/*
* Refresh the thresholds for each zone.
*/
void refresh_zone_stat_thresholds(void)
{
struct zone *zone;
int cpu;
int threshold;
for_each_populated_zone(zone) {
unsigned long max_drift, tolerate_drift;
threshold = calculate_normal_threshold(zone);
for_each_online_cpu(cpu)
per_cpu_ptr(zone->pageset, cpu)->stat_threshold
= threshold;
/*
* Only set percpu_drift_mark if there is a danger that
* NR_FREE_PAGES reports the low watermark is ok when in fact
* the min watermark could be breached by an allocation
*/
tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
max_drift = num_online_cpus() * threshold;
if (max_drift > tolerate_drift)
zone->percpu_drift_mark = high_wmark_pages(zone) +
max_drift;
}
}
int calculate_pressure_threshold(struct zone *zone)
{
int threshold;
int watermark_distance;
watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
threshold = max(1, (int)(watermark_distance / num_online_cpus()));
threshold = min(125, threshold);
return threshold;
}
/*
* Refresh the thresholds for each zone.
*/
void refresh_zone_stat_thresholds(void)
{
struct pglist_data *pgdat;
struct zone *zone;
int cpu;
int threshold;
/* Zero current pgdat thresholds */
for_each_online_pgdat(pgdat) {
for_each_online_cpu(cpu) {
per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
}
}
for_each_populated_zone(zone) {
struct pglist_data *pgdat = zone->zone_pgdat;
unsigned long max_drift, tolerate_drift;
threshold = calculate_normal_threshold(zone);
for_each_online_cpu(cpu) {
int pgdat_threshold;
per_cpu_ptr(zone->pageset, cpu)->stat_threshold
= threshold;
/* Base nodestat threshold on the largest populated zone. */
pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
= max(threshold, pgdat_threshold);
}
/*
* Only set percpu_drift_mark if there is a danger that
* NR_FREE_PAGES reports the low watermark is ok when in fact
* the min watermark could be breached by an allocation
*/
tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
max_drift = num_online_cpus() * threshold;
if (max_drift > tolerate_drift)
zone->percpu_drift_mark = high_wmark_pages(zone) +
max_drift;
}
}
int bad_memory_status(void)
{
struct zone *zone;
unsigned long free_pages, min_pages;
for_each_populated_zone(zone) {
if (!strcmp(zone->name, "Normal")) {
free_pages = zone_page_state(zone, NR_FREE_PAGES);
min_pages = min_wmark_pages(zone);
if (free_pages < (min_pages + HIB_PAGE_FREE_DELTA)) {
hib_warn("abort hibernate due to %s memory status: (%lu:%lu)\n",
zone->name, free_pages, min_pages);
return -1;
} else {
hib_warn("%s memory status: (%lu:%lu)\n", zone->name, free_pages,
min_pages);
}
}
}
return 0;
}
void refresh_zone_stat_thresholds(void)
{
struct zone *zone;
int cpu;
int threshold;
for_each_populated_zone(zone) {
unsigned long max_drift, tolerate_drift;
threshold = calculate_normal_threshold(zone);
for_each_online_cpu(cpu)
per_cpu_ptr(zone->pageset, cpu)->stat_threshold
= threshold;
tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
max_drift = num_online_cpus() * threshold;
if (max_drift > tolerate_drift)
zone->percpu_drift_mark = high_wmark_pages(zone) +
max_drift;
}
}
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;
}
