Re: [PATCH] sched/numa: initialize numa statistics when forking new task

From: Honglei Wang
Date: Mon Jan 17 2022 - 11:18:37 EST


Hello, friendly ping... any comments about this?

At 2022-01-13 21:39:20, "Honglei Wang" <wanghonglei@xxxxxxxxxxxxxxx> wrote:
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@xxxxxxxxxxxxxxx>
---
kernel/sched/fair.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6e476f6d9435..1aa0ec123a4b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2826,6 +2826,8 @@ 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;
--
2.14.1