2023-01-29 02:55:16

by Chen Wandun

Subject: [PATCH] mm/migrate: Continue to migrate for small pages

migrate_hugetlbs returns -ENOMEM when no enough huge page,
however maybe there are still free small pages, so continue
to migrate for small pages.

Signed-off-by: Chen Wandun <[email protected]>
---
mm/migrate.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index b971edbf32fc..c9d0d2058036 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1939,7 +1939,12 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,

rc_gather = migrate_hugetlbs(from, get_new_page, put_new_page, private,
mode, reason, &stats, &ret_folios);
- if (rc_gather < 0)
+ /* Maybe there are free small pages, continue to migrate.
+ * Nowdays the only negtive return value of migrate_hugetlbs
+ * is -ENOMEM, keep compatible for coming negtive return
+ * value instead of ignore return value.
+ */
+ if (rc_gather < 0 && rc_gather != -ENOMEM)
goto out;
again:
nr_pages = 0;
--
2.25.1

2023-01-29 03:02:46

by Huang, Ying

Subject: Re: [PATCH] mm/migrate: Continue to migrate for small pages

Chen Wandun <[email protected]> writes:

> migrate_hugetlbs returns -ENOMEM when no enough huge page,
> however maybe there are still free small pages, so continue
> to migrate for small pages.

Better to replace "page" with "folio", and "small" with "non-hugetlb".

> Signed-off-by: Chen Wandun <[email protected]>
> ---
> mm/migrate.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index b971edbf32fc..c9d0d2058036 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1939,7 +1939,12 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
>
> rc_gather = migrate_hugetlbs(from, get_new_page, put_new_page, private,
> mode, reason, &stats, &ret_folios);
> - if (rc_gather < 0)
> + /* Maybe there are free small pages, continue to migrate.

There may be free non-hugetlb folios available, continue to migrate.

> + * Nowdays the only negtive return value of migrate_hugetlbs
> + * is -ENOMEM, keep compatible for coming negtive return
> + * value instead of ignore return value.

This can be moved to patch description.

> + */
> + if (rc_gather < 0 && rc_gather != -ENOMEM)
> goto out;
> again:
> nr_pages = 0;

Best Regards,
Huang, Ying

2023-01-29 03:33:24

by Chen Wandun

Subject: Re: [PATCH] mm/migrate: Continue to migrate for small pages

On 2023/1/29 11:01, Huang, Ying wrote:
> Chen Wandun <[email protected]> writes:
>
>> migrate_hugetlbs returns -ENOMEM when no enough huge page,
>> however maybe there are still free small pages, so continue
>> to migrate for small pages.
> Better to replace "page" with "folio", and "small" with "non-hugetlb".
Will do.
>
>> Signed-off-by: Chen Wandun <[email protected]>
>> ---
>> mm/migrate.c | 7 ++++++-
>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index b971edbf32fc..c9d0d2058036 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -1939,7 +1939,12 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
>>
>> rc_gather = migrate_hugetlbs(from, get_new_page, put_new_page, private,
>> mode, reason, &stats, &ret_folios);
>> - if (rc_gather < 0)
>> + /* Maybe there are free small pages, continue to migrate.
> There may be free non-hugetlb folios available, continue to migrate.
will do
>
>> + * Nowdays the only negtive return value of migrate_hugetlbs
>> + * is -ENOMEM, keep compatible for coming negtive return
>> + * value instead of ignore return value.
> This can be moved to patch description.
will do
thanks for your review.

Best Regards.
Wandun
>
>> + */
>> + if (rc_gather < 0 && rc_gather != -ENOMEM)
>> goto out;
>> again:
>> nr_pages = 0;
> Best Regards,
> Huang, Ying
> .