mm/damon/sysfs.c

   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/damon.h>
   9 #include <linux/kobject.h>
  10 #include <linux/pid.h>
  11 #include <linux/sched.h>
  12 #include <linux/slab.h>
  13
  14 static DEFINE_MUTEX(damon_sysfs_lock);
  15
  16 /*
  17  * unsigned long range directory
  18  */
  19
  20 struct damon_sysfs_ul_range {
  21         struct kobject kobj;
  22         unsigned long min;
  23         unsigned long max;
  24 };
  25
  26 static struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc(
  27                 unsigned long min,
  28                 unsigned long max)
  29 {
  30         struct damon_sysfs_ul_range *range = kmalloc(sizeof(*range),
  31                         GFP_KERNEL);
  32
  33         if (!range)
  34                 return NULL;
  35         range->kobj = (struct kobject){};
  36         range->min = min;
  37         range->max = max;
  38
  39         return range;
  40 }
  41
  42 static ssize_t min_show(struct kobject *kobj, struct kobj_attribute *attr,
  43                 char *buf)
  44 {
  45         struct damon_sysfs_ul_range *range = container_of(kobj,
  46                         struct damon_sysfs_ul_range, kobj);
  47
  48         return sysfs_emit(buf, "%lu\n", range->min);
  49 }
  50
  51 static ssize_t min_store(struct kobject *kobj, struct kobj_attribute *attr,
  52                 const char *buf, size_t count)
  53 {
  54         struct damon_sysfs_ul_range *range = container_of(kobj,
  55                         struct damon_sysfs_ul_range, kobj);
  56         unsigned long min;
  57         int err;
  58
  59         err = kstrtoul(buf, 0, &min);
  60         if (err)
  61                 return -EINVAL;
  62
  63         range->min = min;
  64         return count;
  65 }
  66
  67 static ssize_t max_show(struct kobject *kobj, struct kobj_attribute *attr,
  68                 char *buf)
  69 {
  70         struct damon_sysfs_ul_range *range = container_of(kobj,
  71                         struct damon_sysfs_ul_range, kobj);
  72
  73         return sysfs_emit(buf, "%lu\n", range->max);
  74 }
  75
  76 static ssize_t max_store(struct kobject *kobj, struct kobj_attribute *attr,
  77                 const char *buf, size_t count)
  78 {
  79         struct damon_sysfs_ul_range *range = container_of(kobj,
  80                         struct damon_sysfs_ul_range, kobj);
  81         unsigned long max;
  82         int err;
  83
  84         err = kstrtoul(buf, 0, &max);
  85         if (err)
  86                 return -EINVAL;
  87
  88         range->max = max;
  89         return count;
  90 }
  91
  92 static void damon_sysfs_ul_range_release(struct kobject *kobj)
  93 {
  94         kfree(container_of(kobj, struct damon_sysfs_ul_range, kobj));
  95 }
  96
  97 static struct kobj_attribute damon_sysfs_ul_range_min_attr =
  98                 __ATTR_RW_MODE(min, 0600);
  99
 100 static struct kobj_attribute damon_sysfs_ul_range_max_attr =
 101                 __ATTR_RW_MODE(max, 0600);
 102
 103 static struct attribute *damon_sysfs_ul_range_attrs[] = {
 104         &damon_sysfs_ul_range_min_attr.attr,
 105         &damon_sysfs_ul_range_max_attr.attr,
 106         NULL,
 107 };
 108 ATTRIBUTE_GROUPS(damon_sysfs_ul_range);
 109
 110 static struct kobj_type damon_sysfs_ul_range_ktype = {
 111         .release = damon_sysfs_ul_range_release,
 112         .sysfs_ops = &kobj_sysfs_ops,
 113         .default_groups = damon_sysfs_ul_range_groups,
 114 };
 115
 116 /*
 117  * schemes/stats directory
 118  */
 119
 120 struct damon_sysfs_stats {
 121         struct kobject kobj;
 122         unsigned long nr_tried;
 123         unsigned long sz_tried;
 124         unsigned long nr_applied;
 125         unsigned long sz_applied;
 126         unsigned long qt_exceeds;
 127 };
 128
 129 static struct damon_sysfs_stats *damon_sysfs_stats_alloc(void)
 130 {
 131         return kzalloc(sizeof(struct damon_sysfs_stats), GFP_KERNEL);
 132 }
 133
 134 static ssize_t nr_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
 135                 char *buf)
 136 {
 137         struct damon_sysfs_stats *stats = container_of(kobj,
 138                         struct damon_sysfs_stats, kobj);
 139
 140         return sysfs_emit(buf, "%lu\n", stats->nr_tried);
 141 }
 142
 143 static ssize_t sz_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
 144                 char *buf)
 145 {
 146         struct damon_sysfs_stats *stats = container_of(kobj,
 147                         struct damon_sysfs_stats, kobj);
 148
 149         return sysfs_emit(buf, "%lu\n", stats->sz_tried);
 150 }
 151
 152 static ssize_t nr_applied_show(struct kobject *kobj,
 153                 struct kobj_attribute *attr, char *buf)
 154 {
 155         struct damon_sysfs_stats *stats = container_of(kobj,
 156                         struct damon_sysfs_stats, kobj);
 157
 158         return sysfs_emit(buf, "%lu\n", stats->nr_applied);
 159 }
 160
 161 static ssize_t sz_applied_show(struct kobject *kobj,
 162                 struct kobj_attribute *attr, char *buf)
 163 {
 164         struct damon_sysfs_stats *stats = container_of(kobj,
 165                         struct damon_sysfs_stats, kobj);
 166
 167         return sysfs_emit(buf, "%lu\n", stats->sz_applied);
 168 }
 169
 170 static ssize_t qt_exceeds_show(struct kobject *kobj,
 171                 struct kobj_attribute *attr, char *buf)
 172 {
 173         struct damon_sysfs_stats *stats = container_of(kobj,
 174                         struct damon_sysfs_stats, kobj);
 175
 176         return sysfs_emit(buf, "%lu\n", stats->qt_exceeds);
 177 }
 178
 179 static void damon_sysfs_stats_release(struct kobject *kobj)
 180 {
 181         kfree(container_of(kobj, struct damon_sysfs_stats, kobj));
 182 }
 183
 184 static struct kobj_attribute damon_sysfs_stats_nr_tried_attr =
 185                 __ATTR_RO_MODE(nr_tried, 0400);
 186
 187 static struct kobj_attribute damon_sysfs_stats_sz_tried_attr =
 188                 __ATTR_RO_MODE(sz_tried, 0400);
 189
 190 static struct kobj_attribute damon_sysfs_stats_nr_applied_attr =
 191                 __ATTR_RO_MODE(nr_applied, 0400);
 192
 193 static struct kobj_attribute damon_sysfs_stats_sz_applied_attr =
 194                 __ATTR_RO_MODE(sz_applied, 0400);
 195
 196 static struct kobj_attribute damon_sysfs_stats_qt_exceeds_attr =
 197                 __ATTR_RO_MODE(qt_exceeds, 0400);
 198
 199 static struct attribute *damon_sysfs_stats_attrs[] = {
 200         &damon_sysfs_stats_nr_tried_attr.attr,
 201         &damon_sysfs_stats_sz_tried_attr.attr,
 202         &damon_sysfs_stats_nr_applied_attr.attr,
 203         &damon_sysfs_stats_sz_applied_attr.attr,
 204         &damon_sysfs_stats_qt_exceeds_attr.attr,
 205         NULL,
 206 };
 207 ATTRIBUTE_GROUPS(damon_sysfs_stats);
 208
 209 static struct kobj_type damon_sysfs_stats_ktype = {
 210         .release = damon_sysfs_stats_release,
 211         .sysfs_ops = &kobj_sysfs_ops,
 212         .default_groups = damon_sysfs_stats_groups,
 213 };
 214
 215 /*
 216  * watermarks directory
 217  */
 218
 219 struct damon_sysfs_watermarks {
 220         struct kobject kobj;
 221         enum damos_wmark_metric metric;
 222         unsigned long interval_us;
 223         unsigned long high;
 224         unsigned long mid;
 225         unsigned long low;
 226 };
 227
 228 static struct damon_sysfs_watermarks *damon_sysfs_watermarks_alloc(
 229                 enum damos_wmark_metric metric, unsigned long interval_us,
 230                 unsigned long high, unsigned long mid, unsigned long low)
 231 {
 232         struct damon_sysfs_watermarks *watermarks = kmalloc(
 233                         sizeof(*watermarks), GFP_KERNEL);
 234
 235         if (!watermarks)
 236                 return NULL;
 237         watermarks->kobj = (struct kobject){};
 238         watermarks->metric = metric;
 239         watermarks->interval_us = interval_us;
 240         watermarks->high = high;
 241         watermarks->mid = mid;
 242         watermarks->low = low;
 243         return watermarks;
 244 }
 245
 246 /* Should match with enum damos_wmark_metric */
 247 static const char * const damon_sysfs_wmark_metric_strs[] = {
 248         "none",
 249         "free_mem_rate",
 250 };
 251
 252 static ssize_t metric_show(struct kobject *kobj, struct kobj_attribute *attr,
 253                 char *buf)
 254 {
 255         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 256                         struct damon_sysfs_watermarks, kobj);
 257
 258         return sysfs_emit(buf, "%s\n",
 259                         damon_sysfs_wmark_metric_strs[watermarks->metric]);
 260 }
 261
 262 static ssize_t metric_store(struct kobject *kobj, struct kobj_attribute *attr,
 263                 const char *buf, size_t count)
 264 {
 265         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 266                         struct damon_sysfs_watermarks, kobj);
 267         enum damos_wmark_metric metric;
 268
 269         for (metric = 0; metric < NR_DAMOS_WMARK_METRICS; metric++) {
 270                 if (sysfs_streq(buf, damon_sysfs_wmark_metric_strs[metric])) {
 271                         watermarks->metric = metric;
 272                         return count;
 273                 }
 274         }
 275         return -EINVAL;
 276 }
 277
 278 static ssize_t interval_us_show(struct kobject *kobj,
 279                 struct kobj_attribute *attr, char *buf)
 280 {
 281         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 282                         struct damon_sysfs_watermarks, kobj);
 283
 284         return sysfs_emit(buf, "%lu\n", watermarks->interval_us);
 285 }
 286
 287 static ssize_t interval_us_store(struct kobject *kobj,
 288                 struct kobj_attribute *attr, const char *buf, size_t count)
 289 {
 290         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 291                         struct damon_sysfs_watermarks, kobj);
 292         int err = kstrtoul(buf, 0, &watermarks->interval_us);
 293
 294         if (err)
 295                 return -EINVAL;
 296         return count;
 297 }
 298
 299 static ssize_t high_show(struct kobject *kobj,
 300                 struct kobj_attribute *attr, char *buf)
 301 {
 302         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 303                         struct damon_sysfs_watermarks, kobj);
 304
 305         return sysfs_emit(buf, "%lu\n", watermarks->high);
 306 }
 307
 308 static ssize_t high_store(struct kobject *kobj,
 309                 struct kobj_attribute *attr, const char *buf, size_t count)
 310 {
 311         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 312                         struct damon_sysfs_watermarks, kobj);
 313         int err = kstrtoul(buf, 0, &watermarks->high);
 314
 315         if (err)
 316                 return -EINVAL;
 317         return count;
 318 }
 319
 320 static ssize_t mid_show(struct kobject *kobj,
 321                 struct kobj_attribute *attr, char *buf)
 322 {
 323         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 324                         struct damon_sysfs_watermarks, kobj);
 325
 326         return sysfs_emit(buf, "%lu\n", watermarks->mid);
 327 }
 328
 329 static ssize_t mid_store(struct kobject *kobj,
 330                 struct kobj_attribute *attr, const char *buf, size_t count)
 331 {
 332         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 333                         struct damon_sysfs_watermarks, kobj);
 334         int err = kstrtoul(buf, 0, &watermarks->mid);
 335
 336         if (err)
 337                 return -EINVAL;
 338         return count;
 339 }
 340
 341 static ssize_t low_show(struct kobject *kobj,
 342                 struct kobj_attribute *attr, char *buf)
 343 {
 344         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 345                         struct damon_sysfs_watermarks, kobj);
 346
 347         return sysfs_emit(buf, "%lu\n", watermarks->low);
 348 }
 349
 350 static ssize_t low_store(struct kobject *kobj,
 351                 struct kobj_attribute *attr, const char *buf, size_t count)
 352 {
 353         struct damon_sysfs_watermarks *watermarks = container_of(kobj,
 354                         struct damon_sysfs_watermarks, kobj);
 355         int err = kstrtoul(buf, 0, &watermarks->low);
 356
 357         if (err)
 358                 return -EINVAL;
 359         return count;
 360 }
 361
 362 static void damon_sysfs_watermarks_release(struct kobject *kobj)
 363 {
 364         kfree(container_of(kobj, struct damon_sysfs_watermarks, kobj));
 365 }
 366
 367 static struct kobj_attribute damon_sysfs_watermarks_metric_attr =
 368                 __ATTR_RW_MODE(metric, 0600);
 369
