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