Re: [PATCH v2 11/15] mm: pgtable: introduce generic __tlb_remove_table()

[Alexander Gordeev <agordeev@linux.ibm.com>]

On Wed, Dec 18, 2024 at 09:04:47PM +0800, Qi Zheng wrote:
> Several architectures (arm, arm64, riscv, s390 and x86) define exactly the
> same __tlb_remove_table(), just introduce generic __tlb_remove_table() to
> eliminate these duplications.

s390 is nearly the same, but not exactly (see below).

>  arch/s390/include/asm/tlb.h     |  1 -
>  arch/s390/mm/pgalloc.c          |  7 -------
...
> --- a/arch/s390/mm/pgalloc.c
> +++ b/arch/s390/mm/pgalloc.c
> @@ -193,13 +193,6 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
>  	pagetable_dtor_free(ptdesc);
>  }
>  
> -void __tlb_remove_table(void *table)
> -{
> -	struct ptdesc *ptdesc = virt_to_ptdesc(table);
> -
> -	pagetable_dtor_free(ptdesc);

With this change you introduce these duplication in __tlb_remove_table()
and in pagetable_dtor_free():

	pagetable_dtor(ptdesc);
	pagetable_free(ptdesc);

But I still would prefer to avoid __HAVE_ARCH_TLB_REMOVE_TABLE.
Could it be possible to move pagetable_dtor_free() to asm-generic and
make s390 __tlb_remove_table() version generic?

> -}
> -
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  static void pte_free_now(struct rcu_head *head)
>  {

Thanks!