From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751289AbdGQGGo (ORCPT ); Mon, 17 Jul 2017 02:06:44 -0400 Received: from mx2.suse.de ([195.135.220.15]:38257 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751261AbdGQGGn (ORCPT ); Mon, 17 Jul 2017 02:06:43 -0400 Date: Mon, 17 Jul 2017 08:06:40 +0200 From: Michal Hocko To: Mel Gorman Cc: linux-mm@kvack.org, Andrew Morton , Johannes Weiner , Vlastimil Babka , LKML Subject: Re: [PATCH 6/9] mm, page_alloc: simplify zonelist initialization Message-ID: <20170717060639.GA7397@dhcp22.suse.cz> References: <20170714080006.7250-1-mhocko@kernel.org> <20170714080006.7250-7-mhocko@kernel.org> <20170714124645.i3duhuie6cczlybr@suse.de> <20170714130242.GQ2618@dhcp22.suse.cz> <20170714141823.2j7t37t6zdzdf3sv@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170714141823.2j7t37t6zdzdf3sv@suse.de> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 14-07-17 15:18:23, Mel Gorman wrote: > On Fri, Jul 14, 2017 at 03:02:42PM +0200, Michal Hocko wrote: [...] > > What do you think about this on top? > > --- > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 49bade7ff049..3b98524c04ec 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -4913,20 +4913,21 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask) > > * This results in maximum locality--normal zone overflows into local > > * DMA zone, if any--but risks exhausting DMA zone. > > */ > > -static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order) > > +static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, > > + unsigned nr_nodes) > > { > > struct zonelist *zonelist; > > - int i, zoneref_idx = 0; > > + int i, nr_zones = 0; > > > > zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK]; > > > > - for (i = 0; i < MAX_NUMNODES; i++) { > > + for (i = 0; i < nr_nodes; i++) { > > The first iteration is then -- for (i = 0; i < 0; i++) find_next_best_node always returns at least one node (the local one) so I believe that nr_nodes should never be 0. > Fairly sure that's not what you meant. > > > > pg_data_t *node = NODE_DATA(node_order[i]); > > > > - zoneref_idx = build_zonelists_node(node, zonelist, zoneref_idx); > > + nr_zones = build_zonelists_node(node, zonelist, nr_zones); > > I meant converting build_zonelists_node and passing in &nr_zones and > returning false when an empty node is encountered. In this context, > it's also not about zones, it really is nr_zonerefs. Rename nr_zones in > build_zonelists_node as well. hmm, why don't we rather make it zonerefs based then. Something like the following? --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3b98524c04ec..01e67e629351 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4772,18 +4772,17 @@ static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) * * Add all populated zones of a node to the zonelist. */ -static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist, - int nr_zones) +static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs) { struct zone *zone; enum zone_type zone_type = MAX_NR_ZONES; + int nr_zones = 0; do { zone_type--; zone = pgdat->node_zones + zone_type; if (managed_zone(zone)) { - zoneref_set_zone(zone, - &zonelist->_zonerefs[nr_zones++]); + zoneref_set_zone(zone, &zonerefs[nr_zones++]); check_highest_zone(zone_type); } } while (zone_type); @@ -4916,18 +4915,21 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask) static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, unsigned nr_nodes) { - struct zonelist *zonelist; - int i, nr_zones = 0; + struct zoneref *zonerefs; + int i; - zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK]; + zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; for (i = 0; i < nr_nodes; i++) { + int nr_zones; + pg_data_t *node = NODE_DATA(node_order[i]); - nr_zones = build_zonelists_node(node, zonelist, nr_zones); + nr_zones = build_zonerefs_node(node, zonerefs); + zonerefs += nr_zones; } - zonelist->_zonerefs[nr_zones].zone = NULL; - zonelist->_zonerefs[nr_zones].zone_idx = 0; + zonerefs->zone = NULL; + zonerefs->zone_idx = 0; } /* @@ -4935,13 +4937,14 @@ static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, */ static void build_thisnode_zonelists(pg_data_t *pgdat) { - struct zonelist *zonelist; - int nr_zones = 0; + struct zoneref *zonerefs; + int nr_zones; - zonelist = &pgdat->node_zonelists[ZONELIST_NOFALLBACK]; - nr_zones = build_zonelists_node(pgdat, zonelist, nr_zones); - zonelist->_zonerefs[nr_zones].zone = NULL; - zonelist->_zonerefs[nr_zones].zone_idx = 0; + zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs; + nr_zones = build_zonerefs_node(pgdat, zonerefs); + zonerefs += nr_zones; + zonerefs->zone = NULL; + zonerefs->zone_idx = 0; } /* @@ -5009,13 +5012,13 @@ static void setup_min_slab_ratio(void); static void build_zonelists(pg_data_t *pgdat) { int node, local_node; - enum zone_type j; - struct zonelist *zonelist; + struct zoneref *zonerefs; local_node = pgdat->node_id; - zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK]; - j = build_zonelists_node(pgdat, zonelist, 0); + zonrefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; + nr_zones = build_zonerefs_node(pgdat, zonerefs); + zonerefs += nr_zones; /* * Now we build the zonelist so that it contains the zones @@ -5028,16 +5031,18 @@ static void build_zonelists(pg_data_t *pgdat) for (node = local_node + 1; node < MAX_NUMNODES; node++) { if (!node_online(node)) continue; - j = build_zonelists_node(NODE_DATA(node), zonelist, j); + nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); + zonerefs += nr_zones; } for (node = 0; node < local_node; node++) { if (!node_online(node)) continue; - j = build_zonelists_node(NODE_DATA(node), zonelist, j); + nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); + zonerefs += nr_zones; } - zonelist->_zonerefs[j].zone = NULL; - zonelist->_zonerefs[j].zone_idx = 0; + zonerefs->zone = NULL; + zonerefs->zone_idx = 0; } #endif /* CONFIG_NUMA */ -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 39CFE6B0279 for ; Mon, 17 Jul 2017 02:06:44 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id p204so18179322wmg.3 for ; Sun, 16 Jul 2017 23:06:44 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id r7si8993221wmg.72.2017.07.16.23.06.42 for (version=TLS1 cipher=AES128-SHA bits=128/128); Sun, 16 Jul 2017 23:06:42 -0700 (PDT) Date: Mon, 17 Jul 2017 08:06:40 +0200 From: Michal Hocko Subject: Re: [PATCH 6/9] mm, page_alloc: simplify zonelist initialization Message-ID: <20170717060639.GA7397@dhcp22.suse.cz> References: <20170714080006.7250-1-mhocko@kernel.org> <20170714080006.7250-7-mhocko@kernel.org> <20170714124645.i3duhuie6cczlybr@suse.de> <20170714130242.GQ2618@dhcp22.suse.cz> <20170714141823.2j7t37t6zdzdf3sv@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170714141823.2j7t37t6zdzdf3sv@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: linux-mm@kvack.org, Andrew Morton , Johannes Weiner , Vlastimil Babka , LKML On Fri 14-07-17 15:18:23, Mel Gorman wrote: > On Fri, Jul 14, 2017 at 03:02:42PM +0200, Michal Hocko wrote: [...] > > What do you think about this on top? > > --- > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 49bade7ff049..3b98524c04ec 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -4913,20 +4913,21 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask) > > * This results in maximum locality--normal zone overflows into local > > * DMA zone, if any--but risks exhausting DMA zone. > > */ > > -static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order) > > +static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, > > + unsigned nr_nodes) > > { > > struct zonelist *zonelist; > > - int i, zoneref_idx = 0; > > + int i, nr_zones = 0; > > > > zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK]; > > > > - for (i = 0; i < MAX_NUMNODES; i++) { > > + for (i = 0; i < nr_nodes; i++) { > > The first iteration is then -- for (i = 0; i < 0; i++) find_next_best_node always returns at least one node (the local one) so I believe that nr_nodes should never be 0. > Fairly