[PATCH v2 1/4] mm/memory_hotplug: Spare unnecessary calls to node_set_state

From: Oscar Salvador
Date: Fri Sep 21 2018 - 09:26:50 EST


From: Oscar Salvador <osalvador@xxxxxxx>

In node_states_check_changes_online, we check if the node will
have to be set for any of the N_*_MEMORY states after the pages
have been onlined.

Later on, we perform the activation in node_states_set_node.
Currently, in node_states_set_node we set the node to N_MEMORY
unconditionally.
This means that we call node_set_state for N_MEMORY every time
pages go online, but we only need to do it if the node has not yet been
set for N_MEMORY.

Fix this by checking status_change_nid.

Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Pavel Tatashin <pavel.tatashin@xxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 38d94b703e9d..63facfc57224 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -753,7 +753,8 @@ static void node_states_set_node(int node, struct memory_notify *arg)
if (arg->status_change_nid_high >= 0)
node_set_state(node, N_HIGH_MEMORY);

- node_set_state(node, N_MEMORY);
+ if (arg->status_change_nid >= 0)
+ node_set_state(node, N_MEMORY);
}

static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
--
2.13.6