| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/debugfs.h> |
| #include <linux/mm.h> |
| #include <linux/slab.h> |
| #include <linux/uaccess.h> |
| #include <linux/memblock.h> |
| #include <linux/stacktrace.h> |
| #include <linux/page_owner.h> |
| #include <linux/jump_label.h> |
| #include <linux/migrate.h> |
| #include <linux/stackdepot.h> |
| #include <linux/seq_file.h> |
| #include <linux/memcontrol.h> |
| #include <linux/sched/clock.h> |
| |
| #include "internal.h" |
| |
| /* |
| * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) |
| * to use off stack temporal storage |
| */ |
| #define PAGE_OWNER_STACK_DEPTH (16) |
| |
| struct page_owner { |
| unsigned short order; |
| short last_migrate_reason; |
| gfp_t gfp_mask; |
| depot_stack_handle_t handle; |
| depot_stack_handle_t free_handle; |
| u64 ts_nsec; |
| u64 free_ts_nsec; |
| char comm[TASK_COMM_LEN]; |
| pid_t pid; |
| pid_t tgid; |
| pid_t free_pid; |
| pid_t free_tgid; |
| }; |
| |
| struct stack { |
| struct stack_record *stack_record; |
| struct stack *next; |
| }; |
| static struct stack dummy_stack; |
| static struct stack failure_stack; |
| static struct stack *stack_list; |
| static DEFINE_SPINLOCK(stack_list_lock); |
| |
| static bool page_owner_enabled __initdata; |
| DEFINE_STATIC_KEY_FALSE(page_owner_inited); |
| |
| static depot_stack_handle_t dummy_handle; |
| static depot_stack_handle_t failure_handle; |
| static depot_stack_handle_t early_handle; |
| |
| static void init_early_allocated_pages(void); |
| |
| static inline void set_current_in_page_owner(void) |
| { |
| /* |
| * Avoid recursion. |
| * |
| * We might need to allocate more memory from page_owner code, so make |
| * sure to signal it in order to avoid recursion. |
| */ |
| current->in_page_owner = 1; |
| } |
| |
| static inline void unset_current_in_page_owner(void) |
| { |
| current->in_page_owner = 0; |
| } |
| |
| static int __init early_page_owner_param(char *buf) |
| { |
| int ret = kstrtobool(buf, &page_owner_enabled); |
| |
| if (page_owner_enabled) |
| stack_depot_request_early_init(); |
| |
| return ret; |
| } |
| early_param("page_owner", early_page_owner_param); |
| |
| static __init bool need_page_owner(void) |
| { |
| return page_owner_enabled; |
| } |
| |
| static __always_inline depot_stack_handle_t create_dummy_stack(void) |
| { |
| unsigned long entries[4]; |
| unsigned int nr_entries; |
| |
| nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); |
| return stack_depot_save(entries, nr_entries, GFP_KERNEL); |
| } |
| |
| static noinline void register_dummy_stack(void) |
| { |
| dummy_handle = create_dummy_stack(); |
| } |
| |
| static noinline void register_failure_stack(void) |
| { |
| failure_handle = create_dummy_stack(); |
| } |
| |
| static noinline void register_early_stack(void) |
| { |
| early_handle = create_dummy_stack(); |
| } |
| |
| static __init void init_page_owner(void) |
| { |
| if (!page_owner_enabled) |
| return; |
| |
| register_dummy_stack(); |
| register_failure_stack(); |
| register_early_stack(); |
| init_early_allocated_pages(); |
| /* Initialize dummy and failure stacks and link them to stack_list */ |
| dummy_stack.stack_record = __stack_depot_get_stack_record(dummy_handle); |
| failure_stack.stack_record = __stack_depot_get_stack_record(failure_handle); |
| if (dummy_stack.stack_record) |
| refcount_set(&dummy_stack.stack_record->count, 1); |
