On 2022/3/7 13:07, Huang, Ying wrote:
> Miaohe Lin <linmiaohe@xxxxxxxxxx> writes:
>
>> We should return errno (-EBUSY here) when failed to isolate the huge page
>> rather than always return 1 which could confuse the user.
>>
>> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>> ---
>> mm/migrate.c | 6 ++----
>> 1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index 6c2dfed2ddb8..279940c0c064 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -1618,10 +1618,8 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
>> goto out_putpage;
>>
>> if (PageHuge(page)) {
>> - if (PageHead(page)) {
>> - isolate_huge_page(page, pagelist);
>> - err = 1;
>> - }
>> + if (PageHead(page))
>> + err = isolate_huge_page(page, pagelist) ? 1 : -EBUSY;
>
> IMHO, it's better to determine the proper errno inside
> isolate_huge_page() instead of in the caller. If you think it's
> necessary to get errno here. How about change isolate_huge_page()
> instead?
IMO, -EBUSY should be enough for the user (as they could not do much) and this
errno keeps consistent with the non-hugetlb page case. What do you think?
Thanks.
>
> Best Regards,
> Huang, Ying
>
>> } else {
>> struct page *head;
> .
>
