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 %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.nr_tried, s->stat.sz_tried, 121 s->stat.nr_applied, s->stat.sz_applied, 122 s->stat.qt_exceeds); 123 if (!rc) 124 return -ENOMEM; 125 126 written += rc; 127 } 128 return written; 129 } 130 131 static ssize_t dbgfs_schemes_read(struct file *file, char __user *buf, 132 size_t count, loff_t *ppos) 133 { 134 struct damon_ctx *ctx = file->private_data; 135 char *kbuf; 136 ssize_t len; 137 138 kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); 139 if (!kbuf) 140 return -ENOMEM; 141 142 mutex_lock(&ctx->kdamond_lock); 143 len = sprint_schemes(ctx, kbuf, count); 144 mutex_unlock(&ctx->kdamond_lock); 145 if (len < 0) 146 goto out; 147 len = simple_read_from_buffer(buf, count, ppos, kbuf, len); 148 149 out: 150 kfree(kbuf); 151 return len; 152 } 153 154 static void free_schemes_arr(struct damos **schemes, ssize_t nr_schemes) 155 { 156 ssize_t i; 157 158 for (i = 0; i < nr_schemes; i++) 159 kfree(schemes[i]); 160 kfree(schemes); 161 } 162 163 static bool damos_action_valid(int action) 164 { 165 switch (action) { 166 case DAMOS_WILLNEED: 167 case DAMOS_COLD: 168 case DAMOS_PAGEOUT: 169 case DAMOS_HUGEPAGE: 170 case DAMOS_NOHUGEPAGE: 171 case DAMOS_STAT: 172 return true; 173 default: 174 return false; 175 } 176 } 177 178 /* 179 * Converts a string into an array of struct damos pointers 180 * 181 * Returns an array of struct damos pointers that converted if the conversion 182 * success, or NULL otherwise. 183 */ 184 static struct damos **str_to_schemes(const char *str, ssize_t len, 185 ssize_t *nr_schemes) 186 { 187 struct damos *scheme, **schemes; 188 const int max_nr_schemes = 256; 189 int pos = 0, parsed, ret; 190 unsigned long min_sz, max_sz; 191 unsigned int min_nr_a, max_nr_a, min_age, max_age; 192 unsigned int action; 193 194 schemes = kmalloc_array(max_nr_schemes, sizeof(scheme), 195 GFP_KERNEL); 196 if (!schemes) 197 return NULL; 198 199 *nr_schemes = 0; 200 while (pos < len && *nr_schemes < max_nr_schemes) { 201 struct damos_quota quota = {}; 202 struct damos_watermarks wmarks; 203 204 ret = sscanf(&str[pos], 205 "%lu %lu %u %u %u %u %u %lu %lu %lu %u %u %u %u %lu %lu %lu %lu%n", 206 &min_sz, &max_sz, &min_nr_a, &max_nr_a, 207 &min_age, &max_age, &action, "a.ms, 208 "a.sz, "a.reset_interval, 209 "a.weight_sz, "a.weight_nr_accesses, 210 "a.weight_age, &wmarks.metric, 211 &wmarks.interval, &wmarks.high, &wmarks.mid, 212 &wmarks.low, &parsed); 213 if (ret != 18) 214 break; 215 if (!damos_action_valid(action)) 216 goto fail; 217 218 if (min_sz > max_sz || min_nr_a > max_nr_a || min_age > max_age) 219 goto fail; 220 221 if (wmarks.high < wmarks.mid || wmarks.high < wmarks.low || 222 wmarks.mid < wmarks.low) 223 goto fail; 224 225 pos += parsed; 226 scheme = damon_new_scheme(min_sz, max_sz, min_nr_a, max_nr_a, 227 min_age, max_age, action, "a, &wmarks); 228 if (!scheme) 229 goto fail; 230 231 schemes[*nr_schemes] = scheme; 232 *nr_schemes += 1; 233 } 234 