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 312d728976f1..bc0f095791b4 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c | |||
@@ -83,6 +83,30 @@ EXPORT_SYMBOL(vm_stat); | |||
83 | 83 | ||
84 | #ifdef CONFIG_SMP | 84 | #ifdef CONFIG_SMP |
85 | 85 | ||
86 | static int calculate_pressure_threshold(struct zone *zone) | ||
87 | { | ||
88 | int threshold; | ||
89 | int watermark_distance; | ||
90 | |||
91 | /* | ||
92 | * As vmstats are not up to date, there is drift between the estimated | ||
93 | * and real values. For high thresholds and a high number of CPUs, it | ||
94 | * is possible for the min watermark to be breached while the estimated | ||
95 | * value looks fine. The pressure threshold is a reduced value such | ||
96 | * that even the maximum amount of drift will not accidentally breach | ||
97 | * the min watermark | ||
98 | */ | ||
99 | watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone); | ||
100 | threshold = max(1, (int)(watermark_distance / num_online_cpus())); | ||
101 | |||
102 | /* | ||
103 | * Maximum threshold is 125 | ||
104 | */ | ||
105 | threshold = min(125, threshold); | ||
106 | |||
107 | return threshold; | ||
108 | } | ||
109 | |||
86 | static int calculate_threshold(struct zone *zone) | 110 | static int calculate_threshold(struct zone *zone) |
87 | { | 111 | { |
88 | int threshold; | 112 | int threshold; |
@@ -161,6 +185,48 @@ static void refresh_zone_stat_thresholds(void) | |||
161 | } | 185 | } |
162 | } | 186 | } |
163 | 187 | ||
188 | void reduce_pgdat_percpu_threshold(pg_data_t *pgdat) | ||
189 | { | ||
190 | struct zone *zone; | ||
191 | int cpu; | ||
192 | int threshold; | ||
193 | int i; | ||
194 | |||
195 | get_online_cpus(); | ||
196 | for (i = 0; i < pgdat->nr_zones; i++) { | ||
197 | zone = &pgdat->node_zones[i]; | ||
198 | if (!zone->percpu_drift_mark) | ||
199 | continue; | ||
200 | |||
201 | threshold = calculate_pressure_threshold(zone); | ||
202 | for_each_online_cpu(cpu) | ||
203 | per_cpu_ptr(zone->pageset, cpu)->stat_threshold | ||
204 | = threshold; | ||
205 | } | ||
206 | put_online_cpus(); | ||
207 | } | ||
208 | |||
209 | void restore_pgdat_percpu_threshold(pg_data_t *pgdat) | ||
210 | { | ||
211 | struct zone *zone; | ||
212 | int cpu; | ||
213 | int threshold; | ||
214 | int i; | ||
215 | |||
216 | get_online_cpus(); | ||
217 | for (i = 0; i < pgdat->nr_zones; i++) { | ||
218 | zone = &pgdat->node_zones[i]; | ||
219 | if (!zone->percpu_drift_mark) | ||
220 | continue; | ||
221 | |||
222 | threshold = calculate_threshold(zone); | ||
223 | for_each_online_cpu(cpu) | ||
224 | per_cpu_ptr(zone->pageset, cpu)->stat_threshold | ||
225 | = threshold; | ||
226 | } | ||
227 | put_online_cpus(); | ||
228 | } | ||
229 | |||
164 | /* | 230 | /* |
165 | * For use when we know that interrupts are disabled. | 231 | * For use when we know that interrupts are disabled. |
166 | */ | 232 | */ |
@@ -911,7 +977,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, | |||
911 | "\n scanned %lu" | 977 | "\n scanned %lu" |
912 | "\n spanned %lu" | 978 | "\n spanned %lu" |
913 | "\n present %lu", | 979 | "\n present %lu", |
914 | zone_nr_free_pages(zone), | 980 | zone_page_state(zone, NR_FREE_PAGES), |
915 | min_wmark_pages(zone), | 981 | min_wmark_pages(zone), |
916 | low_wmark_pages(zone), | 982 | low_wmark_pages(zone), |
917 | high_wmark_pages(zone), | 983 | high_wmark_pages(zone), |