On 2023/6/12 22:41, Matthew Wilcox wrote:
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()?
This is successfully isolated path, after isolate_hugetlb(), the folio
reference is incremented, so I think the folio can't be dissolved here,
correct me if I am wrong.
@@ -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.
will update
- 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()
ok
Thanks
