Re: [Patch v2 2/4] mm/migrate.c: wrap do_move_pages_to_node() and store_status()

[Wei Yang]

On Wed, Jan 29, 2020 at 10:28:53AM +0100, David Hildenbrand wrote:
>On 29.01.20 01:38, Wei Yang wrote:
>> On Tue, Jan 28, 2020 at 11:14:55AM +0100, David Hildenbrand wrote:
>>> On 22.01.20 02:16, Wei Yang wrote:
>>>> Usually do_move_pages_to_node() and store_status() is a pair. There are
>>>> three places call this pair of functions with almost the same form.
>>>
>>> I'd suggest
>>>
>>> "
>>> Usually, do_move_pages_to_node() and store_status() are used in
>>> combination. We have three similar call sites.
>>>
>>> Let's provide a wrapper for both function calls -
>>> move_pages_and_store_status - to make the calling code easier to
>>> maintain and fix (as noted by Yang Shi, the return value handling of
>>> do_move_pages_to_node() has a flaw).
>>> "
>> 
>> Looks good.
>> 
>>>
>>>>
>>>> This patch just wrap it to make it friendly to audience and also
>>>> consolidate the move and store action into one place. Also mentioned by
>>>> Yang Shi, the handling of do_move_pages_to_node()'s return value is not
>>>> proper. Now we can fix it in one place.
>>>>
>>>> Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>>>> Acked-by: Michal Hocko <mhocko@xxxxxxxx>
>>>> ---
>>>>  mm/migrate.c | 30 +++++++++++++++++++-----------
>>>>  1 file changed, 19 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/mm/migrate.c b/mm/migrate.c
>>>> index 4c2a21856717..a4d3bd6475e1 100644
>>>> --- a/mm/migrate.c
>>>> +++ b/mm/migrate.c
>>>> @@ -1583,6 +1583,19 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
>>>>  	return err;
>>>>  }
>>>>  
>>>> +static int move_pages_and_store_status(struct mm_struct *mm, int node,
>>>> +		struct list_head *pagelist, int __user *status,
>>>> +		int start, int nr)
>>>
>>> nit: indentation
>>>
>> 
>> You mean indent like this?
>> 
>> static int move_pages_and_store_status(struct mm_struct *mm, int node,
>> 				       struct list_head *pagelist,
>> 				       int __user *status,
>> 
>> This would be along list and I am afraid this is not the only valid code
>> style?
>
>Yes, that's what I meant. Documentation/process/coding-style.rst doesn't
>mention any specific way, but this is the most commonly used one.
>
>Indentation in this file mostly sticks to something like this as well,
>but yeah, it's often a mess and not consistent.
>
>That's why I note it whenever I see it, to make it eventually more
>consistent (and only make it a nit) :)
>

You are right. I would leave as it now, if someone else still have the same
suggestion to fix it.

Thanks :-)

>-- 
>Thanks,
>
>David / dhildenb

-- 
Wei Yang
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