diff options
Diffstat (limited to 'Documentation/mm/page_owner.rst')
| -rw-r--r-- | Documentation/mm/page_owner.rst | 86 |
1 files changed, 81 insertions, 5 deletions
diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst index 127514955a5e..6b12f3b007ec 100644 --- a/Documentation/mm/page_owner.rst +++ b/Documentation/mm/page_owner.rst @@ -1,5 +1,3 @@ -.. _page_owner: - ================================================== page owner: Tracking about who allocated each page ================================================== @@ -26,6 +24,14 @@ 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 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. It's also possible to show only a numeric +identifier of all the stacks (without stack traces) and their number of +allocated base pages (faster to read and parse, eg, for monitoring) that +can be matched with stacks later (show_handles and show_stacks_handles). + 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 with page owner and page owner is disabled in runtime due to not enabling @@ -52,7 +58,7 @@ pages are investigated and marked as allocated in initialization phase. Although it doesn't mean that they have the right owner information, at least, we can tell whether the page is allocated or not, more accurately. On 2GB memory x86-64 VM box, 13343 early allocated pages -are catched and marked, although they are mostly allocated from struct +are caught and marked, although they are mostly allocated from struct page extension feature. Anyway, after that, no page is left in un-tracking state. @@ -61,7 +67,7 @@ Usage 1) Build user-space helper:: - cd tools/vm + cd tools/mm make page_owner_sort 2) Enable page owner: add "page_owner=on" to boot cmdline. @@ -70,6 +76,76 @@ Usage 4) Analyze information from page owner:: + cat /sys/kernel/debug/page_owner_stacks/show_stacks > stacks.txt + cat stacks.txt + 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 + 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_stacks/show_handles > handles_7000.txt + cat handles_7000.txt + handle: 42 + nr_base_pages: 20824 + ... + + cat /sys/kernel/debug/page_owner_stacks/show_stacks_handles > stacks_handles.txt + cat stacks_handles.txt + 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 + handle: 42 + ... + cat /sys/kernel/debug/page_owner > page_owner_full.txt ./page_owner_sort page_owner_full.txt sorted_page_owner.txt @@ -178,7 +254,7 @@ STANDARD FORMAT SPECIFIERS at alloc_ts timestamp of the page when it was allocated ator allocator memory allocator for pages - For --curl option: + For --cull option: KEY LONG DESCRIPTION p pid process ID |