From: Aaron Tomlin <atomlin@xxxxxxxxxxx>
Introduce a CPU-specific variable namely vmstat_dirty to indicate
if a vmstat imbalance is present for a given CPU. Therefore, at
the appropriate time, we can fold all the remaining differentials.
This patch also provides trivial helpers for modification and testing.
Signed-off-by: Aaron Tomlin <atomlin@xxxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
---
mm/vmstat.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
Index: linux-2.6/mm/vmstat.c
===================================================================
--- linux-2.6.orig/mm/vmstat.c
+++ linux-2.6/mm/vmstat.c
@@ -194,6 +194,22 @@ void fold_vm_numa_events(void)
#endif
#ifdef CONFIG_SMP
+static DEFINE_PER_CPU_ALIGNED(bool, vmstat_dirty);
+
+static inline void vmstat_mark_dirty(void)
+{
+ this_cpu_write(vmstat_dirty, true);
+}
+
+static inline void vmstat_clear_dirty(void)
+{
+ this_cpu_write(vmstat_dirty, false);
+}
+
+static inline bool is_vmstat_dirty(void)
+{
+ return this_cpu_read(vmstat_dirty);
+}
int calculate_pressure_threshold(struct zone *zone)
{
