| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | #include <linux/debugfs.h> |
| 3 | #include <linux/mm.h> |
| 4 | #include <linux/slab.h> |
| 5 | #include <linux/uaccess.h> |
| 6 | #include <linux/memblock.h> |
| 7 | #include <linux/stacktrace.h> |
| 8 | #include <linux/page_owner.h> |
| 9 | #include <linux/jump_label.h> |
| 10 | #include <linux/migrate.h> |
| 11 | #include <linux/stackdepot.h> |
| 12 | #include <linux/seq_file.h> |
| 13 | #include <linux/memcontrol.h> |
| 14 | #include <linux/sched/clock.h> |
| 15 | |
| 16 | #include "internal.h" |
| 17 | |
| 18 | /* |
| 19 | * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) |
| 20 | * to use off stack temporal storage |
| 21 | */ |
| 22 | #define PAGE_OWNER_STACK_DEPTH (16) |
| 23 | |
| 24 | struct page_owner { |
| 25 | unsigned short order; |
| 26 | short last_migrate_reason; |
| 27 | gfp_t gfp_mask; |
| 28 | depot_stack_handle_t handle; |
| 29 | depot_stack_handle_t free_handle; |
| 30 | u64 ts_nsec; |
| 31 | u64 free_ts_nsec; |
| 32 | char comm[TASK_COMM_LEN]; |
| 33 | pid_t pid; |
| 34 | pid_t tgid; |
| 35 | pid_t free_pid; |
| 36 | pid_t free_tgid; |
| 37 | }; |
| 38 | |
| 39 | struct stack { |
| 40 | struct stack_record *stack_record; |
| 41 | struct stack *next; |
| 42 | }; |
| 43 | static struct stack dummy_stack; |
| 44 | static struct stack failure_stack; |
| 45 | static struct stack *stack_list; |
| 46 | static DEFINE_SPINLOCK(stack_list_lock); |
| 47 | |
| 48 | static bool page_owner_enabled __initdata; |
| 49 | DEFINE_STATIC_KEY_FALSE(page_owner_inited); |
| 50 | |
| 51 | static depot_stack_handle_t dummy_handle; |
| 52 | static depot_stack_handle_t failure_handle; |
| 53 | static depot_stack_handle_t early_handle; |
| 54 | |
| 55 | static void init_early_allocated_pages(void); |
| 56 | |
| 57 | static inline void set_current_in_page_owner(void) |
| 58 | { |
| 59 | /* |
| 60 | * Avoid recursion. |
| 61 | * |
| 62 | * We might need to allocate more memory from page_owner code, so make |
| 63 | * sure to signal it in order to avoid recursion. |
| 64 | */ |
| 65 | current->in_page_owner = 1; |
| 66 | } |
| 67 | |
| 68 | static inline void unset_current_in_page_owner(void) |
| 69 | { |
| 70 | current->in_page_owner = 0; |
| 71 | } |
| 72 | |
| 73 | static int __init early_page_owner_param(char *buf) |
| 74 | { |
| 75 | int ret = kstrtobool(buf, &page_owner_enabled); |
| 76 | |
| 77 | if (page_owner_enabled) |
| 78 | stack_depot_request_early_init(); |
| 79 | |
| 80 | return ret; |
| 81 | } |
| 82 | early_param("page_owner", early_page_owner_param); |
| 83 | |
| 84 | static __init bool need_page_owner(void) |
| 85 | { |
| 86 | return page_owner_enabled; |
| 87 | } |
| 88 | |
| 89 | static __always_inline depot_stack_handle_t create_dummy_stack(void) |
| 90 | { |
| 91 | unsigned long entries[4]; |
| 92 | unsigned int nr_entries; |
| 93 | |
| 94 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); |
| 95 | return stack_depot_save(entries, nr_entries, GFP_KERNEL); |
| 96 | } |
| 97 | |
| 98 | static noinline void register_dummy_stack(void) |
| 99 | { |
| 100 | dummy_handle = create_dummy_stack(); |
| 101 | } |
| 102 | |
| 103 | static noinline void register_failure_stack(void) |
| 104 | { |
| 105 | failure_handle = create_dummy_stack(); |
| 106 | } |
| 107 | |
| 108 | static noinline void register_early_stack(void) |
| 109 | { |
| 110 | early_handle = create_dummy_stack(); |
| 111 | } |
| 112 | |
| 113 | static __init void init_page_owner(void) |
| 114 | { |
| 115 | if (!page_owner_enabled) |
| 116 | return; |
| 117 | |
| 118 | register_dummy_stack(); |
| 119 | register_failure_stack(); |
| 120 | register_early_stack(); |
| 121 | init_early_allocated_pages(); |
| 122 | /* Initialize dummy and failure stacks and link them to stack_list */ |
| 123 | dummy_stack.stack_record = __stack_depot_get_stack_record(dummy_handle); |
| 124 | failure_stack.stack_record = __stack_depot_get_stack_record(failure_handle); |
| 125 | if (dummy_stack.stack_record) |
| 126 | refcount_set(&dummy_stack.stack_record->count, 1); |
| 127 | if (failure_stack.stack_record) |
| 128 | refcount_set(&failure_stack.stack_record->count, 1); |
