Subject: Re: [PATCH v3 4/4] mm/mm_init: Fix pageblock migratetype for ZONE_DEVICE compound pages

From: Oscar Salvador <[email-masked]>
Date: Tue, 21 Apr 2026 06:15:14 +0200

On Tue, Apr 21, 2026 at 10:20:44AM +0800, Muchun Song wrote:
> The memmap_init_zone_device() function only initializes the migratetype
> of the first pageblock of a compound page. If the compound page size
> exceeds pageblock_nr_pages (e.g., 1GB hugepages with 2MB pageblocks),
> subsequent pageblocks in the compound page remain uninitialized.
> 
> Move the migratetype initialization out of __init_zone_device_page()
> and into a separate pageblock_migratetype_init_range() function. This
> iterates over the entire PFN range of the memory, ensuring that all
> pageblocks are correctly initialized.
> 
> Fixes: c4386bd8ee3a ("mm/memremap: add ZONE_DEVICE support for compound pages")
> Signed-off-by: Muchun Song <[email-masked]>
> Reviewed-by: Mike Rapoport (Microsoft) <[email-masked]>

Would not the call to __init_zone_device_page() from
memmap_init_compound() take care of the subsequent pageblocks?

-- 
Oscar Salvador
SUSE Labs