From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752605AbbCFHMr (ORCPT ); Fri, 6 Mar 2015 02:12:47 -0500 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:47725 "EHLO lgemrelse7q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752046AbbCFHMp (ORCPT ); Fri, 6 Mar 2015 02:12:45 -0500 X-Original-SENDERIP: 10.177.222.149 X-Original-MAILFROM: iamjoonsoo.kim@lge.com Date: Fri, 6 Mar 2015 16:13:22 +0900 From: Joonsoo Kim To: "Aneesh Kumar K.V" Cc: Andrew Morton , Rik van Riel , Johannes Weiner , Mel Gorman , Laura Abbott , Minchan Kim , Heesub Shin , Marek Szyprowski , Michal Nazarewicz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hui Zhu , Gioh Kim , Bartlomiej Zolnierkiewicz , Ritesh Harjani , Vlastimil Babka Subject: Re: [RFC 13/16] mm/cma: populate ZONE_CMA and use this zone when GFP_HIGHUSERMOVABLE Message-ID: <20150306071322.GA15051@js1304-P5Q-DELUXE> References: <1423726340-4084-1-git-send-email-iamjoonsoo.kim@lge.com> <1423726340-4084-14-git-send-email-iamjoonsoo.kim@lge.com> <87vbiia3i9.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87vbiia3i9.fsf@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 03, 2015 at 01:58:46PM +0530, Aneesh Kumar K.V wrote: > Joonsoo Kim writes: > > > Until now, reserved pages for CMA are managed altogether with normal > > page in the same zone. This approach has numorous problems and fixing > > them isn't easy. To fix this situation, ZONE_CMA is introduced in > > previous patch, but, not yet populated. This patch implement population > > of ZONE_CMA by stealing reserved pages from normal zones. This stealing > > break one uncertain assumption on zone, that is, zone isn't overlapped. > > In the early of this series, some check is inserted to every zone's span > > iterator to handle zone overlap so there would be no problem with > > this assumption break. > > > > To utilize this zone, user should use GFP_HIGHUSERMOVABLE, because > > these pages are only applicable for movable type and ZONE_CMA could > > contain highmem. > > > > Implementation itself is very easy to understand. Do steal when cma > > area is initialized and recalculate values for per zone data structure. > > > > Signed-off-by: Joonsoo Kim > > --- > > include/linux/gfp.h | 10 ++++++++-- > > include/linux/mm.h | 1 + > > mm/cma.c | 23 ++++++++++++++++------- > > mm/page_alloc.c | 42 +++++++++++++++++++++++++++++++++++++++--- > > 4 files changed, 64 insertions(+), 12 deletions(-) > > > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > > index 619eb20..d125440 100644 > > --- a/include/linux/gfp.h > > +++ b/include/linux/gfp.h > > @@ -186,6 +186,12 @@ static inline int gfpflags_to_migratetype(const gfp_t gfp_flags) > > #define OPT_ZONE_DMA32 ZONE_NORMAL > > #endif > > > > +#ifdef CONFIG_CMA > > +#define OPT_ZONE_CMA ZONE_CMA > > +#else > > +#define OPT_ZONE_CMA ZONE_MOVABLE > > +#endif > > + > > Does that mean with CONFIG_CMA we always try ZONE_CMA first and then > fallback to ZONE_MOVABLE ? If so won't we hit termporary CMA allocation > failures that can result with pinned movable pages ? Hello, Aneesh. IIUC, Johannes's fair allocation policy patchset makes us uses individual zones fairly. So, before freepage on ZONE_CMA is exhausted, ZONE_MOVABLE will be used. :) Thanks.