Per the discussion with David [1], it looks more reasonable to just dump the single excessive slab cache instead of dumping all slab caches when oom.
Dump single excessive slab cache if its size is > 10% of total system memory size when oom regardless it is unreclaimable. [1] https://marc.info/?l=linux-mm&m=150819933626604&w=2 Suggested-by: David Rientjes <rient...@google.com> Signed-off-by: Yang Shi <yan...@alibaba-inc.com> --- mm/oom_kill.c | 22 +--------------------- mm/slab.h | 4 ++-- mm/slab_common.c | 21 ++++++++++++++++----- 3 files changed, 19 insertions(+), 28 deletions(-) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 26add8a..f996f29 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -162,25 +162,6 @@ static bool oom_unkillable_task(struct task_struct *p, return false; } -/* - * Print out unreclaimble slabs info when unreclaimable slabs amount is greater - * than all user memory (LRU pages) - */ -static bool is_dump_unreclaim_slabs(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(NR_SLAB_UNRECLAIMABLE) > nr_lru); -} - /** * oom_badness - heuristic function to determine which candidate task to kill * @p: task struct of which task we should calculate @@ -443,8 +424,7 @@ static void dump_header(struct oom_control *oc, struct task_struct *p) mem_cgroup_print_oom_info(oc->memcg, p); else { show_mem(SHOW_MEM_FILTER_NODES, oc->nodemask); - if (is_dump_unreclaim_slabs()) - dump_unreclaimable_slab(); + dump_slab_cache(); } if (sysctl_oom_dump_tasks) dump_tasks(oc->memcg, oc->nodemask); diff --git a/mm/slab.h b/mm/slab.h index 6a86025..818b569 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -507,9 +507,9 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) int memcg_slab_show(struct seq_file *m, void *p); #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) -void dump_unreclaimable_slab(void); +void dump_slab_cache(void); #else -static inline void dump_unreclaimable_slab(void) +static inline void dump_slab_cache(void) { } #endif diff --git a/mm/slab_common.c b/mm/slab_common.c index 1b14fe0..e5bfa07 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1311,7 +1311,18 @@ static int slab_show(struct seq_file *m, void *p) return 0; } -void dump_unreclaimable_slab(void) +static bool inline is_dump_slabs(struct kmem_cache *s, struct slabinfo *sinfo) +{ + unsigned long total = 0, reserved = 0, highmem = 0; + unsigned long slab_size = sinfo->num_objs * s->size; + + calc_mem_size(&total, &reserved, &highmem); + + /* Check if single slab > 10% of total memory size */ + return (slab_size > (total * PAGE_SIZE / 10)); +} + +void dump_slab_cache(void) { struct kmem_cache *s, *s2; struct slabinfo sinfo; @@ -1324,20 +1335,20 @@ void dump_unreclaimable_slab(void) * without acquiring the mutex. */ if (!mutex_trylock(&slab_mutex)) { - pr_warn("excessive unreclaimable slab but cannot dump stats\n"); + pr_warn("excessive slab cache but cannot dump stats\n"); return; } - pr_info("Unreclaimable slab info:\n"); + pr_info("The list of excessive single slab cache:\n"); pr_info("Name Used Total\n"); list_for_each_entry_safe(s, s2, &slab_caches, list) { - if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT)) + if (!is_root_cache(s)) continue; get_slabinfo(s, &sinfo); - if (sinfo.num_objs > 0) + if (is_dump_slabs(s, &sinfo)) pr_info("%-17s %10luKB %10luKB\n", cache_name(s), (sinfo.active_objs * s->size) / 1024, (sinfo.num_objs * s->size) / 1024); -- 1.8.3.1
