Re: [PATCH mm-hotfixes v2 2/2] mm/huge_memory: separate out CONFIG_PERSISTENT_HUGE_ZERO_FOLIO logic

[David Hildenbrand (Arm)]

On 7/30/26 12:55, Lorenzo Stoakes (ARM) wrote:
> Rather than mixing the refcounted and non-refcounted
> CONFIG_PERSISTENT_HUGE_ZERO_FOLIO logic, separate the two out cleanly
> so it is clear what happens when this configuration option is set and what
> happens when it is not.
> 
> Introduce HUGE_ZERO_UNSET_PFN to abstract the ~0UL assignment, only
> introduce the refcount, lock and shrinker if
> !CONFIG_PERSISTENT_HUGE_ZERO_FOLIO, abstract initialisation and teardown,
> abstract the huge zero folio allocation from refcounting.
> 
> Also change a BUG_ON() to WARN_ON_ONCE() while we're at it.
> 
> No functional change intended.

Ugh. Why is this patch already upsteam with

Fixes: 3b77e8c8cde5 ("mm/thp: make is_huge_zero_pmd() safe and quicker")
Cc: <stable@xxxxxxxxxxxxxxx>

It's absolutely not a fix. It's a cleanup that should have been reviewed properly.

I really wanted to review this.

Making David grumpy in the morning, good job everyone.

-- 
Cheers,

David