linux-kernel - Re: [PATCH 8/9] mm, hugetlb: remove decrement_hugepage_resv

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Message-ID: <87ppujj2rc.fsf@linux.vnet.ibm.com>
Date:	Mon, 15 Jul 2013 20:20:47 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Rik van Riel <riel@...hat.com>, Mel Gorman <mgorman@...e.de>,
	Michal Hocko <mhocko@...e.cz>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Hugh Dickins <hughd@...gle.com>,
	Davidlohr Bueso <davidlohr.bueso@...com>,
	David Gibson <david@...son.dropbear.id.au>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Joonsoo Kim <js1304@...il.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: Re: [PATCH 8/9] mm, hugetlb: remove decrement_hugepage_resv_vma()

Joonsoo Kim <iamjoonsoo.kim@....com> writes:

> Now, Checking condition of decrement_hugepage_resv_vma() and
> vma_has_reserves() is same, so we can clean-up this function with
> vma_has_reserves(). Additionally, decrement_hugepage_resv_vma() has only
> one call site, so we can remove function and embed it into
> dequeue_huge_page_vma() directly. This patch implement it.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>

>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index f6a7a4e..ed2d0af 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -434,25 +434,6 @@ static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
>  	return (get_vma_private_data(vma) & flag) != 0;
>  }
>
> -/* Decrement the reserved pages in the hugepage pool by one */
> -static void decrement_hugepage_resv_vma(struct hstate *h,
> -			struct vm_area_struct *vma)
> -{
> -	if (vma->vm_flags & VM_NORESERVE)
> -		return;
> -
> -	if (vma->vm_flags & VM_MAYSHARE) {
> -		/* Shared mappings always use reserves */
> -		h->resv_huge_pages--;
> -	} else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
> -		/*
> -		 * Only the process that called mmap() has reserves for
> -		 * private mappings.
> -		 */
> -		h->resv_huge_pages--;
> -	}
> -}
> -
>  /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
>  void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
>  {
> @@ -466,10 +447,18 @@ static int vma_has_reserves(struct vm_area_struct *vma)
>  {
>  	if (vma->vm_flags & VM_NORESERVE)
>  		return 0;
> +
> +	/* Shared mappings always use reserves */
>  	if (vma->vm_flags & VM_MAYSHARE)
>  		return 1;
> +
> +	/*
> +	 * Only the process that called mmap() has reserves for
> +	 * private mappings.
> +	 */
>  	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
>  		return 1;
> +
>  	return 0;
>  }
>
> @@ -564,8 +553,8 @@ retry_cpuset:
>  		if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
>  			page = dequeue_huge_page_node(h, zone_to_nid(zone));
>  			if (page) {
> -				if (!avoid_reserve)
> -					decrement_hugepage_resv_vma(h, vma);
> +				if (!avoid_reserve && vma_has_reserves(vma))
> +					h->resv_huge_pages--;
>  				break;
>  			}
>  		}
> -- 
> 1.7.9.5

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