Re: [PATCH 2/4] mm: thp: make deferred split shrinker memcg aware

[Kirill A. Shutemov]

On Fri, Jun 07, 2019 at 02:07:37PM +0800, Yang Shi wrote:
> +	/*
> +	 * The THP may be not on LRU at this point, e.g. the old page of
> +	 * NUMA migration.  And PageTransHuge is not enough to distinguish
> +	 * with other compound page, e.g. skb, THP destructor is not used
> +	 * anymore and will be removed, so the compound order sounds like
> +	 * the only choice here.
> +	 */
> +	if (PageTransHuge(page) && compound_order(page) == HPAGE_PMD_ORDER) {

What happens if the page is the same order as THP is not THP? Why removing
of destructor is required?

-- 
 Kirill A. Shutemov