return schemes; 235 fail: 236 free_schemes_arr(schemes, *nr_schemes); 237 return NULL; 238 } 239 240 static ssize_t dbgfs_schemes_write(struct file *file, const char __user *buf, 241 size_t count, loff_t *ppos) 242 { 243 struct damon_ctx *ctx = file->private_data; 244 char *kbuf; 245 struct damos **schemes; 246 ssize_t nr_schemes = 0, ret; 247 248 kbuf = user_input_str(buf, count, ppos); 249 if (IS_ERR(kbuf)) 250 return PTR_ERR(kbuf); 251 252 schemes = str_to_schemes(kbuf, count, &nr_schemes); 253 if (!schemes) { 254 ret = -EINVAL; 255 goto out; 256 } 257 258 mutex_lock(&ctx->kdamond_lock); 259 if (ctx->kdamond) { 260 ret = -EBUSY; 261 goto unlock_out; 262 } 263 264 ret = damon_set_schemes(ctx, schemes, nr_schemes); 265 if (!ret) { 266 ret = count; 267 nr_schemes = 0; 268 } 269 270 unlock_out: 271 mutex_unlock(&ctx->kdamond_lock); 272 free_schemes_arr(schemes, nr_schemes); 273 out: 274 kfree(kbuf); 275 return ret; 276 } 277 278 static inline bool targetid_is_pid(const struct damon_ctx *ctx) 279 { 280 return ctx->primitive.target_valid == damon_va_target_valid; 281 } 282 283 static ssize_t sprint_target_ids(struct damon_ctx *ctx, char *buf, ssize_t len) 284 { 285 struct damon_target *t; 286 unsigned long id; 287 int written = 0; 288 int rc; 289 290 damon_for_each_target(t, ctx) { 291 id = t->id; 292 if (targetid_is_pid(ctx)) 293 /* Show pid numbers to debugfs users */ 294 id = (unsigned long)pid_vnr((struct pid *)id); 295 296 rc = scnprintf(&buf[written], len - written, "%lu ", id); 297 if (!rc) 298 return -ENOMEM; 299 written += rc; 300 } 301 if (written) 302 written -= 1; 303 written += scnprintf(&buf[written], len - written, "\n"); 304 return written; 305 } 306 307 static ssize_t dbgfs_target_ids_read(struct file *file, 308 char __user *buf, size_t count, loff_t *ppos) 309 { 310 struct damon_ctx *ctx = file->private_data; 311 ssize_t len; 312 char ids_buf[320]; 313 314 mutex_lock(&ctx->kdamond_lock); 315 len = sprint_target_ids(ctx, ids_buf, 320); 316 mutex_unlock(&ctx->kdamond_lock); 317 if (len < 0) 318 return len; 319 320 return simple_read_from_buffer(buf, count, ppos, ids_buf, len); 321 } 322 323 /* 324 * Converts a string into an array of unsigned long integers 325 * 326 * Returns an array of unsigned long integers if the conversion success, or 327 * NULL otherwise. 328 */ 329 static unsigned long *str_to_target_ids(const char *str, ssize_t len, 330 ssize_t *nr_ids) 331 { 332 unsigned long *ids; 333 const int max_nr_ids = 32; 334 unsigned long id; 335 int pos = 0, parsed, ret; 336 337 *nr_ids = 0; 338 ids = kmalloc_array(max_nr_ids, sizeof(id), GFP_KERNEL); 339 if (!ids) 340 return NULL; 341 while (*nr_ids < max_nr_ids && pos < len) { 342 ret = sscanf(&str[pos], "%lu%n", &id, &parsed); 343 pos += parsed; 344 if (ret != 1) 345 break; 346 ids[*nr_ids] = id; 347 *nr_ids += 1; 348 } 349 350 return ids; 351 } 352 353 static void dbgfs_put_pids(unsigned long *ids, int nr_ids) 354 { 355 int i; 356 357 for (i = 0; i < nr_ids; i++) 358 put_pid((struct pid *)ids[i]); 359 } 360 361 static ssize_t dbgfs_target_ids_write(struct file *file, 362 const char __user *buf, size_t count, loff_t *ppos) 363 { 364 struct damon_ctx *ctx = file->private_data; 365 struct damon_target *t, *next_t; 366 bool id_is_pid = true; 367 char *kbuf, *nrs; 368 unsigned long *targets; 369 ssize_t nr_targets; 370 ssize_t ret; 371 int i; 372 373 kbuf = user_input_str(buf, count, ppos); 374 if (IS_ERR(kbuf)) 375 return PTR_ERR(kbuf); 376 377 nrs = kbuf; 378 if (!strncmp(kbuf, "paddr\n", count)) { 379 id_is_pid = false; 380 /* target id is meaningless here, but we set it just for fun */ 381 scnprintf(kbuf, count, "42 "); 382 } 383 384 targets = str_to_target_ids(nrs, count, &nr_targets); 385 if (!targets) { 386 ret = -ENOMEM; 387 goto out; 388 } 389 390 if (id_is_pid) { 391 for (i = 0; i < nr_targets; i++) { 392 targets[i] = (unsigned long)find_get_pid( 393 (int)targets[i]); 394 if (!targets[i]) { 395 dbgfs_put_pids(targets, i); 396 ret = -EINVAL; 397 goto free_targets_out; 398 } 399 } 400 } 401 402 mutex_lock(&ctx->kdamond_lock); 403 if (ctx->kdamond) { 404 if (id_is_pid) 405 dbgfs_put_pids(targets, nr_targets); 406 ret = -EBUSY; 407 goto unlock_out; 408 } 409 410 /* remove previously set targets */ 411 damon_for_each_target_safe(t, next_t, ctx) { 412 if (targetid_is_pid(ctx)) 413 put_pid((struct pid *)t->id); 414 damon_destroy_target(t); 415 } 416 417 /* Configure the context for the address space type */ 418 if (id_is_pid) 419 damon_va_set_primitives(ctx); 420 else 421 damon_pa_set_primitives(ctx); 422 423 ret = damon_set_targets(ctx, targets, nr_targets); 424 if (ret) { 425 if (id_is_pid) 426 dbgfs_put_pids(targets, nr_targets); 427 } else { 428 ret = count; 429 } 430 431 unlock_out: 432 mutex_unlock(&ctx->kdamond_lock); 433 free_targets_out: 434 kfree(targets); 435 out: 436 kfree(kbuf); 437 return ret; 438 } 439 440 static ssize_t sprint_init_regions(struct damon_ctx *c, char *buf, ssize_t len) 441 { 442 struct damon_target *t; 443 struct damon_region *r; 444 int written = 0; 445 int rc; 446 447 damon_for_each_target(t, c) { 448 damon_for_each_region(r, t) { 449 rc = scnprintf(&buf[written], len - written, 450 "%lu %lu %lu\n", 451 t->id, r->ar.start, r->ar.end); 452 if (!rc) 453 return -ENOMEM; 454 written += rc; 455 } 456 } 457 return written; 458 } 459 460 static ssize_t dbgfs_init_regions_read(struct file *file, char __user *buf, 461 size_t count, loff_t *ppos) 462 { 463 struct damon_ctx *ctx = file->private_data; 464 char *kbuf; 465 ssize_t len; 466 467 kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); 468 if (!kbuf) 469 return -ENOMEM; 470 471 mutex_lock(&ctx->kdamond_lock); 472 if (ctx->kdamond) { 473 mutex_unlock(&ctx->kdamond_lock); 474 len = -EBUSY; 475 goto out; 476 } 477 478 len = sprint_init_regions(ctx, kbuf, count); 479 mutex_unlock(&ctx->kdamond_lock); 480 if (len < 0) 481 goto out; 482 len = simple_read_from_buffer(buf, count, ppos, kbuf, len); 483 484 out: 485 kfree(kbuf); 486 return len; 487 } 488 489 static int