Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755061AbdHYIts (ORCPT ); Fri, 25 Aug 2017 04:49:48 -0400 Received: from mx2.suse.de ([195.135.220.15]:53273 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754851AbdHYItq (ORCPT ); Fri, 25 Aug 2017 04:49:46 -0400 Subject: Re: [PATCH] mm/mlock: use page_zone() instead of page_zone_id() To: Joonsoo Kim Cc: Andrew Morton , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mel Gorman References: <1503559211-10259-1-git-send-email-iamjoonsoo.kim@lge.com> <20170824235930.GB29701@js1304-P5Q-DELUXE> From: Vlastimil Babka Message-ID: Date: Fri, 25 Aug 2017 10:48:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20170824235930.GB29701@js1304-P5Q-DELUXE> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1541 Lines: 40 On 08/25/2017 01:59 AM, Joonsoo Kim wrote: > On Thu, Aug 24, 2017 at 01:05:15PM +0200, Vlastimil Babka wrote: >> +CC Mel >> >> On 08/24/2017 09:20 AM, js1304@gmail.com wrote: >>> From: Joonsoo Kim >>> >>> page_zone_id() is a specialized function to compare the zone for the pages >>> that are within the section range. If the section of the pages are >>> different, page_zone_id() can be different even if their zone is the same. >>> This wrong usage doesn't cause any actual problem since >>> __munlock_pagevec_fill() would be called again with failed index. However, >>> it's better to use more appropriate function here. >> >> Hmm using zone id was part of the series making munlock faster. Too bad >> it's doing the wrong thing on some memory models. Looks like it wasn't >> evaluated in isolation, but only as part of the pagevec usage (commit >> 7a8010cd36273) but most likely it wasn't contributing too much to the >> 14% speedup. > > I roughly checked that patch and it seems that performance improvement > of that commit isn't related to page_zone_id() usage. With > page_zone(), we would have more chance that do a job as a batch. > >> >>> This patch is also preparation for futher change about page_zone_id(). >> >> Out of curiosity, what kind of change? >> > > I prepared one more patch that prevent another user of page_zone_id() > since it is too tricky. However, I don't submit it. That description > should be removed. :/ OK. You can add Acked-by: Vlastimil Babka > Thanks. >