1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * DAMON Debugfs Interface 4 * 5 * Author: SeongJae Park <sjpark@amazon.de> 6 */ 7 8 #define pr_fmt(fmt) "damon-dbgfs: " fmt 9 10 #include <linux/damon.h> 11 #include <linux/debugfs.h> 12 #include <linux/file.h> 13 #include <linux/mm.h> 14 #include <linux/module.h> 15 #include <linux/page_idle.h> 16 #include <linux/slab.h> 17 18 static struct damon_ctx **dbgfs_ctxs; 19 static int dbgfs_nr_ctxs; 20 static struct dentry **dbgfs_dirs; 21 static DEFINE_MUTEX(damon_dbgfs_lock); 22 23 /* 24 * Returns non-empty string on success, negative error code otherwise. 25 */ 26 static char *user_input_str(const char __user *buf, size_t count, loff_t *ppos) 27 { 28 char *kbuf; 29 ssize_t ret; 30 31 /* We do not accept continuous write */ 32 if (*ppos) 33 return ERR_PTR(-EINVAL); 34 35 kbuf = kmalloc(count + 1, GFP_KERNEL | __GFP_NOWARN); 36 if (!kbuf) 37 return ERR_PTR(-ENOMEM); 38 39 ret = simple_write_to_buffer(kbuf, count + 1, ppos, buf, count); 40 if (ret != count) { 41 kfree(kbuf); 42 return ERR_PTR(-EIO); 43 } 44 kbuf[ret] = '\0'; 45 46 return kbuf; 47 } 48 49 static ssize_t dbgfs_attrs_read(struct file *file, 50 char __user *buf, size_t count, loff_t *ppos) 51 { 52 struct damon_ctx *ctx = file->private_data; 53 char kbuf[128]; 54 int ret; 55 56 mutex_lock(&ctx->kdamond_lock); 57 ret = scnprintf(kbuf, ARRAY_SIZE(kbuf), "%lu %lu %lu %lu %lu\n", 58 ctx->sample_interval, ctx->aggr_interval, 59 ctx->primitive_update_interval, ctx->min_nr_regions, 60 ctx->max_nr_regions); 61 mutex_unlock(&ctx->kdamond_lock); 62 63 return simple_read_from_buffer(buf, count, ppos, kbuf, ret); 64 } 65 66 static ssize_t dbgfs_attrs_write(struct file *file, 67 const char __user *buf, size_t count, loff_t *ppos) 68 { 69 struct damon_ctx *ctx = file->private_data; 70 unsigned long s, a, r, minr, maxr; 71 char *kbuf; 72 ssize_t ret; 73 74 kbuf = user_input_str(buf, count, ppos); 75 if (IS_ERR(kbuf)) 76 return PTR_ERR(kbuf); 77 78 if (sscanf(kbuf, "%lu %lu %lu %lu %lu", 79 &s, &a, &r, &minr, &maxr) != 5) { 80 ret = -EINVAL; 81 goto out; 82 } 83 84 mutex_lock(&ctx->kdamond_lock); 85 if (ctx->kdamond) { 86 ret = -EBUSY; 87 goto unlock_out; 88 } 89 90 ret = damon_set_attrs(ctx, s, a, r, minr, maxr); 91 if (!ret) 92 ret = count; 93 unlock_out: 94 mutex_unlock(&ctx->kdamond_lock); 95 out: 96 kfree(kbuf); 97 return ret; 98 } 99 100 static ssize_t sprint_schemes(struct damon_ctx *c, char *buf, ssize_t len) 101 { 102 struct damos *s; 103 int written = 0; 104 int rc; 105 106 damon_for_each_scheme(s, c) { 107 rc = scnprintf(&buf[written], len - written, 108 "%lu %lu %u %u %u %u %d %lu %lu %lu %u %u %u %d %lu %lu %lu %lu %lu %lu\n", 109 s->min_sz_region, s->max_sz_region, 110 s->min_nr_accesses, s->max_nr_accesses, 111 s->min_age_region, s->max_age_region, 112 s->action, 113 s->quota.ms, s->quota.sz, 114 s->quota.reset_interval, 115 s->quota.weight_sz, 116 s->quota.weight_nr_accesses, 117 