diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 5da4295e7d6..86f8c341879 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2448,9 +2448,24 @@ static int kswapd(void *p) */ if (!sleeping_prematurely(pgdat, order, remaining)) { trace_mm_vmscan_kswapd_sleep(pgdat->node_id); - restore_pgdat_percpu_threshold(pgdat); + + /* + * vmstat counters are not perfectly + * accurate and the estimated value + * for counters such as NR_FREE_PAGES + * can deviate from the true value by + * nr_online_cpus * threshold. To + * avoid the zone watermarks being + * breached while under pressure, we + * reduce the per-cpu vmstat threshold + * while kswapd is awake and restore + * them before going back to sleep. + */ + set_pgdat_percpu_threshold(pgdat, + calculate_normal_threshold); schedule(); - reduce_pgdat_percpu_threshold(pgdat); + set_pgdat_percpu_threshold(pgdat, + calculate_pressure_threshold); } else { if (remaining) count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); |