Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756766Ab3HZNgx (ORCPT ); Mon, 26 Aug 2013 09:36:53 -0400 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:50201 "EHLO e28smtp08.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751558Ab3HZNgw (ORCPT ); Mon, 26 Aug 2013 09:36:52 -0400 From: "Aneesh Kumar K.V" To: Joonsoo Kim , Andrew Morton Cc: Rik van Riel , Mel Gorman , Michal Hocko , KAMEZAWA Hiroyuki , Hugh Dickins , Davidlohr Bueso , David Gibson , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Joonsoo Kim , Wanpeng Li , Naoya Horiguchi , Hillf Danton , Joonsoo Kim Subject: Re: [PATCH v2 14/20] mm, hugetlb: call vma_needs_reservation before entering alloc_huge_page() In-Reply-To: <1376040398-11212-15-git-send-email-iamjoonsoo.kim@lge.com> References: <1376040398-11212-1-git-send-email-iamjoonsoo.kim@lge.com> <1376040398-11212-15-git-send-email-iamjoonsoo.kim@lge.com> User-Agent: Notmuch/0.15.2+167~g5306b2b (http://notmuchmail.org) Emacs/24.3.50.1 (x86_64-unknown-linux-gnu) Date: Mon, 26 Aug 2013 19:06:45 +0530 Message-ID: <87vc2sd15e.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13082613-2000-0000-0000-00000D766547 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3702 Lines: 116 Joonsoo Kim writes: > In order to validate that this failure is reasonable, we need to know > whether allocation request is for reserved or not on caller function. > So moving vma_needs_reservation() up to the caller of alloc_huge_page(). > There is no functional change in this patch and following patch use > this information. > > Signed-off-by: Joonsoo Kim > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 8dff972..bc666cf 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1110,13 +1110,11 @@ static void vma_commit_reservation(struct hstate *h, > } > > static struct page *alloc_huge_page(struct vm_area_struct *vma, > - unsigned long addr, int avoid_reserve) > + unsigned long addr, int use_reserve) > { > struct hugepage_subpool *spool = subpool_vma(vma); > struct hstate *h = hstate_vma(vma); > struct page *page; > - long chg; > - bool use_reserve; > int ret, idx; > struct hugetlb_cgroup *h_cg; > > @@ -1129,10 +1127,6 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, > * need pages and subpool limit allocated allocated if no reserve > * mapping overlaps. > */ > - chg = vma_needs_reservation(h, vma, addr); > - if (chg < 0) > - return ERR_PTR(-ENOMEM); > - use_reserve = (!chg && !avoid_reserve); > if (!use_reserve) > if (hugepage_subpool_get_pages(spool, 1)) > return ERR_PTR(-ENOSPC); > @@ -2504,6 +2498,8 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, > struct hstate *h = hstate_vma(vma); > struct page *old_page, *new_page; > int outside_reserve = 0; > + long chg; > + bool use_reserve; > unsigned long mmun_start; /* For mmu_notifiers */ > unsigned long mmun_end; /* For mmu_notifiers */ > > @@ -2535,7 +2531,17 @@ retry_avoidcopy: > > /* Drop page_table_lock as buddy allocator may be called */ > spin_unlock(&mm->page_table_lock); > - new_page = alloc_huge_page(vma, address, outside_reserve); > + chg = vma_needs_reservation(h, vma, address); > + if (chg == -ENOMEM) { why not if (chg < 0) ? Should we try to unmap the page from child and avoid cow here ?. May be with outside_reserve = 1 we will never have vma_needs_reservation fail. Any how it would be nice to document why this error case is different from alloc_huge_page error case. > + page_cache_release(old_page); > + > + /* Caller expects lock to be held */ > + spin_lock(&mm->page_table_lock); > + return VM_FAULT_OOM; > + } > + use_reserve = !chg && !outside_reserve; > + > + new_page = alloc_huge_page(vma, address, use_reserve); > > if (IS_ERR(new_page)) { > long err = PTR_ERR(new_page); > @@ -2664,6 +2670,8 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, > struct page *page; > struct address_space *mapping; > pte_t new_pte; > + long chg; > + bool use_reserve; > > /* > * Currently, we are forced to kill the process in the event the > @@ -2689,7 +2697,15 @@ retry: > size = i_size_read(mapping->host) >> huge_page_shift(h); > if (idx >= size) > goto out; > - page = alloc_huge_page(vma, address, 0); > + > + chg = vma_needs_reservation(h, vma, address); > + if (chg == -ENOMEM) { if (chg < 0) > + ret = VM_FAULT_OOM; > + goto out; > + } > + use_reserve = !chg; > + > + page = alloc_huge_page(vma, address, use_reserve); > if (IS_ERR(page)) { > ret = PTR_ERR(page); > if (ret == -ENOMEM) > -- > 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/