 370 static struct kobj_attribute damon_sysfs_watermarks_interval_us_attr =
 371                 __ATTR_RW_MODE(interval_us, 0600);
 372
 373 static struct kobj_attribute damon_sysfs_watermarks_high_attr =
 374                 __ATTR_RW_MODE(high, 0600);
 375
 376 static struct kobj_attribute damon_sysfs_watermarks_mid_attr =
 377                 __ATTR_RW_MODE(mid, 0600);
 378
 379 static struct kobj_attribute damon_sysfs_watermarks_low_attr =
 380                 __ATTR_RW_MODE(low, 0600);
 381
 382 static struct attribute *damon_sysfs_watermarks_attrs[] = {
 383         &damon_sysfs_watermarks_metric_attr.attr,
 384         &damon_sysfs_watermarks_interval_us_attr.attr,
 385         &damon_sysfs_watermarks_high_attr.attr,
 386         &damon_sysfs_watermarks_mid_attr.attr,
 387         &damon_sysfs_watermarks_low_attr.attr,
 388         NULL,
 389 };
 390 ATTRIBUTE_GROUPS(damon_sysfs_watermarks);
 391
 392 static struct kobj_type damon_sysfs_watermarks_ktype = {
 393         .release = damon_sysfs_watermarks_release,
 394         .sysfs_ops = &kobj_sysfs_ops,
 395         .default_groups = damon_sysfs_watermarks_groups,
 396 };
 397
 398 /*
 399  * scheme/weights directory
 400  */
 401
 402 struct damon_sysfs_weights {
 403         struct kobject kobj;
 404         unsigned int sz;
 405         unsigned int nr_accesses;
 406         unsigned int age;
 407 };
 408
 409 static struct damon_sysfs_weights *damon_sysfs_weights_alloc(unsigned int sz,
 410                 unsigned int nr_accesses, unsigned int age)
 411 {
 412         struct damon_sysfs_weights *weights = kmalloc(sizeof(*weights),
 413                         GFP_KERNEL);
 414
 415         if (!weights)
 416                 return NULL;
 417         weights->kobj = (struct kobject){};
 418         weights->sz = sz;
 419         weights->nr_accesses = nr_accesses;
 420         weights->age = age;
 421         return weights;
 422 }
 423
 424 static ssize_t sz_permil_show(struct kobject *kobj,
 425                 struct kobj_attribute *attr, char *buf)
 426 {
 427         struct damon_sysfs_weights *weights = container_of(kobj,
 428                         struct damon_sysfs_weights, kobj);
 429
 430         return sysfs_emit(buf, "%u\n", weights->sz);
 431 }
 432
 433 static ssize_t sz_permil_store(struct kobject *kobj,
 434                 struct kobj_attribute *attr, const char *buf, size_t count)
 435 {
 436         struct damon_sysfs_weights *weights = container_of(kobj,
 437                         struct damon_sysfs_weights, kobj);
 438         int err = kstrtouint(buf, 0, &weights->sz);
 439
 440         if (err)
 441                 return -EINVAL;
 442         return count;
 443 }
 444
 445 static ssize_t nr_accesses_permil_show(struct kobject *kobj,
 446                 struct kobj_attribute *attr, char *buf)
 447 {
 448         struct damon_sysfs_weights *weights = container_of(kobj,
 449                         struct damon_sysfs_weights, kobj);
 450
 451         return sysfs_emit(buf, "%u\n", weights->nr_accesses);
 452 }
 453
 454 static ssize_t nr_accesses_permil_store(struct kobject *kobj,
 455                 struct kobj_attribute *attr, const char *buf, size_t count)
 456 {
 457         struct damon_sysfs_weights *weights = container_of(kobj,
 458                         struct damon_sysfs_weights, kobj);
 459         int err = kstrtouint(buf, 0, &weights->nr_accesses);
 460
 461         if (err)
 462                 return -EINVAL;
 463         return count;
 464 }
 465
 466 static ssize_t age_permil_show(struct kobject *kobj,
 467                 struct kobj_attribute *attr, char *buf)
 468 {
 469         struct damon_sysfs_weights *weights = container_of(kobj,
 470                         struct damon_sysfs_weights, kobj);
 471
 472         return sysfs_emit(buf, "%u\n", weights->age);
 473 }
 474
 475 static ssize_t age_permil_store(struct kobject *kobj,
 476                 struct kobj_attribute *attr, const char *buf, size_t count)
 477 {
 478         struct damon_sysfs_weights *weights = container_of(kobj,
 479                         struct damon_sysfs_weights, kobj);
 480         int err = kstrtouint(buf, 0, &weights->age);
 481
 482         if (err)
 483                 return -EINVAL;
 484         return count;
 485 }
 486
 487 static void damon_sysfs_weights_release(struct kobject *kobj)
 488 {
 489         kfree(container_of(kobj, struct damon_sysfs_weights, kobj));
 490 }
 491
 492 static struct kobj_attribute damon_sysfs_weights_sz_attr =
 493                 __ATTR_RW_MODE(sz_permil, 0600);
 494
 495 static struct kobj_attribute damon_sysfs_weights_nr_accesses_attr =
 496                 __ATTR_RW_MODE(nr_accesses_permil, 0600);
 497
 498 static struct kobj_attribute damon_sysfs_weights_age_attr =
 499                 __ATTR_RW_MODE(age_permil, 0600);
 500
 501 static struct attribute *damon_sysfs_weights_attrs[] = {
 502         &damon_sysfs_weights_sz_attr.attr,
 503         &damon_sysfs_weights_nr_accesses_attr.attr,
 504         &damon_sysfs_weights_age_attr.attr,
 505         NULL,
 506 };
 507 ATTRIBUTE_GROUPS(damon_sysfs_weights);
 508
 509 static struct kobj_type damon_sysfs_weights_ktype = {
 510         .release = damon_sysfs_weights_release,
 511         .sysfs_ops = &kobj_sysfs_ops,
 512         .default_groups = damon_sysfs_weights_groups,
 513 };
 514
 515 /*
 516  * quotas directory
 517  */
 518
 519 struct damon_sysfs_quotas {
 520         struct kobject kobj;
 521         struct damon_sysfs_weights *weights;
 522         unsigned long ms;
 523         unsigned long sz;
 524         unsigned long reset_interval_ms;
 525 };
 526
 527 static struct damon_sysfs_quotas *damon_sysfs_quotas_alloc(void)
 528 {
 529         return kzalloc(sizeof(struct damon_sysfs_quotas), GFP_KERNEL);
 530 }
 531
 532 static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
 533 {
 534         struct damon_sysfs_weights *weights;
 535         int err;
 536
 537         weights = damon_sysfs_weights_alloc(0, 0, 0);
 538         if (!weights)
 539                 return -ENOMEM;
 540
 541         err = kobject_init_and_add(&weights->kobj, &damon_sysfs_weights_ktype,
 542                         &quotas->kobj, "weights");
 543         if (err)
 544                 kobject_put(&weights->kobj);
 545         else
 546                 quotas->weights = weights;
 547         return err;
 548 }
 549
 550 static void damon_sysfs_quotas_rm_dirs(struct damon_sysfs_quotas *quotas)
 551 {
 552         kobject_put(&quotas->weights->kobj);
 553 }
 554
 555 static ssize_t ms_show(struct kobject *kobj, struct kobj_attribute *attr,
 556                 char *buf)
 557 {
 558         struct damon_sysfs_quotas *quotas = container_of(kobj,
 559                         struct damon_sysfs_quotas, kobj);
 560
 561         return sysfs_emit(buf, "%lu\n", quotas->ms);
 562 }
 563
 564 static ssize_t ms_store(struct kobject *kobj, struct kobj_attribute *attr,
 565                 const char *buf, size_t count)
 566 {
 567         struct damon_sysfs_quotas *quotas = container_of(kobj,
 568                         struct damon_sysfs_quotas, kobj);
 569         int err = kstrtoul(buf, 0, &quotas->ms);
 570
 571         if (err)
 572                 return -EINVAL;
 573         return count;
 574 }
 575
 576 static ssize_t bytes_show(struct kobject *kobj, struct kobj_attribute *attr,
 577                 char *buf)
 578 {
 579         struct damon_sysfs_quotas *quotas = container_of(kobj,
 580                         struct damon_sysfs_quotas, kobj);
 581
 582         return sysfs_emit(buf, "%lu\n", quotas->sz);
 583 }
 584
 585 static ssize_t bytes_store(struct kobject *kobj,
 586                 struct kobj_attribute *attr, const char *buf, size_t count)
 587 {
 588         struct damon_sysfs_quotas *quotas = container_of(kobj,
 589                         struct damon_sysfs_quotas, kobj);
 590         int err = kstrtoul(buf, 0, &quotas->sz);
 591
 592         if (err)
 593                 return -EINVAL;
 594         return count;
 595 }
 596
 597 static ssize_t reset_interval_ms_show(struct kobject *kobj,
 598                 struct kobj_attribute *attr, char *buf)
 599 {
 600         struct damon_sysfs_quotas *quotas = container_of(kobj,
 601                         struct damon_sysfs_quotas, kobj);
 602
 603         return sysfs_emit(buf, "%lu\n", quotas->reset_interval_ms);
 604 }
 605
 606 static ssize_t reset_interval_ms_store(struct kobject *kobj,
 607                 struct kobj_attribute *attr, const char *buf, size_t count)
 608 {
 609         struct damon_sysfs_quotas *quotas = container_of(kobj,
 610                         struct damon_sysfs_quotas, kobj);
 611         int err = kstrtoul(buf, 0, &quotas->reset_interval_ms);
 612
 613         if (err)
 614                 return -EINVAL;
 615         return count;
 616 }
 617
 618 static void damon_sysfs_quotas_release(struct kobject *kobj)
 619 {
 620         kfree(container_of(kobj, struct damon_sysfs_quotas, kobj));
 621 }
 622
 623 static struct kobj_attribute damon_sysfs_quotas_ms_attr =
 624                 __ATTR_RW_MODE(ms, 0600);
 625
 626 static struct kobj_attribute damon_sysfs_quotas_sz_attr =
 627                 __ATTR_RW_MODE(bytes, 0600);
 628
 629 static struct kobj_attribute damon_sysfs_quotas_reset_interval_ms_attr =
 630                 __ATTR_RW_MODE(reset_interval_ms, 0600);
 631
 632 static struct attribute *damon_sysfs_quotas_attrs[] = {
 633         &damon_sysfs_quotas_ms_attr.attr,
 634         &damon_sysfs_quotas_sz_attr.attr,
 635         &damon_sysfs_quotas_reset_interval_ms_attr.attr,
 636         NULL,
 637 };
 638 ATTRIBUTE_GROUPS(damon_sysfs_quotas);
 639
 640 static struct kobj_type damon_sysfs_quotas_ktype = {
 641         .release = damon_sysfs_quotas_release,
 642         .sysfs_ops = &kobj_sysfs_ops,
 643         .default_groups = damon_sysfs_quotas_groups,
 644 };
 645
 646 /*
 647  * access_pattern directory
 648  */
 649
 650 struct damon_sysfs_access_pattern {
 651         struct kobject kobj;
 652         struct damon_sysfs_ul_range *sz;
 653         struct damon_sysfs_ul_range *nr_accesses;
 654         struct damon_sysfs_ul_range *age;
 655 };
 656
 657 static
 658 struct damon_sysfs_access_pattern *damon_sysfs_access_pattern_alloc(void)
 659 {
 660         struct damon_sysfs_access_pattern *access_pattern =
 661                 kmalloc(sizeof(*access_pattern), GFP_KERNEL);
 662
 663         if (!access_pattern)
 664                 return NULL;
 665         access_pattern->kobj = (struct kobject){};
 666         return access_pattern;
 667 }
 668
 669 static int damon_sysfs_access_pattern_add_range_dir(
 670                 struct damon_sysfs_access_pattern *access_pattern,
 671                 struct damon_sysfs_ul_range **range_dir_ptr,
 672                 char *name)
 673 {
 674         struct damon_sysfs_ul_range *range = damon_sysfs_ul_range_alloc(0, 0);
 675         int err;
 676
 677         if (!range)
 678                 return -ENOMEM;
 679         err = kobject_init_and_add(&range->kobj, &damon_sysfs_ul_range_ktype,
 680                         &access_pattern->kobj, name);
 681         if (err)
 682                 kobject_put(&range->kobj);
 683         else
 684                 *range_dir_ptr = range;
 685         return err;
 686 }
 687
 688 static int damon_sysfs_access_pattern_add_dirs(
 689                 struct damon_sysfs_access_pattern *access_pattern)
 690 {
 691         int err;
 692
 693         err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
 694                         &access_pattern->sz, "sz");
 695         if (err)
 696                 goto put_sz_out;
 697
 698         err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
 699                         &access_pattern->nr_accesses, "nr_accesses");
 700         if (err)
 701                 goto put_nr_accesses_sz_out;
 702
 703         err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
 704                         &access_pattern->age, "age");
 705         if (err)
 706                 goto put_age_nr_accesses_sz_out;
 707         return 0;
 708
 709 put_age_nr_accesses_sz_out:
 710         kobject_put(&access_pattern->age->kobj);
 711         access_pattern->age = NULL;
 712 put_nr_accesses_sz_out:
 713         kobject_put(&access_pattern->nr_accesses->kobj);
 714         access_pattern->nr_accesses = NULL;
 715 put_sz_out:
 716         kobject_put(&access_pattern->sz->kobj);
 717         access_pattern->sz = NULL;
 718         return err;
 719 }
 720
 721 static void damon_sysfs_access_pattern_rm_dirs(
 722                 struct damon_sysfs_access_pattern *access_pattern)
 723 {
 724         kobject_put(&access_pattern->sz->kobj);
 725         kobject_put(&access_pattern->nr_accesses->kobj);