add_init_region(struct damon_ctx *c, 490 unsigned long target_id, struct damon_addr_range *ar) 491 { 492 struct damon_target *t; 493 struct damon_region *r, *prev; 494 unsigned long id; 495 int rc = -EINVAL; 496 497 if (ar->start >= ar->end) 498 return -EINVAL; 499 500 damon_for_each_target(t, c) { 501 id = t->id; 502 if (targetid_is_pid(c)) 503 id = (unsigned long)pid_vnr((struct pid *)id); 504 if (id == target_id) { 505 r = damon_new_region(ar->start, ar->end); 506 if (!r) 507 return -ENOMEM; 508 damon_add_region(r, t); 509 if (damon_nr_regions(t) > 1) { 510 prev = damon_prev_region(r); 511 if (prev->ar.end > r->ar.start) { 512 damon_destroy_region(r, t); 513 return -EINVAL; 514 } 515 } 516 rc = 0; 517 } 518 } 519 return rc; 520 } 521 522 static int set_init_regions(struct damon_ctx *c, const char *str, ssize_t len) 523 { 524 struct damon_target *t; 525 struct damon_region *r, *next; 526 int pos = 0, parsed, ret; 527 unsigned long target_id; 528 struct damon_addr_range ar; 529 int err; 530 531 damon_for_each_target(t, c) { 532 damon_for_each_region_safe(r, next, t) 533 damon_destroy_region(r, t); 534 } 535 536 while (pos < len) { 537 ret = sscanf(&str[pos], "%lu %lu %lu%n", 538 &target_id, &ar.start, &ar.end, &parsed); 539 if (ret != 3) 540 break; 541 err = add_init_region(c, target_id, &ar); 542 if (err) 543 goto fail; 544 pos += parsed; 545 } 546 547 return 0; 548 549 fail: 550 damon_for_each_target(t, c) { 551 damon_for_each_region_safe(r, next, t) 552 damon_destroy_region(r, t); 553 } 554 return err; 555 } 556 557 static ssize_t dbgfs_init_regions_write(struct file *file, 558 const char __user *buf, size_t count, 559 loff_t *ppos) 560 { 561 struct damon_ctx *ctx = file->private_data; 562 char *kbuf; 563 ssize_t ret = count; 564 int err; 565 566 kbuf = user_input_str(buf, count, ppos); 567 if (IS_ERR(kbuf)) 568 return PTR_ERR(kbuf); 569 570 mutex_lock(&ctx->kdamond_lock); 571 if (ctx->kdamond) { 572 ret = -EBUSY; 573 goto unlock_out; 574 } 575 576 err = set_init_regions(ctx, kbuf, ret); 577 if (err) 578 ret = err; 579 580 unlock_out: 581 mutex_unlock(&ctx->kdamond_lock); 582 kfree(kbuf); 583 return ret; 584 } 585 586 static ssize_t dbgfs_kdamond_pid_read(struct file *file, 587 char __user *buf, size_t count, loff_t *ppos) 588 { 589 struct damon_ctx *ctx = file->private_data; 590 char *kbuf; 591 ssize_t len; 592 593 kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); 594 if (!kbuf) 595 return -ENOMEM; 596 597 mutex_lock(&ctx->kdamond_lock); 598 if (ctx->kdamond) 599 len = scnprintf(kbuf, count, "%d\n", ctx->kdamond->pid); 600 else 601 len = scnprintf(kbuf, count, "none\n"); 602 mutex_unlock(&ctx->kdamond_lock); 603 if (!len) 604 goto out; 605 len = simple_read_from_buffer(buf, count, ppos, kbuf, len); 606 607 out: 608 kfree(kbuf); 609 return len; 610 } 611 612 static int damon_dbgfs_open(struct inode *inode, struct file *file) 613 { 614 file->private_data = inode->i_private; 615 616 return nonseekable_open(inode, file); 617 } 618 619 static const struct