On Mon, Jul 18, 2022 at 09:00:50PM +1200, Barry Song wrote:
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1652a9800ebe..e1c540e80eec 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -101,6 +101,7 @@ config ARM64
> select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
> select ARCH_WANT_LD_ORPHAN_WARN
> select ARCH_WANTS_NO_INSTR
> + select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES
Can't you avoid all the other changes by simply doing:
select ARCH_WANTS_THP_SWAP if ARM64_4K_PAGES && !ARM64_MTE
> select ARCH_HAS_UBSAN_SANITIZE_ALL
> select ARM_AMBA
> select ARM_ARCH_TIMER
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index 0b6632f18364..78d6f6014bfb 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -45,6 +45,12 @@
> __flush_tlb_range(vma, addr, end, PUD_SIZE, false, 1)
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>
> +static inline bool arch_thp_swp_supported(void)
> +{
> + return !system_supports_mte();
> +}
> +#define arch_thp_swp_supported arch_thp_swp_supported
> +
> /*
> * Outside of a few very special situations (e.g. hibernation), we always
> * use broadcast TLB invalidation instructions, therefore a spurious page
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index de29821231c9..4ddaf6ad73ef 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -461,4 +461,16 @@ static inline int split_folio_to_list(struct folio *folio,
> return split_huge_page_to_list(&folio->page, list);
> }
>
> +/*
> + * archs that select ARCH_WANTS_THP_SWAP but don't support THP_SWP due to
> + * limitations in the implementation like arm64 MTE can override this to
> + * false
> + */
> +#ifndef arch_thp_swp_supported
> +static inline bool arch_thp_swp_supported(void)
> +{
> + return true;
> +}
> +#endif
> +
> #endif /* _LINUX_HUGE_MM_H */
> diff --git a/mm/swap_slots.c b/mm/swap_slots.c
> index 2a65a89b5b4d..10b94d64cc25 100644
> --- a/mm/swap_slots.c
> +++ b/mm/swap_slots.c
> @@ -307,7 +307,7 @@ swp_entry_t folio_alloc_swap(struct folio *folio)
> entry.val = 0;
>
> if (folio_test_large(folio)) {
> - if (IS_ENABLED(CONFIG_THP_SWAP))
> + if (IS_ENABLED(CONFIG_THP_SWAP) && arch_thp_swp_supported())
> get_swap_pages(1, &entry, folio_nr_pages(folio));
> goto out;
> }
> --
> 2.25.1
>
>