| 129 | dummy_stack.next = &failure_stack; |
| 130 | stack_list = &dummy_stack; |
| 131 | static_branch_enable(&page_owner_inited); |
| 132 | } |
| 133 | |
| 134 | struct page_ext_operations page_owner_ops = { |
| 135 | .size = sizeof(struct page_owner), |
| 136 | .need = need_page_owner, |
| 137 | .init = init_page_owner, |
| 138 | .need_shared_flags = true, |
| 139 | }; |
| 140 | |
| 141 | static inline struct page_owner *get_page_owner(struct page_ext *page_ext) |
| 142 | { |
| 143 | return page_ext_data(page_ext, &page_owner_ops); |
| 144 | } |
| 145 | |
| 146 | static noinline depot_stack_handle_t save_stack(gfp_t flags) |
| 147 | { |
| 148 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; |
| 149 | depot_stack_handle_t handle; |
| 150 | unsigned int nr_entries; |
| 151 | |
| 152 | if (current->in_page_owner) |
| 153 | return dummy_handle; |
| 154 | |
| 155 | set_current_in_page_owner(); |
| 156 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2); |
| 157 | handle = stack_depot_save(entries, nr_entries, flags); |
| 158 | if (!handle) |
| 159 | handle = failure_handle; |
| 160 | unset_current_in_page_owner(); |
| 161 | |
| 162 | return handle; |
| 163 | } |
| 164 | |
| 165 | static void add_stack_record_to_list(struct stack_record *stack_record, |
| 166 | gfp_t gfp_mask) |
| 167 | { |
| 168 | unsigned long flags; |
| 169 | struct stack *stack; |
| 170 | |
| 171 | /* Filter gfp_mask the same way stackdepot does, for consistency */ |
| 172 | gfp_mask &= ~GFP_ZONEMASK; |
| 173 | gfp_mask &= (GFP_ATOMIC | GFP_KERNEL); |
| 174 | gfp_mask |= __GFP_NOWARN; |
| 175 | |
| 176 | set_current_in_page_owner(); |
| 177 | stack = kmalloc(sizeof(*stack), gfp_mask); |
| 178 | if (!stack) { |
| 179 | unset_current_in_page_owner(); |
| 180 | return; |
| 181 | } |
| 182 | unset_current_in_page_owner(); |
| 183 | |
| 184 | stack->stack_record = stack_record; |
| 185 | stack->next = NULL; |
| 186 | |
| 187 | spin_lock_irqsave(&stack_list_lock, flags); |
| 188 | stack->next = stack_list; |
| 189 | /* |
| 190 | * This pairs with smp_load_acquire() from function |
| 191 | * stack_start(). This guarantees that stack_start() |
| 192 | * will see an updated stack_list before starting to |
| 193 | * traverse the list. |
| 194 | */ |
| 195 | smp_store_release(&stack_list, stack); |
| 196 | spin_unlock_irqrestore(&stack_list_lock, flags); |
| 197 | } |
| 198 | |
| 199 | static void inc_stack_record_count(depot_stack_handle_t handle, gfp_t gfp_mask, |
| 200 | int nr_base_pages) |
| 201 | { |
| 202 | struct stack_record *stack_record = __stack_depot_get_stack_record(handle); |
| 203 | |
| 204 | if (!stack_record) |
| 205 | return; |
| 206 | |
| 207 | /* |
| 208 | * New stack_record's that do not use STACK_DEPOT_FLAG_GET start |
| 209 | * with REFCOUNT_SATURATED to catch spurious increments of their |
| 210 | * refcount. |
| 211 | * Since we do not use STACK_DEPOT_FLAG_GET API, let us |
| 212 | * set a refcount of 1 ourselves. |
| 213 | */ |
| 214 | if (refcount_read(&stack_record->count) == REFCOUNT_SATURATED) { |
| 215 | int old = REFCOUNT_SATURATED; |
| 216 | |
| 217 | if (atomic_try_cmpxchg_relaxed(&stack_record->count.refs, &old, 1)) |
| 218 | /* Add the new stack_record to our list */ |
| 219 | add_stack_record_to_list(stack_record, gfp_mask); |
| 220 | } |
| 221 | refcount_add(nr_base_pages, &stack_record->count); |
| 222 | } |
| 223 | |
| 224 | static void dec_stack_record_count(depot_stack_handle_t handle, |
| 225 | int nr_base_pages) |
| 226 | { |
| 227 | struct stack_record *stack_record = __stack_depot_get_stack_record(handle); |
| 228 | |
| 229 | if (!stack_record) |
| 230 | return; |
| 231 | |
| 232 | if (refcount_sub_and_test(nr_base_pages, &stack_record->count)) |
| 233 | pr_warn("%s: refcount went to 0 for %u handle\n", __func__, |
| 234 | handle); |
| 235 | } |
| 236 | |
| 237 | static inline void __update_page_owner_handle(struct page_ext *page_ext, |
| 238 | depot_stack_handle_t handle, |
| 239 | unsigned short order, |
| 240 | gfp_t gfp_mask, |
| 241 | short last_migrate_reason, u64 ts_nsec, |
| 242 | pid_t pid, pid_t tgid, char *comm) |
