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authorTang Chen <tangchen@cn.fujitsu.com>2013-02-22 16:33:18 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 17:50:13 -0800
commita1e565aa3cfc7c6252cabc93de8391d12b9216aa (patch)
treef02974503acc8b61a7d8857c36dfb8b6cf7897ab /mm/memory_hotplug.c
parentd822b86a99e8d2b7ebbe3aba099288354287a885 (diff)
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>
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 3409134ff20a..e189b1f4a9db 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1017,11 +1017,14 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
unsigned long zholes_size[MAX_NR_ZONES] = {0};
unsigned long start_pfn = start >> PAGE_SHIFT;
- pgdat = arch_alloc_nodedata(nid);
- if (!pgdat)
- return NULL;
+ pgdat = NODE_DATA(nid);
+ if (!pgdat) {
+ pgdat = arch_alloc_nodedata(nid);
+ if (!pgdat)
+ return NULL;
- arch_refresh_nodedata(nid, pgdat);
+ arch_refresh_nodedata(nid, pgdat);
+ }
/* we can use NODE_DATA(nid) from here */
@@ -1074,7 +1077,8 @@ out:
int __ref add_memory(int nid, u64 start, u64 size)
{
pg_data_t *pgdat = NULL;
- int new_pgdat = 0;
+ bool new_pgdat;
+ bool new_node;
struct resource *res;
int ret;
@@ -1085,12 +1089,16 @@ int __ref add_memory(int nid, u64 start, u64 size)
if (!res)
goto out;
- if (!node_online(nid)) {
+ { /* Stupid hack to suppress address-never-null warning */
+ void *p = NODE_DATA(nid);
+ new_pgdat = !p;
+ }
+ new_node = !node_online(nid);
+ if (new_node) {
pgdat = hotadd_new_pgdat(nid, start);
ret = -ENOMEM;
if (!pgdat)
goto error;
- new_pgdat = 1;
}
/* call arch's memory hotadd */
@@ -1102,7 +1110,7 @@ int __ref add_memory(int nid, u64 start, u64 size)
/* we online node here. we can't roll back from here. */
node_set_online(nid);
- if (new_pgdat) {
+ if (new_node) {
ret = register_one_node(nid);
/*
* If sysfs file of new node can't create, cpu on the node