s->quota.weight_age, 118 s->wmarks.metric, s->wmarks.interval, 119 s->wmarks.high, s->wmarks.mid, s->wmarks.low, 120 s->stat_count, s->stat_sz); 121 if (!rc) 122 return -ENOMEM; 123 124 written += rc; 125 } 126 return written; 127 } 128 129 static ssize_t dbgfs_schemes_read(struct file *file, char __user *buf, 130 size_t count, loff_t *ppos) 131 { 132 struct damon_ctx *ctx = file->private_data; 133 char *kbuf; 134 ssize_t len; 135 136 kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); 137 if (!kbuf) 138 return -ENOMEM; 139 140 mutex_lock(&ctx->kdamond_lock); 141 len = sprint_schemes(ctx, kbuf, count); 142 mutex_unlock(&ctx->kdamond_lock); 143 if (len < 0) 144 goto out; 145 len = simple_read_from_buffer(buf, count, ppos, kbuf, len); 146 147 out: 148 kfree(kbuf); 149 return len; 150 } 151 152 static void free_schemes_arr(struct damos **schemes, ssize_t nr_schemes) 153 { 154 ssize_t i; 155 156 for (i = 0; i < nr_schemes; i++) 157 kfree(schemes[i]); 158 kfree(schemes); 159 } 160 161 static bool damos_action_valid(int action) 162 { 163 switch (action) { 164 case DAMOS_WILLNEED: 165 case DAMOS_COLD: 166 case DAMOS_PAGEOUT: 167 case DAMOS_HUGEPAGE: 168 case DAMOS_NOHUGEPAGE: 169 case DAMOS_STAT: 170 return true; 171 default: 172 return false; 173 } 174 } 175 176 /* 177 * Converts a string into an array of struct damos pointers 178 * 179 * Returns an array of struct damos pointers that converted if the conversion 180 * success, or NULL otherwise. 181 */ 182 static struct damos **str_to_schemes(const char *str, ssize_t len, 183 ssize_t *nr_schemes) 184 { 185 struct damos *scheme, **schemes; 186 const int max_nr_schemes = 256; 187 int pos = 0, parsed, ret; 188 unsigned long min_sz, max_sz; 189 unsigned int min_nr_a, max_nr_a, min_age, max_age; 190 unsigned int action; 191 192 schemes = kmalloc_array(max_nr_schemes, sizeof(scheme), 193 GFP_KERNEL); 194 if (!schemes) 195 return NULL; 196 197 *nr_schemes = 0; 198 while (pos < len && *nr_schemes < max_nr_schemes) { 199 struct damos_quota quota = {}; 200 struct damos_watermarks wmarks; 201 202 ret = sscanf(&str[pos], 203 "%lu %lu %u %u %u %u %u %lu %lu %lu %u %u %u %u %lu %lu %lu %lu%n", 204 &min_sz, &max_sz, &min_nr_a, &max_nr_a, 205 &min_age, &max_age, &action, "a.ms, 206 "a.sz, "a.reset_interval, 207 "a.weight_sz, "a.weight_nr_accesses, 208 "a.weight_age, &wmarks.metric, 209 &wmarks.interval, &wmarks.high, &wmarks.mid, 210 &wmarks.low, &parsed); 211 if (ret != 18) 212 break; 213 if (!damos_action_valid(action)) 214 goto fail; 215 216 pos += parsed; 217 scheme = damon_new_scheme(min_sz, max_sz, min_nr_a, max_nr_a, 218 min_age, max_age, action, "a, &wmarks); 219 if (!scheme) 220 goto fail; 221 222 schemes[*nr_schemes] = scheme; 223 *nr_schemes += 1; 224 } 225 return schemes; 226 fail: 227 free_schemes_arr(schemes, *nr_schemes); 228 return NULL; 229 } 230 231 static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf, 232 size_t count, loff_t *ppos) 