Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759635Ab3GSDgV (ORCPT ); Thu, 18 Jul 2013 23:36:21 -0400 Received: from mail-ob0-f177.google.com ([209.85.214.177]:49761 "EHLO mail-ob0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759609Ab3GSDgU (ORCPT ); Thu, 18 Jul 2013 23:36:20 -0400 MIME-Version: 1.0 In-Reply-To: <1374183272-10153-5-git-send-email-n-horiguchi@ah.jp.nec.com> References: <1374183272-10153-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1374183272-10153-5-git-send-email-n-horiguchi@ah.jp.nec.com> Date: Fri, 19 Jul 2013 11:36:19 +0800 Message-ID: Subject: Re: [PATCH 4/8] migrate: add hugepage migration code to move_pages() From: Hillf Danton To: Naoya Horiguchi Cc: linux-mm@kvack.org, Andrew Morton , Mel Gorman , Hugh Dickins , KOSAKI Motohiro , Andi Kleen , Michal Hocko , Rik van Riel , "Aneesh Kumar K.V" , linux-kernel@vger.kernel.org, Naoya Horiguchi Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4193 Lines: 108 On Fri, Jul 19, 2013 at 5:34 AM, Naoya Horiguchi wrote: > This patch extends move_pages() to handle vma with VM_HUGETLB set. > We will be able to migrate hugepage with move_pages(2) after > applying the enablement patch which comes later in this series. > > We avoid getting refcount on tail pages of hugepage, because unlike thp, > hugepage is not split and we need not care about races with splitting. > > And migration of larger (1GB for x86_64) hugepage are not enabled. > > ChangeLog v3: > - revert introducing migrate_movable_pages > - follow_page_mask(FOLL_GET) returns NULL for tail pages > - use isolate_huge_page > > ChangeLog v2: > - updated description and renamed patch title > > Signed-off-by: Naoya Horiguchi > --- > mm/memory.c | 12 ++++++++++-- > mm/migrate.c | 13 +++++++++++-- > 2 files changed, 21 insertions(+), 4 deletions(-) > > diff --git v3.11-rc1.orig/mm/memory.c v3.11-rc1/mm/memory.c > index 1ce2e2a..8c9a2cb 100644 > --- v3.11-rc1.orig/mm/memory.c > +++ v3.11-rc1/mm/memory.c > @@ -1496,7 +1496,8 @@ struct page *follow_page_mask(struct vm_area_struct *vma, > if (pud_none(*pud)) > goto no_page_table; > if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) { > - BUG_ON(flags & FOLL_GET); > + if (flags & FOLL_GET) > + goto out; > page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE); > goto out; > } > @@ -1507,8 +1508,15 @@ struct page *follow_page_mask(struct vm_area_struct *vma, > if (pmd_none(*pmd)) > goto no_page_table; > if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) { > - BUG_ON(flags & FOLL_GET); > page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); > + if (flags & FOLL_GET) { > + if (PageHead(page)) > + get_page_foll(page); > + else { > + page = NULL; > + goto out; > + } > + } Can get_page do the work for us, like the following? if (flags & FOLL_GET) get_page(page); > goto out; > } > if ((flags & FOLL_NUMA) && pmd_numa(*pmd)) > diff --git v3.11-rc1.orig/mm/migrate.c v3.11-rc1/mm/migrate.c > index 3ec47d3..d313737 100644 > --- v3.11-rc1.orig/mm/migrate.c > +++ v3.11-rc1/mm/migrate.c > @@ -1092,7 +1092,11 @@ static struct page *new_page_node(struct page *p, unsigned long private, > > *result = &pm->status; > > - return alloc_pages_exact_node(pm->node, > + if (PageHuge(p)) > + return alloc_huge_page_node(page_hstate(compound_head(p)), > + pm->node); > + else > + return alloc_pages_exact_node(pm->node, > GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0); > } > > @@ -1152,6 +1156,11 @@ static int do_move_page_to_node_array(struct mm_struct *mm, > !migrate_all) > goto put_and_set; > > + if (PageHuge(page)) { > + isolate_huge_page(page, &pagelist); > + goto put_and_set; > + } > + > err = isolate_lru_page(page); > if (!err) { > list_add_tail(&page->lru, &pagelist); > @@ -1174,7 +1183,7 @@ static int do_move_page_to_node_array(struct mm_struct *mm, > err = migrate_pages(&pagelist, new_page_node, > (unsigned long)pm, MIGRATE_SYNC, MR_SYSCALL); > if (err) > - putback_lru_pages(&pagelist); > + putback_movable_pages(&pagelist); > } > > up_read(&mm->mmap_sem); > -- > 1.8.3.1 > -- 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/