On Tue, Apr 13, 2021 at 03:48:53PM -0700, Mike Kravetz wrote:
> The label free_new is:
>
> free_new:
> spin_unlock_irq(&hugetlb_lock);
> __free_pages(new_page, huge_page_order(h));
>
> return ret;
>
> So, we are locking and immediately unlocking without any code in
> between. Usually, I don't like like multiple labels before return.
> However, perhaps we should add another to avoid this unnecessary
> cycle. On the other hand, this is an uncommon race condition so the
> simple code may be acceptable.
I guess we could have something like:
free_new:
spin_unlock_irq(&hugetlb_lock);
free_new_nolock:
__free_pages(new_page, huge_page_order(h));
return ret;
And let the retry go to there without locking. But as you said, the
racecondition is rare enough, so I am not sure if this buys us much.
But I can certainly add it if you feel strong about it.
--
Oscar Salvador
SUSE L3