233 { 234 struct damon_ctx *ctx = file->private_data; 235 char *kbuf; 236 struct damos **schemes; 237 ssize_t nr_schemes = 0, ret; 238 239 kbuf = user_input_str(buf, count, ppos); 240 if (IS_ERR(kbuf)) 241 return PTR_ERR(kbuf); 242 243 schemes = str_to_schemes(kbuf, count, &nr_schemes); 244 if (!schemes) { 245 ret = -EINVAL; 246 goto out; 247 } 248 249 mutex_lock(&ctx->kdamond_lock); 250 if (ctx->kdamond) { 251 ret = -EBUSY; 252 goto unlock_out; 253 } 254 255 ret = damon_set_schemes(ctx, schemes, nr_schemes); 256 if (!ret) { 257 ret = count; 258 nr_schemes = 0; 259 } 260 261 unlock_out: 262 mutex_unlock(&ctx->kdamond_lock); 263 free_schemes_arr(schemes, nr_schemes); 264 out: 265 kfree(kbuf); 266 return ret; 267 } 268 269 static inline bool targetid_is_pid(const struct damon_ctx *ctx) 270 { 271 return ctx->primitive.target_valid == damon_va_target_valid; 272 } 273 274 static ssize_t sprint_target_ids(struct damon_ctx *ctx, char *buf, ssize_t len) 275 { 276 struct damon_target *t; 277 unsigned long id; 278 int written = 0; 279 int rc; 280 281 damon_for_each_target(t, ctx) { 282 id = t->id; 283 if (targetid_is_pid(ctx)) 284 /* Show pid numbers to debugfs users */ 285 id = (unsigned long)pid_vnr((struct pid *)id); 286 287 rc = scnprintf(&buf[written], len - written, "%lu ", id); 288 if (!rc) 289 return -ENOMEM; 290 written += rc; 291 } 292 if (written) 293 written -= 1; 294 written += scnprintf(&buf[written], len - written, "\n"); 295 return written; 296 } 297 298 static ssize_t dbgfs_target_ids_read(struct file *file, 299 char __user *buf, size_t count, loff_t *ppos) 300 { 301 struct damon_ctx *ctx = file->private_data; 302 ssize_t len; 303 char ids_buf[320]; 304 305 mutex_lock(&ctx->kdamond_lock); 306 len = sprint_target_ids(ctx, ids_buf, 320); 307 mutex_unlock(&ctx->kdamond_lock); 308 if (len < 0) 309 return len; 310 311 return simple_read_from_buffer(buf, count, ppos, ids_buf, len); 312 } 313 314 /* 315 * Converts a string into an array of unsigned long integers 316 * 317 * Returns an array of unsigned long integers if the conversion success, or 318 * NULL otherwise. 319 */ 320 static unsigned long *str_to_target_ids(const char *str, ssize_t len, 321 ssize_t *nr_ids) 322 { 323 unsigned long *ids; 324 const int max_nr_ids = 32; 325 unsigned long id; 326 int pos = 0, parsed, ret; 327 328 *nr_ids = 0; 329 ids = kmalloc_array(max_nr_ids, sizeof(id), GFP_KERNEL); 330 if (!ids) 331 return NULL; 332 while (*nr_ids < max_nr_ids && pos < len) { 333 ret = sscanf(&str[pos], "%lu%n", &id, &parsed); 334 pos += parsed; 335 if (ret != 1) 336 break; 337 ids[*nr_ids] = id; 338 *nr_ids += 1; 339 } 340 341 return ids; 342 } 343 344 static void dbgfs_put_pids(unsigned long *ids, int nr_ids) 345 { 346 int i; 347 348 for (i = 0; i < nr_ids; i++) 349 put_pid((struct pid *)ids[i]); 350 } 351 352 static ssize_t dbgfs_target_ids_write(struct file *file, 353 const char __user *buf, size_t count, loff_t *ppos) 354 { 