From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by kanga.kvack.org (Postfix) with ESMTP id E594F6B0902 for ; Fri, 16 Nov 2018 06:26:08 -0500 (EST) Received: by mail-pl1-f198.google.com with SMTP id m1-v6so16703728plb.13 for ; Fri, 16 Nov 2018 03:26:08 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id a20si6685457pgw.195.2018.11.16.03.26.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Nov 2018 03:26:07 -0800 (PST) Date: Fri, 16 Nov 2018 12:26:03 +0100 From: Michal Hocko Subject: Re: [PATCH] mm: use managed_zone() for more exact check in zone iteration Message-ID: <20181116112603.GI14706@dhcp22.suse.cz> References: <20181114235040.36180-1-richard.weiyang@gmail.com> <20181115133735.bb0313ec9293c415d08be550@linux-foundation.org> <20181116095720.GE14706@dhcp22.suse.cz> <1542366304.3020.15.camel@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1542366304.3020.15.camel@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: osalvador Cc: Andrew Morton , Wei Yang , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri 16-11-18 12:05:04, osalvador wrote: > On Fri, 2018-11-16 at 10:57 +0100, Michal Hocko wrote: [...] > > E.g. memory hotplug decreases both managed and present counters. I > > am actually not sure that is 100% correct (put on my TODO list to > > check). There is no consistency in that regards. > > We can only offline non-reserved pages (so, managed pages). Yes > Since present pages holds reserved_pages + managed_pages, decreasing > both should be fine unless I am mistaken. Well, present_pages is defined as "physical pages existing within the zone" and those pages are still existing but they are offline. But as I've said I have to think about it some more -- Michal Hocko SUSE Labs