On 08/14/2015 04:40 AM, Andrew Morton wrote:
On Thu, 13 Aug 2015 11:21:43 +0100 David Vrabel <david.vrabel@xxxxxxxxxx> wrote:
On 30/07/15 18:03, David Vrabel wrote:
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.
Ping? This enables a useful feature for Xen guests.
Looks OK to me. I've cc'ed some memory_hotplug.c developers. If
they're OK with it, please add the patch to the (Xen?) tree which uses
it.
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@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memory_hotplug.h | 2 ++
mm/memory_hotplug.c | 28 +++++++++++++++++++++-------
2 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 6ffa0ac..c76d371 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -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);
extern int arch_add_memory(int nid, u64 start, u64 size);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 003dbe4..169770a 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1224,23 +1224,21 @@ 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;
@@ -1290,6 +1288,22 @@ 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)
Not a big deal, but I think "if (ret)" is enough.
The code looks good.
Reviewed-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Thanks.
+ release_memory_resource(res);
+ return ret;
+}
EXPORT_SYMBOL_GPL(add_memory);
#ifdef CONFIG_MEMORY_HOTREMOVE
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