sched/numa: initialize numa statistics when forking new task

The child processes will inherit numa_pages_migrated and
total_numa_faults from the parent. It means even if there is no numa
fault happen on the child, the statistics in /proc/$pid of the child
process might show huge amount. This is a bit weird. Let's initialize
them when do fork.

Signed-off-by: Honglei Wang <wanghonglei@didichuxing.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Link: https://lore.kernel.org/r/20220113133920.49900-1-wanghonglei@didichuxing.com

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 095b0aa..5dca13f 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2825,6 +2825,8 @@ void init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
        /* Protect against double add, see task_tick_numa and task_numa_work */
        p->numa_work.next               = &p->numa_work;
        p->numa_faults                  = NULL;
+       p->numa_pages_migrated          = 0;
+       p->total_numa_faults            = 0;
        RCU_INIT_POINTER(p->numa_group, NULL);
        p->last_task_numa_placement     = 0;
        p->last_sum_exec_runtime        = 0;