diff options
Diffstat (limited to 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 68 |
1 files changed, 67 insertions, 1 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index 312d728976f..bc0f095791b 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -83,6 +83,30 @@ EXPORT_SYMBOL(vm_stat); #ifdef CONFIG_SMP +static int calculate_pressure_threshold(struct zone *zone) +{ + int threshold; + int watermark_distance; + + /* + * As vmstats are not up to date, there is drift between the estimated + * and real values. For high thresholds and a high number of CPUs, it + * is possible for the min watermark to be breached while the estimated + * value looks fine. The pressure threshold is a reduced value such + * that even the maximum amount of drift will not accidentally breach + * the min watermark + */ + watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone); + threshold = max(1, (int)(watermark_distance / num_online_cpus())); + + /* + * Maximum threshold is 125 + */ + threshold = min(125, threshold); + + return threshold; +} + static int calculate_threshold(struct zone *zone) { int threshold; @@ -161,6 +185,48 @@ static void refresh_zone_stat_thresholds(void) } } +void reduce_pgdat_percpu_threshold(pg_data_t *pgdat) +{ + struct zone *zone; + int cpu; + int threshold; + int i; + + get_online_cpus(); + for (i = 0; i < pgdat->nr_zones; i++) { + zone = &pgdat->node_zones[i]; + if (!zone->percpu_drift_mark) + continue; + + threshold = calculate_pressure_threshold(zone); + for_each_online_cpu(cpu) + per_cpu_ptr(zone->pageset, cpu)->stat_threshold + = threshold; + } + put_online_cpus(); +} + +void restore_pgdat_percpu_threshold(pg_data_t *pgdat) +{ + struct zone *zone; + int cpu; + int threshold; + int i; + + get_online_cpus(); + for (i = 0; i < pgdat->nr_zones; i++) { + zone = &pgdat->node_zones[i]; + if (!zone->percpu_drift_mark) + continue; + + threshold = calculate_threshold(zone); + for_each_online_cpu(cpu) + per_cpu_ptr(zone->pageset, cpu)->stat_threshold + = threshold; + } + put_online_cpus(); +} + /* * For use when we know that interrupts are disabled. */ @@ -911,7 +977,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, "\n scanned %lu" "\n spanned %lu" "\n present %lu", - zone_nr_free_pages(zone), + zone_page_state(zone, NR_FREE_PAGES), min_wmark_pages(zone), low_wmark_pages(zone), high_wmark_pages(zone), |