Re: [PATCH v3 13/14] mm: migrate: move_pages() supports thp migration

[Zi Yan]

On 9 Feb 2017, at 3:16, Naoya Horiguchi wrote:

> On Sun, Feb 05, 2017 at 11:12:51AM -0500, Zi Yan wrote:
>> From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
>>
>> This patch enables thp migration for move_pages(2).
>>
>> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
>> ---
>>  mm/migrate.c | 37 ++++++++++++++++++++++++++++---------
>>  1 file changed, 28 insertions(+), 9 deletions(-)
>>
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index 84181a3668c6..9bcaccb481ac 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -1413,7 +1413,17 @@ static struct page *new_page_node(struct page *p, unsigned long private,
>>  	if (PageHuge(p))
>>  		return alloc_huge_page_node(page_hstate(compound_head(p)),
>>  					pm->node);
>> -	else
>> +	else if (thp_migration_supported() && PageTransHuge(p)) {
>> +		struct page *thp;
>> +
>> +		thp = alloc_pages_node(pm->node,
>> +			(GFP_TRANSHUGE | __GFP_THISNODE) & ~__GFP_RECLAIM,
>> +			HPAGE_PMD_ORDER);
>> +		if (!thp)
>> +			return NULL;
>> +		prep_transhuge_page(thp);
>> +		return thp;
>> +	} else
>>  		return __alloc_pages_node(pm->node,
>>  				GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, 0);
>>  }
>> @@ -1440,6 +1450,8 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
>>  	for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
>>  		struct vm_area_struct *vma;
>>  		struct page *page;
>> +		struct page *head;
>> +		unsigned int follflags;
>>
>>  		err = -EFAULT;
>>  		vma = find_vma(mm, pp->addr);
>> @@ -1447,8 +1459,10 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
>>  			goto set_status;
>>
>>  		/* FOLL_DUMP to ignore special (like zero) pages */
>> -		page = follow_page(vma, pp->addr,
>> -				FOLL_GET | FOLL_SPLIT | FOLL_DUMP);
>> +		follflags = FOLL_GET | FOLL_SPLIT | FOLL_DUMP;
>
> FOLL_SPLIT should be added depending on thp_migration_supported().

Sure. I will fix it.


--
Best Regards
Yan Zi

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