Re: [RFC PATCH v1 6/9] freezer: Set default freeze priority for zombie tasks

在 2025/8/8 22:29, Oleg Nesterov 写道:

On 08/07, Zihuan Zhang wrote:

quoted

@@ -6980,6 +6981,7 @@ void __noreturn do_task_dead(void)
  	current->flags |= PF_NOFREEZE;

  	__schedule(SM_NONE);
+	freeze_set_default_priority(current, FREEZE_PRIORITY_NEVER);
  	BUG();

But this change has no effect?

Firstly, this last __schedule() should not return, note the BUG() we have.

Secondly, this zombie is already PF_NOFREEZE, freeze_task() will return
false anyway.

Sorry, but in our tests with a large number of zombie tasks, returning 
early reduced the overhead. Even though freeze_task() would return false 
for PF_NOFREEZE, skipping the extra path still saved time in our 
suspend/freezer loop.

Oleg.