On 06/12, Boris Ostrovsky wrote:
>
> On 06/12/2015 04:53 PM, Oleg Nesterov wrote:
>>>
>>> for_each_process(p) {
>>>
>>> for_each_thread(p, t) {
>>> if (t->mm) {
>>> do_something(t->mm);
>>> break;
>>> }
>>> }
>>> }
>>>
>>> But either way I don't understand what protects this ->mm. Perhaps this
>>> needs
>>> find_lock_task_mm().
>>
>> And, I don't understand this code, probably this doesn't matter, but.
>>
>> unpin_all() is probably fine, but xen_mm_pin_all() can race with fork()
>> and miss the new child. Is it OK?
>
>
> Currently xen_mm_pin_all() is only called in the suspend path, out of
> stop_machine(), so presumably at that time fork is not possible.
OK, thanks, this also means that this code shouldn't worry about ->mm,
it should be stable.
But for_each_process() in sync_global_pgds() should, afaics.
Oleg.
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