From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx169.postini.com [74.125.245.169]) by kanga.kvack.org (Postfix) with SMTP id 6A8C76B0036 for ; Mon, 29 Jul 2013 03:24:47 -0400 (EDT) Received: by mail-oa0-f49.google.com with SMTP id n16so831854oag.22 for ; Mon, 29 Jul 2013 00:24:46 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1375075929-6119-2-git-send-email-iamjoonsoo.kim@lge.com> References: <1375075929-6119-1-git-send-email-iamjoonsoo.kim@lge.com> <1375075929-6119-2-git-send-email-iamjoonsoo.kim@lge.com> Date: Mon, 29 Jul 2013 15:24:46 +0800 Message-ID: Subject: Re: [PATCH 01/18] mm, hugetlb: protect reserved pages when softofflining requests the pages From: Hillf Danton Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim Cc: Andrew Morton , Rik van Riel , Mel Gorman , Michal Hocko , "Aneesh Kumar K.V" , KAMEZAWA Hiroyuki , Hugh Dickins , Davidlohr Bueso , David Gibson , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim , Wanpeng Li , Naoya Horiguchi On Mon, Jul 29, 2013 at 1:31 PM, Joonsoo Kim wrote: > alloc_huge_page_node() use dequeue_huge_page_node() without > any validation check, so it can steal reserved page unconditionally. Well, why is it illegal to use reserved page here? > To fix it, check the number of free_huge_page in alloc_huge_page_node(). > > Signed-off-by: Joonsoo Kim > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 6782b41..d971233 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -935,10 +935,11 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) > */ > struct page *alloc_huge_page_node(struct hstate *h, int nid) > { > - struct page *page; > + struct page *page = NULL; > > spin_lock(&hugetlb_lock); > - page = dequeue_huge_page_node(h, nid); > + if (h->free_huge_pages - h->resv_huge_pages > 0) > + page = dequeue_huge_page_node(h, nid); > spin_unlock(&hugetlb_lock); > > if (!page) > -- > 1.7.9.5 > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org