| 243 | { |
| 244 | int i; |
| 245 | struct page_owner *page_owner; |
| 246 | |
| 247 | for (i = 0; i < (1 << order); i++) { |
| 248 | page_owner = get_page_owner(page_ext); |
| 249 | page_owner->handle = handle; |
| 250 | page_owner->order = order; |
| 251 | page_owner->gfp_mask = gfp_mask; |
| 252 | page_owner->last_migrate_reason = last_migrate_reason; |
| 253 | page_owner->pid = pid; |
| 254 | page_owner->tgid = tgid; |
| 255 | page_owner->ts_nsec = ts_nsec; |
| 256 | strscpy(page_owner->comm, comm, |
| 257 | sizeof(page_owner->comm)); |
| 258 | __set_bit(PAGE_EXT_OWNER, &page_ext->flags); |
| 259 | __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); |
| 260 | page_ext = page_ext_next(page_ext); |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | static inline void __update_page_owner_free_handle(struct page_ext *page_ext, |
| 265 | depot_stack_handle_t handle, |
| 266 | unsigned short order, |
| 267 | pid_t pid, pid_t tgid, |
| 268 | u64 free_ts_nsec) |
| 269 | { |
| 270 | int i; |
| 271 | struct page_owner *page_owner; |
| 272 | |
| 273 | for (i = 0; i < (1 << order); i++) { |
| 274 | page_owner = get_page_owner(page_ext); |
| 275 | /* Only __reset_page_owner() wants to clear the bit */ |
| 276 | if (handle) { |
| 277 | __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); |
| 278 | page_owner->free_handle = handle; |
| 279 | } |
| 280 | page_owner->free_ts_nsec = free_ts_nsec; |
| 281 | page_owner->free_pid = current->pid; |
| 282 | page_owner->free_tgid = current->tgid; |
| 283 | page_ext = page_ext_next(page_ext); |
| 284 | } |
| 285 | } |
| 286 | |
| 287 | void __reset_page_owner(struct page *page, unsigned short order) |
| 288 | { |
| 289 | struct page_ext *page_ext; |
| 290 | depot_stack_handle_t handle; |
| 291 | depot_stack_handle_t alloc_handle; |
| 292 | struct page_owner *page_owner; |
| 293 | u64 free_ts_nsec = local_clock(); |
| 294 | |
| 295 | page_ext = page_ext_get(page); |
| 296 | if (unlikely(!page_ext)) |
| 297 | return; |
| 298 | |
| 299 | page_owner = get_page_owner(page_ext); |
| 300 | alloc_handle = page_owner->handle; |
| 301 | |
| 302 | handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); |
| 303 | __update_page_owner_free_handle(page_ext, handle, order, current->pid, |
| 304 | current->tgid, free_ts_nsec); |
| 305 | page_ext_put(page_ext); |
| 306 | |
| 307 | if (alloc_handle != early_handle) |
| 308 | /* |
| 309 | * early_handle is being set as a handle for all those |
| 310 | * early allocated pages. See init_pages_in_zone(). |
| 311 | * Since their refcount is not being incremented because |
| 312 | * the machinery is not ready yet, we cannot decrement |
| 313 | * their refcount either. |
| 314 | */ |
| 315 | dec_stack_record_count(alloc_handle, 1 << order); |
| 316 | } |
| 317 | |
| 318 | noinline void __set_page_owner(struct page *page, unsigned short order, |
| 319 | gfp_t gfp_mask) |
| 320 | { |
| 321 | struct page_ext *page_ext; |
| 322 | u64 ts_nsec = local_clock(); |
| 323 | depot_stack_handle_t handle; |
| 324 | |
| 325 | handle = save_stack(gfp_mask); |
| 326 | |
| 327 | page_ext = page_ext_get(page); |
| 328 | if (unlikely(!page_ext)) |
| 329 | return; |
| 330 | __update_page_owner_handle(page_ext, handle, order, gfp_mask, -1, |
| 331 | current->pid, current->tgid, ts_nsec, |
| 332 | current->comm); |
| 333 | page_ext_put(page_ext); |
| 334 | inc_stack_record_count(handle, gfp_mask, 1 << order); |
| 335 | } |
| 336 | |
| 337 | void __set_page_owner_migrate_reason(struct page *page, int reason) |
| 338 | { |
| 339 | struct page_ext *page_ext = page_ext_get(page); |
| 340 | struct page_owner *page_owner; |
| 341 | |
| 342 | if (unlikely(!page_ext)) |
| 343 | return; |
| 344 | |
| 345 | page_owner = get_page_owner(page_ext); |
| 346 | page_owner->last_migrate_reason = reason; |
| 347 | page_ext_put(page_ext); |
| 348 | } |
| 349 | |
| 350 | void __split_page_owner(struct page *page, int old_order, int new_order) |
| 351 | { |
| 352 | int i; |
| 353 | struct page_ext *page_ext = page_ext_get(page); |
| 354 | struct page_owner *page_owner; |
| 355 | |
| 356 | if (unlikely(!page_ext)) |
| 357 | return; |
