From: Oscar Salvador Subject: mm/memory_hotplug: refactor hotadd_init_pgdat and try_online_node Since we pre-allocate all nodes now, hotadd_init_pgdat() does not need to return a pgdat struct, as that was meant for __try_online_node() to check whether the node was successfully allocated. Also get rid of the __ref as all functions hotadd_init_pgdat() calls fall within the same section. Also try to make more clear the return codes from __try_online_node(). __try_online_node() can return either 0, 1 or -errno (the latter not really as the BUG_ON() would catch it before we return) but depending on the caller that has different meanings. For add_memory_resource(), when __try_online_node() returns non-zero, it means that the node was already allocated and it does not need to bring it up. It is fine not to check for -errno values because we do not get to call register_one_node() when !set_node_online. For those who call try_online_node(), so set_node_online is true, a value other than zero means a failure (e.g: cpu_up() or find_and_online_cpu_nid()). Link: https://lkml.kernel.org/r/20220307150725.6810-4-osalvador@suse.de Signed-off-by: Oscar Salvador Cc: David Hildenbrand Cc: Miaohe Lin Cc: Michal Hocko Cc: Wei Yang Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) --- a/mm/memory_hotplug.c~mm-memory_hotplug-refactor-hotadd_init_pgdat-and-try_online_node +++ a/mm/memory_hotplug.c @@ -1146,8 +1146,7 @@ failed_addition: return ret; } -/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ -static pg_data_t __ref *hotadd_init_pgdat(int nid) +static void hotadd_init_pgdat(int nid) { struct pglist_data *pgdat = NODE_DATA(nid); @@ -1167,8 +1166,6 @@ static pg_data_t __ref *hotadd_init_pgda * to access not-initialized zonelist, build here. */ build_all_zonelists(pgdat); - - return pgdat; } /* @@ -1178,31 +1175,27 @@ static pg_data_t __ref *hotadd_init_pgda * called by cpu_up() to online a node without onlined memory. * * Returns: - * 1 -> a new node has been allocated - * 0 -> the node is already online - * -ENOMEM -> the node could not be allocated + * 1 -> The node has been initialized. + * 0 -> Either the node was already online, or we succesfully registered a new + * one. + * -errno -> register_one_node() failed. */ static int __try_online_node(int nid, bool set_node_online) { - pg_data_t *pgdat; - int ret = 1; + int ret; if (node_online(nid)) return 0; - pgdat = hotadd_init_pgdat(nid); - if (!pgdat) { - pr_err("Cannot online node %d due to NULL pgdat\n", nid); - ret = -ENOMEM; - goto out; - } - - if (set_node_online) { - node_set_online(nid); - ret = register_one_node(nid); - BUG_ON(ret); - } -out: + hotadd_init_pgdat(nid); + + if (!set_node_online) + return 1; + + node_set_online(nid); + ret = register_one_node(nid); + BUG_ON(ret); + return ret; } _