| if (failure_stack.stack_record) |
| refcount_set(&failure_stack.stack_record->count, 1); |
| dummy_stack.next = &failure_stack; |
| stack_list = &dummy_stack; |
| static_branch_enable(&page_owner_inited); |
| } |
| |
| struct page_ext_operations page_owner_ops = { |
| .size = sizeof(struct page_owner), |
| .need = need_page_owner, |
| .init = init_page_owner, |
| .need_shared_flags = true, |
| }; |
| |
| static inline struct page_owner *get_page_owner(struct page_ext *page_ext) |
| { |
| return page_ext_data(page_ext, &page_owner_ops); |
| } |
| |
| static noinline depot_stack_handle_t save_stack(gfp_t flags) |
| { |
| unsigned long entries[PAGE_OWNER_STACK_DEPTH]; |
| depot_stack_handle_t handle; |
| unsigned int nr_entries; |
| |
| if (current->in_page_owner) |
| return dummy_handle; |
| |
| set_current_in_page_owner(); |
| nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2); |
| handle = stack_depot_save(entries, nr_entries, flags); |
| if (!handle) |
| handle = failure_handle; |
| unset_current_in_page_owner(); |
| |
| return handle; |
| } |
| |
| static void add_stack_record_to_list(struct stack_record *stack_record, |
| gfp_t gfp_mask) |
| { |
| unsigned long flags; |
| struct stack *stack; |
| |
| /* Filter gfp_mask the same way stackdepot does, for consistency */ |
| gfp_mask &= ~GFP_ZONEMASK; |
| gfp_mask &= (GFP_ATOMIC | GFP_KERNEL | __GFP_NOLOCKDEP); |
| gfp_mask |= __GFP_NOWARN; |
| |
| set_current_in_page_owner(); |
| stack = kmalloc(sizeof(*stack), gfp_mask); |
| if (!stack) { |
| unset_current_in_page_owner(); |
| return; |
| } |
| unset_current_in_page_owner(); |
| |
| stack->stack_record = stack_record; |
| stack->next = NULL; |
| |
| spin_lock_irqsave(&stack_list_lock, flags); |
| stack->next = stack_list; |
| /* |
| * This pairs with smp_load_acquire() from function |
| * stack_start(). This guarantees that stack_start() |
| * will see an updated stack_list before starting to |
| * traverse the list. |
| */ |
| smp_store_release(&stack_list, stack); |
| spin_unlock_irqrestore(&stack_list_lock, flags); |
| } |
| |
| static void inc_stack_record_count(depot_stack_handle_t handle, gfp_t gfp_mask, |
| int nr_base_pages) |
| { |
| struct stack_record *stack_record = __stack_depot_get_stack_record(handle); |
| |
| if (!stack_record) |
| return; |
| |
| /* |
| * New stack_record's that do not use STACK_DEPOT_FLAG_GET start |
| * with REFCOUNT_SATURATED to catch spurious increments of their |
| * refcount. |
| * Since we do not use STACK_DEPOT_FLAG_GET API, let us |
| * set a refcount of 1 ourselves. |
| */ |
| if (refcount_read(&stack_record->count) == REFCOUNT_SATURATED) { |
| int old = REFCOUNT_SATURATED; |
| |
| if (atomic_try_cmpxchg_relaxed(&stack_record->count.refs, &old, 1)) |
| /* Add the new stack_record to our list */ |
| add_stack_record_to_list(stack_record, gfp_mask); |
| } |
| refcount_add(nr_base_pages, &stack_record->count); |
| } |
| |
| static void dec_stack_record_count(depot_stack_handle_t handle, |
| int nr_base_pages) |
| { |
| struct stack_record *stack_record = __stack_depot_get_stack_record(handle); |
| |
| if (!stack_record) |
| return; |
| |
| if (refcount_sub_and_test(nr_base_pages, &stack_record->count)) |
| pr_warn("%s: refcount went to 0 for %u handle\n", __func__, |
| handle); |
| } |
| |
| static inline void __update_page_owner_handle(struct page_ext *page_ext, |
| depot_stack_handle_t handle, |
| unsigned short order, |