| 358 | |
| 359 | for (i = 0; i < (1 << old_order); i++) { |
| 360 | page_owner = get_page_owner(page_ext); |
| 361 | page_owner->order = new_order; |
| 362 | page_ext = page_ext_next(page_ext); |
| 363 | } |
| 364 | page_ext_put(page_ext); |
| 365 | } |
| 366 | |
| 367 | void __folio_copy_owner(struct folio *newfolio, struct folio *old) |
| 368 | { |
| 369 | int i; |
| 370 | struct page_ext *old_ext; |
| 371 | struct page_ext *new_ext; |
| 372 | struct page_owner *old_page_owner; |
| 373 | struct page_owner *new_page_owner; |
| 374 | depot_stack_handle_t migrate_handle; |
| 375 | |
| 376 | old_ext = page_ext_get(&old->page); |
| 377 | if (unlikely(!old_ext)) |
| 378 | return; |
| 379 | |
| 380 | new_ext = page_ext_get(&newfolio->page); |
| 381 | if (unlikely(!new_ext)) { |
| 382 | page_ext_put(old_ext); |
| 383 | return; |
| 384 | } |
| 385 | |
| 386 | old_page_owner = get_page_owner(old_ext); |
| 387 | new_page_owner = get_page_owner(new_ext); |
| 388 | migrate_handle = new_page_owner->handle; |
| 389 | __update_page_owner_handle(new_ext, old_page_owner->handle, |
| 390 | old_page_owner->order, old_page_owner->gfp_mask, |
| 391 | old_page_owner->last_migrate_reason, |
| 392 | old_page_owner->ts_nsec, old_page_owner->pid, |
| 393 | old_page_owner->tgid, old_page_owner->comm); |
| 394 | /* |
| 395 | * Do not proactively clear PAGE_EXT_OWNER{_ALLOCATED} bits as the folio |
| 396 | * will be freed after migration. Keep them until then as they may be |
| 397 | * useful. |
| 398 | */ |
| 399 | __update_page_owner_free_handle(new_ext, 0, old_page_owner->order, |
| 400 | old_page_owner->free_pid, |
| 401 | old_page_owner->free_tgid, |
| 402 | old_page_owner->free_ts_nsec); |
| 403 | /* |
| 404 | * We linked the original stack to the new folio, we need to do the same |
| 405 | * for the new one and the old folio otherwise there will be an imbalance |
| 406 | * when subtracting those pages from the stack. |
| 407 | */ |
| 408 | for (i = 0; i < (1 << new_page_owner->order); i++) { |
| 409 | old_page_owner->handle = migrate_handle; |
| 410 | old_ext = page_ext_next(old_ext); |
| 411 | old_page_owner = get_page_owner(old_ext); |
| 412 | } |
| 413 | |
| 414 | page_ext_put(new_ext); |
| 415 | page_ext_put(old_ext); |
| 416 | } |
| 417 | |
| 418 | void pagetypeinfo_showmixedcount_print(struct seq_file *m, |
| 419 | pg_data_t *pgdat, struct zone *zone) |
| 420 | { |
| 421 | struct page *page; |
| 422 | struct page_ext *page_ext; |
| 423 | struct page_owner *page_owner; |
| 424 | unsigned long pfn, block_end_pfn; |
| 425 | unsigned long end_pfn = zone_end_pfn(zone); |
| 426 | unsigned long count[MIGRATE_TYPES] = { 0, }; |
| 427 | int pageblock_mt, page_mt; |
| 428 | int i; |
| 429 | |
| 430 | /* Scan block by block. First and last block may be incomplete */ |
| 431 | pfn = zone->zone_start_pfn; |
| 432 | |
| 433 | /* |
| 434 | * Walk the zone in pageblock_nr_pages steps. If a page block spans |
| 435 | * a zone boundary, it will be double counted between zones. This does |
| 436 | * not matter as the mixed block count will still be correct |
| 437 | */ |
| 438 | for (; pfn < end_pfn; ) { |
| 439 | page = pfn_to_online_page(pfn); |
| 440 | if (!page) { |
| 441 | pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); |
| 442 | continue; |
| 443 | } |
| 444 | |
| 445 | block_end_pfn = pageblock_end_pfn(pfn); |
| 446 | block_end_pfn = min(block_end_pfn, end_pfn); |
| 447 | |
| 448 | pageblock_mt = get_pageblock_migratetype(page); |
| 449 | |
| 450 | for (; pfn < block_end_pfn; pfn++) { |
| 451 | /* The pageblock is online, no need to recheck. */ |
| 452 | page = pfn_to_page(pfn); |
| 453 | |
| 454 | if (page_zone(page) != zone) |
| 455 | continue; |
| 456 | |
| 457 | if (PageBuddy(page)) { |
| 458 | unsigned long freepage_order; |
| 459 | |
| 460 | freepage_order = buddy_order_unsafe(page); |
| 461 | if (freepage_order <= MAX_PAGE_ORDER) |
| 462 | pfn += (1UL << freepage_order) - 1; |
| 463 | continue; |
| 464 | } |
| 465 | |
| 466 | if (PageReserved(page)) |
| 467 | continue; |
| 468 | |
| 469 | page_ext = page_ext_get(page); |
| 470 | if (unlikely(!page_ext)) |
| 471 | continue; |
