diff options
author | Kent Overstreet <kent.overstreet@gmail.com> | 2022-04-19 16:12:45 -0400 |
---|---|---|
committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-05-13 00:22:30 -0400 |
commit | 46b743e6cc0f9fc8fda3c44e82fff860a084daed (patch) | |
tree | 7986856fb98ad380808045abdd8c57db6febc782 | |
parent | 68937c555ebcaa922e50cf7d91e0b56521c9fc01 (diff) |
mm: Centralize & improve oom reporting in show_mem.c
This 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().
Shrinkers need to be included in OOM/allocation failure reporting
because they're responsible for memory reclaim - if a shrinker isn't
giving up its memory, we need to know which one and why.
More OOM reporting can be moved to show_mem.c and improved, this patch
is only a start.
New example output on OOM/memory allocation failure:
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
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
-rw-r--r-- | mm/oom_kill.c | 23 | ||||
-rw-r--r-- | mm/show_mem.c | 23 | ||||
-rw-r--r-- | mm/slab.h | 6 | ||||
-rw-r--r-- | mm/slab_common.c | 52 |
4 files changed, 70 insertions, 34 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 044e1eed720e..f2657245e1f5 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -168,27 +168,6 @@ static bool oom_unkillable_task(struct task_struct *p) return false; } -/* - * Check whether unreclaimable slab amount is greater than - * all user memory(LRU pages). - * dump_unreclaimable_slab() could help in the case that - * oom due to too much unreclaimable slab used by kernel. -*/ -static bool should_dump_unreclaim_slab(void) -{ - unsigned long nr_lru; - - nr_lru = global_node_page_state(NR_ACTIVE_ANON) + - global_node_page_state(NR_INACTIVE_ANON) + - global_node_page_state(NR_ACTIVE_FILE) + - global_node_page_state(NR_INACTIVE_FILE) + - global_node_page_state(NR_ISOLATED_ANON) + - global_node_page_state(NR_ISOLATED_FILE) + - global_node_page_state(NR_UNEVICTABLE); - - return (global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B) > nr_lru); -} - /** * oom_badness - heuristic function to determine which candidate task to kill * @p: task struct of which task we should calculate @@ -462,8 +441,6 @@ static void dump_header(struct oom_control *oc, struct task_struct *p) mem_cgroup_print_oom_meminfo(oc->memcg); else { __show_mem(SHOW_MEM_FILTER_NODES, oc->nodemask, gfp_zone(oc->gfp_mask)); - if (should_dump_unreclaim_slab()) - dump_unreclaimable_slab(); } if (sysctl_oom_dump_tasks) dump_tasks(oc); diff --git a/mm/show_mem.c b/mm/show_mem.c index 0d7585cde2a6..fe41c21e0ede 100644 --- a/mm/show_mem.c +++ b/mm/show_mem.c @@ -7,11 +7,15 @@ #include <linux/mm.h> #include <linux/cma.h> +#include <linux/seq_buf.h> + +#include "slab.h" void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) { pg_data_t *pgdat; unsigned long total = 0, reserved = 0, highmem = 0; + char *buf; printk("Mem-Info:\n"); __show_free_areas(filter, nodemask, max_zone_idx); @@ -41,4 +45,23 @@ void __show_mem(unsigned int filter, nodemask_t *nodemask, int max_zone_idx) #ifdef CONFIG_MEMORY_FAILURE printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages)); #endif + + buf = kmalloc(4096, GFP_ATOMIC); + if (buf) { + struct seq_buf s; + + printk("Unreclaimable slab info:\n"); + seq_buf_init(&s, buf, 4096); + dump_unreclaimable_slab(&s); + seq_buf_terminate(&s); + printk("%s", buf); + + printk("Shrinkers:\n"); + seq_buf_init(&s, buf, 4096); + shrinkers_to_text(&s); + seq_buf_terminate(&s); + printk("%s", buf); + + kfree(buf); + } } diff --git a/mm/slab.h b/mm/slab.h index 43966aa5fadf..03d320dc1dc5 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -826,10 +826,12 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) #endif +struct seq_buf; + #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) -void dump_unreclaimable_slab(void); +void dump_unreclaimable_slab(struct seq_buf *); #else -static inline void dump_unreclaimable_slab(void) +static inline void dump_unreclaimable_slab(struct seq_buf *out) { } #endif diff --git a/mm/slab_common.c b/mm/slab_common.c index bf4e777cfe90..6f0755854829 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -24,6 +24,7 @@ #include <asm/tlbflush.h> #include <asm/page.h> #include <linux/memcontrol.h> +#include <linux/seq_buf.h> #include <linux/stackdepot.h> #include "internal.h" @@ -1264,10 +1265,15 @@ static int slab_show(struct seq_file *m, void *p) return 0; } -void dump_unreclaimable_slab(void) +void dump_unreclaimable_slab(struct seq_buf *out) { struct kmem_cache *s; struct slabinfo sinfo; + struct slab_by_mem { + struct kmem_cache *s; + size_t total, active; + } slabs_by_mem[10], n; + int i, nr = 0; /* * Here acquiring slab_mutex is risky since we don't prefer to get @@ -1277,24 +1283,52 @@ void dump_unreclaimable_slab(void) * without acquiring the mutex. */ if (!mutex_trylock(&slab_mutex)) { - pr_warn("excessive unreclaimable slab but cannot dump stats\n"); + seq_buf_puts(out, "excessive unreclaimable slab but cannot dump stats\n"); return; } - pr_info("Unreclaimable slab info:\n"); - pr_info("Name Used Total\n"); - list_for_each_entry(s, &slab_caches, list) { if (s->flags & SLAB_RECLAIM_ACCOUNT) continue; get_slabinfo(s, &sinfo); - if (sinfo.num_objs > 0) - pr_info("%-17s %10luKB %10luKB\n", s->name, - (sinfo.active_objs * s->size) / 1024, - (sinfo.num_objs * s->size) / 1024); + if (!sinfo.num_objs) + continue; + + n.s = s; + n.total = sinfo.num_objs * s->size; + n.active = sinfo.active_objs * s->size; + + for (i = 0; i < nr; i++) + if (n.total < slabs_by_mem[i].total) + break; + + if (nr < ARRAY_SIZE(slabs_by_mem)) { + memmove(&slabs_by_mem[i + 1], + &slabs_by_mem[i], + sizeof(slabs_by_mem[0]) * (nr - i)); + nr++; + } else if (i) { + i--; + memmove(&slabs_by_mem[0], + &slabs_by_mem[1], + sizeof(slabs_by_mem[0]) * i); + } else { + continue; + } + + slabs_by_mem[i] = n; + } + + for (i = nr - 1; i >= 0; --i) { + seq_buf_printf(out, "%-17s total: ", slabs_by_mem[i].s->name); + seq_buf_human_readable_u64(out, slabs_by_mem[i].total); + seq_buf_printf(out, " active: "); + seq_buf_human_readable_u64(out, slabs_by_mem[i].active); + seq_buf_putc(out, '\n'); } + mutex_unlock(&slab_mutex); } |