On Mon, Jun 12, 2023 at 10:34:13PM +0800, Kefeng Wang wrote: > @@ -959,7 +960,8 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > * Hugepage was successfully isolated and placed > * on the cc->migratepages list. > */ > - low_pfn += compound_nr(page) - 1; > + folio = page_folio(page); > + low_pfn += folio_nr_pages(folio) - 1; > goto isolate_success_no_list; Why is this safe? That is, how do we know that the folio can't be dissolved under us at this point, then reallocated and hit the VM_BUG_ON_PGFLAGS(PageTail(page), page) in folio_flags() when we test folio_test_large()? > @@ -1132,30 +1137,30 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > * and it's on LRU. It can only be a THP so the order > * is safe to read and it's 0 for tail pages. > */ ^^^ This comment needs to be updated too. > - mod_node_page_state(page_pgdat(page), > - NR_ISOLATED_ANON + page_is_file_lru(page), > - thp_nr_pages(page)); > + lruvec_del_folio(lruvec, folio); > + mod_node_page_state(folio_pgdat(folio), > + NR_ISOLATED_ANON + folio_is_file_lru(folio), > + folio_nr_pages(folio)); node_stat_mod_folio()