| 472 | |
| 473 | if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) |
| 474 | goto ext_put_continue; |
| 475 | |
| 476 | page_owner = get_page_owner(page_ext); |
| 477 | page_mt = gfp_migratetype(page_owner->gfp_mask); |
| 478 | if (pageblock_mt != page_mt) { |
| 479 | if (is_migrate_cma(pageblock_mt)) |
| 480 | count[MIGRATE_MOVABLE]++; |
| 481 | else |
| 482 | count[pageblock_mt]++; |
| 483 | |
| 484 | pfn = block_end_pfn; |
| 485 | page_ext_put(page_ext); |
| 486 | break; |
| 487 | } |
| 488 | pfn += (1UL << page_owner->order) - 1; |
| 489 | ext_put_continue: |
| 490 | page_ext_put(page_ext); |
| 491 | } |
| 492 | } |
| 493 | |
| 494 | /* Print counts */ |
| 495 | seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); |
| 496 | for (i = 0; i < MIGRATE_TYPES; i++) |
| 497 | seq_printf(m, "%12lu ", count[i]); |
| 498 | seq_putc(m, '\n'); |
| 499 | } |
| 500 | |
| 501 | /* |
| 502 | * Looking for memcg information and print it out |
| 503 | */ |
| 504 | static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, |
| 505 | struct page *page) |
| 506 | { |
| 507 | #ifdef CONFIG_MEMCG |
| 508 | unsigned long memcg_data; |
| 509 | struct mem_cgroup *memcg; |
| 510 | bool online; |
| 511 | char name[80]; |
| 512 | |
| 513 | rcu_read_lock(); |
| 514 | memcg_data = READ_ONCE(page->memcg_data); |
| 515 | if (!memcg_data) |
| 516 | goto out_unlock; |
| 517 | |
| 518 | if (memcg_data & MEMCG_DATA_OBJCGS) |
| 519 | ret += scnprintf(kbuf + ret, count - ret, |
| 520 | "Slab cache page\n"); |
| 521 | |
| 522 | memcg = page_memcg_check(page); |
| 523 | if (!memcg) |
| 524 | goto out_unlock; |
| 525 | |
| 526 | online = (memcg->css.flags & CSS_ONLINE); |
| 527 | cgroup_name(memcg->css.cgroup, name, sizeof(name)); |
| 528 | ret += scnprintf(kbuf + ret, count - ret, |
| 529 | "Charged %sto %smemcg %s\n", |
| 530 | PageMemcgKmem(page) ? "(via objcg) " : "", |
| 531 | online ? "" : "offline ", |
| 532 | name); |
| 533 | out_unlock: |
| 534 | rcu_read_unlock(); |
| 535 | #endif /* CONFIG_MEMCG */ |
| 536 | |
| 537 | return ret; |
| 538 | } |
| 539 | |
| 540 | static ssize_t |
| 541 | print_page_owner(char __user *buf, size_t count, unsigned long pfn, |
| 542 | struct page *page, struct page_owner *page_owner, |
| 543 | depot_stack_handle_t handle) |
| 544 | { |
| 545 | int ret, pageblock_mt, page_mt; |
| 546 | char *kbuf; |
| 547 | |
| 548 | count = min_t(size_t, count, PAGE_SIZE); |
| 549 | kbuf = kmalloc(count, GFP_KERNEL); |
| 550 | if (!kbuf) |
| 551 | return -ENOMEM; |
| 552 | |
| 553 | ret = scnprintf(kbuf, count, |
| 554 | "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n", |
| 555 | page_owner->order, page_owner->gfp_mask, |
| 556 | &page_owner->gfp_mask, page_owner->pid, |
| 557 | page_owner->tgid, page_owner->comm, |
| 558 | page_owner->ts_nsec); |
| 559 | |
| 560 | /* Print information relevant to grouping pages by mobility */ |
| 561 | pageblock_mt = get_pageblock_migratetype(page); |
| 562 | page_mt = gfp_migratetype(page_owner->gfp_mask); |
| 563 | ret += scnprintf(kbuf + ret, count - ret, |
| 564 | "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n", |
| 565 | pfn, |
| 566 | migratetype_names[page_mt], |
| 567 | pfn >> pageblock_order, |
| 568 | migratetype_names[pageblock_mt], |
| 569 | &page->flags); |
| 570 | |
| 571 | ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0); |
| 572 | if (ret >= count) |
| 573 | goto err; |
| 574 | |
| 575 | if (page_owner->last_migrate_reason != -1) { |
| 576 | ret += scnprintf(kbuf + ret, count - ret, |
| 577 | "Page has been migrated, last migrate reason: %s\n", |
| 578 | migrate_reason_names[page_owner->last_migrate_reason]); |
| 579 | } |
| 580 | |
| 581 | ret = print_page_owner_memcg(kbuf, count, ret, page); |
| 582 | |
| 583 | ret += snprintf(kbuf + ret, count - ret, "\n"); |
| 584 | if (ret >= count) |
| 585 | goto err; |
| 586 | |
| 587 | if (copy_to_user(buf, kbuf, ret)) |
| 588 | ret = -EFAULT; |
| 589 | |
| 590 | kfree(kbuf); |
| 591 | return ret; |
| 592 | |
| 593 | err: |
| 594 | kfree(kbuf); |
| 595 | return -ENOMEM; |
| 596 | } |
| 597 | |
| 598 | void __dump_page_owner(const struct page *page) |
