Re: [PATCH mm-stable] mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio

[David Hildenbrand]

On 12.12.22 23:55, Sidhartha Kumar wrote:
> folio_set_compound_order() checks if the passed in folio is a large folio.
> A large folio is indicated by the PG_head flag. Call __folio_set_head()
> before setting the order.
>
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
> Reported-by: David Hildenbrand <david@xxxxxxxxxx>
> ---
> Hi David,
> I tested this by doing:
>
> echo 10 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
> echo 0 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages

Thanks, that should be good enough.

> and checking dmesg. Let me know if there are other ways of testing
> you would like to see run.
>
> Hi Andrew,
> This can be folded into d1c6095572d0cf00c0cd30378639ff9387b34edd
> mm/hugetlb: convert hugetlb prep functions to folios.
>
> However, there is still ongoing discussion with this patch series,
> specifically with patch 1 9fd330582b2f mm: add folio dtor and order setter
> functions, so I'm not sure if this series should be a part of the 6.2 merge
> window. I am planning to send a v6 within the next few days to implement
> the suggested changes.

Whatever is in mm-stable is supposed to go upstream as-is and even the
commit ids will remain stable, meaning we an only queue fixes on top.

Therefore, mm-stable now contains:

commit c45bc55a99957b20e4e0333bcd42e12d1833a7f5 (mm/mm-stable)
Author: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Date:   Mon Dec 12 14:55:29 2022 -0800

    mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio
    
    folio_set_compound_order() checks if the passed in folio is a large folio.
    A large folio is indicated by the PG_head flag.  Call __folio_set_head()
    before setting the order.
    
    Link: https://lkml.kernel.org/r/20221212225529.22493-1-sidhartha.kumar@xxxxxxxxxx
    Fixes: d1c6095572d0 ("mm/hugetlb: convert hugetlb prep functions to folios")
    Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
    Reported-by: David Hildenbrand <david@xxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>


So, best send any future changes against mm-stable instead of sending out a v6.

--
Thanks,

David / dhildenb