Commit a1e565aa3cfc7c6252cabc93de8391d12b9216aa
Committed by
Linus Torvalds
Linus Torvalds
1 parent
d822b86a99
Exists in
master
and in
20 other branches
memory-hotplug: do not allocate pgdat if it was not freed when offline.
Since there is no way to guarentee the address of pgdat/zone is not on
stack of any kernel threads or used by other kernel objects without
reference counting or other symchronizing method, we cannot reset
node_data and free pgdat when offlining a node. Just reset pgdat to 0
and reuse the memory when the node is online again.
The problem is suggested by Kamezawa Hiroyuki. The idea is from Wen
Congyang.
NOTE: If we don't reset pgdat to 0, the WARN_ON in free_area_init_node()
will be triggered.
[akpm@linux-foundation.org: fix warning when CONFIG_NEED_MULTIPLE_NODES=n]
[akpm@linux-foundation.org: fix the warning again again]
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 1 changed file with 16 additions and 8 deletions Side-by-side Diff
mm/memory_hotplug.c
| ... | ... | @@ -1017,11 +1017,14 @@ |
| 1017 | 1017 | unsigned long zholes_size[MAX_NR_ZONES] = {0}; |
| 1018 | 1018 | unsigned long start_pfn = start >> PAGE_SHIFT; |
| 1019 | 1019 | |
| 1020 | - pgdat = arch_alloc_nodedata(nid); | |
| 1021 | - if (!pgdat) | |
| 1022 | - return NULL; | |
| 1020 | + pgdat = NODE_DATA(nid); | |
| 1021 | + if (!pgdat) { | |
| 1022 | + pgdat = arch_alloc_nodedata(nid); | |
| 1023 | + if (!pgdat) | |
| 1024 | + return NULL; | |
| 1023 | 1025 | |
| 1024 | - arch_refresh_nodedata(nid, pgdat); | |
| 1026 | + arch_refresh_nodedata(nid, pgdat); | |
| 1027 | + } | |
| 1025 | 1028 | |
| 1026 | 1029 | /* we can use NODE_DATA(nid) from here */ |
| 1027 | 1030 | |
| ... | ... | @@ -1074,7 +1077,8 @@ |
| 1074 | 1077 | int __ref add_memory(int nid, u64 start, u64 size) |
| 1075 | 1078 | { |
| 1076 | 1079 | pg_data_t *pgdat = NULL; |
| 1077 | - int new_pgdat = 0; | |
| 1080 | + bool new_pgdat; | |
| 1081 | + bool new_node; | |
| 1078 | 1082 | struct resource *res; |
| 1079 | 1083 | int ret; |
| 1080 | 1084 | |
| 1081 | 1085 | |
| ... | ... | @@ -1085,12 +1089,16 @@ |
| 1085 | 1089 | if (!res) |
| 1086 | 1090 | goto out; |
| 1087 | 1091 | |
| 1088 | - if (!node_online(nid)) { | |
| 1092 | + { /* Stupid hack to suppress address-never-null warning */ | |
| 1093 | + void *p = NODE_DATA(nid); | |
| 1094 | + new_pgdat = !p; | |
| 1095 | + } | |
| 1096 | + new_node = !node_online(nid); | |
| 1097 | + if (new_node) { | |
| 1089 | 1098 | pgdat = hotadd_new_pgdat(nid, start); |
| 1090 | 1099 | ret = -ENOMEM; |
| 1091 | 1100 | if (!pgdat) |
| 1092 | 1101 | goto error; |
| 1093 | - new_pgdat = 1; | |
| 1094 | 1102 | } |
| 1095 | 1103 | |
| 1096 | 1104 | /* call arch's memory hotadd */ |
| ... | ... | @@ -1102,7 +1110,7 @@ |
| 1102 | 1110 | /* we online node here. we can't roll back from here. */ |
| 1103 | 1111 | node_set_online(nid); |
| 1104 | 1112 | |
| 1105 | - if (new_pgdat) { | |
| 1113 | + if (new_node) { | |
| 1106 | 1114 | ret = register_one_node(nid); |
| 1107 | 1115 | /* |
| 1108 | 1116 | * If sysfs file of new node can't create, cpu on the node |