Subject: [RFC PATCH V5 4/6] arm: mm: Enable RCU fast_gup

From: [email-masked] (Christopher Covington)
Date: Tue, 13 May 2014 11:31:24 -0400

Hi Steve,

On 05/06/2014 11:30 AM, Steve Capper wrote:
> Activate the RCU fast_gup for ARM. We also need to force THP splits to
> broadcast an IPI s.t. we block in the fast_gup page walker. As THP
> splits are comparatively rare, this should not lead to a noticeable
> performance degradation.

> diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
> index 3387e60..91a2b59 100644
> --- a/arch/arm/mm/flush.c
> +++ b/arch/arm/mm/flush.c
> @@ -377,3 +377,22 @@ void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned l
>  	 */
>  	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
>  }
> +
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +#ifdef CONFIG_HAVE_RCU_TABLE_FREE

This is trivia, but I for one find the form #if defined(a) && defined(b)
easier to read. (Applies to the A64 version as well).

Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.