_intervals_goal_ktype = {
591 	.release = damon_sysfs_intervals_goal_release,
592 	.sysfs_ops = &kobj_sysfs_ops,
593 	.default_groups = damon_sysfs_intervals_goal_groups,
594 };
595 
596 /*
597  * intervals directory
598  */
599 
600 struct damon_sysfs_intervals {
601 	struct kobject kobj;
602 	unsigned long sample_us;
603 	unsigned long aggr_us;
604 	unsigned long update_us;
605 	struct damon_sysfs_intervals_goal *intervals_goal;
606 };
607 
608 static struct damon_sysfs_intervals *damon_sysfs_intervals_alloc(
609 		unsigned long sample_us, unsigned long aggr_us,
610 		unsigned long update_us)
611 {
612 	struct damon_sysfs_intervals *intervals = kmalloc_obj(*intervals);
613 
614 	if (!intervals)
615 		return NULL;
616 
617 	intervals->kobj = (struct kobject){};
618 	intervals->sample_us = sample_us;
619 	intervals->aggr_us = aggr_us;
620 	intervals->update_us = update_us;
621 	return intervals;
622 }
623 
624 static int damon_sysfs_intervals_add_dirs(struct damon_sysfs_intervals *intervals)
625 {
626 	struct damon_sysfs_intervals_goal *goal;
627 	int err;
628 
629 	goal = damon_sysfs_intervals_goal_alloc(0, 0, 0, 0);
630 	if (!goal)
631 		return -ENOMEM;
632 
633 	err = kobject_init_and_add(&goal->kobj,
634 			&damon_sysfs_intervals_goal_ktype, &intervals->kobj,
635 			"intervals_goal");
636 	if (err) {
637 		kobject_put(&goal->kobj);
638 		intervals->intervals_goal = NULL;
639 		return err;
640 	}
641 	intervals->intervals_goal = goal;
642 	return 0;
643 }
644 
645 static void damon_sysfs_intervals_rm_dirs(struct damon_sysfs_intervals *intervals)
646 {
647 	kobject_put(&intervals->intervals_goal->kobj);
648 }
649 
650 static ssize_t sample_us_show(struct kobject *kobj,
651 		struct kobj_attribute *attr, char *buf)
652 {
653 	struct damon_sysfs_intervals *intervals = container_of(kobj,
654 			struct damon_sysfs_intervals, kobj);
655 
656 	return sysfs_emit(buf, "%lu\n", intervals->sample_us);
657 }
658 
659 static ssize_t sample_us_store(struct kobject *kobj,
660 		struct kobj_attribute *attr, const char *buf, size_t count)
661 {
662 	struct damon_sysfs_intervals *intervals = container_of(kobj,
663 			struct damon_sysfs_intervals, kobj);
664 	unsigned long us;
665 	int err = kstrtoul(buf, 0, &us);
666 
667 	if (err)
668 		return err;
669 
670 	intervals->sample_us = us;
671 	return count;
672 }
673 
674 static ssize_t aggr_us_show(struct kobject *kobj, struct kobj_attribute *attr,
675 		char *buf)
676 {
677 	struct damon_sysfs_intervals *intervals = container_of(kobj,
678 			struct damon_sysfs_intervals, kobj);
679 
680 	return sysfs_emit(buf, "%lu\n", intervals->aggr_us);
681 }
682 
683 static ssize_t aggr_us_store(struct kobject *kobj, struct kobj_attribute *attr,
684 		const char *buf, size_t count)
685 {
686 	struct damon_sysfs_intervals *intervals = container_of(kobj,
687 			struct damon_sysfs_intervals, kobj);
688 	unsigned long us;
689 	int err = kstrtoul(buf, 0, &us);
690 
691 	if (err)
692 		return err;
693 
694 	intervals->aggr_us = us;
695 	return count;
696 }
697 
698 static ssize_t update_us_show(struct kobject *kobj,
699 		struct kobj_attribute *attr, char *buf)
700 {
701 	struct damon_sysfs_intervals *intervals = container_of(kobj,
702 			struct damon_sysfs_intervals, kobj);
703 
704 	return sysfs_emit(buf, "%lu\n", intervals->update_us);
705 }
706 
707 static ssize_t update_us_store(struct kobject *kobj,
708 		struct kobj_attribute *attr, const char *buf, size_t count)
709 {
710 	struct damon_sysfs_intervals *intervals = container_of(kobj,
711 			struct damon_sysfs_intervals, kobj);
712 	unsigned long us;
713 	int err = kstrtoul(buf, 0, &us);
714 
715 	if (err)
716 		return err;
717 
718 	intervals->update_us = us;
719 	return count;
720 }
721 
722 static void damon_sysfs_intervals_release(struct kobject *kobj)
723 {
724 	kfree(container_of(kobj, struct damon_sysfs_intervals, kobj));
725 }
726 
727 static struct kobj_attribute damon_sysfs_intervals_sample_us_attr =
728 		__ATTR_RW_MODE(sample_us, 0600);
729 
730 static struct kobj_attribute damon_sysfs_intervals_aggr_us_attr =
731 		__ATTR_RW_MODE(aggr_us, 0600);
732 
733 static struct kobj_attribute damon_sysfs_intervals_update_us_attr =
734 		__ATTR_RW_MODE(update_us, 0600);
735 
736 static struct attribute *damon_sysfs_intervals_attrs[] = {
737 	&damon_sysfs_intervals_sample_us_attr.attr,
738 	&damon_sysfs_intervals_aggr_us_attr.attr,
739 	&damon_sysfs_intervals_update_us_attr.attr,
740 	NULL,
741 };
742 ATTRIBUTE_GROUPS(damon_sysfs_intervals);
743 
744 static const struct kobj_type damon_sysfs_intervals_ktype = {
745 	.release = damon_sysfs_intervals_release,
746 	.sysfs_ops = &kobj_sysfs_ops,
747 	.default_groups = damon_sysfs_intervals_groups,
748 };
749 
750 /*
751  * monitoring_attrs directory
752  */
753 
754 struct damon_sysfs_attrs {
755 	struct kobject kobj;
756 	struct damon_sysfs_intervals *intervals;
757 	struct damon_sysfs_ul_range *nr_regions_range;
758 };
759 
760 static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
761 {
762 	struct damon_sysfs_attrs *attrs = kmalloc_obj(*attrs);
763 
764 	if (!attrs)
765 		return NULL;
766 	attrs->kobj = (struct kobject){};
767 	return attrs;
768 }
769 
770 static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
771 {
772 	struct damon_sysfs_intervals *intervals;
773 	struct damon_sysfs_ul_range *nr_regions_range;
774 	int err;
775 
776 	intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
777 	if (!intervals)
778 		return -ENOMEM;
779 
780 	err = kobject_init_and_add(&intervals->kobj,
781 			&damon_sysfs_intervals_ktype, &attrs->kobj,
782 			"intervals");
783 	if (err)
784 		goto put_intervals_out;
