From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 2C0AB6B0006 for ; Tue, 3 Apr 2018 03:57:40 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id k6so7498781wmi.6 for ; Tue, 03 Apr 2018 00:57:40 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id l14si1603640wre.77.2018.04.03.00.57.38 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 03 Apr 2018 00:57:38 -0700 (PDT) Date: Tue, 3 Apr 2018 09:57:37 +0200 From: Michal Hocko Subject: Re: [PATCH] mm/page_alloc: call set_pageblock_order() once for each node Message-ID: <20180403075737.GB5501@dhcp22.suse.cz> References: <20180329033607.8440-1-richard.weiyang@gmail.com> <20180329121109.xg5tfk6dyqzkrgrh@suse.de> <20180330010243.GA14446@WeideMacBook-Pro.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180330010243.GA14446@WeideMacBook-Pro.local> Sender: owner-linux-mm@kvack.org List-ID: To: Wei Yang Cc: Mel Gorman , akpm@linux-foundation.org, linux-mm@kvack.org On Fri 30-03-18 09:02:43, Wei Yang wrote: > On Thu, Mar 29, 2018 at 01:11:09PM +0100, Mel Gorman wrote: > >On Thu, Mar 29, 2018 at 11:36:07AM +0800, Wei Yang wrote: > >> set_pageblock_order() is a standalone function which sets pageblock_order, > >> while current implementation calls this function on each ZONE of each node > >> in free_area_init_core(). > >> > >> Since free_area_init_node() is the only user of free_area_init_core(), > >> this patch moves set_pageblock_order() up one level to invoke > >> set_pageblock_order() only once on each node. > >> > >> Signed-off-by: Wei Yang > > > >The patch looks ok but given that set_pageblock_order returns immediately > >if it has already been called, I expect the benefit is marginal. Was any > >improvement in boot time measured? > > No, I don't expect measurable improvement from this since the number of nodes > and zones are limited. > > This is just a code refine from logic point of view. Then, please make sure it is a real refinement. Calling this function per node is only half way to get there as the function is by no means per node. -- Michal Hocko SUSE Labs