On Wed, Apr 20, 2022 at 08:58:36AM +0200, Michal Hocko wrote: > On Tue 19-04-22 16:32:01, Kent Overstreet wrote: > > This patch: > > - Moves lib/show_mem.c to mm/show_mem.c > > Sure, why not. Should be a separate patch. > > > - Changes show_mem() to always report on slab usage > > - Instead of reporting on all slabs, we only report on top 10 slabs, > > and in sorted order > > - Also reports on shrinkers, with the new shrinkers_to_text(). > > Why do we need/want this? It would be also great to provide an example > of why the new output is better (in which cases) than the existing one. Did you read the cover letter to the patch series? But sure, I can give you an example of the new output: 00177 018: page allocation failure: order:5, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null) 00177 CPU: 0 PID: 32171 Comm: 018 Not tainted 5.17.0-01346-g09b56740d418-dirty #154 00177 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 00177 Call Trace: 00177 <TASK> 00177 dump_stack_lvl+0x38/0x49 00177 dump_stack+0x10/0x12 00177 warn_alloc+0x128/0x150 00177 ? __alloc_pages_direct_compact+0x171/0x1f0 00177 __alloc_pages_slowpath.constprop.0+0xac6/0xc30 00177 ? make_kgid+0x17/0x20 00177 ? p9pdu_readf+0x28c/0xb00 00177 __alloc_pages+0x215/0x230 00177 kmalloc_order+0x30/0x80 00177 kmalloc_order_trace+0x1d/0x80 00177 __kmalloc+0x1a2/0x1d0 00177 v9fs_alloc_rdir_buf.isra.0+0x28/0x40 00177 v9fs_dir_readdir_dotl+0x55/0x160 00177 ? __alloc_pages+0x151/0x230 00177 ? lru_cache_add+0x1c/0x20 00177 ? lru_cache_add_inactive_or_unevictable+0x27/0x80 00177 ? __handle_mm_fault+0x666/0xae0 00177 iterate_dir+0x151/0x1b0 00177 __x64_sys_getdents64+0x80/0x120 00177 ? compat_fillonedir+0x160/0x160 00177 do_syscall_64+0x35/0x80 00177 entry_SYSCALL_64_after_hwframe+0x44/0xae 00177 RIP: 0033:0x7f0b15e2f9c7 00177 Code: 00 00 0f 05 eb b3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 81 fa ff ff ff 7f b8 ff ff ff 7f 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 79 b4 10 00 f7 d8 64 89 02 48 00177 RSP: 002b:00007ffcf9445b88 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 00177 RAX: ffffffffffffffda RBX: 000056137dd23ba0 RCX: 00007f0b15e2f9c7 00177 RDX: 000000000001f000 RSI: 000056137dd23bd0 RDI: 0000000000000003 00177 RBP: 000056137dd23bd0 R08: 0000000000000030 R09: 00007f0b15f3bc00 00177 R10: fffffffffffff776 R11: 0000000000000293 R12: ffffffffffffff88 00177 R13: 000056137dd23ba4 R14: 0000000000000000 R15: 000056137dd23ba0 00177 </TASK> 00177 Mem-Info: 00177 active_anon:13706 inactive_anon:32266 isolated_anon:16 00177 active_file:1653 inactive_file:1822 isolated_file:0 00177 unevictable:0 dirty:0 writeback:0 00177 slab_reclaimable:6242 slab_unreclaimable:11168 00177 mapped:3824 shmem:3 pagetables:1266 bounce:0 00177 kernel_misc_reclaimable:0 00177 free:4362 free_pcp:35 free_cma:0 00177 Node 0 active_anon:54824kB inactive_anon:129064kB active_file:6612kB inactive_file:7288kB unevictable:0kB isolated(anon):64kB isolated(file):0kB mapped:15296kB dirty:0kB writeback:0kB shmem:12kB writeback_tmp:0kB kernel_stack:3392kB pagetables:5064kB all_unreclaimable? no 00177 DMA free:2232kB boost:0kB min:88kB low:108kB high:128kB reserved_highatomic:0KB active_anon:2924kB inactive_anon:6596kB active_file:428kB inactive_file:384kB unevictable:0kB writepending:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB 00177 lowmem_reserve[]: 0 426 426 426 00177 DMA32 free:15092kB boost:5836kB min:8432kB low:9080kB high:9728kB reserved_highatomic:0KB active_anon:52196kB inactive_anon:122392kB active_file:6176kB inactive_file:7068kB unevictable:0kB writepending:0kB present:507760kB managed:441816kB mlocked:0kB bounce:0kB free_pcp:72kB local_pcp:0kB free_cma:0kB 00177 lowmem_reserve[]: 0 0 0 0 00177 DMA: 284*4kB (UM) 53*8kB (UM) 21*16kB (U) 11*32kB (U) 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2248kB 00177 DMA32: 2765*4kB (UME) 375*8kB (UME) 57*16kB (UM) 5*32kB (U) 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 15132kB 00177 4656 total pagecache pages 00177 1031 pages in swap cache 00177 Swap cache stats: add 6572399, delete 6572173, find 488603/3286476 00177 Free swap = 509112kB 00177 Total swap = 2097148kB 00177 130938 pages RAM 00177 0 pages HighMem/MovableOnly 00177 16644 pages reserved 00177 Unreclaimable slab info: 00177 9p-fcall-cache total: 8.25 MiB active: 8.25 MiB 00177 kernfs_node_cache total: 2.15 MiB active: 2.15 MiB 00177 kmalloc-64 total: 2.08 MiB active: 2.07 MiB 00177 task_struct total: 1.95 MiB active: 1.95 MiB 00177 kmalloc-4k total: 1.50 MiB active: 1.50 MiB 00177 signal_cache total: 1.34 MiB active: 1.34 MiB 00177 kmalloc-2k total: 1.16 MiB active: 1.16 MiB 00177 bch_inode_info total: 1.02 MiB active: 922 KiB 00177 perf_event total: 1.02 MiB active: 1.02 MiB 00177 biovec-max total: 992 KiB active: 960 KiB 00177 Shrinkers: 00177 super_cache_scan: objects: 127 00177 super_cache_scan: objects: 106 00177 jbd2_journal_shrink_scan: objects: 32 00177 ext4_es_scan: objects: 32 00177 bch2_btree_cache_scan: objects: 8 00177 nr nodes: 24 00177 nr dirty: 0 00177 cannibalize lock: 0000000000000000 00177 00177 super_cache_scan: objects: 8 00177 super_cache_scan: objects: 1
