From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: Huang Ying <ying.huang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Zi Yan <ziy@nvidia.com>, Yang Shi <shy828301@gmail.com>
Subject: Re: [PATCH 5/7] migrate_pages(): fix failure counting for THP on -ENOSYS
Date: Fri, 24 Jun 2022 17:51:25 +0800 [thread overview]
Message-ID: <cd8caffe-fe65-f489-32f6-7ad7b46d4419@linux.alibaba.com> (raw)
In-Reply-To: <20220624025309.1033400-6-ying.huang@intel.com>
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:
> /*
next prev parent reply other threads:[~2022-06-24 9:51 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-24 2:53 [PATCH 0/7] migrate_pages(): fix several bugs in error path Huang Ying
2022-06-24 2:53 ` [PATCH 1/7] migrate: fix syscall move_pages() return value for failure Huang Ying
2022-06-24 2:53 ` [PATCH 2/7] migrate_pages(): remove unnecessary list_safe_reset_next() Huang Ying
2022-06-24 9:22 ` Baolin Wang
2022-06-24 2:53 ` [PATCH 3/7] migrate_pages(): fix THP failure counting for -ENOMEM Huang Ying
2022-06-24 9:36 ` Baolin Wang
2022-06-24 2:53 ` [PATCH 4/7] migrate_pages(): fix failure counting for THP subpages retrying Huang Ying
2022-06-24 9:45 ` Baolin Wang
2022-06-27 1:46 ` Huang, Ying
2022-06-27 3:59 ` Baolin Wang
2022-06-27 4:23 ` Huang, Ying
2022-06-27 5:56 ` Baolin Wang
2022-06-24 2:53 ` [PATCH 5/7] migrate_pages(): fix failure counting for THP on -ENOSYS Huang Ying
2022-06-24 9:51 ` Baolin Wang [this message]
2022-06-24 10:11 ` [PATCH 0/7] migrate_pages(): fix several bugs in error path Baolin Wang
2022-06-27 2:30 ` Huang, Ying
2022-06-27 2:24 ` [PATCH 6/7] migrate_pages(): fix failure counting for THP splitting Huang Ying
2022-06-27 4:24 ` Baolin Wang
2022-06-27 2:25 ` [PATCH 7/7] migrate_pages(): fix failure counting for retry Huang Ying
2022-06-27 4:29 ` Baolin Wang
2022-06-27 6:21 ` Huang, Ying
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