Re: + mm-hugetlb-remove-decrement_hugepage_resv_vma.patch added to -mm tree

Re: + mm-hugetlb-remove-decrement_hugepage_resv_vma.patch added to -mm tree

[Michal Hocko]

> From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Subject: mm, hugetlb: remove decrement_hugepage_resv_vma()
> 
> 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>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Acked-by: Hillf Danton <dhillf@gmail.com>
> Cc: Michal Hocko <mhocko@suse.cz>

Acked-by: Michal Hocko <mhocko@suse.cz>

> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  mm/hugetlb.c |   31 ++++++++++---------------------
>  1 file changed, 10 insertions(+), 21 deletions(-)
> 
> diff -puN mm/hugetlb.c~mm-hugetlb-remove-decrement_hugepage_resv_vma mm/hugetlb.c
> --- a/mm/hugetlb.c~mm-hugetlb-remove-decrement_hugepage_resv_vma
> +++ a/mm/hugetlb.c
> @@ -434,25 +434,6 @@ static int is_vma_resv_set(struct vm_are
>  	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_ar
>  {
>  	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;
>  			}
>  		}
> _
> 
> Patches currently in -mm which might be from iamjoonsoo.kim@lge.com are
> 
> mm-hugetlb-move-up-the-code-which-check-availability-of-free-huge-page.patch
> mm-hugetlb-trivial-commenting-fix.patch
> mm-hugetlb-clean-up-alloc_huge_page.patch
> mm-hugetlb-fix-and-clean-up-node-iteration-code-to-alloc-or-free.patch
> mm-hugetlb-remove-redundant-list_empty-check-in-gather_surplus_pages.patch
> mm-hugetlb-do-not-use-a-page-in-page-cache-for-cow-optimization.patch
> mm-hugetlb-add-vm_noreserve-check-in-vma_has_reserves.patch
> mm-hugetlb-remove-decrement_hugepage_resv_vma.patch
> mm-hugetlb-decrement-reserve-count-if-vm_noreserve-alloc-page-cache.patch
> mm-hugetlb-decrement-reserve-count-if-vm_noreserve-alloc-page-cache-fix.patch
> 

-- 
Michal Hocko
SUSE Labs

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