Re: [PATCH v1 05/29] mm/balloon_compaction: make PageOffline sticky until the page is freed

Zi Yan
2025-06-30T16:14:08Z

On 30 Jun 2025, at 12:01, Lorenzo Stoakes wrote:

> On Mon, Jun 30, 2025 at 02:59:46PM +0200, David Hildenbrand wrote:
>> Let the page freeing code handle clearing the page type.
>
> Why is this advantageous? We want to keep the page marked offline for longer?
>
>>
>> Acked-by: Zi Yan <ziy@nvidia.com>
>> Acked-by: Harry Yoo <harry.yoo@oracle.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>
> On assumption this UINT_MAX stuff is sane :)) I mean this is straightforward I
> guess:

This is how page type is cleared.
See: https://elixir.bootlin.com/linux/v6.15.4/source/include/linux/page-flags.h#L1013.

I agree with you that patch 4 should have a comment in free_pages_prepare()
about what the code is for and why UINT_MAX is used.

Best Regards,
Yan, Zi