From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752142AbdBFX3f (ORCPT ); Mon, 6 Feb 2017 18:29:35 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:34926 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751592AbdBFX3e (ORCPT ); Mon, 6 Feb 2017 18:29:34 -0500 Date: Mon, 6 Feb 2017 15:29:32 -0800 From: Andrew Morton To: Wei Yang Cc: vbabka@suse.cz, mgorman@techsingularity.net, mhocko@suse.com, 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: <20170206152932.19e7947df487b96b8912e524@linux-foundation.org> In-Reply-To: <20170206154314.15705-1-richard.weiyang@gmail.com> References: <20170206154314.15705-1-richard.weiyang@gmail.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 6 Feb 2017 23:43:14 +0800 Wei Yang wrote: > The whole memory space is divided into several zones and nodes may have no > page in some zones. In this case, the __absent_pages_in_range() would > return 0, since the range it is searching for is an empty range. > > Also this happens more often to those nodes with higher memory range when > there are more nodes, which is a trend for future architectures. > > This patch checks the zone range after clamp and adjustment, return 0 if > the range is an empty range. What are the user-visible runtime effects of this change?