sure that's not what you meant. > > > > pg_data_t *node = NODE_DATA(node_order[i]); > > > > - zoneref_idx = build_zonelists_node(node, zonelist, zoneref_idx); > > + nr_zones = build_zonelists_node(node, zonelist, nr_zones); > > I meant converting build_zonelists_node and passing in &nr_zones and > returning false when an empty node is encountered. In this context, > it's also not about zones, it really is nr_zonerefs. Rename nr_zones in > build_zonelists_node as well. hmm, why don't we rather make it zonerefs based then. Something like the following? --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3b98524c04ec..01e67e629351 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4772,18 +4772,17 @@ static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) * * Add all populated zones of a node to the zonelist. */ -static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist, - int nr_zones) +static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs) { struct zone *zone; enum zone_type zone_type = MAX_NR_ZONES; + int nr_zones = 0; do { zone_type--; zone = pgdat->node_zones + zone_type; if (managed_zone(zone)) { - zoneref_set_zone(zone, - &zonelist->_zonerefs[nr_zones++]); + zoneref_set_zone(zone, &zonerefs[nr_zones++]); check_highest_zone(zone_type); } } while (zone_type); @@ -4916,18 +4915,21 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask) static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, unsigned nr_nodes) { - struct zonelist *zonelist; - int i, nr_zones = 0; + struct zoneref *zonerefs; + int i; - zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK]; + zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; for (i = 0; i < nr_nodes; i++) { + int nr_zones; + pg_data_t *node = NODE_DATA(node_order[i]); - nr_zones = build_zonelists_node(node, zonelist, nr_zones); + nr_zones = build_zonerefs_node(node, zonerefs); + zonerefs += nr_zones; } - zonelist->_zonerefs[nr_zones].zone = NULL; - zonelist->_zonerefs[nr_zones].zone_idx = 0; + zonerefs->zone = NULL; + zonerefs->zone_idx = 0; } /* @@ -4935,13 +4937,14 @@ static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, */ static void build_thisnode_zonelists(pg_data_t *pgdat) { - struct zonelist *zonelist; - int nr_zones = 0; + struct zoneref *zonerefs; + int nr_zones; - zonelist = &pgdat->node_zonelists[ZONELIST_NOFALLBACK]; - nr_zones = build_zonelists_node(pgdat, zonelist, nr_zones); - zonelist->_zonerefs[nr_zones].zone = NULL; - zonelist->_zonerefs[nr_zones].zone_idx = 0; + zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs; + nr_zones = build_zonerefs_node(pgdat, zonerefs); + zonerefs += nr_zones; + zonerefs->zone = NULL; + zonerefs->zone_idx = 0; } /* @@ -5009,13 +5012,13 @@ static void setup_min_slab_ratio(void); static void build_zonelists(pg_data_t *pgdat) { int node, local_node; - enum zone_type j; - struct zonelist *zonelist; + struct zoneref *zonerefs; local_node = pgdat->node_id; - zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK]; - j = build_zonelists_node(pgdat, zonelist, 0); + zonrefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; + nr_zones = build_zonerefs_node(pgdat, zonerefs); + zonerefs += nr_zones; /* * Now we build the zonelist so that it contains the zones @@ -5028,16 +5031,18 @@ static void build_zonelists(pg_data_t *pgdat) for (node = local_node + 1; node < MAX_NUMNODES; node++) { if (!node_online(node)) continue; - j = build_zonelists_node(NODE_DATA(node), zonelist, j); + nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); + zonerefs += nr_zones; } for (node = 0; node < local_node; node++) { if (!node_online(node)) continue; - j = build_zonelists_node(NODE_DATA(node), zonelist, j); + nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); + zonerefs += nr_zones; } - zonelist->_zonerefs[j].zone = NULL; - zonelist->_zonerefs[j].zone_idx = 0; + zonerefs->zone = NULL; + zonerefs->zone_idx = 0; } #endif /* CONFIG_NUMA */ -- Michal Hocko SUSE Labs -- 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