355 struct damon_ctx *ctx = file->private_data; 356 bool id_is_pid = true; 357 char *kbuf, *nrs; 358 unsigned long *targets; 359 ssize_t nr_targets; 360 ssize_t ret; 361 int i; 362 363 kbuf = user_input_str(buf, count, ppos); 364 if (IS_ERR(kbuf)) 365 return PTR_ERR(kbuf); 366 367 nrs = kbuf; 368 if (!strncmp(kbuf, "paddr\n", count)) { 369 id_is_pid = false; 370 /* target id is meaningless here, but we set it just for fun */ 371 scnprintf(kbuf, count, "42 "); 372 } 373 374 targets = str_to_target_ids(nrs, count, &nr_targets); 375 if (!targets) { 376 ret = -ENOMEM; 377 goto out; 378 } 379 380 if (id_is_pid) { 381 for (i = 0; i < nr_targets; i++) { 382 targets[i] = (unsigned long)find_get_pid( 383 (int)targets[i]); 384 if (!targets[i]) { 385 dbgfs_put_pids(targets, i); 386 ret = -EINVAL; 387 goto free_targets_out; 388 } 389 } 390 } 391 392 mutex_lock(&ctx->kdamond_lock); 393 if (ctx->kdamond) { 394 if (id_is_pid) 395 dbgfs_put_pids(targets, nr_targets); 396 ret = -EBUSY; 397 goto unlock_out; 398 } 399 400 /* remove targets with previously-set primitive */ 401 damon_set_targets(ctx, NULL, 0); 402 403 /* Configure the context for the address space type */ 404 if (id_is_pid) 405 damon_va_set_primitives(ctx); 406 else 407 damon_pa_set_primitives(ctx); 408 409 ret = damon_set_targets(ctx, targets, nr_targets); 410 if (ret) { 411 if (id_is_pid) 412 dbgfs_put_pids(targets, nr_targets); 413 } else { 414 ret = count; 415 } 416 417 unlock_out: 418 mutex_unlock(&ctx->kdamond_lock); 419 free_targets_out: 420 kfree(targets); 421 out: 422 kfree(kbuf); 423 return ret; 424 } 425 426 static ssize_t sprint_init_regions(struct damon_ctx *c, char *buf, ssize_t len) 427 { 428 struct damon_target *t; 429 struct damon_region *r; 430 int written = 0; 431 int rc; 432 433 damon_for_each_target(t, c) { 434 damon_for_each_region(r, t) { 435 rc = scnprintf(&buf[written], len - written, 436 "%lu %lu %lu\n", 437 t->id, r->ar.start, r->ar.end); 438 if (!rc) 439 return -ENOMEM; 440 written += rc; 441 } 442 } 443 return written; 444 } 445 446 static ssize_t dbgfs_init_regions_read(struct file *file, char __user *buf, 447 size_t count, loff_t *ppos) 448 { 449 struct damon_ctx *ctx = file->private_data; 450 char *kbuf; 451 ssize_t len; 452 453 kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); 454 if (!kbuf) 455 return -ENOMEM; 456 457 mutex_lock(&ctx->kdamond_lock); 458 if (ctx->kdamond) { 459 mutex_unlock(&ctx->kdamond_lock); 460 len = -EBUSY; 461 goto out; 462 } 463 464 len = sprint_init_regions(ctx, kbuf, count); 465 mutex_unlock(&ctx->kdamond_lock); 466 if (len < 0) 467 goto out; 468 len = simple_read_from_buffer(buf, count, ppos, kbuf, len); 469 470 out: 471 kfree(kbuf); 472 return len; 473 } 474 475 static int add_init_region(struct damon_ctx *c, 476 unsigned long target_id, struct damon_addr_range *ar) 477 { 478 struct damon_target *t; 479 struct damon_region *r, *prev; 480 unsigned long id; 481 int rc = -EINVAL; 