Re: [patch] mm, page_alloc: set num_movable in move_freepages()

[Vlastimil Babka]

On 10/5/18 11:21 PM, Andrew Morton wrote:
> On Fri, 5 Oct 2018 13:56:39 -0700 (PDT) David Rientjes <rientjes@xxxxxxxxxx> wrote:
> 
>> If move_freepages() returns 0 because zone_spans_pfn(), *num_movable can
> 
>      move_free_pages_block()?           !zone_spans_pfn()?

Also the subject would be more accurate if it said "initialize
num_movable in move_freepages_block()" ?

Otherwise,
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

>> hold the value from the stack because it does not get initialized in
>> move_freepages().
>>
>> Move the initialization to move_freepages_block() to guarantee the value
>> actually makes sense.
>>
>> This currently doesn't affect its only caller where num_movable != NULL,
>> so no bug fix, but just more robust.
>>
>> ...
>