file_operations attrs_fops = { 620 .open = damon_dbgfs_open, 621 .read = dbgfs_attrs_read, 622 .write = dbgfs_attrs_write, 623 }; 624 625 static const struct file_operations schemes_fops = { 626 .open = damon_dbgfs_open, 627 .read = dbgfs_schemes_read, 628 .write = dbgfs_schemes_write, 629 }; 630 631 static const struct file_operations target_ids_fops = { 632 .open = damon_dbgfs_open, 633 .read = dbgfs_target_ids_read, 634 .write = dbgfs_target_ids_write, 635 }; 636 637 static const struct file_operations init_regions_fops = { 638 .open = damon_dbgfs_open, 639 .read = dbgfs_init_regions_read, 640 .write = dbgfs_init_regions_write, 641 }; 642 643 static const struct file_operations kdamond_pid_fops = { 644 .open = damon_dbgfs_open, 645 .read = dbgfs_kdamond_pid_read, 646 }; 647 648 static void dbgfs_fill_ctx_dir(struct dentry *dir, struct damon_ctx *ctx) 649 { 650 const char * const file_names[] = {"attrs", "schemes", "target_ids", 651 "init_regions", "kdamond_pid"}; 652 const struct file_operations *fops[] = {&attrs_fops, &schemes_fops, 653 &target_ids_fops, &init_regions_fops, &kdamond_pid_fops}; 654 int i; 655 656 for (i = 0; i < ARRAY_SIZE(file_names); i++) 657 debugfs_create_file(file_names[i], 0600, dir, ctx, fops[i]); 658 } 659 660 static void dbgfs_before_terminate(struct damon_ctx *ctx) 661 { 662 struct damon_target *t, *next; 663 664 if (!targetid_is_pid(ctx)) 665 return; 666 667 mutex_lock(&ctx->kdamond_lock); 668 damon_for_each_target_safe(t, next, ctx) { 669 put_pid((struct pid *)t->id); 670 damon_destroy_target(t); 671 } 672 mutex_unlock(&ctx->kdamond_lock); 673 } 674 675 static struct damon_ctx *dbgfs_new_ctx(void) 676 { 677 struct damon_ctx *ctx; 678 679 ctx = damon_new_ctx(); 680 if (!ctx) 681 return NULL; 682 683 damon_va_set_primitives(ctx); 684 ctx->callback.before_terminate = dbgfs_before_terminate; 685 return ctx; 686 } 687 688 static void dbgfs_destroy_ctx(struct damon_ctx *ctx) 689 { 690 damon_destroy_ctx(ctx); 691 } 692 693 /* 694 * Make a context of @name and create a debugfs directory for it. 695 * 696 * This function should be called while holding damon_dbgfs_lock. 697 * 698 * Returns 0 on success, negative error code otherwise. 699 */ 700 static int dbgfs_mk_context(char *name) 701 { 702 struct dentry *root, **new_dirs, *new_dir; 703 struct damon_ctx **new_ctxs, *new_ctx; 704 705 if (damon_nr_running_ctxs()) 706 return -EBUSY; 707 708 new_ctxs = krealloc(dbgfs_ctxs, sizeof(*dbgfs_ctxs) * 709 (dbgfs_nr_ctxs + 1), GFP_KERNEL); 710 if (!new_ctxs) 711 return -ENOMEM; 712 dbgfs_ctxs = new_ctxs; 713 714 new_dirs = krealloc(dbgfs_dirs, sizeof(*dbgfs_dirs) * 715 (dbgfs_nr_ctxs + 1), GFP_KERNEL); 716 if (!new_dirs) 717 return -ENOMEM; 718 dbgfs_dirs = new_dirs; 719 720 root = dbgfs_dirs[0]; 721 if (!root) 722 return -ENOENT; 723 724 new_dir = debugfs_create_dir(name, root); 725 dbgfs_dirs[dbgfs_nr_ctxs] = new_dir; 726 727 new_ctx = dbgfs_new_ctx(); 728 if (!new_ctx) { 729 debugfs_remove(new_dir); 730 dbgfs_dirs[dbgfs_nr_ctxs] = NULL; 731 