The patch titled
Subject: memory-hotplug: do not allocate pdgat if it was not freed when offline.
has been added to the -mm tree. Its filename is
memory-hotplug-do-not-allocate-pdgat-if-it-was-not-freed-when-offline.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Subject: memory-hotplug: do not allocate pdgat 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.
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 | 20 ++++++++++++--------
1 file changed, 12 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
@@ -1015,11 +1015,14 @@ 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 */
@@ -1072,7 +1075,7 @@ out:
int __ref add_memory(int nid, u64 start, u64 size)
{
pg_data_t *pgdat = NULL;
- int new_pgdat = 0;
+ int new_pgdat = 0, new_node = 0;
struct resource *res;
int ret;
@@ -1083,12 +1086,13 @@ int __ref add_memory(int nid, u64 start,
if (!res)
goto out;
- if (!node_online(nid)) {
+ new_pgdat = NODE_DATA(nid) ? 0 : 1;
+ new_node = node_online(nid) ? 0 : 1;
+ if (new_node) {
pgdat = hotadd_new_pgdat(nid, start);
ret = -ENOMEM;
if (!pgdat)
goto error;
- new_pgdat = 1;
}
/* call arch's memory hotadd */
@@ -1100,7 +1104,7 @@ 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
memory-hotplug-try-to-offline-the-memory-twice-to-avoid-dependence.patch
memory-hotplug-check-whether-all-memory-blocks-are-offlined-or-not-when-removing-memory.patch
memory-hotplug-remove-redundant-codes.patch
memory-hotplug-remove-sys-firmware-memmap-x-sysfs.patch
memory-hotplug-introduce-new-arch_remove_memory-for-removing-page-table.patch
memory-hotplug-implement-register_page_bootmem_info_section-of-sparse-vmemmap.patch
memory-hotplug-move-pgdat_resize_lock-into-sparse_remove_one_section.patch
memory-hotplug-common-apis-to-support-page-tables-hot-remove.patch
memory-hotplug-common-apis-to-support-page-tables-hot-remove-fix.patch
memory-hotplug-remove-page-table-of-x86_64-architecture.patch
memory-hotplug-remove-page-table-of-x86_64-architecture-fix.patch
memory-hotplug-remove-memmap-of-sparse-vmemmap.patch
memory-hotplug-integrated-__remove_section-of-config_sparsemem_vmemmap.patch
memory_hotplug-clear-zone-when-removing-the-memory.patch
memory-hotplug-remove-sysfs-file-of-node.patch
memory-hotplug-free-node_data-when-a-node-is-offlined.patch
memory-hotplug-do-not-allocate-pdgat-if-it-was-not-freed-when-offline.patch
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