| gfp_t gfp_mask, |
| short last_migrate_reason, u64 ts_nsec, |
| pid_t pid, pid_t tgid, char *comm) |
| { |
| int i; |
| struct page_owner *page_owner; |
| |
| for (i = 0; i < (1 << order); i++) { |
| page_owner = get_page_owner(page_ext); |
| page_owner->handle = handle; |
| page_owner->order = order; |
| page_owner->gfp_mask = gfp_mask; |
| page_owner->last_migrate_reason = last_migrate_reason; |
| page_owner->pid = pid; |
| page_owner->tgid = tgid; |
| page_owner->ts_nsec = ts_nsec; |
| strscpy(page_owner->comm, comm, |
| sizeof(page_owner->comm)); |
| __set_bit(PAGE_EXT_OWNER, &page_ext->flags); |
| __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); |
| page_ext = page_ext_next(page_ext); |
| } |
| } |
| |
| static inline void __update_page_owner_free_handle(struct page_ext *page_ext, |
| depot_stack_handle_t handle, |
| unsigned short order, |
| pid_t pid, pid_t tgid, |
| u64 free_ts_nsec) |
| { |
| int i; |
| struct page_owner *page_owner; |
| |
| for (i = 0; i < (1 << order); i++) { |
| page_owner = get_page_owner(page_ext); |
| /* Only __reset_page_owner() wants to clear the bit */ |
| if (handle) { |
| __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); |
| page_owner->free_handle = handle; |
| } |
| page_owner->free_ts_nsec = free_ts_nsec; |
| page_owner->free_pid = current->pid; |
| page_owner->free_tgid = current->tgid; |
| page_ext = page_ext_next(page_ext); |
| } |
| } |
| |
| void __reset_page_owner(struct page *page, unsigned short order) |
| { |
| struct page_ext *page_ext; |
| depot_stack_handle_t handle; |
| depot_stack_handle_t alloc_handle; |
| struct page_owner *page_owner; |
| u64 free_ts_nsec = local_clock(); |
| |
| page_ext = page_ext_get(page); |
| if (unlikely(!page_ext)) |
| return; |
| |
| page_owner = get_page_owner(page_ext); |
| alloc_handle = page_owner->handle; |
| |
| handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); |
| __update_page_owner_free_handle(page_ext, handle, order, current->pid, |
| current->tgid, free_ts_nsec); |
| page_ext_put(page_ext); |
| |
| if (alloc_handle != early_handle) |
| /* |
| * early_handle is being set as a handle for all those |
| * early allocated pages. See init_pages_in_zone(). |
| * Since their refcount is not being incremented because |
| * the machinery is not ready yet, we cannot decrement |
| * their refcount either. |
| */ |
| dec_stack_record_count(alloc_handle, 1 << order); |
| } |
| |
| noinline void __set_page_owner(struct page *page, unsigned short order, |
| gfp_t gfp_mask) |
| { |
| struct page_ext *page_ext; |
| u64 ts_nsec = local_clock(); |
| depot_stack_handle_t handle; |
| |
| handle = save_stack(gfp_mask); |
| |
| page_ext = page_ext_get(page); |
| if (unlikely(!page_ext)) |
| return; |
| __update_page_owner_handle(page_ext, handle, order, gfp_mask, -1, |
| ts_nsec, current->pid, current->tgid, |
| current->comm); |
| page_ext_put(page_ext); |
| inc_stack_record_count(handle, gfp_mask, 1 << order); |
| } |
| |
| void __set_page_owner_migrate_reason(struct page *page, int reason) |
| { |
| struct page_ext *page_ext = page_ext_get(page); |
| struct page_owner *page_owner; |
| |
| if (unlikely(!page_ext)) |
| return; |
| |
| page_owner = get_page_owner(page_ext); |
| page_owner->last_migrate_reason = reason; |
| page_ext_put(page_ext); |
| } |
| |
| void __split_page_owner(struct page *page, int old_order, int new_order) |
| { |
| int i; |
