On 09/04, Peter Zijlstra wrote:
>
> + struct task_struct *g, *t;
> +
> + read_lock(&tasklist_lock);
> + do_each_thread(g, t) {
for_each_process_thread() looks better
> + if (t->mm == mm) {
> + atomic_or(MEMBARRIER_STATE_GLOBAL_EXPEDITED,
> + &t->membarrier_state);
> + }
then you also need to change dup_task_struct(), it should clear
->membarrier_state unless CLONE_VM.
And probably unuse_mm() should clear current->membarrier_state too.
Hmm. And it can race with copy_process() anyway, tasklist_lock can't
really help. So copy_process() needs to do
write_lock_irq(&tasklist_lock);
...
if (clone_flags & CLONE_VM)
p->membarrier_state = current->membarrier_state;
else
p->membarrier_state = 0;
Oleg.