 726         kobject_put(&access_pattern->age->kobj);
 727 }
 728
 729 static void damon_sysfs_access_pattern_release(struct kobject *kobj)
 730 {
 731         kfree(container_of(kobj, struct damon_sysfs_access_pattern, kobj));
 732 }
 733
 734 static struct attribute *damon_sysfs_access_pattern_attrs[] = {
 735         NULL,
 736 };
 737 ATTRIBUTE_GROUPS(damon_sysfs_access_pattern);
 738
 739 static struct kobj_type damon_sysfs_access_pattern_ktype = {
 740         .release = damon_sysfs_access_pattern_release,
 741         .sysfs_ops = &kobj_sysfs_ops,
 742         .default_groups = damon_sysfs_access_pattern_groups,
 743 };
 744
 745 /*
 746  * scheme directory
 747  */
 748
 749 struct damon_sysfs_scheme {
 750         struct kobject kobj;
 751         enum damos_action action;
 752         struct damon_sysfs_access_pattern *access_pattern;
 753         struct damon_sysfs_quotas *quotas;
 754         struct damon_sysfs_watermarks *watermarks;
 755         struct damon_sysfs_stats *stats;
 756 };
 757
 758 /* This should match with enum damos_action */
 759 static const char * const damon_sysfs_damos_action_strs[] = {
 760         "willneed",
 761         "cold",
 762         "pageout",
 763         "hugepage",
 764         "nohugepage",
 765         "stat",
 766 };
 767
 768 static struct damon_sysfs_scheme *damon_sysfs_scheme_alloc(
 769                 enum damos_action action)
 770 {
 771         struct damon_sysfs_scheme *scheme = kmalloc(sizeof(*scheme),
 772                                 GFP_KERNEL);
 773
 774         if (!scheme)
 775                 return NULL;
 776         scheme->kobj = (struct kobject){};
 777         scheme->action = action;
 778         return scheme;
 779 }
 780
 781 static int damon_sysfs_scheme_set_access_pattern(
 782                 struct damon_sysfs_scheme *scheme)
 783 {
 784         struct damon_sysfs_access_pattern *access_pattern;
 785         int err;
 786
 787         access_pattern = damon_sysfs_access_pattern_alloc();
 788         if (!access_pattern)
 789                 return -ENOMEM;
 790         err = kobject_init_and_add(&access_pattern->kobj,
 791                         &damon_sysfs_access_pattern_ktype, &scheme->kobj,
 792                         "access_pattern");
 793         if (err)
 794                 goto out;
 795         err = damon_sysfs_access_pattern_add_dirs(access_pattern);
 796         if (err)
 797                 goto out;
 798         scheme->access_pattern = access_pattern;
 799         return 0;
 800
 801 out:
 802         kobject_put(&access_pattern->kobj);
 803         return err;
 804 }
 805
 806 static int damon_sysfs_scheme_set_quotas(struct damon_sysfs_scheme *scheme)
 807 {
 808         struct damon_sysfs_quotas *quotas = damon_sysfs_quotas_alloc();
 809         int err;
 810
 811         if (!quotas)
 812                 return -ENOMEM;
 813         err = kobject_init_and_add(&quotas->kobj, &damon_sysfs_quotas_ktype,
 814                         &scheme->kobj, "quotas");
 815         if (err)
 816                 goto out;
 817         err = damon_sysfs_quotas_add_dirs(quotas);
 818         if (err)
 819                 goto out;
 820         scheme->quotas = quotas;
 821         return 0;
 822
 823 out:
 824         kobject_put(&quotas->kobj);
 825         return err;
 826 }
 827
 828 static int damon_sysfs_scheme_set_watermarks(struct damon_sysfs_scheme *scheme)
 829 {
 830         struct damon_sysfs_watermarks *watermarks =
 831                 damon_sysfs_watermarks_alloc(DAMOS_WMARK_NONE, 0, 0, 0, 0);
 832         int err;
 833
 834         if (!watermarks)
 835                 return -ENOMEM;
 836         err = kobject_init_and_add(&watermarks->kobj,
 837                         &damon_sysfs_watermarks_ktype, &scheme->kobj,
 838                         "watermarks");
 839         if (err)
 840                 kobject_put(&watermarks->kobj);
 841         else
 842                 scheme->watermarks = watermarks;
 843         return err;
 844 }
 845
 846 static int damon_sysfs_scheme_set_stats(struct damon_sysfs_scheme *scheme)
 847 {
 848         struct damon_sysfs_stats *stats = damon_sysfs_stats_alloc();
 849         int err;
 850
 851         if (!stats)
 852                 return -ENOMEM;
 853         err = kobject_init_and_add(&stats->kobj, &damon_sysfs_stats_ktype,
 854                         &scheme->kobj, "stats");
 855         if (err)
 856                 kobject_put(&stats->kobj);
 857         else
 858                 scheme->stats = stats;
 859         return err;
 860 }
 861
 862 static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
 863 {
 864         int err;
 865
 866         err = damon_sysfs_scheme_set_access_pattern(scheme);
 867         if (err)
 868                 return err;
 869         err = damon_sysfs_scheme_set_quotas(scheme);
 870         if (err)
 871                 goto put_access_pattern_out;
 872         err = damon_sysfs_scheme_set_watermarks(scheme);
 873         if (err)
 874                 goto put_quotas_access_pattern_out;
 875         err = damon_sysfs_scheme_set_stats(scheme);
 876         if (err)
 877                 goto put_watermarks_quotas_access_pattern_out;
 878         return 0;
 879
 880 put_watermarks_quotas_access_pattern_out:
 881         kobject_put(&scheme->watermarks->kobj);
 882         scheme->watermarks = NULL;
 883 put_quotas_access_pattern_out:
 884         kobject_put(&scheme->quotas->kobj);
 885         scheme->quotas = NULL;
 886 put_access_pattern_out:
 887         kobject_put(&scheme->access_pattern->kobj);
 888         scheme->access_pattern = NULL;
 889         return err;
 890 }
 891
 892 static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
 893 {
 894         damon_sysfs_access_pattern_rm_dirs(scheme->access_pattern);
 895         kobject_put(&scheme->access_pattern->kobj);
 896         damon_sysfs_quotas_rm_dirs(scheme->quotas);
 897         kobject_put(&scheme->quotas->kobj);
 898         kobject_put(&scheme->watermarks->kobj);
 899         kobject_put(&scheme->stats->kobj);
 900 }
 901
 902 static ssize_t action_show(struct kobject *kobj, struct kobj_attribute *attr,
 903                 char *buf)
 904 {
 905         struct damon_sysfs_scheme *scheme = container_of(kobj,
 906                         struct damon_sysfs_scheme, kobj);
 907
 908         return sysfs_emit(buf, "%s\n",
 909                         damon_sysfs_damos_action_strs[scheme->action]);
 910 }
 911
 912 static ssize_t action_store(struct kobject *kobj, struct kobj_attribute *attr,
 913                 const char *buf, size_t count)
 914 {
 915         struct damon_sysfs_scheme *scheme = container_of(kobj,
 916                         struct damon_sysfs_scheme, kobj);
 917         enum damos_action action;
 918
 919         for (action = 0; action < NR_DAMOS_ACTIONS; action++) {
 920                 if (sysfs_streq(buf, damon_sysfs_damos_action_strs[action])) {
 921                         scheme->action = action;
 922                         return count;
 923                 }
 924         }
 925         return -EINVAL;
 926 }
 927
 928 static void damon_sysfs_scheme_release(struct kobject *kobj)
 929 {
 930         kfree(container_of(kobj, struct damon_sysfs_scheme, kobj));
 931 }
 932
 933 static struct kobj_attribute damon_sysfs_scheme_action_attr =
 934                 __ATTR_RW_MODE(action, 0600);
 935
 936 static struct attribute *damon_sysfs_scheme_attrs[] = {
 937         &damon_sysfs_scheme_action_attr.attr,
 938         NULL,
 939 };
 940 ATTRIBUTE_GROUPS(damon_sysfs_scheme);
 941
 942 static struct kobj_type damon_sysfs_scheme_ktype = {
 943         .release = damon_sysfs_scheme_release,
 944         .sysfs_ops = &kobj_sysfs_ops,
 945         .default_groups = damon_sysfs_scheme_groups,
 946 };
 947
 948 /*
 949  * schemes directory
 950  */
 951
 952 struct damon_sysfs_schemes {
 953         struct kobject kobj;
 954         struct damon_sysfs_scheme **schemes_arr;
 955         int nr;
 956 };
 957
 958 static struct damon_sysfs_schemes *damon_sysfs_schemes_alloc(void)
 959 {
 960         return kzalloc(sizeof(struct damon_sysfs_schemes), GFP_KERNEL);
 961 }
 962
 963 static void damon_sysfs_schemes_rm_dirs(struct damon_sysfs_schemes *schemes)
 964 {
 965         struct damon_sysfs_scheme **schemes_arr = schemes->schemes_arr;
 966         int i;
 967
 968         for (i = 0; i < schemes->nr; i++) {
 969                 damon_sysfs_scheme_rm_dirs(schemes_arr[i]);
 970                 kobject_put(&schemes_arr[i]->kobj);
 971         }
 972         schemes->nr = 0;
 973         kfree(schemes_arr);
 974         schemes->schemes_arr = NULL;
 975 }
 976
 977 static int damon_sysfs_schemes_add_dirs(struct damon_sysfs_schemes *schemes,
 978                 int nr_schemes)
 979 {
 980         struct damon_sysfs_scheme **schemes_arr, *scheme;
 981         int err, i;
 982
 983         damon_sysfs_schemes_rm_dirs(schemes);
 984         if (!nr_schemes)
 985                 return 0;
 986
 987         schemes_arr = kmalloc_array(nr_schemes, sizeof(*schemes_arr),
 988                         GFP_KERNEL | __GFP_NOWARN);
 989         if (!schemes_arr)
 990                 return -ENOMEM;
 991         schemes->schemes_arr = schemes_arr;
 992
 993         for (i = 0; i < nr_schemes; i++) {
 994                 scheme = damon_sysfs_scheme_alloc(DAMOS_STAT);
 995                 if (!scheme) {
 996                         damon_sysfs_schemes_rm_dirs(schemes);
 997                         return -ENOMEM;
 998                 }
 999
1000                 err = kobject_init_and_add(&scheme->kobj,
1001                                 &damon_sysfs_scheme_ktype, &schemes->kobj,
1002                                 "%d", i);
1003                 if (err)
1004                         goto out;
1005                 err = damon_sysfs_scheme_add_dirs(scheme);
1006                 if (err)
1007                         goto out;
1008
1009                 schemes_arr[i] = scheme;
1010                 schemes->nr++;
1011         }
1012         return 0;
1013
1014 out:
1015         damon_sysfs_schemes_rm_dirs(schemes);
1016         kobject_put(&scheme->kobj);
1017         return err;
1018 }
1019
1020 static ssize_t nr_schemes_show(struct kobject *kobj,
1021                 struct kobj_attribute *attr, char *buf)
1022 {
1023         struct damon_sysfs_schemes *schemes = container_of(kobj,
1024                         struct damon_sysfs_schemes, kobj);
1025
1026         return sysfs_emit(buf, "%d\n", schemes->nr);
1027 }
1028
1029 static ssize_t nr_schemes_store(struct kobject *kobj,
1030                 struct kobj_attribute *attr, const char *buf, size_t count)
1031 {
1032         struct damon_sysfs_schemes *schemes = container_of(kobj,
1033                         struct damon_sysfs_schemes, kobj);
1034         int nr, err = kstrtoint(buf, 0, &nr);
1035
1036         if (err)
1037                 return err;
1038         if (nr < 0)
1039                 return -EINVAL;
1040
1041         if (!mutex_trylock(&damon_sysfs_lock))
1042                 return -EBUSY;
1043         err = damon_sysfs_schemes_add_dirs(schemes, nr);
1044         mutex_unlock(&damon_sysfs_lock);
1045         if (err)
1046                 return err;
1047         return count;
1048 }
1049
1050 static void damon_sysfs_schemes_release(struct kobject *kobj)
1051 {
1052         kfree(container_of(kobj, struct damon_sysfs_schemes, kobj));
1053 }
1054
1055 static struct kobj_attribute damon_sysfs_schemes_nr_attr =
1056                 __ATTR_RW_MODE(nr_schemes, 0600);
1057
1058 static struct attribute *damon_sysfs_schemes_attrs[] = {
1059         &damon_sysfs_schemes_nr_attr.attr,
1060         NULL,
1061 };
1062 ATTRIBUTE_GROUPS(damon_sysfs_schemes);
1063
1064 static struct kobj_type damon_sysfs_schemes_ktype = {
1065         .release = damon_sysfs_schemes_release,
1066         .sysfs_ops = &kobj_sysfs_ops,
1067         .default_groups = damon_sysfs_schemes_groups,
1068 };
1069
1070 /*
1071  * init region directory
1072  */
1073
1074 struct damon_sysfs_region {
1075         struct kobject kobj;
1076         unsigned long start;
1077         unsigned long end;
1078 };
1079
1080 static struct damon_sysfs_region *damon_sysfs_region_alloc(
1081                 unsigned long start,
1082                 unsigned long end)
1083 {
1084         struct damon_sysfs_region *region = kmalloc(sizeof(*region),
1085                         GFP_KERNEL);
1086
1087         if (!region)
1088                 return NULL;
1089         region->kobj = (struct kobject){};
1090         region->start = start;
1091         region->end = end;
1092         return region;
1093 }
1094
1095 static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
1096                 char *buf)
1097 {
