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Subject: Re: [Patch v2 2/4] mm/migrate.c: wrap do_move_pages_to_node() and
 store_status()
To:     Wei Yang <richardw.yang@linux.intel.com>
Cc:     akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, mhocko@suse.com,
        yang.shi@linux.alibaba.com, rientjes@google.com
References: <20200122011647.13636-1-richardw.yang@linux.intel.com>
 <20200122011647.13636-3-richardw.yang@linux.intel.com>
 <15777c05-2f2c-b818-dacd-3ec31f83be8d@redhat.com>
 <20200129003812.GC12835@richard>
From:   David Hildenbrand <david@redhat.com>
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Organization: Red Hat GmbH
Message-ID: <68d4f7fb-2f37-2b11-dd0f-2e059415daf2@redhat.com>
Date:   Wed, 29 Jan 2020 10:28:53 +0100
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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 a=
re
>>> 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).
>> "
>=20
> Looks good.
>=20
>>
>>>
>>> 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 n=
ot
>>> proper. Now we can fix it in one place.
>>>
>>> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
>>> Acked-by: Michal Hocko <mhocko@suse.com>
>>> ---
>>>  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_st=
ruct *mm, unsigned long addr,
>>>  	return err;
>>>  }
>>> =20
>>> +static int move_pages_and_store_status(struct mm_struct *mm, int nod=
e,
>>> +		struct list_head *pagelist, int __user *status,
>>> +		int start, int nr)
>>
>> nit: indentation
>>
>=20
> You mean indent like this?
>=20
> static int move_pages_and_store_status(struct mm_struct *mm, int node,
> 				       struct list_head *pagelist,
> 				       int __user *status,
>=20
> This would be along list and I am afraid this is not the only valid cod=
e
> 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) :)

--=20
Thanks,

David / dhildenb