| 599 | { |
| 600 | struct page_ext *page_ext = page_ext_get((void *)page); |
| 601 | struct page_owner *page_owner; |
| 602 | depot_stack_handle_t handle; |
| 603 | gfp_t gfp_mask; |
| 604 | int mt; |
| 605 | |
| 606 | if (unlikely(!page_ext)) { |
| 607 | pr_alert("There is not page extension available.\n"); |
| 608 | return; |
| 609 | } |
| 610 | |
| 611 | page_owner = get_page_owner(page_ext); |
| 612 | gfp_mask = page_owner->gfp_mask; |
| 613 | mt = gfp_migratetype(gfp_mask); |
| 614 | |
| 615 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { |
| 616 | pr_alert("page_owner info is not present (never set?)\n"); |
| 617 | page_ext_put(page_ext); |
| 618 | return; |
| 619 | } |
| 620 | |
| 621 | if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) |
| 622 | pr_alert("page_owner tracks the page as allocated\n"); |
| 623 | else |
| 624 | pr_alert("page_owner tracks the page as freed\n"); |
| 625 | |
| 626 | pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu, free_ts %llu\n", |
| 627 | page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask, |
| 628 | page_owner->pid, page_owner->tgid, page_owner->comm, |
| 629 | page_owner->ts_nsec, page_owner->free_ts_nsec); |
| 630 | |
| 631 | handle = READ_ONCE(page_owner->handle); |
| 632 | if (!handle) |
| 633 | pr_alert("page_owner allocation stack trace missing\n"); |
| 634 | else |
| 635 | stack_depot_print(handle); |
| 636 | |
| 637 | handle = READ_ONCE(page_owner->free_handle); |
| 638 | if (!handle) { |
| 639 | pr_alert("page_owner free stack trace missing\n"); |
| 640 | } else { |
| 641 | pr_alert("page last free pid %d tgid %d stack trace:\n", |
| 642 | page_owner->free_pid, page_owner->free_tgid); |
| 643 | stack_depot_print(handle); |
| 644 | } |
| 645 | |
| 646 | if (page_owner->last_migrate_reason != -1) |
| 647 | pr_alert("page has been migrated, last migrate reason: %s\n", |
| 648 | migrate_reason_names[page_owner->last_migrate_reason]); |
| 649 | page_ext_put(page_ext); |
| 650 | } |
| 651 | |
| 652 | static ssize_t |
| 653 | read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| 654 | { |
| 655 | unsigned long pfn; |
| 656 | struct page *page; |
| 657 | struct page_ext *page_ext; |
| 658 | struct page_owner *page_owner; |
| 659 | depot_stack_handle_t handle; |
| 660 | |
| 661 | if (!static_branch_unlikely(&page_owner_inited)) |
| 662 | return -EINVAL; |
| 663 | |
| 664 | page = NULL; |
| 665 | if (*ppos == 0) |
| 666 | pfn = min_low_pfn; |
| 667 | else |
| 668 | pfn = *ppos; |
| 669 | /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ |
| 670 | while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) |
| 671 | pfn++; |
| 672 | |
| 673 | /* Find an allocated page */ |
| 674 | for (; pfn < max_pfn; pfn++) { |
| 675 | /* |
| 676 | * This temporary page_owner is required so |
| 677 | * that we can avoid the context switches while holding |
| 678 | * the rcu lock and copying the page owner information to |
| 679 | * user through copy_to_user() or GFP_KERNEL allocations. |
| 680 | */ |
| 681 | struct page_owner page_owner_tmp; |
| 682 | |
| 683 | /* |
| 684 | * If the new page is in a new MAX_ORDER_NR_PAGES area, |
| 685 | * validate the area as existing, skip it if not |
| 686 | */ |
| 687 | if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { |
| 688 | pfn += MAX_ORDER_NR_PAGES - 1; |
| 689 | continue; |
| 690 | } |
| 691 | |
| 692 | page = pfn_to_page(pfn); |
| 693 | if (PageBuddy(page)) { |
| 694 | unsigned long freepage_order = buddy_order_unsafe(page); |
| 695 | |
| 696 | if (freepage_order <= MAX_PAGE_ORDER) |
| 697 | pfn += (1UL << freepage_order) - 1; |
| 698 | continue; |
| 699 | } |
| 700 | |
| 701 | page_ext = page_ext_get(page); |
| 702 | if (unlikely(!page_ext)) |
| 703 | continue; |
| 704 | |
| 705 | /* |
| 706 | * Some pages could be missed by concurrent allocation or free, |
| 707 | * because we don't hold the zone lock. |
| 708 | */ |
| 709 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) |
| 710 | goto ext_put_continue; |
| 711 | |
| 712 | /* |
| 713 | * Although we do have the info about past allocation of free |
| 714 | * pages, it's not relevant for current memory usage. |
