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