1098         struct damon_sysfs_region *region = container_of(kobj,
1099                         struct damon_sysfs_region, kobj);
1100
1101         return sysfs_emit(buf, "%lu\n", region->start);
1102 }
1103
1104 static ssize_t start_store(struct kobject *kobj, struct kobj_attribute *attr,
1105                 const char *buf, size_t count)
1106 {
1107         struct damon_sysfs_region *region = container_of(kobj,
1108                         struct damon_sysfs_region, kobj);
1109         int err = kstrtoul(buf, 0, &region->start);
1110
1111         if (err)
1112                 return -EINVAL;
1113         return count;
1114 }
1115
1116 static ssize_t end_show(struct kobject *kobj, struct kobj_attribute *attr,
1117                 char *buf)
1118 {
1119         struct damon_sysfs_region *region = container_of(kobj,
1120                         struct damon_sysfs_region, kobj);
1121
1122         return sysfs_emit(buf, "%lu\n", region->end);
1123 }
1124
1125 static ssize_t end_store(struct kobject *kobj, struct kobj_attribute *attr,
1126                 const char *buf, size_t count)
1127 {
1128         struct damon_sysfs_region *region = container_of(kobj,
1129                         struct damon_sysfs_region, kobj);
1130         int err = kstrtoul(buf, 0, &region->end);
1131
1132         if (err)
1133                 return -EINVAL;
1134         return count;
1135 }
1136
1137 static void damon_sysfs_region_release(struct kobject *kobj)
1138 {
1139         kfree(container_of(kobj, struct damon_sysfs_region, kobj));
1140 }
1141
1142 static struct kobj_attribute damon_sysfs_region_start_attr =
1143                 __ATTR_RW_MODE(start, 0600);
1144
1145 static struct kobj_attribute damon_sysfs_region_end_attr =
1146                 __ATTR_RW_MODE(end, 0600);
1147
1148 static struct attribute *damon_sysfs_region_attrs[] = {
1149         &damon_sysfs_region_start_attr.attr,
1150         &damon_sysfs_region_end_attr.attr,
1151         NULL,
1152 };
1153 ATTRIBUTE_GROUPS(damon_sysfs_region);
1154
1155 static struct kobj_type damon_sysfs_region_ktype = {
1156         .release = damon_sysfs_region_release,
1157         .sysfs_ops = &kobj_sysfs_ops,
1158         .default_groups = damon_sysfs_region_groups,
1159 };
1160
1161 /*
1162  * init_regions directory
1163  */
1164
1165 struct damon_sysfs_regions {
1166         struct kobject kobj;
1167         struct damon_sysfs_region **regions_arr;
1168         int nr;
1169 };
1170
1171 static struct damon_sysfs_regions *damon_sysfs_regions_alloc(void)
1172 {
1173         return kzalloc(sizeof(struct damon_sysfs_regions), GFP_KERNEL);
1174 }
1175
1176 static void damon_sysfs_regions_rm_dirs(struct damon_sysfs_regions *regions)
1177 {
1178         struct damon_sysfs_region **regions_arr = regions->regions_arr;
1179         int i;
1180
1181         for (i = 0; i < regions->nr; i++)
1182                 kobject_put(&regions_arr[i]->kobj);
1183         regions->nr = 0;
1184         kfree(regions_arr);
1185         regions->regions_arr = NULL;
1186 }
1187
1188 static int damon_sysfs_regions_add_dirs(struct damon_sysfs_regions *regions,
1189                 int nr_regions)
1190 {
1191         struct damon_sysfs_region **regions_arr, *region;
1192         int err, i;
1193
1194         damon_sysfs_regions_rm_dirs(regions);
1195         if (!nr_regions)
1196                 return 0;
1197
1198         regions_arr = kmalloc_array(nr_regions, sizeof(*regions_arr),
1199                         GFP_KERNEL | __GFP_NOWARN);
1200         if (!regions_arr)
1201                 return -ENOMEM;
1202         regions->regions_arr = regions_arr;
1203
1204         for (i = 0; i < nr_regions; i++) {
1205                 region = damon_sysfs_region_alloc(0, 0);
1206                 if (!region) {
1207                         damon_sysfs_regions_rm_dirs(regions);
1208                         return -ENOMEM;
1209                 }
1210
1211                 err = kobject_init_and_add(&region->kobj,
1212                                 &damon_sysfs_region_ktype, &regions->kobj,
1213                                 "%d", i);
1214                 if (err) {
1215                         kobject_put(&region->kobj);
1216                         damon_sysfs_regions_rm_dirs(regions);
1217                         return err;
1218                 }
1219
1220                 regions_arr[i] = region;
1221                 regions->nr++;
1222         }
1223         return 0;
1224 }
1225
1226 static ssize_t nr_regions_show(struct kobject *kobj,
1227                 struct kobj_attribute *attr, char *buf)
1228 {
1229         struct damon_sysfs_regions *regions = container_of(kobj,
1230                         struct damon_sysfs_regions, kobj);
1231
1232         return sysfs_emit(buf, "%d\n", regions->nr);
1233 }
1234
1235 static ssize_t nr_regions_store(struct kobject *kobj,
1236                 struct kobj_attribute *attr, const char *buf, size_t count)
1237 {
1238         struct damon_sysfs_regions *regions = container_of(kobj,
1239                         struct damon_sysfs_regions, kobj);
1240         int nr, err = kstrtoint(buf, 0, &nr);
1241
1242         if (err)
1243                 return err;
1244         if (nr < 0)
1245                 return -EINVAL;
1246
1247         if (!mutex_trylock(&damon_sysfs_lock))
1248                 return -EBUSY;
1249         err = damon_sysfs_regions_add_dirs(regions, nr);
1250         mutex_unlock(&damon_sysfs_lock);
1251         if (err)
1252                 return err;
1253
1254         return count;
1255 }
1256
1257 static void damon_sysfs_regions_release(struct kobject *kobj)
1258 {
1259         kfree(container_of(kobj, struct damon_sysfs_regions, kobj));
1260 }
1261
1262 static struct kobj_attribute damon_sysfs_regions_nr_attr =
1263                 __ATTR_RW_MODE(nr_regions, 0600);
1264
1265 static struct attribute *damon_sysfs_regions_attrs[] = {
1266         &damon_sysfs_regions_nr_attr.attr,
1267         NULL,
1268 };
1269 ATTRIBUTE_GROUPS(damon_sysfs_regions);
1270
1271 static struct kobj_type damon_sysfs_regions_ktype = {
1272         .release = damon_sysfs_regions_release,
1273         .sysfs_ops = &kobj_sysfs_ops,
1274         .default_groups = damon_sysfs_regions_groups,
1275 };
1276
1277 /*
1278  * target directory
1279  */
1280
1281 struct damon_sysfs_target {
1282         struct kobject kobj;
1283         struct damon_sysfs_regions *regions;
1284         int pid;
1285 };
1286
1287 static struct damon_sysfs_target *damon_sysfs_target_alloc(void)
1288 {
1289         return kzalloc(sizeof(struct damon_sysfs_target), GFP_KERNEL);
1290 }
1291
1292 static int damon_sysfs_target_add_dirs(struct damon_sysfs_target *target)
1293 {
1294         struct damon_sysfs_regions *regions = damon_sysfs_regions_alloc();
1295         int err;
1296
1297         if (!regions)
1298                 return -ENOMEM;
1299
1300         err = kobject_init_and_add(&regions->kobj, &damon_sysfs_regions_ktype,
1301                         &target->kobj, "regions");
1302         if (err)
1303                 kobject_put(&regions->kobj);
1304         else
1305                 target->regions = regions;
1306         return err;
1307 }
1308
1309 static void damon_sysfs_target_rm_dirs(struct damon_sysfs_target *target)
1310 {
1311         damon_sysfs_regions_rm_dirs(target->regions);
1312         kobject_put(&target->regions->kobj);
1313 }
1314
1315 static ssize_t pid_target_show(struct kobject *kobj,
1316                 struct kobj_attribute *attr, char *buf)
1317 {
1318         struct damon_sysfs_target *target = container_of(kobj,
1319                         struct damon_sysfs_target, kobj);
1320
1321         return sysfs_emit(buf, "%d\n", target->pid);
1322 }
1323
1324 static ssize_t pid_target_store(struct kobject *kobj,
1325                 struct kobj_attribute *attr, const char *buf, size_t count)
1326 {
1327         struct damon_sysfs_target *target = container_of(kobj,
1328                         struct damon_sysfs_target, kobj);
1329         int err = kstrtoint(buf, 0, &target->pid);
1330
1331         if (err)
1332                 return -EINVAL;
1333         return count;
1334 }
1335
1336 static void damon_sysfs_target_release(struct kobject *kobj)
1337 {
1338         kfree(container_of(kobj, struct damon_sysfs_target, kobj));
1339 }
1340
1341 static struct kobj_attribute damon_sysfs_target_pid_attr =
1342                 __ATTR_RW_MODE(pid_target, 0600);
1343
1344 static struct attribute *damon_sysfs_target_attrs[] = {
1345         &damon_sysfs_target_pid_attr.attr,
1346         NULL,
1347 };
1348 ATTRIBUTE_GROUPS(damon_sysfs_target);
1349
1350 static struct kobj_type damon_sysfs_target_ktype = {
1351         .release = damon_sysfs_target_release,
1352         .sysfs_ops = &kobj_sysfs_ops,
1353         .default_groups = damon_sysfs_target_groups,
1354 };
1355
1356 /*
1357  * targets directory
1358  */
1359
1360 struct damon_sysfs_targets {
1361         struct kobject kobj;
1362         struct damon_sysfs_target **targets_arr;
1363         int nr;
1364 };
1365
1366 static struct damon_sysfs_targets *damon_sysfs_targets_alloc(void)
1367 {
1368         return kzalloc(sizeof(struct damon_sysfs_targets), GFP_KERNEL);
1369 }
1370
1371 static void damon_sysfs_targets_rm_dirs(struct damon_sysfs_targets *targets)
1372 {
1373         struct damon_sysfs_target **targets_arr = targets->targets_arr;
1374         int i;
1375
1376         for (i = 0; i < targets->nr; i++) {
1377                 damon_sysfs_target_rm_dirs(targets_arr[i]);
1378                 kobject_put(&targets_arr[i]->kobj);
1379         }
1380         targets->nr = 0;
1381         kfree(targets_arr);
1382         targets->targets_arr = NULL;
1383 }
1384
1385 static int damon_sysfs_targets_add_dirs(struct damon_sysfs_targets *targets,
1386                 int nr_targets)
1387 {
1388         struct damon_sysfs_target **targets_arr, *target;
1389         int err, i;
1390
1391         damon_sysfs_targets_rm_dirs(targets);
1392         if (!nr_targets)
1393                 return 0;
1394
1395         targets_arr = kmalloc_array(nr_targets, sizeof(*targets_arr),
1396                         GFP_KERNEL | __GFP_NOWARN);
1397         if (!targets_arr)
1398                 return -ENOMEM;
1399         targets->targets_arr = targets_arr;
1400
1401         for (i = 0; i < nr_targets; i++) {
1402                 target = damon_sysfs_target_alloc();
1403                 if (!target) {
1404                         damon_sysfs_targets_rm_dirs(targets);
1405                         return -ENOMEM;
1406                 }
1407
1408                 err = kobject_init_and_add(&target->kobj,
1409                                 &damon_sysfs_target_ktype, &targets->kobj,
1410                                 "%d", i);
1411                 if (err)
1412                         goto out;
1413
1414                 err = damon_sysfs_target_add_dirs(target);
1415                 if (err)
1416                         goto out;
1417
1418                 targets_arr[i] = target;
1419                 targets->nr++;
1420         }
1421         return 0;
1422
1423 out:
1424         damon_sysfs_targets_rm_dirs(targets);
1425         kobject_put(&target->kobj);
1426         return err;
1427 }
1428
1429 static ssize_t nr_targets_show(struct kobject *kobj,
1430                 struct kobj_attribute *attr, char *buf)
1431 {
1432         struct damon_sysfs_targets *targets = container_of(kobj,
1433                         struct damon_sysfs_targets, kobj);
1434
1435         return sysfs_emit(buf, "%d\n", targets->nr);
1436 }
1437
1438 static ssize_t nr_targets_store(struct kobject *kobj,
1439                 struct kobj_attribute *attr, const char *buf, size_t count)
1440 {
1441         struct damon_sysfs_targets *targets = container_of(kobj,
1442                         struct damon_sysfs_targets, kobj);
1443         int nr, err = kstrtoint(buf, 0, &nr);
1444
1445         if (err)
1446                 return err;
1447         if (nr < 0)
1448                 return -EINVAL;
1449
1450         if (!mutex_trylock(&damon_sysfs_lock))
1451                 return -EBUSY;
1452         err = damon_sysfs_targets_add_dirs(targets, nr);
1453         mutex_unlock(&damon_sysfs_lock);
1454         if (err)
1455                 return err;
1456
1457         return count;
1458 }
1459
1460 static void damon_sysfs_targets_release(struct kobject *kobj)
1461 {
1462         kfree(container_of(kobj, struct damon_sysfs_targets, kobj));
1463 }
1464
1465 static struct kobj_attribute damon_sysfs_targets_nr_attr =
1466                 __ATTR_RW_MODE(nr_targets, 0600);
1467
1468 static struct attribute *damon_sysfs_targets_attrs[] = {
1469         &damon_sysfs_targets_nr_attr.attr,
1470         NULL,
1471 };
1472 ATTRIBUTE_GROUPS(damon_sysfs_targets);
1473
