Re: [PATCH RFC 3/4] mm/page_alloc: always move pages to the tail of the freelist in unset_migratetype_isolate()

From: David Hildenbrand
Date: Fri Sep 18 2020 - 03:31:10 EST

On 18.09.20 04:29, Wei Yang wrote:
> On Wed, Sep 16, 2020 at 08:34:10PM +0200, David Hildenbrand wrote:
>> Page isolation doesn't actually touch the pages, it simply isolates
>> pageblocks and moves all free pages to the MIGRATE_ISOLATE freelist.
>> We already place pages to the tail of the freelists when undoing
>> isolation via __putback_isolated_page(), let's do it in any case
>> (e.g., if order == pageblock_order) and document the behavior.
>> This change results in all pages getting onlined via online_pages() to
>> be placed to the tail of the freelist.
> I am sorry to not follow again. unset_migratetype_isolate() is used in
> __offline_pages if my understanding is correct. How does it contribute on
> online_pages?

See -next / -mm, that should make it clearer.


David / dhildenb