482 483 if (ar->start >= ar->end) 484 return -EINVAL; 485 486 damon_for_each_target(t, c) { 487 id = t->id; 488 if (targetid_is_pid(c)) 489 id = (unsigned long)pid_vnr((struct pid *)id); 490 if (id == target_id) { 491 r = damon_new_region(ar->start, ar->end); 492 if (!r) 493 return -ENOMEM; 494 damon_add_region(r, t); 495 if (damon_nr_regions(t) > 1) { 496 prev = damon_prev_region(r); 497 if (prev->ar.end > r->ar.start) { 498 damon_destroy_region(r, t); 499 return -EINVAL; 500 } 501 } 502 rc = 0; 503 } 504 } 505 return rc; 506 } 507 508 static int set_init_regions(struct damon_ctx *c, const char *str, ssize_t len) 509 { 510 struct damon_target *t; 511 struct damon_region *r, *next; 512 int pos = 0, parsed, ret; 513 unsigned long target_id; 514 struct damon_addr_range ar; 515 int err; 516 517 damon_for_each_target(t, c) { 518 damon_for_each_region_safe(r, next, t) 519 damon_destroy_region(r, t); 520 } 521 522 while (pos < len) { 523 ret = sscanf(&str[pos], "%lu %lu %lu%n", 524 &target_id, &ar.start, &ar.end, &parsed); 525 if (ret != 3) 526 break; 527 err = add_init_region(c, target_id, &ar); 528 if (err) 529 goto fail; 530 pos += parsed; 531 } 532 533 return 0; 534 535 fail: 536 damon_for_each_target(t, c) { 537 damon_for_each_region_safe(r, next, t) 538 damon_destroy_region(r, t); 539 } 540 return err; 541 } 542 543 static ssize_t dbgfs_init_regions_write(struct file *file, 544 const char __user *buf, size_t count, 545 loff_t *ppos) 546 { 547 struct damon_ctx *ctx = file->private_data; 548 char *kbuf; 549 ssize_t ret = count; 550 int err; 551 552 kbuf = user_input_str(buf, count, ppos); 553 if (IS_ERR(kbuf)) 554 return PTR_ERR(kbuf); 555 556 mutex_lock(&ctx->kdamond_lock); 557 if (ctx->kdamond) { 558 ret = -EBUSY; 559 goto unlock_out; 560 } 561 562 err = set_init_regions(ctx, kbuf, ret); 563 if (err) 564 ret = err; 565 566 unlock_out: 567 mutex_unlock(&ctx->kdamond_lock); 568 kfree(kbuf); 569 return ret; 570 } 571 572 static ssize_t dbgfs_kdamond_pid_read(struct file *file, 573 char __user *buf, size_t count, loff_t *ppos) 574 { 575 struct damon_ctx *ctx = file->private_data; 576 char *kbuf; 577 ssize_t len; 578 579 kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); 580 if (!kbuf) 581 return -ENOMEM; 582 583 mutex_lock(&ctx->kdamond_lock); 584 if (ctx->kdamond) 585 len = scnprintf(kbuf, count, "%d\n", ctx->kdamond->pid); 586 else 587 len = scnprintf(kbuf, count, "none\n"); 588 mutex_unlock(&ctx->kdamond_lock); 589 if (!len) 590 goto out; 591 len = simple_read_from_buffer(buf, count, ppos, kbuf, len); 592 593 out: 594 kfree(kbuf); 595 return len; 596 } 597 598 static int damon_dbgfs_open(struct inode *inode, struct file *file) 599 { 600 file->private_data = inode->i_private; 601 602 return nonseekable_open(inode, file); 603 } 604 605 static const struct file_operations attrs_fops = { 606 .open = damon_dbgfs_open, 607 .read = dbgfs_attrs_read, 608 .write = dbgfs_attrs_write, 609 }; 610 