vmstat: small revisions to refresh_cpu_vm_stats()

[mirror_ubuntu-focal-kernel.git] / mm / vmstat.c

diff --git a/mm/vmstat.c b/mm/vmstat.c
index e8d846f57774ee631adc5836aeaa6498b39736a0..9ffc573ceb6e8539ade001d949d880009aef3208 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -284,6 +284,10 @@ EXPORT_SYMBOL(dec_zone_page_state);
 /*
  * Update the zone counters for one cpu.
  *
+ * The cpu specified must be either the current cpu or a processor that
+ * is not online. If it is the current cpu then the execution thread must
+ * be pinned to the current cpu.
+ *
  * Note that refresh_cpu_vm_stats strives to only access
  * node local memory. The per cpu pagesets on remote zones are placed
  * in the memory local to the processor using that pageset. So the
@@ -299,7 +303,7 @@ void refresh_cpu_vm_stats(int cpu)
 {
        struct zone *zone;
        int i;
-       unsigned long flags;
+       int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 
        for_each_zone(zone) {
                struct per_cpu_pageset *p;
@@ -311,15 +315,19 @@ void refresh_cpu_vm_stats(int cpu)
 
                for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
                        if (p->vm_stat_diff[i]) {
+                               unsigned long flags;
+                               int v;
+
                                local_irq_save(flags);
-                               zone_page_state_add(p->vm_stat_diff[i],
-                                       zone, i);
+                               v = p->vm_stat_diff[i];
                                p->vm_stat_diff[i] = 0;
+                               local_irq_restore(flags);
+                               atomic_long_add(v, &zone->vm_stat[i]);
+                               global_diff[i] += v;
 #ifdef CONFIG_NUMA
                                /* 3 seconds idle till flush */
                                p->expire = 3;
 #endif
-                               local_irq_restore(flags);
                        }
 #ifdef CONFIG_NUMA
                /*
@@ -351,6 +359,10 @@ void refresh_cpu_vm_stats(int cpu)
                        drain_zone_pages(zone, p->pcp + 1);
 #endif
        }
+
+       for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+               if (global_diff[i])
+                       atomic_long_add(global_diff[i], &vm_stat[i]);
 }
 
 #endif