return -ENOMEM; 732 } 733 734 dbgfs_ctxs[dbgfs_nr_ctxs] = new_ctx; 735 dbgfs_fill_ctx_dir(dbgfs_dirs[dbgfs_nr_ctxs], 736 dbgfs_ctxs[dbgfs_nr_ctxs]); 737 dbgfs_nr_ctxs++; 738 739 return 0; 740 } 741 742 static ssize_t dbgfs_mk_context_write(struct file *file, 743 const char __user *buf, size_t count, loff_t *ppos) 744 { 745 char *kbuf; 746 char *ctx_name; 747 ssize_t ret; 748 749 kbuf = user_input_str(buf, count, ppos); 750 if (IS_ERR(kbuf)) 751 return PTR_ERR(kbuf); 752 ctx_name = kmalloc(count + 1, GFP_KERNEL); 753 if (!ctx_name) { 754 kfree(kbuf); 755 return -ENOMEM; 756 } 757 758 /* Trim white space */ 759 if (sscanf(kbuf, "%s", ctx_name) != 1) { 760 ret = -EINVAL; 761 goto out; 762 } 763 764 mutex_lock(&damon_dbgfs_lock); 765 ret = dbgfs_mk_context(ctx_name); 766 if (!ret) 767 ret = count; 768 mutex_unlock(&damon_dbgfs_lock); 769 770 out: 771 kfree(kbuf); 772 kfree(ctx_name); 773 return ret; 774 } 775 776 /* 777 * Remove a context of @name and its debugfs directory. 778 * 779 * This function should be called while holding damon_dbgfs_lock. 780 * 781 * Return 0 on success, negative error code otherwise. 782 */ 783 static int dbgfs_rm_context(char *name) 784 { 785 struct dentry *root, *dir, **new_dirs; 786 struct damon_ctx **new_ctxs; 787 int i, j; 788 789 if (damon_nr_running_ctxs()) 790 return -EBUSY; 791 792 root = dbgfs_dirs[0]; 793 if (!root) 794 return -ENOENT; 795 796 dir = debugfs_lookup(name, root); 797 if (!dir) 798 return -ENOENT; 799 800 new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs), 801 GFP_KERNEL); 802 if (!new_dirs) 803 return -ENOMEM; 804 805 new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs), 806 GFP_KERNEL); 807 if (!new_ctxs) { 808 kfree(new_dirs); 809 return -ENOMEM; 810 } 811 812 for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) { 813 if (dbgfs_dirs[i] == dir) { 814 debugfs_remove(dbgfs_dirs[i]); 815 dbgfs_destroy_ctx(dbgfs_ctxs[i]); 816 continue; 817 } 818 new_dirs[j] = dbgfs_dirs[i]; 819 new_ctxs[j++] = dbgfs_ctxs[i]; 820 } 821 822 kfree(dbgfs_dirs); 823 kfree(dbgfs_ctxs); 824 825 dbgfs_dirs = new_dirs; 826 dbgfs_ctxs = new_ctxs; 827 dbgfs_nr_ctxs--; 828 829 return 0; 830 } 831 832 static ssize_t dbgfs_rm_context_write(struct file *file, 833 const char __user *buf, size_t count, loff_t *ppos) 834 { 835 char *kbuf; 836 ssize_t ret; 837 char *ctx_name; 838 839 kbuf = user_input_str(buf, count, ppos); 840 if (IS_ERR(kbuf)) 841 return PTR_ERR(kbuf); 842 ctx_name = kmalloc(count + 1, GFP_KERNEL); 843 if (!ctx_name) { 844 kfree(kbuf); 845 return -ENOMEM; 846 } 847 848 /* Trim white space */ 849 if (sscanf(kbuf, "%s", ctx_name) != 1) { 850 ret = -EINVAL; 851 goto out; 852 } 853 854 mutex_lock(&damon_dbgfs_lock); 855 ret = dbgfs_rm_context(ctx_name); 856 if (!ret) 857 ret = count; 858 mutex_unlock(&damon_dbgfs_lock); 859 860 out: 861 kfree(kbuf); 862 kfree(ctx_name); 863 return ret; 864 } 865 866 static ssize_t dbgfs_monitor_on_read(struct file *file, 867 char __user *buf, size_t count, loff_t *ppos) 868 { 869 