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-rw-r--r--kernel/sched/fair.c29
1 files changed, 21 insertions, 8 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index dd18087..4b57786 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -784,7 +784,8 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
* numa task sample period in ms
*/
unsigned int sysctl_numa_balancing_scan_period_min = 100;
-unsigned int sysctl_numa_balancing_scan_period_max = 100*16;
+unsigned int sysctl_numa_balancing_scan_period_max = 100*50;
+unsigned int sysctl_numa_balancing_scan_period_reset = 100*600;
/* Portion of address space to scan in MB */
unsigned int sysctl_numa_balancing_scan_size = 256;
@@ -806,20 +807,19 @@ static void task_numa_placement(struct task_struct *p)
/*
* Got a PROT_NONE fault for a page on @node.
*/
-void task_numa_fault(int node, int pages)
+void task_numa_fault(int node, int pages, bool migrated)
{
struct task_struct *p = current;
/* FIXME: Allocate task-specific structure for placement policy here */
/*
- * Assume that as faults occur that pages are getting properly placed
- * and fewer NUMA hints are required. Note that this is a big
- * assumption, it assumes processes reach a steady steady with no
- * further phase changes.
+ * If pages are properly placed (did not migrate) then scan slower.
+ * This is reset periodically in case of phase changes
*/
- p->numa_scan_period = min(sysctl_numa_balancing_scan_period_max,
- p->numa_scan_period + jiffies_to_msecs(2));
+ if (!migrated)
+ p->numa_scan_period = min(sysctl_numa_balancing_scan_period_max,
+ p->numa_scan_period + jiffies_to_msecs(10));
task_numa_placement(p);
}
@@ -858,6 +858,19 @@ void task_numa_work(struct callback_head *work)
return;
/*
+ * Reset the scan period if enough time has gone by. Objective is that
+ * scanning will be reduced if pages are properly placed. As tasks
+ * can enter different phases this needs to be re-examined. Lacking
+ * proper tracking of reference behaviour, this blunt hammer is used.
+ */
+ migrate = mm->numa_next_reset;
+ if (time_after(now, migrate)) {
+ p->numa_scan_period = sysctl_numa_balancing_scan_period_min;
+ next_scan = now + msecs_to_jiffies(sysctl_numa_balancing_scan_period_reset);
+ xchg(&mm->numa_next_reset, next_scan);
+ }
+
+ /*
* Enforce maximal scan/migration frequency..
*/
migrate = mm->numa_next_scan;
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