1474 static struct kobj_type damon_sysfs_targets_ktype = {
1475         .release = damon_sysfs_targets_release,
1476         .sysfs_ops = &kobj_sysfs_ops,
1477         .default_groups = damon_sysfs_targets_groups,
1478 };
1479
1480 /*
1481  * intervals directory
1482  */
1483
1484 struct damon_sysfs_intervals {
1485         struct kobject kobj;
1486         unsigned long sample_us;
1487         unsigned long aggr_us;
1488         unsigned long update_us;
1489 };
1490
1491 static struct damon_sysfs_intervals *damon_sysfs_intervals_alloc(
1492                 unsigned long sample_us, unsigned long aggr_us,
1493                 unsigned long update_us)
1494 {
1495         struct damon_sysfs_intervals *intervals = kmalloc(sizeof(*intervals),
1496                         GFP_KERNEL);
1497
1498         if (!intervals)
1499                 return NULL;
1500
1501         intervals->kobj = (struct kobject){};
1502         intervals->sample_us = sample_us;
1503         intervals->aggr_us = aggr_us;
1504         intervals->update_us = update_us;
1505         return intervals;
1506 }
1507
1508 static ssize_t sample_us_show(struct kobject *kobj,
1509                 struct kobj_attribute *attr, char *buf)
1510 {
1511         struct damon_sysfs_intervals *intervals = container_of(kobj,
1512                         struct damon_sysfs_intervals, kobj);
1513
1514         return sysfs_emit(buf, "%lu\n", intervals->sample_us);
1515 }
1516
1517 static ssize_t sample_us_store(struct kobject *kobj,
1518                 struct kobj_attribute *attr, const char *buf, size_t count)
1519 {
1520         struct damon_sysfs_intervals *intervals = container_of(kobj,
1521                         struct damon_sysfs_intervals, kobj);
1522         unsigned long us;
1523         int err = kstrtoul(buf, 0, &us);
1524
1525         if (err)
1526                 return -EINVAL;
1527
1528         intervals->sample_us = us;
1529         return count;
1530 }
1531
1532 static ssize_t aggr_us_show(struct kobject *kobj, struct kobj_attribute *attr,
1533                 char *buf)
1534 {
1535         struct damon_sysfs_intervals *intervals = container_of(kobj,
1536                         struct damon_sysfs_intervals, kobj);
1537
1538         return sysfs_emit(buf, "%lu\n", intervals->aggr_us);
1539 }
1540
1541 static ssize_t aggr_us_store(struct kobject *kobj, struct kobj_attribute *attr,
1542                 const char *buf, size_t count)
1543 {
1544         struct damon_sysfs_intervals *intervals = container_of(kobj,
1545                         struct damon_sysfs_intervals, kobj);
1546         unsigned long us;
1547         int err = kstrtoul(buf, 0, &us);
1548
1549         if (err)
1550                 return -EINVAL;
1551
1552         intervals->aggr_us = us;
1553         return count;
1554 }
1555
1556 static ssize_t update_us_show(struct kobject *kobj,
1557                 struct kobj_attribute *attr, char *buf)
1558 {
1559         struct damon_sysfs_intervals *intervals = container_of(kobj,
1560                         struct damon_sysfs_intervals, kobj);
1561
1562         return sysfs_emit(buf, "%lu\n", intervals->update_us);
1563 }
1564
1565 static ssize_t update_us_store(struct kobject *kobj,
1566                 struct kobj_attribute *attr, const char *buf, size_t count)
1567 {
1568         struct damon_sysfs_intervals *intervals = container_of(kobj,
1569                         struct damon_sysfs_intervals, kobj);
1570         unsigned long us;
1571         int err = kstrtoul(buf, 0, &us);
1572
1573         if (err)
1574                 return -EINVAL;
1575
1576         intervals->update_us = us;
1577         return count;
1578 }
1579
1580 static void damon_sysfs_intervals_release(struct kobject *kobj)
1581 {
1582         kfree(container_of(kobj, struct damon_sysfs_intervals, kobj));
1583 }
1584
1585 static struct kobj_attribute damon_sysfs_intervals_sample_us_attr =
1586                 __ATTR_RW_MODE(sample_us, 0600);
1587
1588 static struct kobj_attribute damon_sysfs_intervals_aggr_us_attr =
1589                 __ATTR_RW_MODE(aggr_us, 0600);
1590
1591 static struct kobj_attribute damon_sysfs_intervals_update_us_attr =
1592                 __ATTR_RW_MODE(update_us, 0600);
1593
1594 static struct attribute *damon_sysfs_intervals_attrs[] = {
1595         &damon_sysfs_intervals_sample_us_attr.attr,
1596         &damon_sysfs_intervals_aggr_us_attr.attr,
1597         &damon_sysfs_intervals_update_us_attr.attr,
1598         NULL,
1599 };
1600 ATTRIBUTE_GROUPS(damon_sysfs_intervals);
1601
1602 static struct kobj_type damon_sysfs_intervals_ktype = {
1603         .release = damon_sysfs_intervals_release,
1604         .sysfs_ops = &kobj_sysfs_ops,
1605         .default_groups = damon_sysfs_intervals_groups,
1606 };
1607
1608 /*
1609  * monitoring_attrs directory
1610  */
1611
1612 struct damon_sysfs_attrs {
1613         struct kobject kobj;
1614         struct damon_sysfs_intervals *intervals;
1615         struct damon_sysfs_ul_range *nr_regions_range;
1616 };
1617
1618 static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
1619 {
1620         struct damon_sysfs_attrs *attrs = kmalloc(sizeof(*attrs), GFP_KERNEL);
1621
1622         if (!attrs)
1623                 return NULL;
1624         attrs->kobj = (struct kobject){};
1625         return attrs;
1626 }
1627
1628 static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
1629 {
1630         struct damon_sysfs_intervals *intervals;
1631         struct damon_sysfs_ul_range *nr_regions_range;
1632         int err;
1633
1634         intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
1635         if (!intervals)
1636                 return -ENOMEM;
1637
1638         err = kobject_init_and_add(&intervals->kobj,
1639                         &damon_sysfs_intervals_ktype, &attrs->kobj,
1640                         "intervals");
1641         if (err)
1642                 goto put_intervals_out;
1643         attrs->intervals = intervals;
1644
1645         nr_regions_range = damon_sysfs_ul_range_alloc(10, 1000);
1646         if (!nr_regions_range) {
1647                 err = -ENOMEM;
1648                 goto put_intervals_out;
1649         }
1650
1651         err = kobject_init_and_add(&nr_regions_range->kobj,
1652                         &damon_sysfs_ul_range_ktype, &attrs->kobj,
1653                         "nr_regions");
1654         if (err)
1655                 goto put_nr_regions_intervals_out;
1656         attrs->nr_regions_range = nr_regions_range;
1657         return 0;
1658
1659 put_nr_regions_intervals_out:
1660         kobject_put(&nr_regions_range->kobj);
1661         attrs->nr_regions_range = NULL;
1662 put_intervals_out:
1663         kobject_put(&intervals->kobj);
1664         attrs->intervals = NULL;
1665         return err;
1666 }
1667
1668 static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
1669 {
1670         kobject_put(&attrs->nr_regions_range->kobj);
1671         kobject_put(&attrs->intervals->kobj);
1672 }
1673
1674 static void damon_sysfs_attrs_release(struct kobject *kobj)
1675 {
1676         kfree(container_of(kobj, struct damon_sysfs_attrs, kobj));
1677 }
1678
1679 static struct attribute *damon_sysfs_attrs_attrs[] = {
1680         NULL,
1681 };
1682 ATTRIBUTE_GROUPS(damon_sysfs_attrs);
1683
1684 static struct kobj_type damon_sysfs_attrs_ktype = {
1685         .release = damon_sysfs_attrs_release,
1686         .sysfs_ops = &kobj_sysfs_ops,
1687         .default_groups = damon_sysfs_attrs_groups,
1688 };
1689
1690 /*
1691  * context directory
1692  */
1693
1694 /* This should match with enum damon_ops_id */
1695 static const char * const damon_sysfs_ops_strs[] = {
1696         "vaddr",
1697         "fvaddr",
1698         "paddr",
1699 };
1700
1701 struct damon_sysfs_context {
1702         struct kobject kobj;
1703         enum damon_ops_id ops_id;
1704         struct damon_sysfs_attrs *attrs;
1705         struct damon_sysfs_targets *targets;
1706         struct damon_sysfs_schemes *schemes;
1707 };
1708
1709 static struct damon_sysfs_context *damon_sysfs_context_alloc(
1710                 enum damon_ops_id ops_id)
1711 {
1712         struct damon_sysfs_context *context = kmalloc(sizeof(*context),
1713                                 GFP_KERNEL);
1714
1715         if (!context)
1716                 return NULL;
1717         context->kobj = (struct kobject){};
1718         context->ops_id = ops_id;
1719         return context;
1720 }
1721
1722 static int damon_sysfs_context_set_attrs(struct damon_sysfs_context *context)
1723 {
1724         struct damon_sysfs_attrs *attrs = damon_sysfs_attrs_alloc();
1725         int err;
1726
1727         if (!attrs)
1728                 return -ENOMEM;
1729         err = kobject_init_and_add(&attrs->kobj, &damon_sysfs_attrs_ktype,
1730                         &context->kobj, "monitoring_attrs");
1731         if (err)
1732                 goto out;
1733         err = damon_sysfs_attrs_add_dirs(attrs);
1734         if (err)
1735                 goto out;
1736         context->attrs = attrs;
1737         return 0;
1738
1739 out:
1740         kobject_put(&attrs->kobj);
1741         return err;
1742 }
1743
1744 static int damon_sysfs_context_set_targets(struct damon_sysfs_context *context)
1745 {
1746         struct damon_sysfs_targets *targets = damon_sysfs_targets_alloc();
1747         int err;
1748
1749         if (!targets)
1750                 return -ENOMEM;
1751         err = kobject_init_and_add(&targets->kobj, &damon_sysfs_targets_ktype,
1752                         &context->kobj, "targets");
1753         if (err) {
1754                 kobject_put(&targets->kobj);
1755                 return err;
1756         }
1757         context->targets = targets;
1758         return 0;
1759 }
1760
1761 static int damon_sysfs_context_set_schemes(struct damon_sysfs_context *context)
1762 {
1763         struct damon_sysfs_schemes *schemes = damon_sysfs_schemes_alloc();
1764         int err;
1765
1766         if (!schemes)
1767                 return -ENOMEM;
1768         err = kobject_init_and_add(&schemes->kobj, &damon_sysfs_schemes_ktype,
1769                         &context->kobj, "schemes");
1770         if (err) {
1771                 kobject_put(&schemes->kobj);
1772                 return err;
1773         }
1774         context->schemes = schemes;
1775         return 0;
1776 }
1777
1778 static int damon_sysfs_context_add_dirs(struct damon_sysfs_context *context)
1779 {
1780         int err;
1781
1782         err = damon_sysfs_context_set_attrs(context);
1783         if (err)
1784                 return err;
1785
1786         err = damon_sysfs_context_set_targets(context);
1787         if (err)
1788                 goto put_attrs_out;
1789
1790         err = damon_sysfs_context_set_schemes(context);
1791         if (err)
1792                 goto put_targets_attrs_out;
1793         return 0;
1794
1795 put_targets_attrs_out:
1796         kobject_put(&context->targets->kobj);
1797         context->targets = NULL;
1798 put_attrs_out:
1799         kobject_put(&context->attrs->kobj);
1800         context->attrs = NULL;
1801         return err;
1802 }
1803
1804 static void damon_sysfs_context_rm_dirs(struct damon_sysfs_context *context)
1805 {
1806         damon_sysfs_attrs_rm_dirs(context->attrs);
1807         kobject_put(&context->attrs->kobj);
1808         damon_sysfs_targets_rm_dirs(context->targets);
1809         kobject_put(&context->targets->kobj);
1810         damon_sysfs_schemes_rm_dirs(context->schemes);
1811         kobject_put(&context->schemes->kobj);
1812 }
1813
1814 static ssize_t avail_operations_show(struct kobject *kobj,
1815                 struct kobj_attribute *attr, char *buf)
1816 {
1817         enum damon_ops_id id;
1818         int len = 0;
1819
1820         for (id = 0; id < NR_DAMON_OPS; id++) {
1821                 if (!damon_is_registered_ops(id))
1822                         continue;
1823                 len += sysfs_emit_at(buf, len, "%s\n",
1824                                 damon_sysfs_ops_strs[id]);
1825         }
1826         return len;
1827 }
1828
1829 static ssize_t operations_show(struct kobject *kobj,
1830                 struct kobj_attribute *attr, char *buf)
1831 {
1832         struct damon_sysfs_context *context = container_of(kobj,
1833                         struct damon_sysfs_context, kobj);
1834
1835         return sysfs_emit(buf, "%s\n", damon_sysfs_ops_strs[context->ops_id]);
1836 }
1837
1838 static ssize_t operations_store(struct kobject *kobj,
1839                 struct kobj_attribute *attr, const char *buf, size_t count)
1840 {
1841         struct damon_sysfs_context *context = container_of(kobj,
1842                         struct damon_sysfs_context, kobj);
1843         enum damon_ops_id id;
1844
