On Thu 26-10-17 06:49:00, Yang Shi wrote: > Per the discussion with David [1], it looks more reasonable to just dump
Please try to avoid external references in the changelog as much as possible. > the single excessive slab cache instead of dumping all slab caches when > oom. You meant to say "to just dump all slab caches which excess 10% of the total memory." While we are at it. Abusing calc_mem_size seems to be rather clumsy and tt is not nodemask aware so you the whole thing is dubious for NUMA constrained OOMs. The more I think about this the more I am convinced that this is just fiddling with the code without a good reason and without much better outcome. > Dump single excessive slab cache if its size is > 10% of total system s@single@all@ > 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 -- Michal Hocko SUSE Labs