| 715 | */ |
| 716 | if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) |
| 717 | goto ext_put_continue; |
| 718 | |
| 719 | page_owner = get_page_owner(page_ext); |
| 720 | |
| 721 | /* |
| 722 | * Don't print "tail" pages of high-order allocations as that |
| 723 | * would inflate the stats. |
| 724 | */ |
| 725 | if (!IS_ALIGNED(pfn, 1 << page_owner->order)) |
| 726 | goto ext_put_continue; |
| 727 | |
| 728 | /* |
| 729 | * Access to page_ext->handle isn't synchronous so we should |
| 730 | * be careful to access it. |
| 731 | */ |
| 732 | handle = READ_ONCE(page_owner->handle); |
| 733 | if (!handle) |
| 734 | goto ext_put_continue; |
| 735 | |
| 736 | /* Record the next PFN to read in the file offset */ |
| 737 | *ppos = pfn + 1; |
| 738 | |
| 739 | page_owner_tmp = *page_owner; |
| 740 | page_ext_put(page_ext); |
| 741 | return print_page_owner(buf, count, pfn, page, |
| 742 | &page_owner_tmp, handle); |
| 743 | ext_put_continue: |
| 744 | page_ext_put(page_ext); |
| 745 | } |
| 746 | |
| 747 | return 0; |
| 748 | } |
| 749 | |
| 750 | static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig) |
| 751 | { |
| 752 | switch (orig) { |
| 753 | case SEEK_SET: |
| 754 | file->f_pos = offset; |
| 755 | break; |
| 756 | case SEEK_CUR: |
| 757 | file->f_pos += offset; |
| 758 | break; |
| 759 | default: |
| 760 | return -EINVAL; |
| 761 | } |
| 762 | return file->f_pos; |
| 763 | } |
| 764 | |
| 765 | static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) |
| 766 | { |
| 767 | unsigned long pfn = zone->zone_start_pfn; |
| 768 | unsigned long end_pfn = zone_end_pfn(zone); |
| 769 | unsigned long count = 0; |
| 770 | |
| 771 | /* |
| 772 | * Walk the zone in pageblock_nr_pages steps. If a page block spans |
| 773 | * a zone boundary, it will be double counted between zones. This does |
| 774 | * not matter as the mixed block count will still be correct |
| 775 | */ |
| 776 | for (; pfn < end_pfn; ) { |
| 777 | unsigned long block_end_pfn; |
| 778 | |
| 779 | if (!pfn_valid(pfn)) { |
| 780 | pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); |
| 781 | continue; |
| 782 | } |
| 783 | |
| 784 | block_end_pfn = pageblock_end_pfn(pfn); |
| 785 | block_end_pfn = min(block_end_pfn, end_pfn); |
| 786 | |
| 787 | for (; pfn < block_end_pfn; pfn++) { |
| 788 | struct page *page = pfn_to_page(pfn); |
| 789 | struct page_ext *page_ext; |
| 790 | |
| 791 | if (page_zone(page) != zone) |
| 792 | continue; |
| 793 | |
| 794 | /* |
| 795 | * To avoid having to grab zone->lock, be a little |
| 796 | * careful when reading buddy page order. The only |
| 797 | * danger is that we skip too much and potentially miss |
| 798 | * some early allocated pages, which is better than |
| 799 | * heavy lock contention. |
| 800 | */ |
| 801 | if (PageBuddy(page)) { |
| 802 | unsigned long order = buddy_order_unsafe(page); |
| 803 | |
| 804 | if (order > 0 && order <= MAX_PAGE_ORDER) |
| 805 | pfn += (1UL << order) - 1; |
| 806 | continue; |
| 807 | } |
| 808 | |
| 809 | if (PageReserved(page)) |
| 810 | continue; |
| 811 | |
| 812 | page_ext = page_ext_get(page); |
| 813 | if (unlikely(!page_ext)) |
| 814 | continue; |
| 815 | |
| 816 | /* Maybe overlapping zone */ |
| 817 | if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) |
| 818 | goto ext_put_continue; |
| 819 | |
| 820 | /* Found early allocated page */ |
| 821 | __update_page_owner_handle(page_ext, early_handle, 0, 0, |
| 822 | -1, local_clock(), current->pid, |
| 823 | current->tgid, current->comm); |
| 824 | count++; |
| 825 | ext_put_continue: |
| 826 | page_ext_put(page_ext); |
| 827 | } |
| 828 | cond_resched(); |
| 829 | } |
| 830 | |
| 831 | pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n", |
| 832 | pgdat->node_id, zone->name, count); |
| 833 | } |
| 834 | |
| 835 | static void init_zones_in_node(pg_data_t *pgdat) |
| 836 | { |
| 837 | struct zone *zone; |
| 838 | struct zone *node_zones = pgdat->node_zones; |
| 839 | |
| 840 | for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { |
| 841 | if (!populated_zone(zone)) |
| 842 | continue; |
| 843 | |
| 844 | init_pages_in_zone(pgdat, zone); |
