From 577be05c8927aa593cf7e29e2b4940607f5756ff Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Wed, 17 Aug 2022 16:14:05 +0800 Subject: migrate_pages(): fix failure counting for THP on -ENOSYS If THP or hugetlbfs page migration isn't supported, unmap_and_move() or unmap_and_move_huge_page() will return -ENOSYS. For THP, splitting will be tried, but if splitting doesn't succeed, the THP will be left in "from" list wrongly. If some other pages are retried, the THP migration failure will counted again. This is fixed via moving the failure THP from "from" to "ret_pages". Another issue of the original code is that the unsupported failure processing isn't consistent between THP and hugetlbfs page. Make them consistent in this patch to make the code easier to be understood too. Link: https://lkml.kernel.org/r/20220817081408.513338-6-ying.huang@intel.com Fixes: 5984fabb6e82 ("mm: move_pages: report the number of non-attempted pages") Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Cc: Zi Yan Cc: Yang Shi Cc: Oscar Salvador Signed-off-by: Andrew Morton --- mm/migrate.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 0018b5191799..0223673e42d1 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1260,10 +1260,8 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, * tables or check whether the hugepage is pmd-based or not before * kicking migration. */ - if (!hugepage_migration_supported(page_hstate(hpage))) { - list_move_tail(&hpage->lru, ret); + if (!hugepage_migration_supported(page_hstate(hpage))) return -ENOSYS; - } if (page_count(hpage) == 1) { /* page was freed from under us. So we are done. */ @@ -1460,6 +1458,7 @@ retry: * page will be put back * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list + * -ENOSYS: stay on the from list * Other errno: put on ret_pages list then splice to * from list */ @@ -1489,6 +1488,7 @@ retry: } nr_failed_pages += nr_subpages; + list_move_tail(&page->lru, &ret_pages); break; case -ENOMEM: /* -- cgit v1.2.3-59-g8ed1b