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mm: memory hotplug with an existing resource

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Add add_memory_resource() to add memory using an existing "System RAM"
resource.  This is useful if the memory region is being located by
finding a free resource slot with allocate_resource().

Xen guests will make use of this in their balloon driver to hotplug
arbitrary amounts of memory in response to toolstack requests.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
This commit is contained in:
David Vrabel 2015-06-25 16:35:49 +01:00
parent 7379047d55
commit 62cedb9f13
2 changed files with 23 additions and 8 deletions
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2
include/linux/memory_hotplug.h
View File

@ -11,6 +11,7 @@ struct zone;
struct pglist_data;
struct mem_section;
struct memory_block;
struct resource;
#ifdef CONFIG_MEMORY_HOTPLUG
@ -266,6 +267,7 @@ static inline void remove_memory(int nid, u64 start, u64 size) {}
extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
void *arg, int (*func)(struct memory_block *, void *));
extern int add_memory(int nid, u64 start, u64 size);
extern int add_memory_resource(int nid, struct resource *resource);
extern int zone_for_memory(int nid, u64 start, u64 size, int zone_default,
bool for_device);
extern int arch_add_memory(int nid, u64 start, u64 size, bool for_device);

29
mm/memory_hotplug.c
View File

@ -1232,23 +1232,21 @@ int zone_for_memory(int nid, u64 start, u64 size, int zone_default,
}
/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
int __ref add_memory(int nid, u64 start, u64 size)
int __ref add_memory_resource(int nid, struct resource *res)
{
u64 start, size;
pg_data_t *pgdat = NULL;
bool new_pgdat;
bool new_node;
struct resource *res;
int ret;
start = res->start;
size = resource_size(res);
ret = check_hotplug_memory_range(start, size);
if (ret)
return ret;
res = register_memory_resource(start, size);
ret = -EEXIST;
if (!res)
return ret;
{ /* Stupid hack to suppress address-never-null warning */
void *p = NODE_DATA(nid);
new_pgdat = !p;
@ -1300,13 +1298,28 @@ error:
/* rollback pgdat allocation and others */
if (new_pgdat)
rollback_node_hotadd(nid, pgdat);
release_memory_resource(res);
memblock_remove(start, size);
out:
mem_hotplug_done();
return ret;
}
EXPORT_SYMBOL_GPL(add_memory_resource);
int __ref add_memory(int nid, u64 start, u64 size)
{
struct resource *res;
int ret;
res = register_memory_resource(start, size);
if (!res)
return -EEXIST;
ret = add_memory_resource(nid, res);
if (ret < 0)
release_memory_resource(res);
return ret;
}
EXPORT_SYMBOL_GPL(add_memory);
#ifdef CONFIG_MEMORY_HOTREMOVE