Off-topic, but...
On 07/28, Oleg Nesterov wrote:
>
> But we should always call user_exit() unconditionally?
Frederic, don't we need the patch below? In fact clear_() can be moved
under "if ()" too. and probably copy_process() should clear this flag...
Or. __context_tracking_task_switch() can simply do
if (context_tracking_cpu_is_enabled())
set_tsk_thread_flag(next, TIF_NOHZ);
else
clear_tsk_thread_flag(next, TIF_NOHZ);
and then we can forget about copy_process(). Or I am totally confused?
I am also wondering if we can extend user_return_notifier to handle
enter/exit and kill TIF_NOHZ.
Oleg.
--- x/kernel/context_tracking.c
+++ x/kernel/context_tracking.c
@@ -202,7 +202,8 @@ void __context_tracking_task_switch(stru
struct task_struct *next)
{
clear_tsk_thread_flag(prev, TIF_NOHZ);
- set_tsk_thread_flag(next, TIF_NOHZ);
+ if (context_tracking_cpu_is_enabled())
+ set_tsk_thread_flag(next, TIF_NOHZ);
}
#ifdef CONFIG_CONTEXT_TRACKING_FORCE
