Commit c1152583 authored Sep 06, 2017 by Wei Yang Committed by Linus Torvalds Sep 06, 2017

mm/memory_hotplug: just build zonelist for newly added node

Commit 9adb62a5 ("mm/hotplug: correctly setup fallback zonelists
when creating new pgdat") tries to build the correct zonelist for a
newly 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 newly
added node, it will have memory until node_states_set_node() is called
in online_pages().

This patch avoids rebuilding the zonelists for already existing nodes.

build_zonelists_node() uses managed_zone(zone) checks, so it should not
include empty zones anyway.  So effectively we avoid some pointless work
under stop_machine().

[akpm@linux-foundation.org: tweak comment text]
[akpm@linux-foundation.org: coding-style tweak, per Vlastimil]
Link: http://lkml.kernel.org/r/20170626035822.50155-1-richard.weiyang@gmail.com


Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 912d572d

mm/page_alloc.c

+9 −5

Original line number	Diff line number	Diff line
		@@ -5282,15 +5282,19 @@ static int __build_all_zonelists(void *data)
		memset(node_load, 0, sizeof(node_load));
		#endif

		/*
		* This node is hotadded and no memory is yet present. So just
		* building zonelists is fine - no need to touch other nodes.
		*/
		if (self && !node_online(self->node_id)) {
		build_zonelists(self);
		}

		} else {
		for_each_online_node(nid) {
		pg_data_t *pgdat = NODE_DATA(nid);

		build_zonelists(pgdat);
		}
		}

		/*
		* Initialize the boot_pagesets that are going to be used

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