From 30361e51cae7a4df3fec89f935a450a6fe6f16fa Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 24 Sep 2013 15:27:36 -0700 Subject: [PATCH] revert "memcg: track children in soft limit excess to improve soft limit" Revert commit 7d910c054be4 ("memcg: track children in soft limit excess to improve soft limit") I merged this prematurely - Michal and Johannes still disagree about the overall design direction and the future remains unclear. Cc: Michal Hocko Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 71 ------------------------------------------------- 1 file changed, 71 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 5cf7726764cc..916892c2b8e0 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -124,7 +124,6 @@ static const char * const mem_cgroup_lru_names[] = { */ enum mem_cgroup_events_target { MEM_CGROUP_TARGET_THRESH, - MEM_CGROUP_TARGET_SOFTLIMIT, MEM_CGROUP_TARGET_NUMAINFO, MEM_CGROUP_NTARGETS, }; @@ -303,22 +302,6 @@ struct mem_cgroup { atomic_t numainfo_events; atomic_t numainfo_updating; #endif - /* - * Protects soft_contributed transitions. - * See mem_cgroup_update_soft_limit - */ - spinlock_t soft_lock; - - /* - * If true then this group has increased parents' children_in_excess - * when it got over the soft limit. - * When a group falls bellow the soft limit, parents' children_in_excess - * is decreased and soft_contributed changed to false. - */ - bool soft_contributed; - - /* Number of children that are in soft limit excess */ - atomic_t children_in_excess; struct mem_cgroup_per_node *nodeinfo[0]; /* WARNING: nodeinfo must be the last member here */ @@ -806,9 +789,6 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, case MEM_CGROUP_TARGET_THRESH: next = val + THRESHOLDS_EVENTS_TARGET; break; - case MEM_CGROUP_TARGET_SOFTLIMIT: - next = val + SOFTLIMIT_EVENTS_TARGET; - break; case MEM_CGROUP_TARGET_NUMAINFO: next = val + NUMAINFO_EVENTS_TARGET; break; @@ -821,42 +801,6 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, return false; } -/* - * Called from rate-limited memcg_check_events when enough - * MEM_CGROUP_TARGET_SOFTLIMIT events are accumulated and it makes sure - * that all the parents up the hierarchy will be notified that this group - * is in excess or that it is not in excess anymore. mmecg->soft_contributed - * makes the transition a single action whenever the state flips from one to - * the other. - */ -static void mem_cgroup_update_soft_limit(struct mem_cgroup *memcg) -{ - unsigned long long excess = res_counter_soft_limit_excess(&memcg->res); - struct mem_cgroup *parent = memcg; - int delta = 0; - - spin_lock(&memcg->soft_lock); - if (excess) { - if (!memcg->soft_contributed) { - delta = 1; - memcg->soft_contributed = true; - } - } else { - if (memcg->soft_contributed) { - delta = -1; - memcg->soft_contributed = false; - } - } - - /* - * Necessary to update all ancestors when hierarchy is used - * because their event counter is not touched. - */ - while (delta && (parent = parent_mem_cgroup(parent))) - atomic_add(delta, &parent->children_in_excess); - spin_unlock(&memcg->soft_lock); -} - /* * Check events in order. * @@ -867,11 +811,8 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) /* threshold event is triggered in finer grain than soft limit */ if (unlikely(mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_THRESH))) { - bool do_softlimit; bool do_numainfo __maybe_unused; - do_softlimit = mem_cgroup_event_ratelimit(memcg, - MEM_CGROUP_TARGET_SOFTLIMIT); #if MAX_NUMNODES > 1 do_numainfo = mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_NUMAINFO); @@ -879,8 +820,6 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) preempt_enable(); mem_cgroup_threshold(memcg); - if (unlikely(do_softlimit)) - mem_cgroup_update_soft_limit(memcg); #if MAX_NUMNODES > 1 if (unlikely(do_numainfo)) atomic_inc(&memcg->numainfo_events); @@ -1864,9 +1803,6 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) * hierarchy if * a) it is over its soft limit * b) any parent up the hierarchy is over its soft limit - * - * If the given group doesn't have any children over the limit then it - * doesn't make any sense to iterate its subtree. */ enum mem_cgroup_filter_t mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg, @@ -1888,8 +1824,6 @@ mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg, break; } - if (!atomic_read(&memcg->children_in_excess)) - return SKIP_TREE; return SKIP; } @@ -6021,7 +5955,6 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) mutex_init(&memcg->thresholds_lock); spin_lock_init(&memcg->move_lock); vmpressure_init(&memcg->vmpressure); - spin_lock_init(&memcg->soft_lock); return &memcg->css; @@ -6099,10 +6032,6 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) mem_cgroup_invalidate_reclaim_iterators(memcg); mem_cgroup_reparent_charges(memcg); - if (memcg->soft_contributed) { - while ((memcg = parent_mem_cgroup(memcg))) - atomic_dec(&memcg->children_in_excess); - } mem_cgroup_destroy_all_caches(memcg); vmpressure_cleanup(&memcg->vmpressure); }