Re: [PATCH v4 16/21] mm/mm_init: simplify deferred_free_pages() migratetype init

From: Muchun Song

Date: Sun Jul 26 2026 - 23:44:05 EST




> On Jul 27, 2026, at 11:25, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Sun, 26 Jul 2026 13:16:54 +0300 Mike Rapoport <rppt@xxxxxxxxxx> wrote:
>
>> On Sat, Jul 25, 2026 at 07:21:16PM +0200, Pratyush Yadav wrote:
>>> From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
>>>
>>> deferred_free_pages() open-codes two loops to initialize the pageblock
>>> migratetype for a range of pages.
>>>
>>> Replace them with pageblock_migratetype_init_range() to remove the
>>> duplication and make the code clearer (Note that deferred_free_pages() may
>>> be called from atomic context).
>>>
>>> Link: https://lore.kernel.org/20260612035903.2468601-6-songmuchun@xxxxxxxxxxxxx
>>> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
>>> Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
>>> Acked-by: Oscar Salvador <osalvador@xxxxxxx>
>>> Signed-off-by: Pratyush Yadav (Google) <pratyush@xxxxxxxxxx>
>>> ---
>>>
>>> Notes:
>>> This patch is taken from Muchun's series [0]. The patch as of today is
>>> in mm-unstable.
>>
>> @Andrew,
>>
>> It looks like it'll take some time for this patch to get into mm-stable so
>> we can't base this work on a branch in the mm tree :(
>
> I didn't know anyone was using mm-stable :(
>
> Series is adequately reviewed and is near head-of-queue so I can move
> it into mm-stable a few days hence if that helps?
>
>> I'd like to expose the KHO scratch extension to linux-next ASAP so I'm
>> inclined to take this patch as a part of this series and live for a while
>> with a duplicated commit in linux-next. Once this patch would be in
>> mm-stable we can rebase kho-scratch work on top of mm-stable and hopefully
>> there will be enough time for it to live in linux-next so that Linus won't
>> get angry at us :)
>>
>> How does that sound to you?
>
> That's fine - let me know what you choose to do and I'll adapt to it.
>
> An unknown (to me) is whether Muchun's series "mm: Refactor bootmem
> gigantic hugepage allocation, v4" still works with this patch removed. Everything
> applies OK for what that's worth.

Hi Andrew,

I'd like to confirm that this is a completely independent cleanup patch,
so it can be merged on its own.

Thanks.