char monitor_on_buf[5]; 870 bool monitor_on = damon_nr_running_ctxs() != 0; 871 int len; 872 873 len = scnprintf(monitor_on_buf, 5, monitor_on ? "on\n" : "off\n"); 874 875 return simple_read_from_buffer(buf, count, ppos, monitor_on_buf, len); 876 } 877 878 static ssize_t dbgfs_monitor_on_write(struct file *file, 879 const char __user *buf, size_t count, loff_t *ppos) 880 { 881 ssize_t ret; 882 char *kbuf; 883 884 kbuf = user_input_str(buf, count, ppos); 885 if (IS_ERR(kbuf)) 886 return PTR_ERR(kbuf); 887 888 /* Remove white space */ 889 if (sscanf(kbuf, "%s", kbuf) != 1) { 890 kfree(kbuf); 891 return -EINVAL; 892 } 893 894 mutex_lock(&damon_dbgfs_lock); 895 if (!strncmp(kbuf, "on", count)) { 896 int i; 897 898 for (i = 0; i < dbgfs_nr_ctxs; i++) { 899 if (damon_targets_empty(dbgfs_ctxs[i])) { 900 kfree(kbuf); 901 mutex_unlock(&damon_dbgfs_lock); 902 return -EINVAL; 903 } 904 } 905 ret = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs); 906 } else if (!strncmp(kbuf, "off", count)) { 907 ret = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs); 908 } else { 909 ret = -EINVAL; 910 } 911 mutex_unlock(&damon_dbgfs_lock); 912 913 if (!ret) 914 ret = count; 915 kfree(kbuf); 916 return ret; 917 } 918 919 static const struct file_operations mk_contexts_fops = { 920 .write = dbgfs_mk_context_write, 921 }; 922 923 static const struct file_operations rm_contexts_fops = { 924 .write = dbgfs_rm_context_write, 925 }; 926 927 static const struct file_operations monitor_on_fops = { 928 .read = dbgfs_monitor_on_read, 929 .write = dbgfs_monitor_on_write, 930 }; 931 932 static int __init __damon_dbgfs_init(void) 933 { 934 struct dentry *dbgfs_root; 935 const char * const file_names[] = {"mk_contexts", "rm_contexts", 936 "monitor_on"}; 937 const struct file_operations *fops[] = {&mk_contexts_fops, 938 &rm_contexts_fops, &monitor_on_fops}; 939 int i; 940 941 dbgfs_root = debugfs_create_dir("damon", NULL); 942 943 for (i = 0; i < ARRAY_SIZE(file_names); i++) 944 debugfs_create_file(file_names[i], 0600, dbgfs_root, NULL, 945 fops[i]); 946 dbgfs_fill_ctx_dir(dbgfs_root, dbgfs_ctxs[0]); 947 948 dbgfs_dirs = kmalloc_array(1, sizeof(dbgfs_root), GFP_KERNEL); 949 if (!dbgfs_dirs) { 950 debugfs_remove(dbgfs_root); 951 return -ENOMEM; 952 } 953 dbgfs_dirs[0] = dbgfs_root; 954 955 return 0; 956 } 957 958 /* 959 * Functions for the initialization 960 */ 961 962 static int __init damon_dbgfs_init(void) 963 { 964 int rc = -ENOMEM; 965 966 mutex_lock(&damon_dbgfs_lock); 967 dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL); 968 if (!dbgfs_ctxs) 969 goto out; 970 dbgfs_ctxs[0] = dbgfs_new_ctx(); 971 if (!dbgfs_ctxs[0]) { 972 kfree(dbgfs_ctxs); 973 goto out; 974 } 975 dbgfs_nr_ctxs = 1; 976 977 rc = __damon_dbgfs_init(); 978 if (rc) { 979 kfree(dbgfs_ctxs[0]); 980 kfree(dbgfs_ctxs); 981 pr_err("%s: dbgfs init failed\n", __func__); 982 } 983 984 out: 985 mutex_unlock(&damon_dbgfs_lock); 986 return rc; 987 } 988 989 module_init(damon_dbgfs_init); 990 991 #include "dbgfs-test.h" 992