From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753397AbbC3PXt (ORCPT ); Mon, 30 Mar 2015 11:23:49 -0400 Received: from mta-out1.inet.fi ([62.71.2.227]:49452 "EHLO jenni1.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752803AbbC3PXq (ORCPT ); Mon, 30 Mar 2015 11:23:46 -0400 Date: Mon, 30 Mar 2015 18:23:21 +0300 From: "Kirill A. Shutemov" To: "Aneesh Kumar K.V" Cc: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli , Dave Hansen , Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , Johannes Weiner , Michal Hocko , Jerome Marchand , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv4 19/24] thp, mm: use migration entries to freeze page counts on split Message-ID: <20150330152321.GB5849@node.dhcp.inet.fi> References: <1425486792-93161-1-git-send-email-kirill.shutemov@linux.intel.com> <1425486792-93161-20-git-send-email-kirill.shutemov@linux.intel.com> <87k2xylg8w.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87k2xylg8w.fsf@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 30, 2015 at 07:49:43PM +0530, Aneesh Kumar K.V wrote: > "Kirill A. Shutemov" writes: > > > Currently, we rely on compound_lock() to get page counts stable on > > splitting page refcounting. To get it work we also take the lock on > > get_page() and put_page() which is hot path. > > > > This patch rework splitting code to setup migration entries to stabilaze > > page count/mapcount before distribute refcounts. It means we don't need > > to compound lock in get_page()/put_page(). > > > > Signed-off-by: Kirill A. Shutemov > > --- > > include/linux/migrate.h | 3 + > > include/linux/mm.h | 1 + > > include/linux/pagemap.h | 9 ++- > > mm/huge_memory.c | 188 +++++++++++++++++++++++++++++++++++------------- > > mm/internal.h | 26 +++++-- > > mm/migrate.c | 79 +++++++++++--------- > > mm/rmap.c | 21 ------ > > 7 files changed, 218 insertions(+), 109 deletions(-) > > > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > > index 78baed5f2952..b9bc86c24829 100644 > > --- a/include/linux/migrate.h > > +++ b/include/linux/migrate.h > > @@ -43,6 +43,9 @@ extern int migrate_page_move_mapping(struct address_space *mapping, > > struct page *newpage, struct page *page, > > struct buffer_head *head, enum migrate_mode mode, > > int extra_count); > > +extern int __remove_migration_pte(struct page *new, struct vm_area_struct *vma, > > + unsigned long addr, pte_t *ptep, struct page *old); > > + > > #else > > > > static inline void putback_movable_pages(struct list_head *l) {} > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index 28aeae6e553b..43a9993f1333 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -981,6 +981,7 @@ extern struct address_space *page_mapping(struct page *page); > > /* Neutral page->mapping pointer to address_space or anon_vma or other */ > > static inline void *page_rmapping(struct page *page) > > { > > + page = compound_head(page); > > return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS); > > } > > > > The above hunk is related to this patch ?. Are we calling page_rmapping > on tail pages now ? If so it needs additonal comment why we handle them > differently now. Or split it to a seperate patch ? This change is already in -mm via my patchset on tail pages vs. ->mapping and page falgs. -- Kirill A. Shutemov