785 	err = damon_sysfs_intervals_add_dirs(intervals);
786 	if (err)
787 		goto put_intervals_out;
788 	attrs->intervals = intervals;
789 
790 	nr_regions_range = damon_sysfs_ul_range_alloc(10, 1000);
791 	if (!nr_regions_range) {
792 		err = -ENOMEM;
793 		goto rmdir_put_intervals_out;
794 	}
795 
796 	err = kobject_init_and_add(&nr_regions_range->kobj,
797 			&damon_sysfs_ul_range_ktype, &attrs->kobj,
798 			"nr_regions");
799 	if (err)
800 		goto put_nr_regions_intervals_out;
801 	attrs->nr_regions_range = nr_regions_range;
802 	return 0;
803 
804 put_nr_regions_intervals_out:
805 	kobject_put(&nr_regions_range->kobj);
806 	attrs->nr_regions_range = NULL;
807 rmdir_put_intervals_out:
808 	damon_sysfs_intervals_rm_dirs(intervals);
809 put_intervals_out:
810 	kobject_put(&intervals->kobj);
811 	attrs->intervals = NULL;
812 	return err;
813 }
814 
815 static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
816 {
817 	kobject_put(&attrs->nr_regions_range->kobj);
818 	damon_sysfs_intervals_rm_dirs(attrs->intervals);
819 	kobject_put(&attrs->intervals->kobj);
820 }
821 
822 static void damon_sysfs_attrs_release(struct kobject *kobj)
823 {
824 	kfree(container_of(kobj, struct damon_sysfs_attrs, kobj));
825 }
826 
827 static struct attribute *damon_sysfs_attrs_attrs[] = {
828 	NULL,
829 };
830 ATTRIBUTE_GROUPS(damon_sysfs_attrs);
831 
832 static const struct kobj_type damon_sysfs_attrs_ktype = {
833 	.release = damon_sysfs_attrs_release,
834 	.sysfs_ops = &kobj_sysfs_ops,
835 	.default_groups = damon_sysfs_attrs_groups,
836 };
837 
838 /*
839  * context directory
840  */
841 
842 struct damon_sysfs_ops_name {
843 	enum damon_ops_id ops_id;
844 	char *name;
845 };
846 
847 static const struct damon_sysfs_ops_name damon_sysfs_ops_names[] = {
848 	{
849 		.ops_id = DAMON_OPS_VADDR,
850 		.name = "vaddr",
851 	},
852 	{
853 		.ops_id = DAMON_OPS_FVADDR,
854 		.name = "fvaddr",
855 	},
856 	{
857 		.ops_id = DAMON_OPS_PADDR,
858 		.name = "paddr",
859 	},
860 };
861 
862 struct damon_sysfs_context {
863 	struct kobject kobj;
864 	enum damon_ops_id ops_id;
865 	unsigned long addr_unit;
866 	struct damon_sysfs_attrs *attrs;
867 	struct damon_sysfs_targets *targets;
868 	struct damon_sysfs_schemes *schemes;
869 	bool pause;
870 };
871 
872 static struct damon_sysfs_context *damon_sysfs_context_alloc(
873 		enum damon_ops_id ops_id)
874 {
875 	struct damon_sysfs_context *context = kmalloc_obj(*context);
876 
877 	if (!context)
878 		return NULL;
879 	context->kobj = (struct kobject){};
880 	context->ops_id = ops_id;
881 	context->addr_unit = 1;
882 	context->pause = false;
883 	return context;
884 }
885 
886 static int damon_sysfs_context_set_attrs(struct damon_sysfs_context *context)
887 {
888 	struct damon_sysfs_attrs *attrs = damon_sysfs_attrs_alloc();
889 	int err;
890 
891 	if (!attrs)
892 		return -ENOMEM;
893 	err = kobject_init_and_add(&attrs->kobj, &damon_sysfs_attrs_ktype,
894 			&context->kobj, "monitoring_attrs");
895 	if (err)
896 		goto out;
897 	err = damon_sysfs_attrs_add_dirs(attrs);
898 	if (err)
899 		goto out;
900 	context->attrs = attrs;
901 	return 0;
902 
903 out:
904 	kobject_put(&attrs->kobj);
905 	return err;
906 }
907 
908 static int damon_sysfs_context_set_targets(struct damon_sysfs_context *context)
909 {
910 	struct damon_sysfs_targets *targets = damon_sysfs_targets_alloc();
911 	int err;
912 
913 	if (!targets)
914 		return -ENOMEM;
915 	err = kobject_init_and_add(&targets->kobj, &damon_sysfs_targets_ktype,
916 			&context->kobj, "targets");
917 	if (err) {
918 		kobject_put(&targets->kobj);
919 		return err;
920 	}
921 	context->targets = targets;
922 	return 0;
923 }
924 
925 static int damon_sysfs_context_set_schemes(struct damon_sysfs_context *context)
926 {
927 	struct damon_sysfs_schemes *schemes = damon_sysfs_schemes_alloc();
928 	int err;
929 
930 	if (!schemes)
931 		return -ENOMEM;
932 	err = kobject_init_and_add(&schemes->kobj, &damon_sysfs_schemes_ktype,
933 			&context->kobj, "schemes");
934 	if (err) {
935 		kobject_put(&schemes->kobj);
936 		return err;
937 	}
938 	context->schemes = schemes;
939 	return 0;
940 }
941 
942 static int damon_sysfs_context_add_dirs(struct damon_sysfs_context *context)
943 {
944 	int err;
945 
946 	err = damon_sysfs_context_set_attrs(context);
947 	if (err)
948 		return err;
949 
950 	err = damon_sysfs_context_set_targets(context);
951 	if (err)
952 		goto rmdir_put_attrs_out;
953 
954 	err = damon_sysfs_context_set_schemes(context);
955 	if (err)
956 		goto put_targets_attrs_out;
957 	return 0;
958 
959 put_targets_attrs_out:
960 	kobject_put(&context->targets->kobj);
961 	context->targets = NULL;
962 rmdir_put_attrs_out:
963 	damon_sysfs_attrs_rm_dirs(context->attrs);
964 	kobject_put(&context->attrs->kobj);
965 	context->attrs = NULL;
966 	return err;
967 }
968 
969 static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context)
970 {
971 	damon_sysfs_attrs_rm_dirs(context->attrs);
972 	kobject_put(&context->attrs->kobj);
973 	damon_sysfs_targets_rm_dirs(context->targets);
974 	kobject_put(&context->targets->kobj);
975 	damon_sysfs_schemes_rm_dirs(context->schemes);
976 	kobject_put(&context->schemes->kobj);
977 }
978 
979 static ssize_t avail_operations_show(struct kobject *kobj,
980 		struct kobj_attribute *attr, char *buf)
981 {
982 	int len = 0;
983 	int i;
984 
985 	for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
986 		const struct damon_sysfs_ops_name *ops_name;
987 
988 		ops_name = &damon_sysfs_ops_names[i];
989 		if (!damon_is_registered_ops(ops_name->ops_id))
990 			continue;
991 		len += sysfs_emit_at(buf, len, "%s\n", ops_name->name);