1845         for (id = 0; id < NR_DAMON_OPS; id++) {
1846                 if (sysfs_streq(buf, damon_sysfs_ops_strs[id])) {
1847                         context->ops_id = id;
1848                         return count;
1849                 }
1850         }
1851         return -EINVAL;
1852 }
1853
1854 static void damon_sysfs_context_release(struct kobject *kobj)
1855 {
1856         kfree(container_of(kobj, struct damon_sysfs_context, kobj));
1857 }
1858
1859 static struct kobj_attribute damon_sysfs_context_avail_operations_attr =
1860                 __ATTR_RO_MODE(avail_operations, 0400);
1861
1862 static struct kobj_attribute damon_sysfs_context_operations_attr =
1863                 __ATTR_RW_MODE(operations, 0600);
1864
1865 static struct attribute *damon_sysfs_context_attrs[] = {
1866         &damon_sysfs_context_avail_operations_attr.attr,
1867         &damon_sysfs_context_operations_attr.attr,
1868         NULL,
1869 };
1870 ATTRIBUTE_GROUPS(damon_sysfs_context);
1871
1872 static struct kobj_type damon_sysfs_context_ktype = {
1873         .release = damon_sysfs_context_release,
1874         .sysfs_ops = &kobj_sysfs_ops,
1875         .default_groups = damon_sysfs_context_groups,
1876 };
1877
1878 /*
1879  * contexts directory
1880  */
1881
1882 struct damon_sysfs_contexts {
1883         struct kobject kobj;
1884         struct damon_sysfs_context **contexts_arr;
1885         int nr;
1886 };
1887
1888 static struct damon_sysfs_contexts *damon_sysfs_contexts_alloc(void)
1889 {
1890         return kzalloc(sizeof(struct damon_sysfs_contexts), GFP_KERNEL);
1891 }
1892
1893 static void damon_sysfs_contexts_rm_dirs(struct damon_sysfs_contexts *contexts)
1894 {
1895         struct damon_sysfs_context **contexts_arr = contexts->contexts_arr;
1896         int i;
1897
1898         for (i = 0; i < contexts->nr; i++) {
1899                 damon_sysfs_context_rm_dirs(contexts_arr[i]);
1900                 kobject_put(&contexts_arr[i]->kobj);
1901         }
1902         contexts->nr = 0;
1903         kfree(contexts_arr);
1904         contexts->contexts_arr = NULL;
1905 }
1906
1907 static int damon_sysfs_contexts_add_dirs(struct damon_sysfs_contexts *contexts,
1908                 int nr_contexts)
1909 {
1910         struct damon_sysfs_context **contexts_arr, *context;
1911         int err, i;
1912
1913         damon_sysfs_contexts_rm_dirs(contexts);
1914         if (!nr_contexts)
1915                 return 0;
1916
1917         contexts_arr = kmalloc_array(nr_contexts, sizeof(*contexts_arr),
1918                         GFP_KERNEL | __GFP_NOWARN);
1919         if (!contexts_arr)
1920                 return -ENOMEM;
1921         contexts->contexts_arr = contexts_arr;
1922
1923         for (i = 0; i < nr_contexts; i++) {
1924                 context = damon_sysfs_context_alloc(DAMON_OPS_VADDR);
1925                 if (!context) {
1926                         damon_sysfs_contexts_rm_dirs(contexts);
1927                         return -ENOMEM;
1928                 }
1929
1930                 err = kobject_init_and_add(&context->kobj,
1931                                 &damon_sysfs_context_ktype, &contexts->kobj,
1932                                 "%d", i);
1933                 if (err)
1934                         goto out;
1935
1936                 err = damon_sysfs_context_add_dirs(context);
1937                 if (err)
1938                         goto out;
1939
1940                 contexts_arr[i] = context;
1941                 contexts->nr++;
1942         }
1943         return 0;
1944
1945 out:
1946         damon_sysfs_contexts_rm_dirs(contexts);
1947         kobject_put(&context->kobj);
1948         return err;
1949 }
1950
1951 static ssize_t nr_contexts_show(struct kobject *kobj,
1952                 struct kobj_attribute *attr, char *buf)
1953 {
1954         struct damon_sysfs_contexts *contexts = container_of(kobj,
1955                         struct damon_sysfs_contexts, kobj);
1956
1957         return sysfs_emit(buf, "%d\n", contexts->nr);
1958 }
1959
1960 static ssize_t nr_contexts_store(struct kobject *kobj,
1961                 struct kobj_attribute *attr, const char *buf, size_t count)
1962 {
1963         struct damon_sysfs_contexts *contexts = container_of(kobj,
1964                         struct damon_sysfs_contexts, kobj);
1965         int nr, err;
1966
1967         err = kstrtoint(buf, 0, &nr);
1968         if (err)
1969                 return err;
1970         /* TODO: support multiple contexts per kdamond */
1971         if (nr < 0 || 1 < nr)
1972                 return -EINVAL;
1973
1974         if (!mutex_trylock(&damon_sysfs_lock))
1975                 return -EBUSY;
1976         err = damon_sysfs_contexts_add_dirs(contexts, nr);
1977         mutex_unlock(&damon_sysfs_lock);
1978         if (err)
1979                 return err;
1980
1981         return count;
1982 }
1983
1984 static void damon_sysfs_contexts_release(struct kobject *kobj)
1985 {
1986         kfree(container_of(kobj, struct damon_sysfs_contexts, kobj));
1987 }
1988
1989 static struct kobj_attribute damon_sysfs_contexts_nr_attr
1990                 = __ATTR_RW_MODE(nr_contexts, 0600);
1991
1992 static struct attribute *damon_sysfs_contexts_attrs[] = {
1993         &damon_sysfs_contexts_nr_attr.attr,
1994         NULL,
1995 };
1996 ATTRIBUTE_GROUPS(damon_sysfs_contexts);
1997
1998 static struct kobj_type damon_sysfs_contexts_ktype = {
1999         .release = damon_sysfs_contexts_release,
2000         .sysfs_ops = &kobj_sysfs_ops,
2001         .default_groups = damon_sysfs_contexts_groups,
2002 };
2003
2004 /*
2005  * kdamond directory
2006  */
2007
2008 struct damon_sysfs_kdamond {
2009         struct kobject kobj;
2010         struct damon_sysfs_contexts *contexts;
2011         struct damon_ctx *damon_ctx;
2012 };
2013
2014 static struct damon_sysfs_kdamond *damon_sysfs_kdamond_alloc(void)
2015 {
2016         return kzalloc(sizeof(struct damon_sysfs_kdamond), GFP_KERNEL);
2017 }
2018
2019 static int damon_sysfs_kdamond_add_dirs(struct damon_sysfs_kdamond *kdamond)
2020 {
2021         struct damon_sysfs_contexts *contexts;
2022         int err;
2023
2024         contexts = damon_sysfs_contexts_alloc();
2025         if (!contexts)
2026                 return -ENOMEM;
2027
2028         err = kobject_init_and_add(&contexts->kobj,
2029                         &damon_sysfs_contexts_ktype, &kdamond->kobj,
2030                         "contexts");
2031         if (err) {
2032                 kobject_put(&contexts->kobj);
2033                 return err;
2034         }
2035         kdamond->contexts = contexts;
2036
2037         return err;
2038 }
2039
2040 static void damon_sysfs_kdamond_rm_dirs(struct damon_sysfs_kdamond *kdamond)
2041 {
2042         damon_sysfs_contexts_rm_dirs(kdamond->contexts);
2043         kobject_put(&kdamond->contexts->kobj);
2044 }
2045
2046 static bool damon_sysfs_ctx_running(struct damon_ctx *ctx)
2047 {
2048         bool running;
2049
2050         mutex_lock(&ctx->kdamond_lock);
2051         running = ctx->kdamond != NULL;
2052         mutex_unlock(&ctx->kdamond_lock);
2053         return running;
2054 }
2055
2056 /*
2057  * enum damon_sysfs_cmd - Commands for a specific kdamond.
2058  */
2059 enum damon_sysfs_cmd {
2060         /* @DAMON_SYSFS_CMD_ON: Turn the kdamond on. */
2061         DAMON_SYSFS_CMD_ON,
2062         /* @DAMON_SYSFS_CMD_OFF: Turn the kdamond off. */
2063         DAMON_SYSFS_CMD_OFF,
2064         /* @DAMON_SYSFS_CMD_COMMIT: Update kdamond inputs. */
2065         DAMON_SYSFS_CMD_COMMIT,
2066         /*
2067          * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS: Update scheme stats sysfs
2068          * files.
2069          */
2070         DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,
2071         /*
2072          * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
2073          */
2074         NR_DAMON_SYSFS_CMDS,
2075 };
2076
2077 /* Should match with enum damon_sysfs_cmd */
2078 static const char * const damon_sysfs_cmd_strs[] = {
2079         "on",
2080         "off",
2081         "commit",
2082         "update_schemes_stats",
2083 };
2084
2085 /*
2086  * struct damon_sysfs_cmd_request - A request to the DAMON callback.
2087  * @cmd:        The command that needs to be handled by the callback.
2088  * @kdamond:    The kobject wrapper that associated to the kdamond thread.
2089  *
2090  * This structure represents a sysfs command request that need to access some
2091  * DAMON context-internal data.  Because DAMON context-internal data can be
2092  * safely accessed from DAMON callbacks without additional synchronization, the
2093  * request will be handled by the DAMON callback.  None-``NULL`` @kdamond means
2094  * the request is valid.
2095  */
2096 struct damon_sysfs_cmd_request {
2097         enum damon_sysfs_cmd cmd;
2098         struct damon_sysfs_kdamond *kdamond;
2099 };
2100
2101 /* Current DAMON callback request.  Protected by damon_sysfs_lock. */
2102 static struct damon_sysfs_cmd_request damon_sysfs_cmd_request;
2103
2104 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
2105                 char *buf)
2106 {
2107         struct damon_sysfs_kdamond *kdamond = container_of(kobj,
2108                         struct damon_sysfs_kdamond, kobj);
2109         struct damon_ctx *ctx = kdamond->damon_ctx;
2110         bool running;
2111
2112         if (!ctx)
2113                 running = false;
2114         else
2115                 running = damon_sysfs_ctx_running(ctx);
2116
2117         return sysfs_emit(buf, "%s\n", running ?
2118                         damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_ON] :
2119                         damon_sysfs_cmd_strs[DAMON_SYSFS_CMD_OFF]);
2120 }
2121
2122 static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
2123                 struct damon_sysfs_attrs *sys_attrs)
2124 {
2125         struct damon_sysfs_intervals *sys_intervals = sys_attrs->intervals;
2126         struct damon_sysfs_ul_range *sys_nr_regions =
2127                 sys_attrs->nr_regions_range;
2128
2129         return damon_set_attrs(ctx, sys_intervals->sample_us,
2130                         sys_intervals->aggr_us, sys_intervals->update_us,
2131                         sys_nr_regions->min, sys_nr_regions->max);
2132 }
2133
2134 static void damon_sysfs_destroy_targets(struct damon_ctx *ctx)
2135 {
2136         struct damon_target *t, *next;
2137
2138         damon_for_each_target_safe(t, next, ctx) {
2139                 if (ctx->ops.id == DAMON_OPS_VADDR ||
2140                                 ctx->ops.id == DAMON_OPS_FVADDR)
2141                         put_pid(t->pid);
2142                 damon_destroy_target(t);
2143         }
2144 }
2145
2146 static int damon_sysfs_set_regions(struct damon_target *t,
2147                 struct damon_sysfs_regions *sysfs_regions)
2148 {
2149         struct damon_addr_range *ranges = kmalloc_array(sysfs_regions->nr,
2150                         sizeof(*ranges), GFP_KERNEL | __GFP_NOWARN);
2151         int i, err = -EINVAL;
2152
2153         if (!ranges)
2154                 return -ENOMEM;
2155         for (i = 0; i < sysfs_regions->nr; i++) {
2156                 struct damon_sysfs_region *sys_region =
2157                         sysfs_regions->regions_arr[i];
2158
2159                 if (sys_region->start > sys_region->end)
2160                         goto out;
2161
2162                 ranges[i].start = sys_region->start;
2163                 ranges[i].end = sys_region->end;
2164                 if (i == 0)
2165                         continue;
2166                 if (ranges[i - 1].end > ranges[i].start)
2167                         goto out;
2168         }
2169         err = damon_set_regions(t, ranges, sysfs_regions->nr);
2170 out:
2171         kfree(ranges);
2172         return err;
2173
2174 }
2175
2176 static int damon_sysfs_add_target(struct damon_sysfs_target *sys_target,
2177                 struct damon_ctx *ctx)
2178 {
2179         struct damon_target *t = damon_new_target();
2180         int err = -EINVAL;
2181
2182         if (!t)
2183                 return -ENOMEM;
2184         if (ctx->ops.id == DAMON_OPS_VADDR ||
2185                         ctx->ops.id == DAMON_OPS_FVADDR) {
2186                 t->pid = find_get_pid(sys_target->pid);
2187                 if (!t->pid)
2188                         goto destroy_targets_out;
2189         }
2190         damon_add_target(ctx, t);
2191         err = damon_sysfs_set_regions(t, sys_target->regions);
2192         if (err)
2193                 goto destroy_targets_out;
2194         return 0;
2195
2196 destroy_targets_out:
2197         damon_sysfs_destroy_targets(ctx);
2198         return err;
2199 }
2200
2201 /*
2202  * Search a target in a context that corresponds to the sysfs target input.
