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Commit 62cedb9f authored by David Vrabel's avatar David Vrabel
Browse files

mm: memory hotplug with an existing resource 



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: default avatarDavid Vrabel <david.vrabel@citrix.com>
Reviewed-by: default avatarDaniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: default avatarTang Chen <tangchen@cn.fujitsu.com>
parent 7379047d

include/linux/memory_hotplug.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

mm/memory_hotplug.c

+21 −8
Original line number Diff line number Diff line
@@ -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 @@ int __ref add_memory(int nid, u64 start, u64 size) 
	/* 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