992 	}
993 	return len;
994 }
995 
996 static ssize_t operations_show(struct kobject *kobj,
997 		struct kobj_attribute *attr, char *buf)
998 {
999 	struct damon_sysfs_context *context = container_of(kobj,
1000 			struct damon_sysfs_context, kobj);
1001 	int i;
1002 
1003 	for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
1004 		const struct damon_sysfs_ops_name *ops_name;
1005 
1006 		ops_name = &damon_sysfs_ops_names[i];
1007 		if (ops_name->ops_id == context->ops_id)
1008 			return sysfs_emit(buf, "%s\n", ops_name->name);
1009 	}
1010 	return -EINVAL;
1011 }
1012 
1013 static ssize_t operations_store(struct kobject *kobj,
1014 		struct kobj_attribute *attr, const char *buf, size_t count)
1015 {
1016 	struct damon_sysfs_context *context = container_of(kobj,
1017 			struct damon_sysfs_context, kobj);
1018 	int i;
1019 
1020 	for (i = 0; i < ARRAY_SIZE(damon_sysfs_ops_names); i++) {
1021 		const struct damon_sysfs_ops_name *ops_name;
1022 
1023 		ops_name = &damon_sysfs_ops_names[i];
1024 		if (sysfs_streq(buf, ops_name->name)) {
1025 			context->ops_id = ops_name->ops_id;
1026 			return count;
1027 		}
1028 	}
1029 	return -EINVAL;
1030 }
1031 
1032 static ssize_t addr_unit_show(struct kobject *kobj,
1033 		struct kobj_attribute *attr, char *buf)
1034 {
1035 	struct damon_sysfs_context *context = container_of(kobj,
1036 			struct damon_sysfs_context, kobj);
1037 
1038 	return sysfs_emit(buf, "%lu\n", context->addr_unit);
1039 }
1040 
1041 static ssize_t addr_unit_store(struct kobject *kobj,
1042 		struct kobj_attribute *attr, const char *buf, size_t count)
1043 {
1044 	struct damon_sysfs_context *context = container_of(kobj,
1045 			struct damon_sysfs_context, kobj);
1046 	unsigned long input_addr_unit;
1047 	int err = kstrtoul(buf, 0, &input_addr_unit);
1048 
1049 	if (err)
1050 		return err;
1051 	if (!input_addr_unit)
1052 		return -EINVAL;
1053 
1054 	context->addr_unit = input_addr_unit;
1055 	return count;
1056 }
1057 
1058 static ssize_t pause_show(struct kobject *kobj, struct kobj_attribute *attr,
1059 		char *buf)
1060 {
1061 	struct damon_sysfs_context *context = container_of(kobj,
1062 			struct damon_sysfs_context, kobj);
1063 
1064 	return sysfs_emit(buf, "%c\n", context->pause ? 'Y' : 'N');
1065 }
1066 
1067 static ssize_t pause_store(struct kobject *kobj, struct kobj_attribute *attr,
1068 		const char *buf, size_t count)
1069 {
1070 	struct damon_sysfs_context *context = container_of(kobj,
1071 			struct damon_sysfs_context, kobj);
1072 	bool pause;
1073 	int err = kstrtobool(buf, &pause);
1074 
1075 	if (err)
1076 		return err;
1077 	context->pause = pause;
1078 	return count;
1079 }
1080 
1081 
1082 static void damon_sysfs_context_release(struct kobject *kobj)
1083 {
1084 	kfree(container_of(kobj, struct damon_sysfs_context, kobj));
1085 }
1086 
1087 static struct kobj_attribute damon_sysfs_context_avail_operations_attr =
1088 		__ATTR_RO_MODE(avail_operations, 0400);
1089 
1090 static struct kobj_attribute damon_sysfs_context_operations_attr =
1091 		__ATTR_RW_MODE(operations, 0600);
1092 
1093 static struct kobj_attribute damon_sysfs_context_addr_unit_attr =
1094 		__ATTR_RW_MODE(addr_unit, 0600);
1095 
1096 static struct kobj_attribute damon_sysfs_context_pause_attr =
1097 		__ATTR_RW_MODE(pause, 0600);
1098 
1099 static struct attribute *damon_sysfs_context_attrs[] = {
1100 	&damon_sysfs_context_avail_operations_attr.attr,
1101 	&damon_sysfs_context_operations_attr.attr,
1102 	&damon_sysfs_context_addr_unit_attr.attr,
1103 	&damon_sysfs_context_pause_attr.attr,
1104 	NULL,
1105 };
1106 ATTRIBUTE_GROUPS(damon_sysfs_context);
1107 
1108 static const struct kobj_type damon_sysfs_context_ktype = {
1109 	.release = damon_sysfs_context_release,
1110 	.sysfs_ops = &kobj_sysfs_ops,
1111 	.default_groups = damon_sysfs_context_groups,
1112 };
1113 
1114 /*
1115  * contexts directory
1116  */
1117 
1118 struct damon_sysfs_contexts {
1119 	struct kobject kobj;
1120 	struct damon_sysfs_context **contexts_arr;
1121 	int nr;
1122 };
1123 
1124 static struct damon_sysfs_contexts *damon_sysfs_contexts_alloc(void)
1125 {
1126 	return kzalloc_obj(struct damon_sysfs_contexts);
1127 }
1128 
1129 static void damon_sysfs_contexts_rm_dirs(struct damon_sysfs_contexts *contexts)
1130 {
1131 	struct damon_sysfs_context **contexts_arr = contexts->contexts_arr;
1132 	int i;
1133 
1134 	for (i = 0; i < contexts->nr; i++) {
1135 		damon_sysfs_context_rm_dirs(contexts_arr[i]);
1136 		kobject_put(&contexts_arr[i]->kobj);
1137 	}
1138 	contexts->nr = 0;
1139 	kfree(contexts_arr);
1140 	contexts->contexts_arr = NULL;
1141 }
1142 
1143 static int damon_sysfs_contexts_add_dirs(struct damon_sysfs_contexts *contexts,
1144 		int nr_contexts)
1145 {
1146 	struct damon_sysfs_context **contexts_arr, *context;
1147 	int err, i;
1148 
1149 	damon_sysfs_contexts_rm_dirs(contexts);
1150 	if (!nr_contexts)
1151 		return 0;
1152 
1153 	contexts_arr = kmalloc_objs(*contexts_arr, nr_contexts,
1154 				    GFP_KERNEL | __GFP_NOWARN);
1155 	if (!contexts_arr)
1156 		return -ENOMEM;
1157 	contexts->contexts_arr = contexts_arr;
1158 
1159 	for (i = 0; i < nr_contexts; i++) {
1160 		context = damon_sysfs_context_alloc(DAMON_OPS_VADDR);
1161 		if (!context) {
1162 			damon_sysfs_contexts_rm_dirs(contexts);
1163 			return -ENOMEM;
1164 		}
1165 
1166 		err = kobject_init_and_add(&context->kobj,
1167 				&damon_sysfs_context_ktype, &contexts->kobj,
1168 				"%d", i);
1169 		if (err)
1170 			goto out;
1171 
1172 		err = damon_sysfs_context_add_dirs(context);
1173 		if (err)
1174 			goto out;
1175 
1176 		contexts_arr[i] = context;
1177 		contexts->nr++;
