diff options
Diffstat (limited to 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 134 |
1 files changed, 81 insertions, 53 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index a2d70ef74db7..9d8936c7b40d 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -460,7 +460,7 @@ static int fold_diff(int *diff) * * The function returns the number of global counters updated. */ -static int refresh_cpu_vm_stats(void) +static int refresh_cpu_vm_stats(bool do_pagesets) { struct zone *zone; int i; @@ -484,33 +484,35 @@ static int refresh_cpu_vm_stats(void) #endif } } - cond_resched(); #ifdef CONFIG_NUMA - /* - * Deal with draining the remote pageset of this - * processor - * - * Check if there are pages remaining in this pageset - * if not then there is nothing to expire. - */ - if (!__this_cpu_read(p->expire) || + if (do_pagesets) { + cond_resched(); + /* + * Deal with draining the remote pageset of this + * processor + * + * Check if there are pages remaining in this pageset + * if not then there is nothing to expire. + */ + if (!__this_cpu_read(p->expire) || !__this_cpu_read(p->pcp.count)) - continue; + continue; - /* - * We never drain zones local to this processor. - */ - if (zone_to_nid(zone) == numa_node_id()) { - __this_cpu_write(p->expire, 0); - continue; - } + /* + * We never drain zones local to this processor. + */ + if (zone_to_nid(zone) == numa_node_id()) { + __this_cpu_write(p->expire, 0); + continue; + } - if (__this_cpu_dec_return(p->expire)) - continue; + if (__this_cpu_dec_return(p->expire)) + continue; - if (__this_cpu_read(p->pcp.count)) { - drain_zone_pages(zone, this_cpu_ptr(&p->pcp)); - changes++; + if (__this_cpu_read(p->pcp.count)) { + drain_zone_pages(zone, this_cpu_ptr(&p->pcp)); + changes++; + } } #endif } @@ -855,13 +857,8 @@ const char * const vmstat_text[] = { #endif #endif /* CONFIG_MEMORY_BALLOON */ #ifdef CONFIG_DEBUG_TLBFLUSH -#ifdef CONFIG_SMP "nr_tlb_remote_flush", "nr_tlb_remote_flush_received", -#else - "", /* nr_tlb_remote_flush */ - "", /* nr_tlb_remote_flush_received */ -#endif /* CONFIG_SMP */ "nr_tlb_local_flush_all", "nr_tlb_local_flush_one", #endif /* CONFIG_DEBUG_TLBFLUSH */ @@ -1393,15 +1390,20 @@ static cpumask_var_t cpu_stat_off; static void vmstat_update(struct work_struct *w) { - if (refresh_cpu_vm_stats()) { + if (refresh_cpu_vm_stats(true)) { /* * Counters were updated so we expect more updates * to occur in the future. Keep on running the * update worker thread. + * If we were marked on cpu_stat_off clear the flag + * so that vmstat_shepherd doesn't schedule us again. */ - queue_delayed_work_on(smp_processor_id(), vmstat_wq, - this_cpu_ptr(&vmstat_work), - round_jiffies_relative(sysctl_stat_interval)); + if (!cpumask_test_and_clear_cpu(smp_processor_id(), + cpu_stat_off)) { + queue_delayed_work_on(smp_processor_id(), vmstat_wq, + this_cpu_ptr(&vmstat_work), + round_jiffies_relative(sysctl_stat_interval)); + } } else { /* * We did not update any counters so the app may be in @@ -1410,21 +1412,16 @@ static void vmstat_update(struct work_struct *w) * Defer the checking for differentials to the * shepherd thread on a different processor. */ - int r; - /* - * Shepherd work thread does not race since it never - * changes the bit if its zero but the cpu - * online / off line code may race if - * worker threads are still allowed during - * shutdown / startup. - */ - r = cpumask_test_and_set_cpu(smp_processor_id(), - cpu_stat_off); - VM_BUG_ON(r); + cpumask_set_cpu(smp_processor_id(), cpu_stat_off); } } /* + * Switch off vmstat processing and then fold all the remaining differentials + * until the diffs stay at zero. The function is used by NOHZ and can only be + * invoked when tick processing is not active. + */ +/* * Check if the diffs for a certain cpu indicate that * an update is needed. */ @@ -1447,6 +1444,30 @@ static bool need_update(int cpu) return false; } +void quiet_vmstat(void) +{ + if (system_state != SYSTEM_RUNNING) + return; + + /* + * If we are already in hands of the shepherd then there + * is nothing for us to do here. + */ + if (cpumask_test_and_set_cpu(smp_processor_id(), cpu_stat_off)) + return; + + if (!need_update(smp_processor_id())) + return; + + /* + * Just refresh counters and do not care about the pending delayed + * vmstat_update. It doesn't fire that often to matter and canceling + * it would be too expensive from this path. + * vmstat_shepherd will take care about that for us. + */ + refresh_cpu_vm_stats(false); +} + /* * Shepherd worker thread that checks the @@ -1456,7 +1477,7 @@ static bool need_update(int cpu) */ static void vmstat_shepherd(struct work_struct *w); -static DECLARE_DELAYED_WORK(shepherd, vmstat_shepherd); +static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd); static void vmstat_shepherd(struct work_struct *w) { @@ -1464,18 +1485,25 @@ static void vmstat_shepherd(struct work_struct *w) get_online_cpus(); /* Check processors whose vmstat worker threads have been disabled */ - for_each_cpu(cpu, cpu_stat_off) - if (need_update(cpu) && - cpumask_test_and_clear_cpu(cpu, cpu_stat_off)) - - queue_delayed_work_on(cpu, vmstat_wq, - &per_cpu(vmstat_work, cpu), 0); - + for_each_cpu(cpu, cpu_stat_off) { + struct delayed_work *dw = &per_cpu(vmstat_work, cpu); + + if (need_update(cpu)) { + if (cpumask_test_and_clear_cpu(cpu, cpu_stat_off)) + queue_delayed_work_on(cpu, vmstat_wq, dw, 0); + } else { + /* + * Cancel the work if quiet_vmstat has put this + * cpu on cpu_stat_off because the work item might + * be still scheduled + */ + cancel_delayed_work(dw); + } + } put_online_cpus(); schedule_delayed_work(&shepherd, round_jiffies_relative(sysctl_stat_interval)); - } static void __init start_shepherd_timer(void) @@ -1561,7 +1589,7 @@ static int __init setup_vmstat(void) #endif #ifdef CONFIG_PROC_FS proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations); - proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops); + proc_create("pagetypeinfo", 0400, NULL, &pagetypeinfo_file_ops); proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations); proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations); #endif |