Re: [PATCHv2 10/14] mm: Drop fake head checks

[Muchun Song]

> On Dec 18, 2025, at 23:09, Kiryl Shutsemau <kas@xxxxxxxxxx> wrote:
> 
> With fake head pages eliminated in the previous commit, remove the
> supporting infrastructure:
> 
>  - page_fixed_fake_head(): no longer needed to detect fake heads;
>  - page_is_fake_head(): no longer needed;
>  - page_count_writable(): no longer needed for RCU protection;
>  - RCU read_lock in page_ref_add_unless(): no longer needed;
> 
> This substantially simplifies compound_head() and page_ref_add_unless(),
> removing both branches and RCU overhead from these hot paths.
> 
> Signed-off-by: Kiryl Shutsemau <kas@xxxxxxxxxx>

Reviewed-by: Muchun Song <muchun.song@xxxxxxxxx>

Thanks.