1178 	}
1179 	return 0;
1180 
1181 out:
1182 	damon_sysfs_contexts_rm_dirs(contexts);
1183 	kobject_put(&context->kobj);
1184 	return err;
1185 }
1186 
1187 static ssize_t nr_contexts_show(struct kobject *kobj,
1188 		struct kobj_attribute *attr, char *buf)
1189 {
1190 	struct damon_sysfs_contexts *contexts = container_of(kobj,
1191 			struct damon_sysfs_contexts, kobj);
1192 
1193 	return sysfs_emit(buf, "%d\n", contexts->nr);
1194 }
1195 
1196 static ssize_t nr_contexts_store(struct kobject *kobj,
1197 		struct kobj_attribute *attr, const char *buf, size_t count)
1198 {
1199 	struct damon_sysfs_contexts *contexts;
1200 	int nr, err;
1201 
1202 	err = kstrtoint(buf, 0, &nr);
1203 	if (err)
1204 		return err;
1205 	/* TODO: support multiple contexts per kdamond */
1206 	if (nr < 0 || 1 < nr)
1207 		return -EINVAL;
1208 
1209 	contexts = container_of(kobj, struct damon_sysfs_contexts, kobj);
1210 	if (!mutex_trylock(&damon_sysfs_lock))
1211 		return -EBUSY;
1212 	err = damon_sysfs_contexts_add_dirs(contexts, nr);
1213 	mutex_unlock(&damon_sysfs_lock);
1214 	if (err)
1215 		return err;
1216 
1217 	return count;
1218 }
1219 
1220 static void damon_sysfs_contexts_release(struct kobject *kobj)
1221 {
1222 	kfree(container_of(kobj, struct damon_sysfs_contexts, kobj));
1223 }
1224 
1225 static struct kobj_attribute damon_sysfs_contexts_nr_attr
1226 		= __ATTR_RW_MODE(nr_contexts, 0600);
1227 
1228 static struct attribute *damon_sysfs_contexts_attrs[] = {
1229 	&damon_sysfs_contexts_nr_attr.attr,
1230 	NULL,
1231 };
1232 ATTRIBUTE_GROUPS(damon_sysfs_contexts);
1233 
1234 static const struct kobj_type damon_sysfs_contexts_ktype = {
1235 	.release = damon_sysfs_contexts_release,
1236 	.sysfs_ops = &kobj_sysfs_ops,
1237 	.default_groups = damon_sysfs_contexts_groups,
1238 };
1239 
1240 /*
1241  * kdamond directory
1242  */
1243 
1244 struct damon_sysfs_kdamond {
1245 	struct kobject kobj;
1246 	struct damon_sysfs_contexts *contexts;
1247 	struct damon_ctx *damon_ctx;
1248 	unsigned int refresh_ms;
1249 };
1250 
1251 static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void)
1252 {
1253 	return kzalloc_obj(struct damon_sysfs_kdamond);
1254 }
1255 
1256 static int damon_sysfs_kdamond_add_dirs(struct damon_sysfs_kdamond *kdamond)
1257 {
1258 	struct damon_sysfs_contexts *contexts;
1259 	int err;
1260 
1261 	contexts = damon_sysfs_contexts_alloc();
1262 	if (!contexts)
1263 		return -ENOMEM;
1264 
1265 	err = kobject_init_and_add(&contexts->kobj,
1266 			&damon_sysfs_contexts_ktype, &kdamond->kobj,
1267 			"contexts");
1268 	if (err) {
1269 		kobject_put(&contexts->kobj);
1270 		return err;
1271 	}
1272 	kdamond->contexts = contexts;
1273 
1274 	return err;
1275 }
1276 
1277 static void damon_sysfs_kdamond_rm_dirs(struct damon_sysfs_kdamond *kdamond)
1278 {
1279 	damon_sysfs_contexts_rm_dirs(kdamond->contexts);
1280 	kobject_put(&kdamond->contexts->kobj);
1281 }
1282 
1283 /*
1284  * enum damon_sysfs_cmd - Commands for a specific kdamond.
1285  */
1286 enum damon_sysfs_cmd {
1287 	/* @DAMON_SYSFS_CMD_ON: Turn the kdamond on. */
1288 	DAMON_SYSFS_CMD_ON,
1289 	/* @DAMON_SYSFS_CMD_OFF: Turn the kdamond off. */
1290 	DAMON_SYSFS_CMD_OFF,
1291 	/* @DAMON_SYSFS_CMD_COMMIT: Update kdamond inputs. */
1292 	DAMON_SYSFS_CMD_COMMIT,
1293 	/*
1294 	 * @DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS: Commit the quota goals
1295 	 * to DAMON.
1296 	 */
1297 	DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS,
1298 	/*
1299 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS: Update scheme stats sysfs
1300 	 * files.
1301 	 */
1302 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,
1303 	/*
1304 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES: Update
1305 	 * tried_regions/total_bytes sysfs files for each scheme.
1306 	 */
1307 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES,
1308 	/*
1309 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS: Update schemes tried
1310 	 * regions
1311 	 */
1312 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS,
1313 	/*
1314 	 * @DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS: Clear schemes tried
1315 	 * regions
1316 	 */
1317 	DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS,
1318 	/*
1319 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS: Update the
1320 	 * effective size quota of the scheme in bytes.
1321 	 */
1322 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS,
1323 	/*
1324 	 * @DAMON_SYSFS_CMD_UPDATE_TUNED_INTERVALS: Update the tuned monitoring
1325 	 * intervals.
1326 	 */
1327 	DAMON_SYSFS_CMD_UPDATE_TUNED_INTERVALS,
1328 	/*
1329 	 * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
1330 	 */
1331 	NR_DAMON_SYSFS_CMDS,
1332 };
1333 
1334 /* Should match with enum damon_sysfs_cmd */
1335 static const char * const damon_sysfs_cmd_strs[] = {
1336 	"on",
1337 	"off",
1338 	"commit",
1339 	"commit_schemes_quota_goals",
1340 	"update_schemes_stats",
1341 	"update_schemes_tried_bytes",
1342 	"update_schemes_tried_regions",
1343 	"clear_schemes_tried_regions",
1344 	"update_schemes_effective_quotas",
1345 	"update_tuned_intervals",
1346 };
1347 
1348 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
1349 		char *buf)
1350 {
1351 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1352 			struct damon_sysfs_kdamond, kobj);
1353 	struct damon_ctx *ctx;
1354 	bool running = false;
1355 
1356 	if (!mutex_trylock(&damon_sysfs_lock))
1357 		return -EBUSY;
1358 
1359 	ctx = kdamond->damon_ctx;
1360 	if (ctx)
1361 		running = damon_is_running(ctx);
1362 
1363 	mutex_unlock(&damon_sysfs_lock);
1364 
1365 	return sysfs_emit(buf, "%s\n", running ?
