From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2796CC433ED for ; Wed, 21 Apr 2021 08:35:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0A266143C for ; Wed, 21 Apr 2021 08:35:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235573AbhDUIgD (ORCPT ); Wed, 21 Apr 2021 04:36:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:32956 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234407AbhDUIgC (ORCPT ); Wed, 21 Apr 2021 04:36:02 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 83531B143; Wed, 21 Apr 2021 08:35:28 +0000 (UTC) Date: Wed, 21 Apr 2021 10:35:26 +0200 From: Oscar Salvador To: Michal Hocko Cc: Andrew Morton , David Hildenbrand , Anshuman Khandual , Pavel Tatashin , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 3/8] mm,memory_hotplug: Factor out adjusting present pages into adjust_present_page_count() Message-ID: <20210421083525.GF22456@linux> References: <20210416112411.9826-1-osalvador@suse.de> <20210416112411.9826-4-osalvador@suse.de> <20210421080036.GC22456@linux> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 21, 2021 at 10:31:30AM +0200, Michal Hocko wrote: > > Given that {offline,online}_pages() is serialized by the memory_hotplug lock, > > I would say that {node,zone}->{spanned,present}_pages is, at any time, stable? > > So, no need for the lock even without considering this patch? > > Yes. The resize lock is really only relevant to the parallel struct page > initialization during early boot. The hotplug usage seems just a left > over from the past or maybe it has never been really relevant in that > context. Ok, I will prepare a follow-up patch to remove the lock in such situations when this work goes in. -- Oscar Salvador SUSE L3