611 static const struct file_operations schemes_fops = { 612 .open = damon_dbgfs_open, 613 .read = dbgfs_schemes_read, 614 .write = dbgfs_schemes_write, 615 }; 616 617 static const struct file_operations target_ids_fops = { 618 .open = damon_dbgfs_open, 619 .read = dbgfs_target_ids_read, 620 .write = dbgfs_target_ids_write, 621 }; 622 623 static const struct file_operations init_regions_fops = { 624 .open = damon_dbgfs_open, 625 .read = dbgfs_init_regions_read, 626 .write = dbgfs_init_regions_write, 627 }; 628 629 static const struct file_operations kdamond_pid_fops = { 630 .open = damon_dbgfs_open, 631 .read = dbgfs_kdamond_pid_read, 632 }; 633 634 static void dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx) 635 { 636 const char * const file_names[] = {"attrs", "schemes", "target_ids", 637 "init_regions", "kdamond_pid"}; 638 const struct file_operations *fops[] = {&attrs_fops, &schemes_fops, 639 &target_ids_fops, &init_regions_fops, &kdamond_pid_fops}; 640 int i; 641 642 for (i = 0; i < ARRAY_SIZE(file_names); i++) 643 debugfs_create_file(file_names[i], 0600, dir, ctx, fops[i]); 644 } 645 646 static void dbgfs_before_terminate(struct damon_ctx *ctx) 647 { 648 struct damon_target *t, *next; 649 650 if (!targetid_is_pid(ctx)) 651 return; 652 653 damon_for_each_target_safe(t, next, ctx) { 654 put_pid((struct pid *)t->id); 655 damon_destroy_target(t); 656 } 657 } 658 659 static struct damon_ctx *dbgfs_new_ctx(void) 660 { 661 struct damon_ctx *ctx; 662 663 ctx = damon_new_ctx(); 664 if (!ctx) 665 return NULL; 666 667 damon_va_set_primitives(ctx); 668 ctx->callback.before_terminate = dbgfs_before_terminate; 669 return ctx; 670 } 671 672 static void dbgfs_destroy_ctx(struct damon_ctx *ctx) 673 { 674 damon_destroy_ctx(ctx); 675 } 676 677 /* 678 * Make a context of @name and create a debugfs directory for it. 679 * 680 * This function should be called while holding damon_dbgfs_lock. 681 * 682 * Returns 0 on success, negative error code otherwise. 683 */ 684 static int dbgfs_mk_context(char *name) 685 { 686 struct dentry *root, **new_dirs, *new_dir; 687 struct damon_ctx **new_ctxs, *new_ctx; 688 689 if (damon_nr_running_ctxs()) 690 return -EBUSY; 691 692 new_ctxs = krealloc(dbgfs_ctxs, sizeof(*dbgfs_ctxs) * 693 (dbgfs_nr_ctxs + 1), GFP_KERNEL); 694 if (!new_ctxs) 695 return -ENOMEM; 696 dbgfs_ctxs = new_ctxs; 697 698 new_dirs = krealloc(dbgfs_dirs, sizeof(*dbgfs_dirs) * 699 (dbgfs_nr_ctxs + 1), GFP_KERNEL); 700 if (!new_dirs) 701 return -ENOMEM; 702 dbgfs_dirs = new_dirs; 703 704 root = dbgfs_dirs[0]; 705 if (!root) 706 return -ENOENT; 707 708 new_dir = debugfs_create_dir(name, root); 709 dbgfs_dirs[dbgfs_nr_ctxs] = new_dir; 710 711 new_ctx = dbgfs_new_ctx(); 712 if (!new_ctx) { 713 debugfs_remove(new_dir); 714 dbgfs_dirs[dbgfs_nr_ctxs] = NULL; 715 return -ENOMEM; 716 } 717 718 dbgfs_ctxs[dbgfs_nr_ctxs] = new_ctx; 719 dbgfs_fill_ctx_dir(dbgfs_dirs[dbgfs_nr_ctxs], 720 dbgfs_ctxs[dbgfs_nr_ctxs]); 