1366 			damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_ON] :
1367 			damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_OFF]);
1368 }
1369 
1370 static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
1371 		struct damon_sysfs_attrs *sys_attrs)
1372 {
1373 	struct damon_sysfs_intervals *sys_intervals = sys_attrs->intervals;
1374 	struct damon_sysfs_intervals_goal *sys_goal =
1375 		sys_intervals->intervals_goal;
1376 	struct damon_sysfs_ul_range *sys_nr_regions =
1377 		sys_attrs->nr_regions_range;
1378 	struct damon_attrs attrs = {
1379 		.sample_interval = sys_intervals->sample_us,
1380 		.aggr_interval = sys_intervals->aggr_us,
1381 		.intervals_goal = {
1382 			.access_bp = sys_goal->access_bp,
1383 			.aggrs = sys_goal->aggrs,
1384 			.min_sample_us = sys_goal->min_sample_us,
1385 			.max_sample_us = sys_goal->max_sample_us},
1386 		.ops_update_interval = sys_intervals->update_us,
1387 		.min_nr_regions = sys_nr_regions->min,
1388 		.max_nr_regions = sys_nr_regions->max,
1389 	};
1390 	return damon_set_attrs(ctx, &attrs);
1391 }
1392 
1393 static int damon_sysfs_set_regions(struct damon_target *t,
1394 		struct damon_sysfs_regions *sysfs_regions,
1395 		unsigned long min_region_sz)
1396 {
1397 	struct damon_addr_range *ranges = kmalloc_objs(*ranges,
1398 						       sysfs_regions->nr,
1399 						       GFP_KERNEL | __GFP_NOWARN);
1400 	int i, err = -EINVAL;
1401 
1402 	if (!ranges)
1403 		return -ENOMEM;
1404 	for (i = 0; i < sysfs_regions->nr; i++) {
1405 		struct damon_sysfs_region *sys_region =
1406 			sysfs_regions->regions_arr[i];
1407 
1408 		if (sys_region->ar.start > sys_region->ar.end)
1409 			goto out;
1410 
1411 		ranges[i].start = sys_region->ar.start;
1412 		ranges[i].end = sys_region->ar.end;
1413 		if (i == 0)
1414 			continue;
1415 		if (ranges[i - 1].end > ranges[i].start)
1416 			goto out;
1417 	}
1418 	err = damon_set_regions(t, ranges, sysfs_regions->nr, min_region_sz);
1419 out:
1420 	kfree(ranges);
1421 	return err;
1422 
1423 }
1424 
1425 static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
1426 		struct damon_ctx *ctx)
1427 {
1428 	struct damon_target *t = damon_new_target();
1429 
1430 	if (!t)
1431 		return -ENOMEM;
1432 	damon_add_target(ctx, t);
1433 	if (damon_target_has_pid(ctx)) {
1434 		t->pid = find_get_pid(sys_target->pid);
1435 		if (!t->pid)
1436 			/* caller will destroy targets */
1437 			return -EINVAL;
1438 	}
1439 	t->obsolete = sys_target->obsolete;
1440 	return damon_sysfs_set_regions(t, sys_target->regions,
1441 			ctx->min_region_sz);
1442 }
1443 
1444 static int damon_sysfs_add_targets(struct damon_ctx *ctx,
1445 		struct damon_sysfs_targets *sysfs_targets)
1446 {
1447 	int i, err;
1448 
1449 	/* Multiple physical address space monitoring targets makes no sense */
1450 	if (ctx->ops.id == DAMON_OPS_PADDR && sysfs_targets->nr > 1)
1451 		return -EINVAL;
1452 
1453 	for (i = 0; i < sysfs_targets->nr; i++) {
1454 		struct damon_sysfs_target *st = sysfs_targets->targets_arr[i];
1455 
1456 		err = damon_sysfs_add_target(st, ctx);
1457 		if (err)
1458 			return err;
1459 	}
1460 	return 0;
1461 }
1462 
1463 /*
1464  * damon_sysfs_upd_schemes_stats() - Update schemes stats sysfs files.
1465  * @data:	The kobject wrapper that associated to the kdamond thread.
1466  *
1467  * This function reads the schemes stats of specific kdamond and update the
1468  * related values for sysfs files.  This function should be called from DAMON
1469  * worker thread,to safely access the DAMON contexts-internal data.  Caller
1470  * should also ensure holding ``damon_syfs_lock``, and ->damon_ctx of @data is
1471  * not NULL but a valid pointer, to safely access DAMON sysfs variables.
1472  */
1473 static int damon_sysfs_upd_schemes_stats(void *data)
1474 {
1475 	struct damon_sysfs_kdamond *kdamond = data;
1476 	struct damon_ctx *ctx = kdamond->damon_ctx;
1477 
1478 	damon_sysfs_schemes_update_stats(
1479 			kdamond->contexts->contexts_arr[0]->schemes, ctx);
1480 	return 0;
1481 }
1482 
1483 static inline bool damon_sysfs_kdamond_running(
1484 		struct damon_sysfs_kdamond *kdamond)
1485 {
1486 	return kdamond->damon_ctx &&
1487 		damon_is_running(kdamond->damon_ctx);
1488 }
1489 
1490 static int damon_sysfs_apply_inputs(struct damon_ctx *ctx,
1491 		struct damon_sysfs_context *sys_ctx)
1492 {
1493 	int err;
1494 
1495 	err = damon_select_ops(ctx, sys_ctx->ops_id);
1496 	if (err)
1497 		return err;
1498 	ctx->addr_unit = sys_ctx->addr_unit;
1499 	/* addr_unit is respected by only DAMON_OPS_PADDR */
1500 	if (sys_ctx->ops_id == DAMON_OPS_PADDR)
1501 		ctx->min_region_sz = max(
1502 				DAMON_MIN_REGION_SZ / sys_ctx->addr_unit, 1);
1503 	ctx->pause = sys_ctx->pause;
1504 	err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
1505 	if (err)
1506 		return err;
1507 	err = damon_sysfs_add_targets(ctx, sys_ctx->targets);
1508 	if (err)
1509 		return err;
1510 	return damon_sysfs_add_schemes(ctx, sys_ctx->schemes);
1511 }
1512 
1513 static struct damon_ctx *damon_sysfs_build_ctx(
1514 		struct damon_sysfs_context *sys_ctx);
1515 
1516 /*
1517  * Return a new damon_ctx for testing new parameters to commit.
1518  */
1519 static struct damon_ctx *damon_sysfs_new_test_ctx(
1520 		struct damon_ctx *running_ctx)
1521 {
1522 	struct damon_ctx *test_ctx;
1523 	int err;
1524 
1525 	test_ctx = damon_new_ctx();
1526 	if (!test_ctx)
1527 		return NULL;
1528 	err = damon_commit_ctx(test_ctx, running_ctx);
1529 	if (err) {
1530 		damon_destroy_ctx(test_ctx);
1531 		return NULL;
1532 	}
1533 	return test_ctx;
1534 }
1535 
1536 /*
1537  * damon_sysfs_commit_input() - Commit user inputs to a running kdamond.
1538  * @kdamond:	The kobject wrapper for the associated kdamond.
1539  *
1540  * Returns error if the sysfs input is wrong.
1541  */
1542 static int damon_sysfs_commit_input(void *data)
1543 {
1544 	struct damon_sysfs_kdamond *kdamond = data;
1545 	struct damon_ctx *param_ctx, *test_ctx;
1546 	int err;
1547 
1548 	if (!damon_sysfs_kdamond_running(kdamond))
1549 		return -EINVAL;
1550 	/* TODO: Support multiple contexts per kdamond */
1551 	if (kdamond->contexts->nr != 1)
1552 		return -EINVAL;
1553 
1554 	param_ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
1555 	if (IS_ERR(param_ctx))
1556 		return PTR_ERR(param_ctx);
1557 	test_ctx = damon_sysfs_new_test_ctx(kdamond->damon_ctx);
1558 	if (!test_ctx) {
1559 		damon_destroy_ctx(param_ctx);
1560 		return -ENOMEM;
1561 	}
1562 	err = damon_commit_ctx(test_ctx, param_ctx);
1563 	if (err)
1564 		goto out;
1565 	err = damon_commit_ctx(kdamond->damon_ctx, param_ctx);
1566 out:
1567 	damon_destroy_ctx(test_ctx);
1568 	damon_destroy_ctx(param_ctx);
1569 	return err;
1570 }
1571 
1572 static int damon_sysfs_commit_schemes_quota_goals(void *data)
1573 {
1574 	struct damon_sysfs_kdamond *sysfs_kdamond = data;
1575 	struct damon_ctx *ctx;
1576 	struct damon_sysfs_context *sysfs_ctx;
1577 
1578 	if (!damon_sysfs_kdamond_running(sysfs_kdamond))
1579 		return -EINVAL;
1580 	/* TODO: Support multiple contexts per kdamond */
1581 	if (sysfs_kdamond->contexts->nr != 1)
1582 		return -EINVAL;
1583 
1584 	ctx = sysfs_kdamond->damon_ctx;
1585 	sysfs_ctx = sysfs_kdamond->contexts->contexts_arr[0];
1586 	return damos_sysfs_set_quota_scores(sysfs_ctx->schemes, ctx);
1587 }
1588 
1589 /*
1590  * damon_sysfs_upd_schemes_effective_quotas() - Update schemes effective quotas
1591  * sysfs files.
