Re: [PATCH v2 1/1] mm: initialize pages on demand during boot

[Pavel Tatashin]

>>
>> It would be nice to have a little comment explaining why READ_ONCE was
>> needed.
>>
>> Would it still be needed if this code was moved into the locked region?
>
>
> No, we would need to use READ_ONCE() if we grabbed deferred_zone_grow_lock
> before this code. In fact I do not even think we strictly need READ_ONCE()
> here, as it is a single load anyway. But, because we are outside of the
> lock, and we want to quickly fetch the data with a single load, I think it
> makes sense to emphasize it using READ_ONCE() without expected compiler to
> simply do the write thing for us.
>
>

Correction:

No, we would NOT need ...