On 2023/7/5 15:30, Zhen Lei wrote:
> The stacks of all stalled CPUs will be dumped. If the CPU on where RCU GP
> kthread last ran is stalled, its stack does not need to be dumped again.
Should I add Fixes?
Fixes: 243027a3c805 ("rcu: For RCU grace-period kthread starvation, dump last CPU it ran on")
>
> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
> ---
> kernel/rcu/tree_stall.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
> index dcfaa3d5db2cbc7..cc884cd49e026a3 100644
> --- a/kernel/rcu/tree_stall.h
> +++ b/kernel/rcu/tree_stall.h
> @@ -534,12 +534,14 @@ static void rcu_check_gp_kthread_starvation(void)
> data_race(READ_ONCE(rcu_state.gp_state)),
> gpk ? data_race(READ_ONCE(gpk->__state)) : ~0, cpu);
> if (gpk) {
> + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
> +
> pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name);
> pr_err("RCU grace-period kthread stack dump:\n");
> sched_show_task(gpk);
> if (cpu_is_offline(cpu)) {
> pr_err("RCU GP kthread last ran on offline CPU %d.\n", cpu);
> - } else {
> + } else if (!(data_race(READ_ONCE(rdp->mynode->qsmask)) & rdp->grpmask)) {
> pr_err("Stack dump where RCU GP kthread last ran:\n");
> dump_cpu_task(cpu);
> }
>
--
Regards,
Zhen Lei
