Messages in this thread | | | Date | Fri, 24 Jun 2022 17:51:25 +0800 | Subject | Re: [PATCH 5/7] migrate_pages(): fix failure counting for THP on -ENOSYS | From | Baolin Wang <> |
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On 6/24/2022 10:53 AM, Huang Ying wrote: > 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. > > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > Fixes: 5984fabb6e82 ("mm: move_pages: report the number of non-attempted pages") > Cc: Baolin Wang <baolin.wang@linux.alibaba.com> > Cc: Zi Yan <ziy@nvidia.com> > Cc: Yang Shi <shy828301@gmail.com> > ---
LGTM. Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> mm/migrate.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 61dab3025a1d..9d1883d5927f 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1191,10 +1191,8 @@ 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. */ > @@ -1391,6 +1389,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > * 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 > */ > @@ -1420,6 +1419,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > } > > nr_failed_pages += nr_subpages; > + list_move_tail(&page->lru, &ret_pages); > break; > case -ENOMEM: > /*
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