| struct page_ext *page_ext = page_ext_get(page); |
| struct page_owner *page_owner; |
| |
| if (unlikely(!page_ext)) |
| return; |
| |
| for (i = 0; i < (1 << old_order); i++) { |
| page_owner = get_page_owner(page_ext); |
| page_owner->order = new_order; |
| page_ext = page_ext_next(page_ext); |
| } |
| page_ext_put(page_ext); |
| } |
| |
| void __folio_copy_owner(struct folio *newfolio, struct folio *old) |
| { |
| int i; |
| struct page_ext *old_ext; |
| struct page_ext *new_ext; |
| struct page_owner *old_page_owner; |
| struct page_owner *new_page_owner; |
| depot_stack_handle_t migrate_handle; |
| |
| old_ext = page_ext_get(&old->page); |
| if (unlikely(!old_ext)) |
| return; |
| |
| new_ext = page_ext_get(&newfolio->page); |
| if (unlikely(!new_ext)) { |
| page_ext_put(old_ext); |
| return; |
| } |
| |
| old_page_owner = get_page_owner(old_ext); |
| new_page_owner = get_page_owner(new_ext); |
| migrate_handle = new_page_owner->handle; |
| __update_page_owner_handle(new_ext, old_page_owner->handle, |
| old_page_owner->order, old_page_owner->gfp_mask, |
| old_page_owner->last_migrate_reason, |
| old_page_owner->ts_nsec, old_page_owner->pid, |
| old_page_owner->tgid, old_page_owner->comm); |
| /* |
| * Do not proactively clear PAGE_EXT_OWNER{_ALLOCATED} bits as the folio |
| * will be freed after migration. Keep them until then as they may be |
| * useful. |
| */ |
| __update_page_owner_free_handle(new_ext, 0, old_page_owner->order, |
| old_page_owner->free_pid, |
| old_page_owner->free_tgid, |
| old_page_owner->free_ts_nsec); |
| /* |
| * We linked the original stack to the new folio, we need to do the same |
| * for the new one and the old folio otherwise there will be an imbalance |
| * when subtracting those pages from the stack. |
| */ |
| for (i = 0; i < (1 << new_page_owner->order); i++) { |
| old_page_owner->handle = migrate_handle; |
| old_ext = page_ext_next(old_ext); |
| old_page_owner = get_page_owner(old_ext); |
| } |
| |
| page_ext_put(new_ext); |
| page_ext_put(old_ext); |
| } |
| |
| void pagetypeinfo_showmixedcount_print(struct seq_file *m, |
| pg_data_t *pgdat, struct zone *zone) |
| { |
| struct page *page; |
| struct page_ext *page_ext; |
| struct page_owner *page_owner; |
| unsigned long pfn, block_end_pfn; |
| unsigned long end_pfn = zone_end_pfn(zone); |
| unsigned long count[MIGRATE_TYPES] = { 0, }; |
| int pageblock_mt, page_mt; |
| int i; |
| |
| /* Scan block by block. First and last block may be incomplete */ |
| pfn = zone->zone_start_pfn; |
| |
| /* |
| * Walk the zone in pageblock_nr_pages steps. If a page block spans |
| * a zone boundary, it will be double counted between zones. This does |
| * not matter as the mixed block count will still be correct |
| */ |
| for (; pfn < end_pfn; ) { |
| page = pfn_to_online_page(pfn); |
| if (!page) { |
| pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); |
| continue; |
| } |
| |
| block_end_pfn = pageblock_end_pfn(pfn); |
| block_end_pfn = min(block_end_pfn, end_pfn); |
| |
| pageblock_mt = get_pageblock_migratetype(page); |
| |
| for (; pfn < block_end_pfn; pfn++) { |
| /* The pageblock is online, no need to recheck. */ |
| page = pfn_to_page(pfn); |
| |
| if (page_zone(page) != zone) |
| continue; |
| |
| if (PageBuddy(page)) { |
| unsigned long freepage_order; |
| |
| freepage_order = buddy_order_unsafe(page); |
| if (freepage_order <= MAX_PAGE_ORDER) |
