Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751566AbdF1H32 (ORCPT ); Wed, 28 Jun 2017 03:29:28 -0400 Received: from mail-vk0-f66.google.com ([209.85.213.66]:36693 "EHLO mail-vk0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751312AbdF1H3U (ORCPT ); Wed, 28 Jun 2017 03:29:20 -0400 MIME-Version: 1.0 In-Reply-To: <855068c0-8361-9789-4208-36d43e8fd80d@suse.cz> References: <20170626035822.50155-1-richard.weiyang@gmail.com> <855068c0-8361-9789-4208-36d43e8fd80d@suse.cz> From: Wei Yang Date: Wed, 28 Jun 2017 15:28:59 +0800 Message-ID: Subject: Re: [PATCH] mm/memory_hotplug: just build zonelist for new added node To: Vlastimil Babka Cc: Andrew Morton , Michal Hocko , Linux-MM , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2404 Lines: 80 On Wed, Jun 28, 2017 at 3:06 PM, Vlastimil Babka wrote: > 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 > No memory at this point. > 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 "/*" > Thanks, I will pay attention next time. > 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. > I am not quite sure about this. The checkpatch.py script doesn't complain. Thanks for your comment again~ >> /* >> * Initialize the boot_pagesets that are going to be used >> >