Re: [PATCH 5/9] mm, memory_hotplug: remove explicit build_all_zonelists from try_online_node

From: Michal Hocko <mhocko@suse.com>

try_online_node calls hotadd_new_pgdat which already calls
build_all_zonelists. So the additional call is redundant.  Even though
hotadd_new_pgdat will only initialize zonelists of the new node this is
the right thing to do because such a node doesn't have any memory so
other zonelists would ignore all the zones from this node anyway.

Cc: Toshi Kani <redacted>
Signed-off-by: Michal Hocko <mhocko@suse.com>
---
 mm/memory_hotplug.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 639b8af37c45..0d2f6a11075c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c

@@ -1104,13 +1104,6 @@ int try_online_node(int nid)
 	node_set_online(nid);
 	ret = register_one_node(nid);
 	BUG_ON(ret);
-
-	if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
-		mutex_lock(&zonelists_mutex);
-		build_all_zonelists(NULL);
-		mutex_unlock(&zonelists_mutex);
-	}
-
 out:
 	mem_hotplug_done();
 	return ret;

-- 
2.11.0