From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id A9C2F6B0292 for ; Wed, 28 Jun 2017 03:06:35 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id t3so8706622wme.9 for ; Wed, 28 Jun 2017 00:06:35 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id i186si4828694wmd.88.2017.06.28.00.06.32 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 28 Jun 2017 00:06:33 -0700 (PDT) Subject: Re: [PATCH] mm/memory_hotplug: just build zonelist for new added node References: <20170626035822.50155-1-richard.weiyang@gmail.com> From: Vlastimil Babka Message-ID: <855068c0-8361-9789-4208-36d43e8fd80d@suse.cz> Date: Wed, 28 Jun 2017 09:06:31 +0200 MIME-Version: 1.0 In-Reply-To: <20170626035822.50155-1-richard.weiyang@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Wei Yang , akpm@linux-foundation.org, mhocko@suse.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On 06/26/2017 05:58 AM, Wei Yang wrote: > In commit (9adb62a5df9c0fbef7) "mm/hotplug: correctly setup fallback > zonelists when creating new pgdat" tries to build the correct zonelist for > a new added node, while it is not necessary to rebuild it for already exist > nodes. > > In build_zonelists(), it will iterate on nodes with memory. For a new added > node, it will have memory until node_states_set_node() is called in it will not have memory right? > online_pages(). > > This patch will avoid to rebuild the zonelists for already exist nodes. > > Signed-off-by: Wei Yang Sounds correct, as far as the memory hotplug mess allows. Acked-by: Vlastimil Babka Some style nitpicks below: > --- > mm/page_alloc.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 560eafe8234d..fc8181b44fd8 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5200,15 +5200,17 @@ static int __build_all_zonelists(void *data) > memset(node_load, 0, sizeof(node_load)); > #endif > > - if (self && !node_online(self->node_id)) { > + /* This node is hotadded and no memory preset yet. On multiline comments, the first line should be empty after "/*" But I see Andrew already fixed that. > + * So just build zonelists is fine, no need to touch other nodes. > + */ > + if (self && !node_online(self->node_id)) > build_zonelists(self); > - } > - > - for_each_online_node(nid) { > - pg_data_t *pgdat = NODE_DATA(nid); > + else > + for_each_online_node(nid) { > + pg_data_t *pgdat = NODE_DATA(nid); > > - build_zonelists(pgdat); > - } > + build_zonelists(pgdat); > + } Personally I would use { } for the else block, and thus leave them also for the if block, not sure if this is recommended by the style guide though. > /* > * Initialize the boot_pagesets that are going to be used > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org