Re: [PATCH 8/9] mm, hugetlb: remove decrement_hugepage_resv_vma()

[Wanpeng Li <liwanp@linux.vnet.ibm.com>]

On Mon, Jul 15, 2013 at 06:52:46PM +0900, Joonsoo Kim wrote:
>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@lge.com>
>

Reviewed-by: Wanpeng Li <liwanp@linux.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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