1592  * @data:	The kobject wrapper that associated to the kdamond thread.
1593  *
1594  * This function reads the schemes' effective quotas of specific kdamond and
1595  * update the related values for sysfs files.  This function should be called
1596  * from DAMON callbacks while holding ``damon_syfs_lock``, to safely access the
1597  * DAMON contexts-internal data and DAMON sysfs variables.
1598  */
1599 static int damon_sysfs_upd_schemes_effective_quotas(void *data)
1600 {
1601 	struct damon_sysfs_kdamond *kdamond = data;
1602 	struct damon_ctx *ctx = kdamond->damon_ctx;
1603 
1604 	damos_sysfs_update_effective_quotas(
1605 			kdamond->contexts->contexts_arr[0]->schemes, ctx);
1606 	return 0;
1607 }
1608 
1609 static int damon_sysfs_upd_tuned_intervals(void *data)
1610 {
1611 	struct damon_sysfs_kdamond *kdamond = data;
1612 	struct damon_ctx *ctx = kdamond->damon_ctx;
1613 
1614 	kdamond->contexts->contexts_arr[0]->attrs->intervals->sample_us =
1615 		ctx->attrs.sample_interval;
1616 	kdamond->contexts->contexts_arr[0]->attrs->intervals->aggr_us =
1617 		ctx->attrs.aggr_interval;
1618 	return 0;
1619 }
1620 
1621 static struct damon_ctx *damon_sysfs_build_ctx(
1622 		struct damon_sysfs_context *sys_ctx)
1623 {
1624 	struct damon_ctx *ctx = damon_new_ctx();
1625 	int err;
1626 
1627 	if (!ctx)
1628 		return ERR_PTR(-ENOMEM);
1629 
1630 	err = damon_sysfs_apply_inputs(ctx, sys_ctx);
1631 	if (err) {
1632 		damon_destroy_ctx(ctx);
1633 		return ERR_PTR(err);
1634 	}
1635 
1636 	return ctx;
1637 }
1638 
1639 static unsigned long damon_sysfs_next_update_jiffies;
1640 
1641 static int damon_sysfs_repeat_call_fn(void *data)
1642 {
1643 	struct damon_sysfs_kdamond *sysfs_kdamond = data;
1644 
1645 	if (!sysfs_kdamond->refresh_ms)
1646 		return 0;
1647 	if (time_before(jiffies, damon_sysfs_next_update_jiffies))
1648 		return 0;
1649 	damon_sysfs_next_update_jiffies = jiffies +
1650 		msecs_to_jiffies(sysfs_kdamond->refresh_ms);
1651 
1652 	if (!mutex_trylock(&damon_sysfs_lock))
1653 		return 0;
1654 	if (sysfs_kdamond->contexts->nr != 1)
1655 		goto out;
1656 	damon_sysfs_upd_tuned_intervals(sysfs_kdamond);
1657 	damon_sysfs_upd_schemes_stats(sysfs_kdamond);
1658 	damon_sysfs_upd_schemes_effective_quotas(sysfs_kdamond);
1659 out:
1660 	mutex_unlock(&damon_sysfs_lock);
1661 	return 0;
1662 }
1663 
1664 static int damon_sysfs_turn_damon_on(struct damon_sysfs_kdamond *kdamond)
1665 {
1666 	struct damon_ctx *ctx;
1667 	struct damon_call_control *repeat_call_control;
1668 	int err;
1669 
1670 	if (damon_sysfs_kdamond_running(kdamond))
1671 		return -EBUSY;
1672 	/* TODO: support multiple contexts per kdamond */
1673 	if (kdamond->contexts->nr != 1)
1674 		return -EINVAL;
1675 
1676 	if (kdamond->damon_ctx)
1677 		damon_destroy_ctx(kdamond->damon_ctx);
1678 	kdamond->damon_ctx = NULL;
1679 
1680 	repeat_call_control = kmalloc_obj(*repeat_call_control);
1681 	if (!repeat_call_control)
1682 		return -ENOMEM;
1683 
1684 	ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
1685 	if (IS_ERR(ctx)) {
1686 		kfree(repeat_call_control);
1687 		return PTR_ERR(ctx);
1688 	}
1689 	err = damon_start(&ctx, 1, false);
1690 	if (err) {
1691 		kfree(repeat_call_control);
1692 		damon_destroy_ctx(ctx);
1693 		return err;
1694 	}
1695 	kdamond->damon_ctx = ctx;
1696 
1697 	damon_sysfs_next_update_jiffies =
1698 		jiffies + msecs_to_jiffies(kdamond->refresh_ms);
1699 
1700 	repeat_call_control->fn = damon_sysfs_repeat_call_fn;
1701 	repeat_call_control->data = kdamond;
1702 	repeat_call_control->repeat = true;
1703 	repeat_call_control->dealloc_on_cancel = true;
1704 	if (damon_call(ctx, repeat_call_control))
1705 		kfree(repeat_call_control);
1706 	return err;
1707 }
1708 
1709 static int damon_sysfs_turn_damon_off(struct damon_sysfs_kdamond *kdamond)
1710 {
1711 	if (!kdamond->damon_ctx)
1712 		return -EINVAL;
1713 	return damon_stop(&kdamond->damon_ctx, 1);
1714 	/*
1715 	 * To allow users show final monitoring results of already turned-off
1716 	 * DAMON, we free kdamond->damon_ctx in next
1717 	 * damon_sysfs_turn_damon_on(), or kdamonds_nr_store()
1718 	 */
1719 }
1720 
1721 static int damon_sysfs_damon_call(int (*fn)(void *data),
1722 		struct damon_sysfs_kdamond *kdamond)
1723 {
1724 	struct damon_call_control call_control = {};
1725 	int err;
1726 
1727 	if (!kdamond->damon_ctx)
1728 		return -EINVAL;
1729 	call_control.fn = fn;
1730 	call_control.data = kdamond;
1731 	err = damon_call(kdamond->damon_ctx, &call_control);
1732 	return err ? err : call_control.return_code;
1733 }
1734 
1735 struct damon_sysfs_schemes_walk_data {
1736 	struct damon_sysfs_kdamond *sysfs_kdamond;
1737 	bool total_bytes_only;
1738 };
1739 
1740 /* populate the region directory */
1741 static void damon_sysfs_schemes_tried_regions_upd_one(void *data, struct damon_ctx *ctx,
1742 		struct damon_target *t, struct damon_region *r,
1743 		struct damos *s, unsigned long sz_filter_passed)
1744 {
1745 	struct damon_sysfs_schemes_walk_data *walk_data = data;
1746 	struct damon_sysfs_kdamond *sysfs_kdamond = walk_data->sysfs_kdamond;
1747 
1748 	damos_sysfs_populate_region_dir(
1749 			sysfs_kdamond->contexts->contexts_arr[0]->schemes,
1750 			ctx, t, r, s, walk_data->total_bytes_only,
1751 			sz_filter_passed);
1752 }
1753 
1754 static int damon_sysfs_update_schemes_tried_regions(
1755 		struct damon_sysfs_kdamond *sysfs_kdamond, bool total_bytes_only)
1756 {
1757 	struct damon_sysfs_schemes_walk_data walk_data = {
1758 		.sysfs_kdamond = sysfs_kdamond,
1759 		.total_bytes_only = total_bytes_only,
1760 	};
1761 	struct damos_walk_control control = {
1762 		.walk_fn = damon_sysfs_schemes_tried_regions_upd_one,
1763 		.data = &walk_data,
1764 	};
1765 	struct damon_ctx *ctx = sysfs_kdamond->damon_ctx;
1766 
1767 	if (!ctx)
1768 		return -EINVAL;
1769 
1770 	damon_sysfs_schemes_clear_regions(
1771 			sysfs_kdamond->contexts->contexts_arr[0]->schemes);
1772 	return damos_walk(ctx, &control);
1773 }
1774 
1775 /*
1776  * damon_sysfs_handle_cmd() - Handle a command for a specific kdamond.
