From 8efe33f40f3e69ac6069ed46666d2d527ddc2c04 Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Fri, 26 Oct 2018 15:07:34 -0700 Subject: [PATCH] mm/memory_hotplug.c: simplify node_states_check_changes_online While looking at node_states_check_changes_online, I stumbled upon some confusing things. Right after entering the function, we find this: if (N_MEMORY == N_NORMAL_MEMORY) zone_last = ZONE_MOVABLE; This is wrong. N_MEMORY cannot really be equal to N_NORMAL_MEMORY. My guess is that this wanted to be something like: if (N_NORMAL_MEMORY == N_HIGH_MEMORY) to check if we have CONFIG_HIGHMEM. Later on, in the CONFIG_HIGHMEM block, we have: if (N_MEMORY == N_HIGH_MEMORY) zone_last = ZONE_MOVABLE; Again, this is wrong, and will never be evaluated to true. Besides removing these wrong if statements, I simplified the function a bit. [osalvador@suse.de: address feedback from Pavel] Link: http://lkml.kernel.org/r/20180921132634.10103-4-osalvador@techadventures.net Link: http://lkml.kernel.org/r/20180919100819.25518-5-osalvador@techadventures.net Signed-off-by: Oscar Salvador Reviewed-by: Pavel Tatashin Cc: Dan Williams Cc: David Hildenbrand Cc: Jonathan Cameron Cc: Mathieu Malaterre Cc: Michal Hocko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 61 +++++++-------------------------------------- 1 file changed, 9 insertions(+), 52 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 561c44761f95..eadd149eb7bc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -687,62 +687,19 @@ static void node_states_check_changes_online(unsigned long nr_pages, struct zone *zone, struct memory_notify *arg) { int nid = zone_to_nid(zone); - enum zone_type zone_last = ZONE_NORMAL; - /* - * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY] - * contains nodes which have zones of 0...ZONE_NORMAL, - * set zone_last to ZONE_NORMAL. - * - * If we don't have HIGHMEM nor movable node, - * node_states[N_NORMAL_MEMORY] contains nodes which have zones of - * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. - */ - if (N_MEMORY == N_NORMAL_MEMORY) - zone_last = ZONE_MOVABLE; + arg->status_change_nid = -1; + arg->status_change_nid_normal = -1; + arg->status_change_nid_high = -1; - /* - * if the memory to be online is in a zone of 0...zone_last, and - * the zones of 0...zone_last don't have memory before online, we will - * need to set the node to node_states[N_NORMAL_MEMORY] after - * the memory is online. - */ - if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY)) - arg->status_change_nid_normal = nid; - else - arg->status_change_nid_normal = -1; - -#ifdef CONFIG_HIGHMEM - /* - * If we have movable node, node_states[N_HIGH_MEMORY] - * contains nodes which have zones of 0...ZONE_HIGHMEM, - * set zone_last to ZONE_HIGHMEM. - * - * If we don't have movable node, node_states[N_NORMAL_MEMORY] - * contains nodes which have zones of 0...ZONE_MOVABLE, - * set zone_last to ZONE_MOVABLE. - */ - zone_last = ZONE_HIGHMEM; - if (N_MEMORY == N_HIGH_MEMORY) - zone_last = ZONE_MOVABLE; - - if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY)) - arg->status_change_nid_high = nid; - else - arg->status_change_nid_high = -1; -#else - arg->status_change_nid_high = arg->status_change_nid_normal; -#endif - - /* - * if the node don't have memory befor online, we will need to - * set the node to node_states[N_MEMORY] after the memory - * is online. - */ if (!node_state(nid, N_MEMORY)) arg->status_change_nid = nid; - else - arg->status_change_nid = -1; + if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) + arg->status_change_nid_normal = nid; +#ifdef CONFIG_HIGHMEM + if (zone_idx(zone) <= N_HIGH_MEMORY && !node_state(nid, N_HIGH_MEMORY)) + arg->status_change_nid_high = nid; +#endif } static void node_states_set_node(int node, struct memory_notify *arg)