Re: [PATCH v1 02/10] mm: pass gfp flags and order to vma_alloc_zeroed_movable_folio()

Yu Zhao
2023-06-27T02:27:43Z

On Mon, Jun 26, 2023 at 11:14 AM Ryan Roberts <ryan.roberts@arm.com> wrote:
>
> Allow allocation of large folios with vma_alloc_zeroed_movable_folio().
> This prepares the ground for large anonymous folios. The generic
> implementation of vma_alloc_zeroed_movable_folio() now uses
> clear_huge_page() to zero the allocated folio since it may now be a
> non-0 order.
>
> Currently the function is always called with order 0 and no extra gfp
> flags, so no functional change intended. But a subsequent commit will
> take advantage of the new parameters to allocate large folios. The extra
> gfp flags will be used to control the reclaim policy.
>
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
> ---
> arch/alpha/include/asm/page.h | 5 +++--
> arch/arm64/include/asm/page.h | 3 ++-
> arch/arm64/mm/fault.c | 7 ++++---
> arch/ia64/include/asm/page.h | 5 +++--
> arch/m68k/include/asm/page_no.h | 7 ++++---
> arch/s390/include/asm/page.h | 5 +++--
> arch/x86/include/asm/page.h | 5 +++--
> include/linux/highmem.h | 23 +++++++++++++----------
> mm/memory.c | 5 +++--
> 9 files changed, 38 insertions(+), 27 deletions(-)
>
> diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
> index 4db1ebc0ed99..6fc7fe91b6cb 100644
> --- a/arch/alpha/include/asm/page.h
> +++ b/arch/alpha/include/asm/page.h
> @@ -17,8 +17,9 @@
> extern void clear_page(void *page);
> #define clear_user_page(page, vaddr, pg) clear_page(page)
>
> -#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
> - vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
> +#define vma_alloc_zeroed_movable_folio(vma, vaddr, gfp, order) \
> + vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO | (gfp), \
> + order, vma, vaddr, false)

I don't think we need to worry about gfp if we want to make a minimum
series. There would be many discussion points around it, e.g., I
already disagree with what you chose: GFP_TRANSHUGE_LIGHT would be
more suitable than __GFP_NORETRY, and there are even better options
than GFP_TRANSHUGE_LIGHT.