Commit c1152583 authored by Wei Yang's avatar Wei Yang Committed by Linus Torvalds

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.comSigned-off-by: default avatarWei Yang <richard.weiyang@gmail.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 912d572d
...@@ -5282,14 +5282,18 @@ static int __build_all_zonelists(void *data) ...@@ -5282,14 +5282,18 @@ static int __build_all_zonelists(void *data)
memset(node_load, 0, sizeof(node_load)); memset(node_load, 0, sizeof(node_load));
#endif #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)) { if (self && !node_online(self->node_id)) {
build_zonelists(self); build_zonelists(self);
} } else {
for_each_online_node(nid) {
for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid);
pg_data_t *pgdat = NODE_DATA(nid);
build_zonelists(pgdat); build_zonelists(pgdat);
}
} }
/* /*
......
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