1777  * @cmd:	The command to handle.
1778  * @kdamond:	The kobject wrapper for the associated kdamond.
1779  *
1780  * This function handles a DAMON sysfs command for a kdamond.
1781  *
1782  * Return: 0 on success, negative error code otherwise.
1783  */
1784 static int damon_sysfs_handle_cmd(enum damon_sysfs_cmd cmd,
1785 		struct damon_sysfs_kdamond *kdamond)
1786 {
1787 	if (cmd != DAMON_SYSFS_CMD_OFF && kdamond->contexts->nr != 1)
1788 		return -EINVAL;
1789 
1790 	switch (cmd) {
1791 	case DAMON_SYSFS_CMD_ON:
1792 		return damon_sysfs_turn_damon_on(kdamond);
1793 	case DAMON_SYSFS_CMD_OFF:
1794 		return damon_sysfs_turn_damon_off(kdamond);
1795 	case DAMON_SYSFS_CMD_COMMIT:
1796 		return damon_sysfs_damon_call(
1797 				damon_sysfs_commit_input, kdamond);
1798 	case DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS:
1799 		return damon_sysfs_damon_call(
1800 				damon_sysfs_commit_schemes_quota_goals,
1801 				kdamond);
1802 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS:
1803 		return damon_sysfs_damon_call(
1804 				damon_sysfs_upd_schemes_stats, kdamond);
1805 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES:
1806 		return damon_sysfs_update_schemes_tried_regions(kdamond, true);
1807 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS:
1808 		return damon_sysfs_update_schemes_tried_regions(kdamond, false);
1809 	case DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS:
1810 		return damon_sysfs_schemes_clear_regions(
1811 			kdamond->contexts->contexts_arr[0]->schemes);
1812 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS:
1813 		return damon_sysfs_damon_call(
1814 				damon_sysfs_upd_schemes_effective_quotas,
1815 				kdamond);
1816 	case DAMON_SYSFS_CMD_UPDATE_TUNED_INTERVALS:
1817 		return damon_sysfs_damon_call(
1818 				damon_sysfs_upd_tuned_intervals, kdamond);
1819 	default:
1820 		return -EINVAL;
1821 	}
1822 }
1823 
1824 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
1825 		const char *buf, size_t count)
1826 {
1827 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1828 			struct damon_sysfs_kdamond, kobj);
1829 	enum damon_sysfs_cmd cmd;
1830 	ssize_t ret = -EINVAL;
1831 
1832 	if (!mutex_trylock(&damon_sysfs_lock))
1833 		return -EBUSY;
1834 	for (cmd = 0; cmd < NR_DAMON_SYSFS_CMDS; cmd++) {
1835 		if (sysfs_streq(buf, damon_sysfs_cmd_strs[cmd])) {
1836 			ret = damon_sysfs_handle_cmd(cmd, kdamond);
1837 			break;
1838 		}
1839 	}
1840 	mutex_unlock(&damon_sysfs_lock);
1841 	if (!ret)
1842 		ret = count;
1843 	return ret;
1844 }
1845 
1846 static ssize_t pid_show(struct kobject *kobj,
1847 		struct kobj_attribute *attr, char *buf)
1848 {
1849 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1850 			struct damon_sysfs_kdamond, kobj);
1851 	struct damon_ctx *ctx;
1852 	int pid = -1;
1853 
1854 	if (!mutex_trylock(&damon_sysfs_lock))
1855 		return -EBUSY;
1856 	ctx = kdamond->damon_ctx;
1857 	if (!ctx)
1858 		goto out;
1859 
1860 	pid = damon_kdamond_pid(ctx);
1861 	if (pid < 0)
1862 		pid = -1;
1863 out:
1864 	mutex_unlock(&damon_sysfs_lock);
1865 	return sysfs_emit(buf, "%d\n", pid);
1866 }
1867 
1868 static ssize_t refresh_ms_show(struct kobject *kobj,
1869 		struct kobj_attribute *attr, char *buf)
1870 {
1871 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1872 			struct damon_sysfs_kdamond, kobj);
1873 
1874 	return sysfs_emit(buf, "%u\n", kdamond->refresh_ms);
1875 }
1876 
1877 static ssize_t refresh_ms_store(struct kobject *kobj,
1878 		struct kobj_attribute *attr, const char *buf, size_t count)
1879 {
1880 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1881 			struct damon_sysfs_kdamond, kobj);
1882 	unsigned int nr;
1883 	int err = kstrtouint(buf, 0, &nr);
1884 
1885 	if (err)
1886 		return err;
1887 
1888 	kdamond->refresh_ms = nr;
1889 	return count;
1890 }
1891 
1892 static void damon_sysfs_kdamond_release(struct kobject *kobj)
1893 {
1894 	struct damon_sysfs_kdamond *kdamond = container_of(kobj,
1895 			struct damon_sysfs_kdamond, kobj);
1896 
1897 	if (kdamond->damon_ctx)
1898 		damon_destroy_ctx(kdamond->damon_ctx);
1899 	kfree(kdamond);
1900 }
1901 
1902 static struct kobj_attribute damon_sysfs_kdamond_state_attr =
1903 		__ATTR_RW_MODE(state, 0600);
1904 
1905 static struct kobj_attribute damon_sysfs_kdamond_pid_attr =
1906 		__ATTR_RO_MODE(pid, 0400);
1907 
1908 static struct kobj_attribute damon_sysfs_kdamond_refresh_ms_attr =
1909 		__ATTR_RW_MODE(refresh_ms, 0600);
1910 
1911 static struct attribute *damon_sysfs_kdamond_attrs[] = {
1912 	&damon_sysfs_kdamond_state_attr.attr,
1913 	&damon_sysfs_kdamond_pid_attr.attr,
1914 	&damon_sysfs_kdamond_refresh_ms_attr.attr,
1915 	NULL,
1916 };
1917 ATTRIBUTE_GROUPS(damon_sysfs_kdamond);
1918 
1919 static const struct kobj_type damon_sysfs_kdamond_ktype = {
1920 	.release = damon_sysfs_kdamond_release,
1921 	.sysfs_ops = &kobj_sysfs_ops,
1922 	.default_groups = damon_sysfs_kdamond_groups,
1923 };
1924 
1925 /*
1926  * kdamonds directory
1927  */
1928 
1929 struct damon_sysfs_kdamonds {
1930 	struct kobject kobj;
1931 	struct damon_sysfs_kdamond **kdamonds_arr;
1932 	int nr;
1933 };
1934 
1935 static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void)
1936 {
1937 	return kzalloc_obj(struct damon_sysfs_kdamonds);
1938 }
1939 
1940 static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
1941 {
1942 	struct damon_sysfs_kdamond **kdamonds_arr = kdamonds->kdamonds_arr;
1943 	int i;
1944 
1945 	for (i = 0; i < kdamonds->nr; i++) {
