From b9ff036082cd1793a59b35c4432644fe44620664 Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Fri, 17 Aug 2018 15:46:15 -0700 Subject: [PATCH] mm/memory_hotplug.c: make add_memory_resource use __try_online_node This is a small cleanup for the memhotplug code. A lot more could be done, but it is better to start somewhere. I tried to unify/remove duplicated code. The following is what this patchset does: 1) add_memory_resource() has code to allocate a node in case it was offline. Since try_online_node has some code for that as well, I just made add_memory_resource() to use that so we can remove duplicated code.. This is better explained in patch 1/4. 2) register_mem_sect_under_node() will be called only from link_mem_sections() 3) Make register_mem_sect_under_node() a callback of walk_memory_range() 4) Drop unnecessary checks from register_mem_sect_under_node() I have done some tests and I could not see anything broken because of this patchset. add_memory_resource() contains code to allocate a new node in case it is necessary. Since try_online_node() also has some code for this purpose, let us make use of that and remove duplicate code. This introduces __try_online_node(), which is called by add_memory_resource() and try_online_node(). __try_online_node() has two new parameters, start_addr of the node, and if the node should be onlined and registered right away. This is always wanted if we are calling from do_cpu_up(), but not when we are calling from memhotplug code. Nothing changes from the point of view of the users of try_online_node(), since try_online_node passes start_addr=0 and online_node=true to __try_online_node(). Link: http://lkml.kernel.org/r/20180622111839.10071-2-osalvador@techadventures.net Signed-off-by: Oscar Salvador Reviewed-by: Pavel Tatashin Tested-by: Reza Arbab Tested-by: Jonathan Cameron Cc: Pasha Tatashin Cc: Michal Hocko Cc: Vlastimil Babka Cc: Pavel Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 67 ++++++++++++++++++++++++++------------------- 1 file changed, 39 insertions(+), 28 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 7deb49f69e27..504ba120bdfc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1034,8 +1034,10 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) return pgdat; } -static void rollback_node_hotadd(int nid, pg_data_t *pgdat) +static void rollback_node_hotadd(int nid) { + pg_data_t *pgdat = NODE_DATA(nid); + arch_refresh_nodedata(nid, NULL); free_percpu(pgdat->per_cpu_nodestats); arch_free_nodedata(pgdat); @@ -1046,28 +1048,48 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat) /** * try_online_node - online a node if offlined * @nid: the node ID - * + * @start: start addr of the node + * @set_node_online: Whether we want to online the node * 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 */ -int try_online_node(int nid) +static int __try_online_node(int nid, u64 start, bool set_node_online) { - pg_data_t *pgdat; - int ret; + pg_data_t *pgdat; + int ret = 1; if (node_online(nid)) return 0; - mem_hotplug_begin(); - pgdat = hotadd_new_pgdat(nid, 0); + pgdat = hotadd_new_pgdat(nid, start); if (!pgdat) { pr_err("Cannot online node %d due to NULL pgdat\n", nid); ret = -ENOMEM; goto out; } - node_set_online(nid); - ret = register_one_node(nid); - BUG_ON(ret); + + if (set_node_online) { + node_set_online(nid); + ret = register_one_node(nid); + BUG_ON(ret); + } out: + return ret; +} + +/* + * Users of this function always want to online/register the node + */ +int try_online_node(int nid) +{ + int ret; + + mem_hotplug_begin(); + ret = __try_online_node(nid, 0, true); mem_hotplug_done(); return ret; } @@ -1099,9 +1121,7 @@ static int online_memory_block(struct memory_block *mem, void *arg) int __ref add_memory_resource(int nid, struct resource *res, bool online) { u64 start, size; - pg_data_t *pgdat = NULL; - bool new_pgdat; - bool new_node; + bool new_node = false; int ret; start = res->start; @@ -1111,11 +1131,6 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) if (ret) return ret; - { /* Stupid hack to suppress address-never-null warning */ - void *p = NODE_DATA(nid); - new_pgdat = !p; - } - mem_hotplug_begin(); /* @@ -1126,17 +1141,13 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) */ memblock_add_node(start, size, nid); - new_node = !node_online(nid); - if (new_node) { - pgdat = hotadd_new_pgdat(nid, start); - ret = -ENOMEM; - if (!pgdat) - goto error; - } + ret = __try_online_node(nid, start, false); + if (ret < 0) + goto error; + new_node = ret; /* call arch's memory hotadd */ ret = arch_add_memory(nid, start, size, NULL, true); - if (ret < 0) goto error; @@ -1180,8 +1191,8 @@ register_fail: error: /* rollback pgdat allocation and others */ - if (new_pgdat && pgdat) - rollback_node_hotadd(nid, pgdat); + if (new_node) + rollback_node_hotadd(nid); memblock_remove(start, size); out: -- 2.30.2