| pfn += (1UL << freepage_order) - 1; |
| continue; |
| } |
| |
| if (PageReserved(page)) |
| continue; |
| |
| page_ext = page_ext_get(page); |
| if (unlikely(!page_ext)) |
| continue; |
| |
| if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) |
| goto ext_put_continue; |
| |
| page_owner = get_page_owner(page_ext); |
| page_mt = gfp_migratetype(page_owner->gfp_mask); |
| if (pageblock_mt != page_mt) { |
| if (is_migrate_cma(pageblock_mt)) |
| count[MIGRATE_MOVABLE]++; |
| else |
| count[pageblock_mt]++; |
| |
| pfn = block_end_pfn; |
| page_ext_put(page_ext); |
| break; |
| } |
| pfn += (1UL << page_owner->order) - 1; |
| ext_put_continue: |
| page_ext_put(page_ext); |
| } |
| } |
| |
| /* Print counts */ |
| seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); |
| for (i = 0; i < MIGRATE_TYPES; i++) |
| seq_printf(m, "%12lu ", count[i]); |
| seq_putc(m, '\n'); |
| } |
| |
| /* |
| * Looking for memcg information and print it out |
| */ |
| static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, |
| struct page *page) |
| { |
| #ifdef CONFIG_MEMCG |
| unsigned long memcg_data; |
| struct mem_cgroup *memcg; |
| bool online; |
| char name[80]; |
| |
| rcu_read_lock(); |
| memcg_data = READ_ONCE(page->memcg_data); |
| if (!memcg_data) |
| goto out_unlock; |
| |
| if (memcg_data & MEMCG_DATA_OBJCGS) |
| ret += scnprintf(kbuf + ret, count - ret, |
| "Slab cache page\n"); |
| |
| memcg = page_memcg_check(page); |
| if (!memcg) |
| goto out_unlock; |
| |
| online = (memcg->css.flags & CSS_ONLINE); |
| cgroup_name(memcg->css.cgroup, name, sizeof(name)); |
| ret += scnprintf(kbuf + ret, count - ret, |
| "Charged %sto %smemcg %s\n", |
| PageMemcgKmem(page) ? "(via objcg) " : "", |
| online ? "" : "offline ", |
| name); |
| out_unlock: |
| rcu_read_unlock(); |
| #endif /* CONFIG_MEMCG */ |
| |
| return ret; |
| } |
| |
| static ssize_t |
| print_page_owner(char __user *buf, size_t count, unsigned long pfn, |
| struct page *page, struct page_owner *page_owner, |
| depot_stack_handle_t handle) |
| { |
| int ret, pageblock_mt, page_mt; |
| char *kbuf; |
| |
| count = min_t(size_t, count, PAGE_SIZE); |
| kbuf = kmalloc(count, GFP_KERNEL); |
| if (!kbuf) |
| return -ENOMEM; |
| |
| ret = scnprintf(kbuf, count, |
| "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n", |
| page_owner->order, page_owner->gfp_mask, |
| &page_owner->gfp_mask, page_owner->pid, |
| page_owner->tgid, page_owner->comm, |
| page_owner->ts_nsec); |
| |
| /* Print information relevant to grouping pages by mobility */ |
| pageblock_mt = get_pageblock_migratetype(page); |
| page_mt = gfp_migratetype(page_owner->gfp_mask); |
| ret += scnprintf(kbuf + ret, count - ret, |
| "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n", |
| pfn, |
| migratetype_names[page_mt], |
| pfn >> pageblock_order, |
| migratetype_names[pageblock_mt], |
| &page->flags); |
| |
| ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0); |
| if (ret >= count) |
| goto err; |
| |
| if (page_owner->last_migrate_reason != -1) { |
| ret += scnprintf(kbuf + ret, count - ret, |
| "Page has been migrated, last migrate reason: %s\n", |
| migrate_reason_names[page_owner->last_migrate_reason]); |
| } |
| |
| ret = print_page_owner_memcg(kbuf, count, ret, page); |
| |
| ret += snprintf(kbuf + ret, count - ret, "\n"); |
| if (ret >= count) |
| goto err; |
| |
| if (copy_to_user(buf, kbuf, ret)) |
| ret = -EFAULT; |
| |