721 dbgfs_nr_ctxs++; 722 723 return 0; 724 } 725 726 static ssize_t dbgfs_mk_context_write(struct file *file, 727 const char __user *buf, size_t count, loff_t *ppos) 728 { 729 char *kbuf; 730 char *ctx_name; 731 ssize_t ret; 732 733 kbuf = user_input_str(buf, count, ppos); 734 if (IS_ERR(kbuf)) 735 return PTR_ERR(kbuf); 736 ctx_name = kmalloc(count + 1, GFP_KERNEL); 737 if (!ctx_name) { 738 kfree(kbuf); 739 return -ENOMEM; 740 } 741 742 /* Trim white space */ 743 if (sscanf(kbuf, "%s", ctx_name) != 1) { 744 ret = -EINVAL; 745 goto out; 746 } 747 748 mutex_lock(&damon_dbgfs_lock); 749 ret = dbgfs_mk_context(ctx_name); 750 if (!ret) 751 ret = count; 752 mutex_unlock(&damon_dbgfs_lock); 753 754 out: 755 kfree(kbuf); 756 kfree(ctx_name); 757 return ret; 758 } 759 760 /* 761 * Remove a context of @name and its debugfs directory. 762 * 763 * This function should be called while holding damon_dbgfs_lock. 764 * 765 * Return 0 on success, negative error code otherwise. 766 */ 767 static int dbgfs_rm_context(char *name) 768 { 769 struct dentry *root, *dir, **new_dirs; 770 struct damon_ctx **new_ctxs; 771 int i, j; 772 773 if (damon_nr_running_ctxs()) 774 return -EBUSY; 775 776 root = dbgfs_dirs[0]; 777 if (!root) 778 return -ENOENT; 779 780 dir = debugfs_lookup(name, root); 781 if (!dir) 782 return -ENOENT; 783 784 new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs), 785 GFP_KERNEL); 786 if (!new_dirs) 787 return -ENOMEM; 788 789 new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs), 790 GFP_KERNEL); 791 if (!new_ctxs) { 792 kfree(new_dirs); 793 return -ENOMEM; 794 } 795 796 for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) { 797 if (dbgfs_dirs[i] == dir) { 798 debugfs_remove(dbgfs_dirs[i]); 799 dbgfs_destroy_ctx(dbgfs_ctxs[i]); 800 continue; 801 } 802 new_dirs[j] = dbgfs_dirs[i]; 803 new_ctxs[j++] = dbgfs_ctxs[i]; 804 } 805 806 kfree(dbgfs_dirs); 807 kfree(dbgfs_ctxs); 808 809 dbgfs_dirs = new_dirs; 810 dbgfs_ctxs = new_ctxs; 811 dbgfs_nr_ctxs--; 812 813 return 0; 814 } 815 816 static ssize_t dbgfs_rm_context_write(struct file *file, 817 const char __user *buf, size_t count, loff_t *ppos) 818 { 819 char *kbuf; 820 ssize_t ret; 821 char *ctx_name; 822 823 kbuf = user_input_str(buf, count, ppos); 824 if (IS_ERR(kbuf)) 825 return PTR_ERR(kbuf); 826 ctx_name = kmalloc(count + 1, GFP_KERNEL); 827 if (!ctx_name) { 828 kfree(kbuf); 829 return -ENOMEM; 830 } 831 832 /* Trim white space */ 833 if (sscanf(kbuf, "%s", ctx_name) != 1) { 834 ret = -EINVAL; 835 goto out; 836 } 837 838 mutex_lock(&damon_dbgfs_lock); 839 ret = dbgfs_rm_context(ctx_name); 840 if (!ret) 841 ret = count; 842 mutex_unlock(&damon_dbgfs_lock); 843 844 out: 845 kfree(kbuf); 846 kfree(ctx_name); 847 return ret; 848 } 849 850 static ssize_t dbgfs_monitor_on_read(struct file *file, 851 char __user *buf, size_t count, loff_t *ppos) 852 { 853 char monitor_on_buf[5]; 854 bool monitor_on = damon_nr_running_ctxs() != 0; 855 