The patch titled
Subject: memory-hotplug: do not allocate pgdat if it was not freed when offline.
has been removed from the -mm tree. Its filename was
memory-hotplug-do-not-allocate-pdgat-if-it-was-not-freed-when-offline.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxxxxx: fix warning when CONFIG_NEED_MULTIPLE_NODES=n]
[akpm@xxxxxxxxxxxxxxxxxxxx: fix the warning again again]
Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Reviewed-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Jiang Liu <jiang.liu@xxxxxxxxxx>
Cc: Jianguo Wu <wujianguo@xxxxxxxxxx>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Cc: Wu Jianguo <wujianguo@xxxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff -puN mm/memory_hotplug.c~memory-hotplug-do-not-allocate-pdgat-if-it-was-not-freed-when-offline mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~memory-hotplug-do-not-allocate-pdgat-if-it-was-not-freed-when-offline
+++ a/mm/memory_hotplug.c
@@ -1017,11 +1017,14 @@ static pg_data_t __ref *hotadd_new_pgdat
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,
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,
/* 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
_
Patches currently in -mm which might be from tangchen@xxxxxxxxxxxxxx are
origin.patch
linux-next.patch
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