diff options
| -rw-r--r-- | mm/memcontrol.c | 56 |
1 files changed, 35 insertions, 21 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 46d8d02114cf..1ed40f9d3a27 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -621,6 +621,15 @@ static inline int memcg_events_index(enum vm_event_item idx) } struct memcg_vmstats_percpu { + /* Stats updates since the last flush */ + unsigned int stats_updates; + + /* Cached pointers for fast iteration in memcg_rstat_updated() */ + struct memcg_vmstats_percpu *parent; + struct memcg_vmstats *vmstats; + + /* The above should fit a single cacheline for memcg_rstat_updated() */ + /* Local (CPU and cgroup) page state & events */ long state[MEMCG_NR_STAT]; unsigned long events[NR_MEMCG_EVENTS]; @@ -632,10 +641,7 @@ struct memcg_vmstats_percpu { /* Cgroup1: threshold notifications & softlimit tree updates */ unsigned long nr_page_events; unsigned long targets[MEM_CGROUP_NTARGETS]; - - /* Stats updates since the last flush */ - unsigned int stats_updates; -}; +} ____cacheline_aligned; struct memcg_vmstats { /* Aggregated (CPU and subtree) page state & events */ @@ -698,36 +704,35 @@ static void memcg_stats_unlock(void) } -static bool memcg_should_flush_stats(struct mem_cgroup *memcg) +static bool memcg_vmstats_needs_flush(struct memcg_vmstats *vmstats) { - return atomic64_read(&memcg->vmstats->stats_updates) > + return atomic64_read(&vmstats->stats_updates) > MEMCG_CHARGE_BATCH * num_online_cpus(); } static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val) { + struct memcg_vmstats_percpu *statc; int cpu = smp_processor_id(); - unsigned int x; if (!val) return; cgroup_rstat_updated(memcg->css.cgroup, cpu); - - for (; memcg; memcg = parent_mem_cgroup(memcg)) { - x = __this_cpu_add_return(memcg->vmstats_percpu->stats_updates, - abs(val)); - - if (x < MEMCG_CHARGE_BATCH) + statc = this_cpu_ptr(memcg->vmstats_percpu); + for (; statc; statc = statc->parent) { + statc->stats_updates += abs(val); + if (statc->stats_updates < MEMCG_CHARGE_BATCH) continue; /* * If @memcg is already flush-able, increasing stats_updates is * redundant. Avoid the overhead of the atomic update. */ - if (!memcg_should_flush_stats(memcg)) - atomic64_add(x, &memcg->vmstats->stats_updates); - __this_cpu_write(memcg->vmstats_percpu->stats_updates, 0); + if (!memcg_vmstats_needs_flush(statc->vmstats)) + atomic64_add(statc->stats_updates, + &statc->vmstats->stats_updates); + statc->stats_updates = 0; } } @@ -756,7 +761,7 @@ void mem_cgroup_flush_stats(struct mem_cgroup *memcg) if (!memcg) memcg = root_mem_cgroup; - if (memcg_should_flush_stats(memcg)) + if (memcg_vmstats_needs_flush(memcg->vmstats)) do_flush_stats(memcg); } @@ -770,7 +775,7 @@ void mem_cgroup_flush_stats_ratelimited(struct mem_cgroup *memcg) static void flush_memcg_stats_dwork(struct work_struct *w) { /* - * Deliberately ignore memcg_should_flush_stats() here so that flushing + * Deliberately ignore memcg_vmstats_needs_flush() here so that flushing * in latency-sensitive paths is as cheap as possible. */ do_flush_stats(root_mem_cgroup); @@ -5477,10 +5482,11 @@ static void mem_cgroup_free(struct mem_cgroup *memcg) __mem_cgroup_free(memcg); } -static struct mem_cgroup *mem_cgroup_alloc(void) +static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent) { + struct memcg_vmstats_percpu *statc, *pstatc; struct mem_cgroup *memcg; - int node; + int node, cpu; int __maybe_unused i; long error = -ENOMEM; @@ -5504,6 +5510,14 @@ static struct mem_cgroup *mem_cgroup_alloc(void) if (!memcg->vmstats_percpu) goto fail; + for_each_possible_cpu(cpu) { + if (parent) + pstatc = per_cpu_ptr(parent->vmstats_percpu, cpu); + statc = per_cpu_ptr(memcg->vmstats_percpu, cpu); + statc->parent = parent ? pstatc : NULL; + statc->vmstats = memcg->vmstats; + } + for_each_node(node) if (alloc_mem_cgroup_per_node_info(memcg, node)) goto fail; @@ -5549,7 +5563,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) struct mem_cgroup *memcg, *old_memcg; old_memcg = set_active_memcg(parent); - memcg = mem_cgroup_alloc(); + memcg = mem_cgroup_alloc(parent); set_active_memcg(old_memcg); if (IS_ERR(memcg)) return ERR_CAST(memcg); |