int len; 856 857 len = scnprintf(monitor_on_buf, 5, monitor_on ? "on\n" : "off\n"); 858 859 return simple_read_from_buffer(buf, count, ppos, monitor_on_buf, len); 860 } 861 862 static ssize_t dbgfs_monitor_on_write(struct file *file, 863 const char __user *buf, size_t count, loff_t *ppos) 864 { 865 ssize_t ret; 866 char *kbuf; 867 868 kbuf = user_input_str(buf, count, ppos); 869 if (IS_ERR(kbuf)) 870 return PTR_ERR(kbuf); 871 872 /* Remove white space */ 873 if (sscanf(kbuf, "%s", kbuf) != 1) { 874 kfree(kbuf); 875 return -EINVAL; 876 } 877 878 mutex_lock(&damon_dbgfs_lock); 879 if (!strncmp(kbuf, "on", count)) { 880 int i; 881 882 for (i = 0; i < dbgfs_nr_ctxs; i++) { 883 if (damon_targets_empty(dbgfs_ctxs[i])) { 884 kfree(kbuf); 885 mutex_unlock(&damon_dbgfs_lock); 886 return -EINVAL; 887 } 888 } 889 ret = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs); 890 } else if (!strncmp(kbuf, "off", count)) { 891 ret = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs); 892 } else { 893 ret = -EINVAL; 894 } 895 mutex_unlock(&damon_dbgfs_lock); 896 897 if (!ret) 898 ret = count; 899 kfree(kbuf); 900 return ret; 901 } 902 903 static const struct file_operations mk_contexts_fops = { 904 .write = dbgfs_mk_context_write, 905 }; 906 907 static const struct file_operations rm_contexts_fops = { 908 .write = dbgfs_rm_context_write, 909 }; 910 911 static const struct file_operations monitor_on_fops = { 912 .read = dbgfs_monitor_on_read, 913 .write = dbgfs_monitor_on_write, 914 }; 915 916 static int __init __damon_dbgfs_init(void) 917 { 918 struct dentry *dbgfs_root; 919 const char * const file_names[] = {"mk_contexts", "rm_contexts", 920 "monitor_on"}; 921 const struct file_operations *fops[] = {&mk_contexts_fops, 922 &rm_contexts_fops, &monitor_on_fops}; 923 int i; 924 925 dbgfs_root = debugfs_create_dir("damon", NULL); 926 927 for (i = 0; i < ARRAY_SIZE(file_names); i++) 928 debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL, 929 fops[i]); 930 dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]); 931 932 dbgfs_dirs = kmalloc_array(1, sizeof(dbgfs_root), GFP_KERNEL); 933 if (!dbgfs_dirs) { 934 debugfs_remove(dbgfs_root); 935 return -ENOMEM; 936 } 937 dbgfs_dirs[0] = dbgfs_root; 938 939 return 0; 940 } 941 942 /* 943 * Functions for the initialization 944 */ 945 946 static int __init damon_dbgfs_init(void) 947 { 948 int rc = -ENOMEM; 949 950 mutex_lock(&damon_dbgfs_lock); 951 dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL); 952 if (!dbgfs_ctxs) 953 goto out; 954 dbgfs_ctxs[0] = dbgfs_new_ctx(); 955 if (!dbgfs_ctxs[0]) { 956 kfree(dbgfs_ctxs); 957 goto out; 958 } 959 dbgfs_nr_ctxs = 1; 960 961 rc = __damon_dbgfs_init(); 962 if (rc) { 963 kfree(dbgfs_ctxs[0]); 964 kfree(dbgfs_ctxs); 965 pr_err("%s: dbgfs init failed\n", __func__); 966 } 967 968 out: 969 mutex_unlock(&damon_dbgfs_lock); 970 return rc; 971 } 972 973 module_init(damon_dbgfs_init); 974 975 #include "dbgfs-test.h" 976