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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58135C433FE for ; Tue, 12 Apr 2022 08:11:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E71306B007D; Tue, 12 Apr 2022 04:11:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DFA2B6B007E; Tue, 12 Apr 2022 04:11:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C73C66B0080; Tue, 12 Apr 2022 04:11:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0162.hostedemail.com [216.40.44.162]) by kanga.kvack.org (Postfix) with ESMTP id B8E536B007D for ; Tue, 12 Apr 2022 04:11:04 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 66B09A89A4 for ; Tue, 12 Apr 2022 08:11:04 +0000 (UTC) X-FDA: 79347506448.27.E2B1030 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf17.hostedemail.com (Postfix) with ESMTP id E25E440004 for ; Tue, 12 Apr 2022 08:11:03 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 7D47A1F856; Tue, 12 Apr 2022 08:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1649751062; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yE2yTS5Roi0zfNnaJ3peYA1qwwdtCKj6aMP7ZgCEQwM=; b=gBGhMc0QmNiJccbrDovFU62R/Z/jT/vZhcyxC9KsY+fG3xcZ+eeNn/MsItLjr91FEzE9rN 4AMLXHJGGaZ3FVMTy1A5F7/vzzTk+mR3zQVzLrfi6aod8wyiUIQ+GZN+pCqEBU5swzOsPG 3o8PotXBGK6N1ooPRYRy5Gvc3dUyExU= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1649751062; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yE2yTS5Roi0zfNnaJ3peYA1qwwdtCKj6aMP7ZgCEQwM=; b=EFBXEltVYR9KP1WH6Zq8ImHdSP478aSwGdS1LpkUJZHyUvYFben6MpPI6IC/8/y8KA0aAy oeARC+79TRYd/7AA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 0AC9713780; Tue, 12 Apr 2022 08:11:01 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id MMjfOhU0VWIEDQAAMHmgww (envelope-from ); Tue, 12 Apr 2022 08:11:01 +0000 Date: Tue, 12 Apr 2022 10:11:00 +0200 From: Oscar Salvador To: Wei Yang Cc: akpm@linux-foundation.org, linux-mm@kvack.org, Vlastimil Babka , David Hildenbrand Subject: Re: [Patch v3] mm/page_alloc: add same penalty is enough to get round-robin order Message-ID: References: <20220412001319.7462-1-richard.weiyang@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220412001319.7462-1-richard.weiyang@gmail.com> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E25E440004 X-Stat-Signature: 6be1ypdxhidfwy7hmiz4pydm716p384b Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=gBGhMc0Q; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=EFBXEltV; dmarc=pass (policy=none) header.from=suse.de; spf=pass (imf17.hostedemail.com: domain of osalvador@suse.de designates 195.135.220.29 as permitted sender) smtp.mailfrom=osalvador@suse.de X-Rspam-User: X-HE-Tag: 1649751063-860050 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Apr 12, 2022 at 12:13:19AM +0000, Wei Yang wrote: > To make node order in round-robin in the same distance group, we add a > penalty to the first node we got in each round. > > To get a round-robin order in the same distance group, we don't need to > decrease the penalty since: > > * find_next_best_node() always iterates node in the same order > * distance matters more then penalty in find_next_best_node() > * in nodes with the same distance, the first one would be picked up > > So it is fine to increase same penalty when we get the first node in the > same distance group. Since we just increase a constance of 1 to node > penalty, it is not necessary to multiply MAX_NODE_LOAD for preference. > > [vbabka@suse.cz: suggests to remove MAX_NODE_LOAD] > > Signed-off-by: Wei Yang > CC: Vlastimil Babka > CC: David Hildenbrand > CC: Oscar Salvador Acked-by: Oscar Salvador > --- > v3: merge into a single patch > v2: adjust constant penalty to 1 > --- > mm/page_alloc.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 5d71b8dcb5f4..0334c06a0a47 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6170,7 +6170,6 @@ int numa_zonelist_order_handler(struct ctl_table *table, int write, > } > > > -#define MAX_NODE_LOAD (nr_online_nodes) > static int node_load[MAX_NUMNODES]; > > /** > @@ -6217,7 +6216,7 @@ int find_next_best_node(int node, nodemask_t *used_node_mask) > val += PENALTY_FOR_NODE_WITH_CPUS; > > /* Slight preference for less loaded node */ > - val *= (MAX_NODE_LOAD*MAX_NUMNODES); > + val *= MAX_NUMNODES; > val += node_load[n]; > > if (val < min_val) { > @@ -6283,13 +6282,12 @@ static void build_thisnode_zonelists(pg_data_t *pgdat) > static void build_zonelists(pg_data_t *pgdat) > { > static int node_order[MAX_NUMNODES]; > - int node, load, nr_nodes = 0; > + int node, nr_nodes = 0; > nodemask_t used_mask = NODE_MASK_NONE; > int local_node, prev_node; > > /* NUMA-aware ordering of nodes */ > local_node = pgdat->node_id; > - load = nr_online_nodes; > prev_node = local_node; > > memset(node_order, 0, sizeof(node_order)); > @@ -6301,11 +6299,10 @@ static void build_zonelists(pg_data_t *pgdat) > */ > if (node_distance(local_node, node) != > node_distance(local_node, prev_node)) > - node_load[node] += load; > + node_load[node] += 1; > > node_order[nr_nodes++] = node; > prev_node = node; > - load--; > } > > build_zonelists_in_node_order(pgdat, node_order, nr_nodes); > -- > 2.33.1 > > -- Oscar Salvador SUSE Labs