1946 		damon_sysfs_kdamond_rm_dirs(kdamonds_arr[i]);
1947 		kobject_put(&kdamonds_arr[i]->kobj);
1948 	}
1949 	kdamonds->nr = 0;
1950 	kfree(kdamonds_arr);
1951 	kdamonds->kdamonds_arr = NULL;
1952 }
1953 
1954 static bool damon_sysfs_kdamonds_busy(struct damon_sysfs_kdamond **kdamonds,
1955 		int nr_kdamonds)
1956 {
1957 	int i;
1958 
1959 	for (i = 0; i < nr_kdamonds; i++) {
1960 		if (damon_sysfs_kdamond_running(kdamonds[i]))
1961 			return true;
1962 	}
1963 
1964 	return false;
1965 }
1966 
1967 static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
1968 		int nr_kdamonds)
1969 {
1970 	struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
1971 	int err, i;
1972 
1973 	if (damon_sysfs_kdamonds_busy(kdamonds->kdamonds_arr, kdamonds->nr))
1974 		return -EBUSY;
1975 
1976 	damon_sysfs_kdamonds_rm_dirs(kdamonds);
1977 	if (!nr_kdamonds)
1978 		return 0;
1979 
1980 	kdamonds_arr = kmalloc_objs(*kdamonds_arr, nr_kdamonds,
1981 				    GFP_KERNEL | __GFP_NOWARN);
1982 	if (!kdamonds_arr)
1983 		return -ENOMEM;
1984 	kdamonds->kdamonds_arr = kdamonds_arr;
1985 
1986 	for (i = 0; i < nr_kdamonds; i++) {
1987 		kdamond = damon_sysfs_kdamond_alloc();
1988 		if (!kdamond) {
1989 			damon_sysfs_kdamonds_rm_dirs(kdamonds);
1990 			return -ENOMEM;
1991 		}
1992 
1993 		err = kobject_init_and_add(&kdamond->kobj,
1994 				&damon_sysfs_kdamond_ktype, &kdamonds->kobj,
1995 				"%d", i);
1996 		if (err)
1997 			goto out;
1998 
1999 		err = damon_sysfs_kdamond_add_dirs(kdamond);
2000 		if (err)
2001 			goto out;
2002 
2003 		kdamonds_arr[i] = kdamond;
2004 		kdamonds->nr++;
2005 	}
2006 	return 0;
2007 
2008 out:
2009 	damon_sysfs_kdamonds_rm_dirs(kdamonds);
2010 	kobject_put(&kdamond->kobj);
2011 	return err;
2012 }
2013 
2014 static ssize_t nr_kdamonds_show(struct kobject *kobj,
2015 		struct kobj_attribute *attr, char *buf)
2016 {
2017 	struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
2018 			struct damon_sysfs_kdamonds, kobj);
2019 
2020 	return sysfs_emit(buf, "%d\n", kdamonds->nr);
2021 }
2022 
2023 static ssize_t nr_kdamonds_store(struct kobject *kobj,
2024 		struct kobj_attribute *attr, const char *buf, size_t count)
2025 {
2026 	struct damon_sysfs_kdamonds *kdamonds;
2027 	int nr, err;
2028 
2029 	err = kstrtoint(buf, 0, &nr);
2030 	if (err)
2031 		return err;
2032 	if (nr < 0)
2033 		return -EINVAL;
2034 
2035 	kdamonds = container_of(kobj, struct damon_sysfs_kdamonds, kobj);
2036 
2037 	if (!mutex_trylock(&damon_sysfs_lock))
2038 		return -EBUSY;
2039 	err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr);
2040 	mutex_unlock(&damon_sysfs_lock);
2041 	if (err)
2042 		return err;
2043 
2044 	return count;
2045 }
2046 
2047 static void damon_sysfs_kdamonds_release(struct kobject *kobj)
2048 {
2049 	kfree(container_of(kobj, struct damon_sysfs_kdamonds, kobj));
2050 }
2051 
2052 static struct kobj_attribute damon_sysfs_kdamonds_nr_attr =
2053 		__ATTR_RW_MODE(nr_kdamonds, 0600);
2054 
2055 static struct attribute *damon_sysfs_kdamonds_attrs[] = {
2056 	&damon_sysfs_kdamonds_nr_attr.attr,
2057 	NULL,
2058 };
2059 ATTRIBUTE_GROUPS(damon_sysfs_kdamonds);
2060 
2061 static const struct kobj_type damon_sysfs_kdamonds_ktype = {
2062 	.release = damon_sysfs_kdamonds_release,
2063 	.sysfs_ops = &kobj_sysfs_ops,
2064 	.default_groups = damon_sysfs_kdamonds_groups,
2065 };
2066 
2067 /*
2068  * damon user interface directory
2069  */
2070 
2071 struct damon_sysfs_ui_dir {
2072 	struct kobject kobj;
2073 	struct damon_sysfs_kdamonds *kdamonds;
2074 };
2075 
2076 static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
2077 {
2078 	return kzalloc_obj(struct damon_sysfs_ui_dir);
2079 }
2080 
2081 static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
2082 {
2083 	struct damon_sysfs_kdamonds *kdamonds;
2084 	int err;
2085 
2086 	kdamonds = damon_sysfs_kdamonds_alloc();
2087 	if (!kdamonds)
2088 		return -ENOMEM;
2089 
2090 	err = kobject_init_and_add(&kdamonds->kobj,
2091 			&damon_sysfs_kdamonds_ktype, &ui_dir->kobj,
2092 			"kdamonds");
2093 	if (err) {
2094 		kobject_put(&kdamonds->kobj);
2095 		return err;
2096 	}
2097 	ui_dir->kdamonds = kdamonds;
2098 	return err;
2099 }
2100 
2101 static void damon_sysfs_ui_dir_release(struct kobject *kobj)
2102 {
2103 	kfree(container_of(kobj, struct damon_sysfs_ui_dir, kobj));
2104 }
2105 
2106 static struct attribute *damon_sysfs_ui_dir_attrs[] = {
2107 	NULL,
2108 };
2109 ATTRIBUTE_GROUPS(damon_sysfs_ui_dir);
2110 
2111 static const struct kobj_type damon_sysfs_ui_dir_ktype = {
2112 	.release = damon_sysfs_ui_dir_release,
2113 	.sysfs_ops = &kobj_sysfs_ops,
2114 	.default_groups = damon_sysfs_ui_dir_groups,
2115 };
2116 
2117 static int __init damon_sysfs_init(void)
2118 {
2119 	struct kobject *damon_sysfs_root;
2120 	struct damon_sysfs_ui_dir *admin;
2121 	int err;
2122 
2123 	damon_sysfs_root = kobject_create_and_add("damon", mm_kobj);
2124 	if (!damon_sysfs_root)
2125 		return -ENOMEM;
2126 
2127 	admin = damon_sysfs_ui_dir_alloc();
2128 	if (!admin) {
2129 		kobject_put(damon_sysfs_root);
2130 		return -ENOMEM;
2131 	}
2132 	err = kobject_init_and_add(&admin->kobj, &damon_sysfs_ui_dir_ktype,
2133 			damon_sysfs_root, "admin");
2134 	if (err)
2135 		goto out;
2136 	err = damon_sysfs_ui_dir_add_dirs(admin);
2137 	if (err)
2138 		goto out;
2139 	return 0;
2140 
2141 out:
2142 	kobject_put(&admin->kobj);
2143 	kobject_put(damon_sysfs_root);
2144 	return err;
2145 }
2146 subsys_initcall(damon_sysfs_init);
2147 
2148 #include "tests/sysfs-kunit.h"
2149