2203  *
2204  * Return: pointer to the target if found, NULL if not found, or negative
2205  * error code if the search failed.
2206  */
2207 static struct damon_target *damon_sysfs_existing_target(
2208                 struct damon_sysfs_target *sys_target, struct damon_ctx *ctx)
2209 {
2210         struct pid *pid;
2211         struct damon_target *t;
2212
2213         if (ctx->ops.id == DAMON_OPS_PADDR) {
2214                 /* Up to only one target for paddr could exist */
2215                 damon_for_each_target(t, ctx)
2216                         return t;
2217                 return NULL;
2218         }
2219
2220         /* ops.id should be DAMON_OPS_VADDR or DAMON_OPS_FVADDR */
2221         pid = find_get_pid(sys_target->pid);
2222         if (!pid)
2223                 return ERR_PTR(-EINVAL);
2224         damon_for_each_target(t, ctx) {
2225                 if (t->pid == pid) {
2226                         put_pid(pid);
2227                         return t;
2228                 }
2229         }
2230         put_pid(pid);
2231         return NULL;
2232 }
2233
2234 static int damon_sysfs_set_targets(struct damon_ctx *ctx,
2235                 struct damon_sysfs_targets *sysfs_targets)
2236 {
2237         int i, err;
2238
2239         /* Multiple physical address space monitoring targets makes no sense */
2240         if (ctx->ops.id == DAMON_OPS_PADDR && sysfs_targets->nr > 1)
2241                 return -EINVAL;
2242
2243         for (i = 0; i < sysfs_targets->nr; i++) {
2244                 struct damon_sysfs_target *st = sysfs_targets->targets_arr[i];
2245                 struct damon_target *t = damon_sysfs_existing_target(st, ctx);
2246
2247                 if (IS_ERR(t))
2248                         return PTR_ERR(t);
2249                 if (!t)
2250                         err = damon_sysfs_add_target(st, ctx);
2251                 else
2252                         err = damon_sysfs_set_regions(t, st->regions);
2253                 if (err)
2254                         return err;
2255         }
2256         return 0;
2257 }
2258
2259 static struct damos *damon_sysfs_mk_scheme(
2260                 struct damon_sysfs_scheme *sysfs_scheme)
2261 {
2262         struct damon_sysfs_access_pattern *pattern =
2263                 sysfs_scheme->access_pattern;
2264         struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
2265         struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights;
2266         struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks;
2267         struct damos_quota quota = {
2268                 .ms = sysfs_quotas->ms,
2269                 .sz = sysfs_quotas->sz,
2270                 .reset_interval = sysfs_quotas->reset_interval_ms,
2271                 .weight_sz = sysfs_weights->sz,
2272                 .weight_nr_accesses = sysfs_weights->nr_accesses,
2273                 .weight_age = sysfs_weights->age,
2274         };
2275         struct damos_watermarks wmarks = {
2276                 .metric = sysfs_wmarks->metric,
2277                 .interval = sysfs_wmarks->interval_us,
2278                 .high = sysfs_wmarks->high,
2279                 .mid = sysfs_wmarks->mid,
2280                 .low = sysfs_wmarks->low,
2281         };
2282
2283         return damon_new_scheme(pattern->sz->min, pattern->sz->max,
2284                         pattern->nr_accesses->min, pattern->nr_accesses->max,
2285                         pattern->age->min, pattern->age->max,
2286                         sysfs_scheme->action, &quota, &wmarks);
2287 }
2288
2289 static int damon_sysfs_set_schemes(struct damon_ctx *ctx,
2290                 struct damon_sysfs_schemes *sysfs_schemes)
2291 {
2292         int i;
2293
2294         for (i = 0; i < sysfs_schemes->nr; i++) {
2295                 struct damos *scheme, *next;
2296
2297                 scheme = damon_sysfs_mk_scheme(sysfs_schemes->schemes_arr[i]);
2298                 if (!scheme) {
2299                         damon_for_each_scheme_safe(scheme, next, ctx)
2300                                 damon_destroy_scheme(scheme);
2301                         return -ENOMEM;
2302                 }
2303                 damon_add_scheme(ctx, scheme);
2304         }
2305         return 0;
2306 }
2307
2308 static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
2309 {
2310         struct damon_target *t, *next;
2311
2312         if (ctx->ops.id != DAMON_OPS_VADDR && ctx->ops.id != DAMON_OPS_FVADDR)
2313                 return;
2314
2315         mutex_lock(&ctx->kdamond_lock);
2316         damon_for_each_target_safe(t, next, ctx) {
2317                 put_pid(t->pid);
2318                 damon_destroy_target(t);
2319         }
2320         mutex_unlock(&ctx->kdamond_lock);
2321 }
2322
2323 /*
2324  * damon_sysfs_upd_schemes_stats() - Update schemes stats sysfs files.
2325  * @kdamond:    The kobject wrapper that associated to the kdamond thread.
2326  *
2327  * This function reads the schemes stats of specific kdamond and update the
2328  * related values for sysfs files.  This function should be called from DAMON
2329  * callbacks while holding ``damon_syfs_lock``, to safely access the DAMON
2330  * contexts-internal data and DAMON sysfs variables.
2331  */
2332 static int damon_sysfs_upd_schemes_stats(struct damon_sysfs_kdamond *kdamond)
2333 {
2334         struct damon_ctx *ctx = kdamond->damon_ctx;
2335         struct damon_sysfs_schemes *sysfs_schemes;
2336         struct damos *scheme;
2337         int schemes_idx = 0;
2338
2339         if (!ctx)
2340                 return -EINVAL;
2341         sysfs_schemes = kdamond->contexts->contexts_arr[0]->schemes;
2342         damon_for_each_scheme(scheme, ctx) {
2343                 struct damon_sysfs_stats *sysfs_stats;
2344
2345                 sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
2346                 sysfs_stats->nr_tried = scheme->stat.nr_tried;
2347                 sysfs_stats->sz_tried = scheme->stat.sz_tried;
2348                 sysfs_stats->nr_applied = scheme->stat.nr_applied;
2349                 sysfs_stats->sz_applied = scheme->stat.sz_applied;
2350                 sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
2351         }
2352         return 0;
2353 }
2354
2355 static inline bool damon_sysfs_kdamond_running(
2356                 struct damon_sysfs_kdamond *kdamond)
2357 {
2358         return kdamond->damon_ctx &&
2359                 damon_sysfs_ctx_running(kdamond->damon_ctx);
2360 }
2361
2362 /*
2363  * damon_sysfs_commit_input() - Commit user inputs to a running kdamond.
2364  * @kdamond:    The kobject wrapper for the associated kdamond.
2365  *
2366  * If the sysfs input is wrong, the kdamond will be terminated.
2367  */
2368 static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
2369 {
2370         struct damon_ctx *ctx = kdamond->damon_ctx;
2371         struct damon_sysfs_context *sys_ctx;
2372         int err = 0;
2373
2374         if (!damon_sysfs_kdamond_running(kdamond))
2375                 return -EINVAL;
2376         /* TODO: Support multiple contexts per kdamond */
2377         if (kdamond->contexts->nr != 1)
2378                 return -EINVAL;
2379
2380         sys_ctx = kdamond->contexts->contexts_arr[0];
2381
2382         err = damon_select_ops(ctx, sys_ctx->ops_id);
2383         if (err)
2384                 return err;
2385         err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
2386         if (err)
2387                 return err;
2388         err = damon_sysfs_set_targets(ctx, sys_ctx->targets);
2389         if (err)
2390                 return err;
2391         err = damon_sysfs_set_schemes(ctx, sys_ctx->schemes);
2392         if (err)
2393                 return err;
2394         return err;
2395 }
2396
2397 /*
2398  * damon_sysfs_cmd_request_callback() - DAMON callback for handling requests.
2399  * @c:  The DAMON context of the callback.
2400  *
2401  * This function is periodically called back from the kdamond thread for @c.
2402  * Then, it checks if there is a waiting DAMON sysfs request and handles it.
2403  */
2404 static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
2405 {
2406         struct damon_sysfs_kdamond *kdamond;
2407         int err = 0;
2408
2409         /* avoid deadlock due to concurrent state_store('off') */
2410         if (!mutex_trylock(&damon_sysfs_lock))
2411                 return 0;
2412         kdamond = damon_sysfs_cmd_request.kdamond;
2413         if (!kdamond || kdamond->damon_ctx != c)
2414                 goto out;
2415         switch (damon_sysfs_cmd_request.cmd) {
2416         case DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS:
2417                 err = damon_sysfs_upd_schemes_stats(kdamond);
2418                 break;
2419         case DAMON_SYSFS_CMD_COMMIT:
2420                 err = damon_sysfs_commit_input(kdamond);
2421                 break;
2422         default:
2423                 break;
2424         }
2425         /* Mark the request as invalid now. */
2426         damon_sysfs_cmd_request.kdamond = NULL;
2427 out:
2428         mutex_unlock(&damon_sysfs_lock);
2429         return err;
2430 }
2431
2432 static struct damon_ctx *damon_sysfs_build_ctx(
2433                 struct damon_sysfs_context *sys_ctx)
2434 {
2435         struct damon_ctx *ctx = damon_new_ctx();
2436         int err;
2437
2438         if (!ctx)
2439                 return ERR_PTR(-ENOMEM);
2440
2441         err = damon_select_ops(ctx, sys_ctx->ops_id);
2442         if (err)
2443                 goto out;
2444         err = damon_sysfs_set_attrs(ctx, sys_ctx->attrs);
2445         if (err)
2446                 goto out;
2447         err = damon_sysfs_set_targets(ctx, sys_ctx->targets);
2448         if (err)
2449                 goto out;
2450         err = damon_sysfs_set_schemes(ctx, sys_ctx->schemes);
2451         if (err)
2452                 goto out;
2453
2454         ctx->callback.after_wmarks_check = damon_sysfs_cmd_request_callback;
2455         ctx->callback.after_aggregation = damon_sysfs_cmd_request_callback;
2456         ctx->callback.before_terminate = damon_sysfs_before_terminate;
2457         return ctx;
2458
2459 out:
2460         damon_destroy_ctx(ctx);
2461         return ERR_PTR(err);
2462 }
2463
2464 static int damon_sysfs_turn_damon_on(struct damon_sysfs_kdamond *kdamond)
2465 {
2466         struct damon_ctx *ctx;
2467         int err;
2468
2469         if (kdamond->damon_ctx &&
2470                         damon_sysfs_ctx_running(kdamond->damon_ctx))
2471                 return -EBUSY;
2472         if (damon_sysfs_cmd_request.kdamond == kdamond)
2473                 return -EBUSY;
2474         /* TODO: support multiple contexts per kdamond */
2475         if (kdamond->contexts->nr != 1)
2476                 return -EINVAL;
2477
2478         if (kdamond->damon_ctx)
2479                 damon_destroy_ctx(kdamond->damon_ctx);
2480         kdamond->damon_ctx = NULL;
2481
2482         ctx = damon_sysfs_build_ctx(kdamond->contexts->contexts_arr[0]);
2483         if (IS_ERR(ctx))
2484                 return PTR_ERR(ctx);
2485         err = damon_start(&ctx, 1, false);
2486         if (err) {
2487                 damon_destroy_ctx(ctx);
2488                 return err;
2489         }
2490         kdamond->damon_ctx = ctx;
2491         return err;
2492 }
2493
2494 static int damon_sysfs_turn_damon_off(struct damon_sysfs_kdamond *kdamond)
2495 {
2496         if (!kdamond->damon_ctx)
2497                 return -EINVAL;
2498         return damon_stop(&kdamond->damon_ctx, 1);
2499         /*
2500          * To allow users show final monitoring results of already turned-off
2501          * DAMON, we free kdamond->damon_ctx in next
2502          * damon_sysfs_turn_damon_on(), or kdamonds_nr_store()
2503          */
2504 }
2505
2506 /*
2507  * damon_sysfs_handle_cmd() - Handle a command for a specific kdamond.
2508  * @cmd:        The command to handle.
2509  * @kdamond:    The kobject wrapper for the associated kdamond.
2510  *
2511  * This function handles a DAMON sysfs command for a kdamond.  For commands
2512  * that need to access running DAMON context-internal data, it requests
2513  * handling of the command to the DAMON callback
2514  * (@damon_sysfs_cmd_request_callback()) and wait until it is properly handled,
2515  * or the context is completed.
2516  *
2517  * Return: 0 on success, negative error code otherwise.
