On Wed, Dec 18, 2013 at 08:20:08PM +0100, Oleg Nesterov wrote:
> +struct page *compound_head_put_tail(struct page *page)
> +{
> + struct page *page_head;
> + unsigned long flags;
> +
> + if (!PageTail(page))
> + return page;
> +
> + page_head = compound_trans_head(page);
> +
> + if (!__compound_tail_refcounted(page_head)) {
This barrier is missing a comment describing the ordering and the
pairing.
> + smp_rmb();
> + if (likely(PageTail(page)))
> + return page_head;
> + else
> + return page;
> + }
> +
> + if (likely(get_lock_thp_head(page_head, page, &flags))) {
> + if (put_page_testzero(page_head))
> + VM_BUG_ON(1);
> + atomic_dec(&page->_mapcount);
> + compound_unlock_irqrestore(page_head, flags);
> +
> + return page_head;
> + }
> +
> + return page;
> +}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