| 845 | } |
| 846 | } |
| 847 | |
| 848 | static void init_early_allocated_pages(void) |
| 849 | { |
| 850 | pg_data_t *pgdat; |
| 851 | |
| 852 | for_each_online_pgdat(pgdat) |
| 853 | init_zones_in_node(pgdat); |
| 854 | } |
| 855 | |
| 856 | static const struct file_operations proc_page_owner_operations = { |
| 857 | .read = read_page_owner, |
| 858 | .llseek = lseek_page_owner, |
| 859 | }; |
| 860 | |
| 861 | static void *stack_start(struct seq_file *m, loff_t *ppos) |
| 862 | { |
| 863 | struct stack *stack; |
| 864 | |
| 865 | if (*ppos == -1UL) |
| 866 | return NULL; |
| 867 | |
| 868 | if (!*ppos) { |
| 869 | /* |
| 870 | * This pairs with smp_store_release() from function |
| 871 | * add_stack_record_to_list(), so we get a consistent |
| 872 | * value of stack_list. |
| 873 | */ |
| 874 | stack = smp_load_acquire(&stack_list); |
| 875 | m->private = stack; |
| 876 | } else { |
| 877 | stack = m->private; |
| 878 | } |
| 879 | |
| 880 | return stack; |
| 881 | } |
| 882 | |
| 883 | static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) |
| 884 | { |
| 885 | struct stack *stack = v; |
| 886 | |
| 887 | stack = stack->next; |
| 888 | *ppos = stack ? *ppos + 1 : -1UL; |
| 889 | m->private = stack; |
| 890 | |
| 891 | return stack; |
| 892 | } |
| 893 | |
| 894 | static unsigned long page_owner_pages_threshold; |
| 895 | |
| 896 | static int stack_print(struct seq_file *m, void *v) |
| 897 | { |
| 898 | int i, nr_base_pages; |
| 899 | struct stack *stack = v; |
| 900 | unsigned long *entries; |
| 901 | unsigned long nr_entries; |
| 902 | struct stack_record *stack_record = stack->stack_record; |
| 903 | |
| 904 | if (!stack->stack_record) |
| 905 | return 0; |
| 906 | |
| 907 | nr_entries = stack_record->size; |
| 908 | entries = stack_record->entries; |
| 909 | nr_base_pages = refcount_read(&stack_record->count) - 1; |
| 910 | |
| 911 | if (nr_base_pages < 1 || nr_base_pages < page_owner_pages_threshold) |
| 912 | return 0; |
| 913 | |
| 914 | for (i = 0; i < nr_entries; i++) |
| 915 | seq_printf(m, " %pS\n", (void *)entries[i]); |
| 916 | seq_printf(m, "nr_base_pages: %d\n\n", nr_base_pages); |
| 917 | |
| 918 | return 0; |
| 919 | } |
| 920 | |
| 921 | static void stack_stop(struct seq_file *m, void *v) |
| 922 | { |
| 923 | } |
| 924 | |
| 925 | static const struct seq_operations page_owner_stack_op = { |
| 926 | .start = stack_start, |
| 927 | .next = stack_next, |
| 928 | .stop = stack_stop, |
| 929 | .show = stack_print |
| 930 | }; |
| 931 | |
| 932 | static int page_owner_stack_open(struct inode *inode, struct file *file) |
| 933 | { |
| 934 | return seq_open_private(file, &page_owner_stack_op, 0); |
| 935 | } |
| 936 | |
| 937 | static const struct file_operations page_owner_stack_operations = { |
| 938 | .open = page_owner_stack_open, |
| 939 | .read = seq_read, |
| 940 | .llseek = seq_lseek, |
| 941 | .release = seq_release, |
| 942 | }; |
| 943 | |
| 944 | static int page_owner_threshold_get(void *data, u64 *val) |
| 945 | { |
| 946 | *val = READ_ONCE(page_owner_pages_threshold); |
| 947 | return 0; |
| 948 | } |
| 949 | |
| 950 | static int page_owner_threshold_set(void *data, u64 val) |
| 951 | { |
| 952 | WRITE_ONCE(page_owner_pages_threshold, val); |
| 953 | return 0; |
| 954 | } |
| 955 | |
| 956 | DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get, |
| 957 | &page_owner_threshold_set, "%llu"); |
| 958 | |
| 959 | |
| 960 | static int __init pageowner_init(void) |
| 961 | { |
| 962 | struct dentry *dir; |
| 963 | |
| 964 | if (!static_branch_unlikely(&page_owner_inited)) { |
| 965 | pr_info("page_owner is disabled\n"); |
| 966 | return 0; |
| 967 | } |
| 968 | |
| 969 | debugfs_create_file("page_owner", 0400, NULL, NULL, |
| 970 | &proc_page_owner_operations); |
| 971 | dir = debugfs_create_dir("page_owner_stacks", NULL); |
| 972 | debugfs_create_file("show_stacks", 0400, dir, NULL, |
| 973 | &page_owner_stack_operations); |
| 974 | debugfs_create_file("count_threshold", 0600, dir, NULL, |
| 975 | &proc_page_owner_threshold); |
| 976 | |
| 977 | return 0; |
| 978 | } |
| 979 | late_initcall(pageowner_init) |