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From:   Oscar Salvador <osalvador@techadventures.net>
To:     akpm@linux-foundation.org
Cc:     mhocko@suse.com, dan.j.williams@intel.com, david@redhat.com,
        Pavel.Tatashin@microsoft.com, Jonathan.Cameron@huawei.com,
        yasu.isimatu@gmail.com, malat@debian.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Oscar Salvador <osalvador@suse.de>
Subject: [PATCH v2 1/4] mm/memory_hotplug: Spare unnecessary calls to node_set_state
Date:   Fri, 21 Sep 2018 15:26:31 +0200
Message-Id: <20180921132634.10103-2-osalvador@techadventures.net>
In-Reply-To: <20180921132634.10103-1-osalvador@techadventures.net>
References: <20180921132634.10103-1-osalvador@techadventures.net>
Sender: linux-kernel-owner@vger.kernel.org
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From: Oscar Salvador <osalvador@suse.de>

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@suse.de>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
---
 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