diff options
| -rw-r--r-- | Documentation/mm/page_owner.rst | 73 | ||||
| -rw-r--r-- | mm/page_owner.c | 34 |
2 files changed, 58 insertions, 49 deletions
diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst index 0d0334cd5179..3a45a20fc05a 100644 --- a/Documentation/mm/page_owner.rst +++ b/Documentation/mm/page_owner.rst @@ -24,10 +24,10 @@ fragmentation statistics can be obtained through gfp flag information of each page. It is already implemented and activated if page owner is enabled. Other usages are more than welcome. -It can also be used to show all the stacks and their outstanding -allocations, which gives us a quick overview of where the memory is going -without the need to screen through all the pages and match the allocation -and free operation. +It can also be used to show all the stacks and their current number of +allocated base pages, which gives us a quick overview of where the memory +is going without the need to screen through all the pages and match the +allocation and free operation. page owner is disabled by default. So, if you'd like to use it, you need to add "page_owner=on" to your boot cmdline. If the kernel is built @@ -75,42 +75,45 @@ Usage cat /sys/kernel/debug/page_owner_stacks/show_stacks > stacks.txt cat stacks.txt - prep_new_page+0xa9/0x120 - get_page_from_freelist+0x7e6/0x2140 - __alloc_pages+0x18a/0x370 - new_slab+0xc8/0x580 - ___slab_alloc+0x1f2/0xaf0 - __slab_alloc.isra.86+0x22/0x40 - kmem_cache_alloc+0x31b/0x350 - __khugepaged_enter+0x39/0x100 - dup_mmap+0x1c7/0x5ce - copy_process+0x1afe/0x1c90 - kernel_clone+0x9a/0x3c0 - __do_sys_clone+0x66/0x90 - do_syscall_64+0x7f/0x160 - entry_SYSCALL_64_after_hwframe+0x6c/0x74 - stack_count: 234 + post_alloc_hook+0x177/0x1a0 + get_page_from_freelist+0xd01/0xd80 + __alloc_pages+0x39e/0x7e0 + allocate_slab+0xbc/0x3f0 + ___slab_alloc+0x528/0x8a0 + kmem_cache_alloc+0x224/0x3b0 + sk_prot_alloc+0x58/0x1a0 + sk_alloc+0x32/0x4f0 + inet_create+0x427/0xb50 + __sock_create+0x2e4/0x650 + inet_ctl_sock_create+0x30/0x180 + igmp_net_init+0xc1/0x130 + ops_init+0x167/0x410 + setup_net+0x304/0xa60 + copy_net_ns+0x29b/0x4a0 + create_new_namespaces+0x4a1/0x820 + nr_base_pages: 16 ... ... echo 7000 > /sys/kernel/debug/page_owner_stacks/count_threshold cat /sys/kernel/debug/page_owner_stacks/show_stacks> stacks_7000.txt cat stacks_7000.txt - prep_new_page+0xa9/0x120 - get_page_from_freelist+0x7e6/0x2140 - __alloc_pages+0x18a/0x370 - alloc_pages_mpol+0xdf/0x1e0 - folio_alloc+0x14/0x50 - filemap_alloc_folio+0xb0/0x100 - page_cache_ra_unbounded+0x97/0x180 - filemap_fault+0x4b4/0x1200 - __do_fault+0x2d/0x110 - do_pte_missing+0x4b0/0xa30 - __handle_mm_fault+0x7fa/0xb70 - handle_mm_fault+0x125/0x300 - do_user_addr_fault+0x3c9/0x840 - exc_page_fault+0x68/0x150 - asm_exc_page_fault+0x22/0x30 - stack_count: 8248 + post_alloc_hook+0x177/0x1a0 + get_page_from_freelist+0xd01/0xd80 + __alloc_pages+0x39e/0x7e0 + alloc_pages_mpol+0x22e/0x490 + folio_alloc+0xd5/0x110 + filemap_alloc_folio+0x78/0x230 + page_cache_ra_order+0x287/0x6f0 + filemap_get_pages+0x517/0x1160 + filemap_read+0x304/0x9f0 + xfs_file_buffered_read+0xe6/0x1d0 [xfs] + xfs_file_read_iter+0x1f0/0x380 [xfs] + __kernel_read+0x3b9/0x730 + kernel_read_file+0x309/0x4d0 + __do_sys_finit_module+0x381/0x730 + do_syscall_64+0x8d/0x150 + entry_SYSCALL_64_after_hwframe+0x62/0x6a + nr_base_pages: 20824 ... cat /sys/kernel/debug/page_owner > page_owner_full.txt diff --git a/mm/page_owner.c b/mm/page_owner.c index 52d1ced0b57f..5df0d6892bdc 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -196,7 +196,8 @@ static void add_stack_record_to_list(struct stack_record *stack_record, spin_unlock_irqrestore(&stack_list_lock, flags); } -static void inc_stack_record_count(depot_stack_handle_t handle, gfp_t gfp_mask) +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); @@ -217,15 +218,20 @@ static void inc_stack_record_count(depot_stack_handle_t handle, gfp_t gfp_mask) /* Add the new stack_record to our list */ add_stack_record_to_list(stack_record, gfp_mask); } - refcount_inc(&stack_record->count); + refcount_add(nr_base_pages, &stack_record->count); } -static void dec_stack_record_count(depot_stack_handle_t handle) +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) - refcount_dec(&stack_record->count); + 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, @@ -306,7 +312,7 @@ void __reset_page_owner(struct page *page, unsigned short order) * the machinery is not ready yet, we cannot decrement * their refcount either. */ - dec_stack_record_count(alloc_handle); + dec_stack_record_count(alloc_handle, 1 << order); } noinline void __set_page_owner(struct page *page, unsigned short order, @@ -325,7 +331,7 @@ noinline void __set_page_owner(struct page *page, unsigned short order, current->pid, current->tgid, ts_nsec, current->comm); page_ext_put(page_ext); - inc_stack_record_count(handle, gfp_mask); + inc_stack_record_count(handle, gfp_mask, 1 << order); } void __set_page_owner_migrate_reason(struct page *page, int reason) @@ -872,11 +878,11 @@ static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) return stack; } -static unsigned long page_owner_stack_threshold; +static unsigned long page_owner_pages_threshold; static int stack_print(struct seq_file *m, void *v) { - int i, stack_count; + int i, nr_base_pages; struct stack *stack = v; unsigned long *entries; unsigned long nr_entries; @@ -887,14 +893,14 @@ static int stack_print(struct seq_file *m, void *v) nr_entries = stack_record->size; entries = stack_record->entries; - stack_count = refcount_read(&stack_record->count) - 1; + nr_base_pages = refcount_read(&stack_record->count) - 1; - if (stack_count < 1 || stack_count < page_owner_stack_threshold) + 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, "stack_count: %d\n\n", stack_count); + seq_printf(m, "nr_base_pages: %d\n\n", nr_base_pages); return 0; } @@ -924,13 +930,13 @@ static const struct file_operations page_owner_stack_operations = { static int page_owner_threshold_get(void *data, u64 *val) { - *val = READ_ONCE(page_owner_stack_threshold); + *val = READ_ONCE(page_owner_pages_threshold); return 0; } static int page_owner_threshold_set(void *data, u64 val) { - WRITE_ONCE(page_owner_stack_threshold, val); + WRITE_ONCE(page_owner_pages_threshold, val); return 0; } |