| kfree(kbuf); |
| return ret; |
| |
| err: |
| kfree(kbuf); |
| return -ENOMEM; |
| } |
| |
| void __dump_page_owner(const struct page *page) |
| { |
| struct page_ext *page_ext = page_ext_get((void *)page); |
| struct page_owner *page_owner; |
| depot_stack_handle_t handle; |
| gfp_t gfp_mask; |
| int mt; |
| |
| if (unlikely(!page_ext)) { |
| pr_alert("There is not page extension available.\n"); |
| return; |
| } |
| |
| page_owner = get_page_owner(page_ext); |
| gfp_mask = page_owner->gfp_mask; |
| mt = gfp_migratetype(gfp_mask); |
| |
| if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { |
| pr_alert("page_owner info is not present (never set?)\n"); |
| page_ext_put(page_ext); |
| return; |
| } |
| |
| if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) |
| pr_alert("page_owner tracks the page as allocated\n"); |
| else |
| pr_alert("page_owner tracks the page as freed\n"); |
| |
| 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", |
| page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask, |
| page_owner->pid, page_owner->tgid, page_owner->comm, |
| page_owner->ts_nsec, page_owner->free_ts_nsec); |
| |
| handle = READ_ONCE(page_owner->handle); |
| if (!handle) |
| pr_alert("page_owner allocation stack trace missing\n"); |
| else |
| stack_depot_print(handle); |
| |
| handle = READ_ONCE(page_owner->free_handle); |
| if (!handle) { |
| pr_alert("page_owner free stack trace missing\n"); |
| } else { |
| pr_alert("page last free pid %d tgid %d stack trace:\n", |
| page_owner->free_pid, page_owner->free_tgid); |
| stack_depot_print(handle); |
| } |
| |
| if (page_owner->last_migrate_reason != -1) |
| pr_alert("page has been migrated, last migrate reason: %s\n", |
| migrate_reason_names[page_owner->last_migrate_reason]); |
| page_ext_put(page_ext); |
| } |
| |
| static ssize_t |
| read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
| { |
| unsigned long pfn; |
| struct page *page; |
| struct page_ext *page_ext; |
| struct page_owner *page_owner; |
| depot_stack_handle_t handle; |
| |
| if (!static_branch_unlikely(&page_owner_inited)) |
| return -EINVAL; |
| |
| page = NULL; |
| if (*ppos == 0) |
| pfn = min_low_pfn; |
| else |
| pfn = *ppos; |
| /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ |
| while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) |
| pfn++; |
| |
| /* Find an allocated page */ |
| for (; pfn < max_pfn; pfn++) { |
| /* |
| * This temporary page_owner is required so |
| * that we can avoid the context switches while holding |
| * the rcu lock and copying the page owner information to |
| * user through copy_to_user() or GFP_KERNEL allocations. |
| */ |
| struct page_owner page_owner_tmp; |
| |
| /* |
| * If the new page is in a new MAX_ORDER_NR_PAGES area, |
| * validate the area as existing, skip it if not |
| */ |
| if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { |
| pfn += MAX_ORDER_NR_PAGES - 1; |
| continue; |
| } |
| |
| page = pfn_to_page(pfn); |
| if (PageBuddy(page)) { |
| unsigned long freepage_order = buddy_order_unsafe(page); |
| |
| if (freepage_order <= MAX_PAGE_ORDER) |
| pfn += (1UL << freepage_order) - 1; |
| continue; |
| } |
| |
| page_ext = page_ext_get(page); |
| if (unlikely(!page_ext)) |
| continue; |
| |
| /* |
| * Some pages could be missed by concurrent allocation or free, |
| * because we don't hold the zone lock. |
| */ |
| if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) |
