task_numa_placement checks current->mm but after buffers for faults
have already been uselessly allocated. Move the check earlier.
[peterz@xxxxxxxxxxxxx: Identified the problem]
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
kernel/sched/fair.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 336074f..3c796b0 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -870,8 +870,6 @@ static void task_numa_placement(struct task_struct *p)
int seq, nid, max_nid = 0;
unsigned long max_faults = 0;
- if (!p->mm) /* for example, ksmd faulting in a user's mm */
- return;
seq = ACCESS_ONCE(p->mm->numa_scan_seq);
if (p->numa_scan_seq == seq)
return;
@@ -945,6 +943,12 @@ void task_numa_fault(int last_nid, int node, int pages, bool migrated)
if (!sched_feat_numa(NUMA))
return;
+ /* for example, ksmd faulting in a user's mm */
+ if (!p->mm) {
+ p->numa_scan_period = sysctl_numa_balancing_scan_period_max;
+ return;
+ }
+
/* Allocate buffer to track faults on a per-node basis */
if (unlikely(!p->numa_faults)) {
int size = sizeof(*p->numa_faults) * 2 * nr_node_ids;
@@ -1072,16 +1076,18 @@ void task_numa_work(struct callback_head *work)
end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
end = min(end, vma->vm_end);
nr_pte_updates += change_prot_numa(vma, start, end);
- pages -= (end - start) >> PAGE_SHIFT;
-
- start = end;
/*
* Scan sysctl_numa_balancing_scan_size but ensure that
- * least one PTE is updated so that unused virtual
- * address space is quickly skipped
+ * at least one PTE is updated so that unused virtual
+ * address space is quickly skipped.
*/
- if (pages <= 0 && nr_pte_updates)
+ if (nr_pte_updates)
+ pages -= (end - start) >> PAGE_SHIFT;
+
+ start = end;
+
+ if (pages <= 0)
goto out;
} while (end != vma->vm_end);
}
--
1.8.1.4
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