From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754705AbdBHOyv (ORCPT ); Wed, 8 Feb 2017 09:54:51 -0500 Received: from mx2.suse.de ([195.135.220.15]:48883 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753378AbdBHOyC (ORCPT ); Wed, 8 Feb 2017 09:54:02 -0500 Date: Wed, 8 Feb 2017 15:39:59 +0100 From: Michal Hocko To: Wei Yang Cc: akpm@linux-foundation.org, vbabka@suse.cz, mgorman@techsingularity.net, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/page_alloc: return 0 in case this node has no page within the zone Message-ID: <20170208143959.GN5686@dhcp22.suse.cz> References: <20170206154314.15705-1-richard.weiyang@gmail.com> <20170207094557.GE5065@dhcp22.suse.cz> <20170207153247.GB31837@WeideMBP.lan> <20170207154120.GW5065@dhcp22.suse.cz> <20170208140518.GA67800@WeideMacBook-Pro.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170208140518.GA67800@WeideMacBook-Pro.local> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 08-02-17 22:05:18, Wei Yang wrote: [...] > BTW, the ZONE_MOVABLE handling looks strange to me and the comment "Treat > pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages and vice versa" is > hard to understand. From the code point of view, if zone_type is ZONE_NORMAL, > each memblock region between zone_start_pfn and zone_end_pfn would be treated > as absent pages if it is not mirrored. Do you have some hint on this? Not really, sorry, this area is full of awkward and subtle code when new changes build on top of previous awkwardness/surprises. Any cleanup would be really appreciated. That is the reason I didn't like the initial check all that much. -- Michal Hocko SUSE Labs