| goto ext_put_continue; |
| |
| /* |
| * Although we do have the info about past allocation of free |
| * pages, it's not relevant for current memory usage. |
| */ |
| if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) |
| goto ext_put_continue; |
| |
| page_owner = get_page_owner(page_ext); |
| |
| /* |
| * Don't print "tail" pages of high-order allocations as that |
| * would inflate the stats. |
| */ |
| if (!IS_ALIGNED(pfn, 1 << page_owner->order)) |
| goto ext_put_continue; |
| |
| /* |
| * Access to page_ext->handle isn't synchronous so we should |
| * be careful to access it. |
| */ |
| handle = READ_ONCE(page_owner->handle); |
| if (!handle) |
| goto ext_put_continue; |
| |
| /* Record the next PFN to read in the file offset */ |
| *ppos = pfn + 1; |
| |
| page_owner_tmp = *page_owner; |
| page_ext_put(page_ext); |
| return print_page_owner(buf, count, pfn, page, |
| &page_owner_tmp, handle); |
| ext_put_continue: |
| page_ext_put(page_ext); |
| } |
| |
| return 0; |
| } |
| |
| static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig) |
| { |
| switch (orig) { |
| case SEEK_SET: |
| file->f_pos = offset; |
| break; |
| case SEEK_CUR: |
| file->f_pos += offset; |
| break; |
| default: |
| return -EINVAL; |
| } |
| return file->f_pos; |
| } |
| |
| static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) |
| { |
| unsigned long pfn = zone->zone_start_pfn; |
| unsigned long end_pfn = zone_end_pfn(zone); |
| unsigned long count = 0; |
| |
| /* |
| * Walk the zone in pageblock_nr_pages steps. If a page block spans |
| * a zone boundary, it will be double counted between zones. This does |
| * not matter as the mixed block count will still be correct |
| */ |
| for (; pfn < end_pfn; ) { |
| unsigned long block_end_pfn; |
| |
| if (!pfn_valid(pfn)) { |
| pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); |
| continue; |
| } |
| |
| block_end_pfn = pageblock_end_pfn(pfn); |
| block_end_pfn = min(block_end_pfn, end_pfn); |
| |
| for (; pfn < block_end_pfn; pfn++) { |
| struct page *page = pfn_to_page(pfn); |
| struct page_ext *page_ext; |
| |
| if (page_zone(page) != zone) |
| continue; |
| |
| /* |
| * To avoid having to grab zone->lock, be a little |
| * careful when reading buddy page order. The only |
| * danger is that we skip too much and potentially miss |
| * some early allocated pages, which is better than |
| * heavy lock contention. |
| */ |
| if (PageBuddy(page)) { |
| unsigned long order = buddy_order_unsafe(page); |
| |
| if (order > 0 && order <= MAX_PAGE_ORDER) |
| pfn += (1UL << order) - 1; |
| continue; |
| } |
| |
| if (PageReserved(page)) |
| continue; |
| |
| page_ext = page_ext_get(page); |
| if (unlikely(!page_ext)) |
| continue; |
| |
| /* Maybe overlapping zone */ |
| if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) |
| goto ext_put_continue; |
| |
| /* Found early allocated page */ |
| __update_page_owner_handle(page_ext, early_handle, 0, 0, |
| -1, local_clock(), current->pid, |
| current->tgid, current->comm); |
| count++; |
| ext_put_continue: |
| page_ext_put(page_ext); |
| } |
| cond_resched(); |
| } |
| |
| pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n", |
| pgdat->node_id, zone->name, count); |
| } |
| |
| static void init_zones_in_node(pg_data_t *pgdat) |
| { |
| struct zone *zone; |
| struct zone *node_zones = pgdat->node_zones; |
| |
