The commit 851a723e45d1c("sched: Always clear user_cpus_ptr in do_set_cpus_allowed()")
would clear the user_cpus_ptr when call the do_set_cpus_allowed.
In order to determine whether the user_cpus_ptr is taking effect,
it is better to print the task's user_cpus_ptr.
For top-cpuset:
ums9621_1h10:/ # while true; do done&
[1] 6786
ums9621_1h10:/ # cat /proc/6786/status | grep Cpus
Cpus_allowed: ff
Cpus_allowed_list: 0-7
Cpus_user_allowed: (null)
Cpus_user_allowed_list: (null)
bind the task to 6-7：
ums9621_1h10:/ # taskset -p c0 6786
pid 6786's current affinity mask: ff
pid 6786's new affinity mask: c0
ums9621_1h10:/ # cat /proc/6786/status | grep Cpus
Cpus_allowed: c0
Cpus_allowed_list: 6-7
Cpus_user_allowed: c0
Cpus_user_allowed_list: 6-7
Offline cpu7:
ums9621_1h10:/ # echo 0 > /sys/devices/system/cpu/cpu7/online
ums9621_1h10:/ # cat /proc/6786/status | grep Cpus
Cpus_allowed: c0
Cpus_allowed_list: 6-7
Cpus_user_allowed: c0
Cpus_user_allowed_list: 6-7
Offline cpu6, and then the do_set_cpus_allowed will clear the user_ptr:
ums9621_1h10:/ # echo 0 > /sys/devices/system/cpu/cpu6/online
ums9621_1h10:/ # cat /proc/6786/status | grep Cpus
Cpus_allowed: ff
Cpus_allowed_list: 0-7
Cpus_user_allowed: (null)
Cpus_user_allowed_list: (null)
Bringup the core6,7:
ums9621_1h10:/ # echo 1 > /sys/devices/system/cpu/cpu6/online
ums9621_1h10:/ # echo 1 > /sys/devices/system/cpu/cpu7/online
ums9621_1h10:/ # cat /proc/6786/status | grep Cpus
Cpus_allowed: ff
Cpus_allowed_list: 0-7
Cpus_user_allowed: (null)
Cpus_user_allowed_list: (null)
Signed-off-by: Xuewen Yan <xuewen.yan@xxxxxxxxxx>
---
fs/proc/array.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 34a47fb0c57f..084bee2a2e2b 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -409,6 +409,10 @@ static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
cpumask_pr_args(&task->cpus_mask));
seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
cpumask_pr_args(&task->cpus_mask));
+ seq_printf(m, "Cpus_user_allowed:\t%*pb\n",
+ cpumask_pr_args(task->user_cpus_ptr));
+ seq_printf(m, "Cpus_user_allowed_list:\t%*pbl\n",
+ cpumask_pr_args(task->user_cpus_ptr));
}
static inline void task_core_dumping(struct seq_file *m, struct task_struct *task)
--
2.25.1