2518  */
2519 static int damon_sysfs_handle_cmd(enum damon_sysfs_cmd cmd,
2520                 struct damon_sysfs_kdamond *kdamond)
2521 {
2522         bool need_wait = true;
2523
2524         /* Handle commands that doesn't access DAMON context-internal data */
2525         switch (cmd) {
2526         case DAMON_SYSFS_CMD_ON:
2527                 return damon_sysfs_turn_damon_on(kdamond);
2528         case DAMON_SYSFS_CMD_OFF:
2529                 return damon_sysfs_turn_damon_off(kdamond);
2530         default:
2531                 break;
2532         }
2533
2534         /* Pass the command to DAMON callback for safe DAMON context access */
2535         if (damon_sysfs_cmd_request.kdamond)
2536                 return -EBUSY;
2537         if (!damon_sysfs_kdamond_running(kdamond))
2538                 return -EINVAL;
2539         damon_sysfs_cmd_request.cmd = cmd;
2540         damon_sysfs_cmd_request.kdamond = kdamond;
2541
2542         /*
2543          * wait until damon_sysfs_cmd_request_callback() handles the request
2544          * from kdamond context
2545          */
2546         mutex_unlock(&damon_sysfs_lock);
2547         while (need_wait) {
2548                 schedule_timeout_idle(msecs_to_jiffies(100));
2549                 if (!mutex_trylock(&damon_sysfs_lock))
2550                         continue;
2551                 if (!damon_sysfs_cmd_request.kdamond) {
2552                         /* damon_sysfs_cmd_request_callback() handled */
2553                         need_wait = false;
2554                 } else if (!damon_sysfs_kdamond_running(kdamond)) {
2555                         /* kdamond has already finished */
2556                         need_wait = false;
2557                         damon_sysfs_cmd_request.kdamond = NULL;
2558                 }
2559                 mutex_unlock(&damon_sysfs_lock);
2560         }
2561         mutex_lock(&damon_sysfs_lock);
2562         return 0;
2563 }
2564
2565 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
2566                 const char *buf, size_t count)
2567 {
2568         struct damon_sysfs_kdamond *kdamond = container_of(kobj,
2569                         struct damon_sysfs_kdamond, kobj);
2570         enum damon_sysfs_cmd cmd;
2571         ssize_t ret = -EINVAL;
2572
2573         if (!mutex_trylock(&damon_sysfs_lock))
2574                 return -EBUSY;
2575         for (cmd = 0; cmd < NR_DAMON_SYSFS_CMDS; cmd++) {
2576                 if (sysfs_streq(buf, damon_sysfs_cmd_strs[cmd])) {
2577                         ret = damon_sysfs_handle_cmd(cmd, kdamond);
2578                         break;
2579                 }
2580         }
2581         mutex_unlock(&damon_sysfs_lock);
2582         if (!ret)
2583                 ret = count;
2584         return ret;
2585 }
2586
2587 static ssize_t pid_show(struct kobject *kobj,
2588                 struct kobj_attribute *attr, char *buf)
2589 {
2590         struct damon_sysfs_kdamond *kdamond = container_of(kobj,
2591                         struct damon_sysfs_kdamond, kobj);
2592         struct damon_ctx *ctx;
2593         int pid;
2594
2595         if (!mutex_trylock(&damon_sysfs_lock))
2596                 return -EBUSY;
2597         ctx = kdamond->damon_ctx;
2598         if (!ctx) {
2599                 pid = -1;
2600                 goto out;
2601         }
2602         mutex_lock(&ctx->kdamond_lock);
2603         if (!ctx->kdamond)
2604                 pid = -1;
2605         else
2606                 pid = ctx->kdamond->pid;
2607         mutex_unlock(&ctx->kdamond_lock);
2608 out:
2609         mutex_unlock(&damon_sysfs_lock);
2610         return sysfs_emit(buf, "%d\n", pid);
2611 }
2612
2613 static void damon_sysfs_kdamond_release(struct kobject *kobj)
2614 {
2615         struct damon_sysfs_kdamond *kdamond = container_of(kobj,
2616                         struct damon_sysfs_kdamond, kobj);
2617
2618         if (kdamond->damon_ctx)
2619                 damon_destroy_ctx(kdamond->damon_ctx);
2620         kfree(kdamond);
2621 }
2622
2623 static struct kobj_attribute damon_sysfs_kdamond_state_attr =
2624                 __ATTR_RW_MODE(state, 0600);
2625
2626 static struct kobj_attribute damon_sysfs_kdamond_pid_attr =
2627                 __ATTR_RO_MODE(pid, 0400);
2628
2629 static struct attribute *damon_sysfs_kdamond_attrs[] = {
2630         &damon_sysfs_kdamond_state_attr.attr,
2631         &damon_sysfs_kdamond_pid_attr.attr,
2632         NULL,
2633 };
2634 ATTRIBUTE_GROUPS(damon_sysfs_kdamond);
2635
2636 static struct kobj_type damon_sysfs_kdamond_ktype = {
2637         .release = damon_sysfs_kdamond_release,
2638         .sysfs_ops = &kobj_sysfs_ops,
2639         .default_groups = damon_sysfs_kdamond_groups,
2640 };
2641
2642 /*
2643  * kdamonds directory
2644  */
2645
2646 struct damon_sysfs_kdamonds {
2647         struct kobject kobj;
2648         struct damon_sysfs_kdamond **kdamonds_arr;
2649         int nr;
2650 };
2651
2652 static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void)
2653 {
2654         return kzalloc(sizeof(struct damon_sysfs_kdamonds), GFP_KERNEL);
2655 }
2656
2657 static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
2658 {
2659         struct damon_sysfs_kdamond **kdamonds_arr = kdamonds->kdamonds_arr;
2660         int i;
2661
2662         for (i = 0; i < kdamonds->nr; i++) {
2663                 damon_sysfs_kdamond_rm_dirs(kdamonds_arr[i]);
2664                 kobject_put(&kdamonds_arr[i]->kobj);
2665         }
2666         kdamonds->nr = 0;
2667         kfree(kdamonds_arr);
2668         kdamonds->kdamonds_arr = NULL;
2669 }
2670
2671 static int damon_sysfs_nr_running_ctxs(struct damon_sysfs_kdamond **kdamonds,
2672                 int nr_kdamonds)
2673 {
2674         int nr_running_ctxs = 0;
2675         int i;
2676
2677         for (i = 0; i < nr_kdamonds; i++) {
2678                 struct damon_ctx *ctx = kdamonds[i]->damon_ctx;
2679
2680                 if (!ctx)
2681                         continue;
2682                 mutex_lock(&ctx->kdamond_lock);
2683                 if (ctx->kdamond)
2684                         nr_running_ctxs++;
2685                 mutex_unlock(&ctx->kdamond_lock);
2686         }
2687         return nr_running_ctxs;
2688 }
2689
2690 static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
2691                 int nr_kdamonds)
2692 {
2693         struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
2694         int err, i;
2695
2696         if (damon_sysfs_nr_running_ctxs(kdamonds->kdamonds_arr, kdamonds->nr))
2697                 return -EBUSY;
2698
2699         for (i = 0; i < kdamonds->nr; i++) {
2700                 if (damon_sysfs_cmd_request.kdamond ==
2701                                 kdamonds->kdamonds_arr[i])
2702                         return -EBUSY;
2703         }
2704
2705         damon_sysfs_kdamonds_rm_dirs(kdamonds);
2706         if (!nr_kdamonds)
2707                 return 0;
2708
2709         kdamonds_arr = kmalloc_array(nr_kdamonds, sizeof(*kdamonds_arr),
2710                         GFP_KERNEL | __GFP_NOWARN);
2711         if (!kdamonds_arr)
2712                 return -ENOMEM;
2713         kdamonds->kdamonds_arr = kdamonds_arr;
2714
2715         for (i = 0; i < nr_kdamonds; i++) {
2716                 kdamond = damon_sysfs_kdamond_alloc();
2717                 if (!kdamond) {
2718                         damon_sysfs_kdamonds_rm_dirs(kdamonds);
2719                         return -ENOMEM;
2720                 }
2721
2722                 err = kobject_init_and_add(&kdamond->kobj,
2723                                 &damon_sysfs_kdamond_ktype, &kdamonds->kobj,
2724                                 "%d", i);
2725                 if (err)
2726                         goto out;
2727
2728                 err = damon_sysfs_kdamond_add_dirs(kdamond);
2729                 if (err)
2730                         goto out;
2731
2732                 kdamonds_arr[i] = kdamond;
2733                 kdamonds->nr++;
2734         }
2735         return 0;
2736
2737 out:
2738         damon_sysfs_kdamonds_rm_dirs(kdamonds);
2739         kobject_put(&kdamond->kobj);
2740         return err;
2741 }
2742
2743 static ssize_t nr_kdamonds_show(struct kobject *kobj,
2744                 struct kobj_attribute *attr, char *buf)
2745 {
2746         struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
2747                         struct damon_sysfs_kdamonds, kobj);
2748
2749         return sysfs_emit(buf, "%d\n", kdamonds->nr);
2750 }
2751
2752 static ssize_t nr_kdamonds_store(struct kobject *kobj,
2753                 struct kobj_attribute *attr, const char *buf, size_t count)
2754 {
2755         struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
2756                         struct damon_sysfs_kdamonds, kobj);
2757         int nr, err;
2758
2759         err = kstrtoint(buf, 0, &nr);
2760         if (err)
2761                 return err;
2762         if (nr < 0)
2763                 return -EINVAL;
2764
2765         if (!mutex_trylock(&damon_sysfs_lock))
2766                 return -EBUSY;
2767         err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr);
2768         mutex_unlock(&damon_sysfs_lock);
2769         if (err)
2770                 return err;
2771
2772         return count;
2773 }
2774
2775 static void damon_sysfs_kdamonds_release(struct kobject *kobj)
2776 {
2777         kfree(container_of(kobj, struct damon_sysfs_kdamonds, kobj));
2778 }
2779
2780 static struct kobj_attribute damon_sysfs_kdamonds_nr_attr =
2781                 __ATTR_RW_MODE(nr_kdamonds, 0600);
2782
2783 static struct attribute *damon_sysfs_kdamonds_attrs[] = {
2784         &damon_sysfs_kdamonds_nr_attr.attr,
2785         NULL,
2786 };
2787 ATTRIBUTE_GROUPS(damon_sysfs_kdamonds);
2788
2789 static struct kobj_type damon_sysfs_kdamonds_ktype = {
2790         .release = damon_sysfs_kdamonds_release,
2791         .sysfs_ops = &kobj_sysfs_ops,
2792         .default_groups = damon_sysfs_kdamonds_groups,
2793 };
2794
2795 /*
2796  * damon user interface directory
2797  */
2798
2799 struct damon_sysfs_ui_dir {
2800         struct kobject kobj;
2801         struct damon_sysfs_kdamonds *kdamonds;
2802 };
2803
2804 static struct damon_sysfs_ui_dir *damon_sysfs_ui_dir_alloc(void)
2805 {
2806         return kzalloc(sizeof(struct damon_sysfs_ui_dir), GFP_KERNEL);
2807 }
2808
2809 static int damon_sysfs_ui_dir_add_dirs(struct damon_sysfs_ui_dir *ui_dir)
2810 {
2811         struct damon_sysfs_kdamonds *kdamonds;
2812         int err;
2813
2814         kdamonds = damon_sysfs_kdamonds_alloc();
2815         if (!kdamonds)
2816                 return -ENOMEM;
2817
2818         err = kobject_init_and_add(&kdamonds->kobj,
2819                         &damon_sysfs_kdamonds_ktype, &ui_dir->kobj,
2820                         "kdamonds");
2821         if (err) {
2822                 kobject_put(&kdamonds->kobj);
2823                 return err;
2824         }
2825         ui_dir->kdamonds = kdamonds;
2826         return err;
2827 }
2828
2829 static void damon_sysfs_ui_dir_release(struct kobject *kobj)
2830 {
2831         kfree(container_of(kobj, struct damon_sysfs_ui_dir, kobj));
2832 }
2833
2834 static struct attribute *damon_sysfs_ui_dir_attrs[] = {
2835         NULL,
2836 };
2837 ATTRIBUTE_GROUPS(damon_sysfs_ui_dir);
2838
2839 static struct kobj_type damon_sysfs_ui_dir_ktype = {
2840         .release = damon_sysfs_ui_dir_release,
2841         .sysfs_ops = &kobj_sysfs_ops,
2842         .default_groups = damon_sysfs_ui_dir_groups,
2843 };
2844
2845 static int __init damon_sysfs_init(void)
2846 {
2847         struct kobject *damon_sysfs_root;
2848         struct damon_sysfs_ui_dir *admin;
2849         int err;
2850
2851         damon_sysfs_root = kobject_create_and_add("damon", mm_kobj);
2852         if (!damon_sysfs_root)
2853                 return -ENOMEM;
2854
2855         admin = damon_sysfs_ui_dir_alloc();
2856         if (!admin) {
2857                 kobject_put(damon_sysfs_root);
2858                 return -ENOMEM;
2859         }
2860         err = kobject_init_and_add(&admin->kobj, &damon_sysfs_ui_dir_ktype,
2861                         damon_sysfs_root, "admin");
2862         if (err)
2863                 goto out;
2864         err = damon_sysfs_ui_dir_add_dirs(admin);
2865         if (err)
2866                 goto out;
2867         return 0;
2868
2869 out:
2870         kobject_put(&admin->kobj);
2871         kobject_put(damon_sysfs_root);
2872         return err;
2873 }
2874 subsys_initcall(damon_sysfs_init);