| for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { |
| if (!populated_zone(zone)) |
| continue; |
| |
| init_pages_in_zone(pgdat, zone); |
| } |
| } |
| |
| static void init_early_allocated_pages(void) |
| { |
| pg_data_t *pgdat; |
| |
| for_each_online_pgdat(pgdat) |
| init_zones_in_node(pgdat); |
| } |
| |
| static const struct file_operations proc_page_owner_operations = { |
| .read = read_page_owner, |
| .llseek = lseek_page_owner, |
| }; |
| |
| static void *stack_start(struct seq_file *m, loff_t *ppos) |
| { |
| struct stack *stack; |
| |
| if (*ppos == -1UL) |
| return NULL; |
| |
| if (!*ppos) { |
| /* |
| * This pairs with smp_store_release() from function |
| * add_stack_record_to_list(), so we get a consistent |
| * value of stack_list. |
| */ |
| stack = smp_load_acquire(&stack_list); |
| m->private = stack; |
| } else { |
| stack = m->private; |
| } |
| |
| return stack; |
| } |
| |
| static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) |
| { |
| struct stack *stack = v; |
| |
| stack = stack->next; |
| *ppos = stack ? *ppos + 1 : -1UL; |
| m->private = stack; |
| |
| return stack; |
| } |
| |
| static unsigned long page_owner_pages_threshold; |
| |
| static int stack_print(struct seq_file *m, void *v) |
| { |
| int i, nr_base_pages; |
| struct stack *stack = v; |
| unsigned long *entries; |
| unsigned long nr_entries; |
| struct stack_record *stack_record = stack->stack_record; |
| |
| if (!stack->stack_record) |
| return 0; |
| |
| nr_entries = stack_record->size; |
| entries = stack_record->entries; |
| nr_base_pages = refcount_read(&stack_record->count) - 1; |
| |
| if (nr_base_pages < 1 || nr_base_pages < page_owner_pages_threshold) |
| return 0; |
| |
| for (i = 0; i < nr_entries; i++) |
| seq_printf(m, " %pS\n", (void *)entries[i]); |
| seq_printf(m, "nr_base_pages: %d\n\n", nr_base_pages); |
| |
| return 0; |
| } |
| |
| static void stack_stop(struct seq_file *m, void *v) |
| { |
| } |
| |
| static const struct seq_operations page_owner_stack_op = { |
| .start = stack_start, |
| .next = stack_next, |
| .stop = stack_stop, |
| .show = stack_print |
| }; |
| |
| static int page_owner_stack_open(struct inode *inode, struct file *file) |
| { |
| return seq_open_private(file, &page_owner_stack_op, 0); |
| } |
| |
| static const struct file_operations page_owner_stack_operations = { |
| .open = page_owner_stack_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = seq_release, |
| }; |
| |
| static int page_owner_threshold_get(void *data, u64 *val) |
| { |
| *val = READ_ONCE(page_owner_pages_threshold); |
| return 0; |
| } |
| |
| static int page_owner_threshold_set(void *data, u64 val) |
| { |
| WRITE_ONCE(page_owner_pages_threshold, val); |
| return 0; |
| } |
| |
| DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get, |
| &page_owner_threshold_set, "%llu"); |
| |
| |
| static int __init pageowner_init(void) |
| { |
| struct dentry *dir; |
| |
| if (!static_branch_unlikely(&page_owner_inited)) { |
| pr_info("page_owner is disabled\n"); |
| return 0; |
| } |
| |
| debugfs_create_file("page_owner", 0400, NULL, NULL, |
| &proc_page_owner_operations); |
| dir = debugfs_create_dir("page_owner_stacks", NULL); |
| debugfs_create_file("show_stacks", 0400, dir, NULL, |
| &page_owner_stack_operations); |
| debugfs_create_file("count_threshold", 0600, dir, NULL, |
| &proc_page_owner_threshold); |
| |
| return 0; |
| } |
| late_initcall(pageowner_init) |