The Xen balloon driver uses hotplug memory to extend the amount of
pseudo-physical memory available to a virtual domain. Since this memory
is virtual, it can go anywhere within the kernel's pseudo-physical
address space.
This patch adds a new hotplug memory call, add_memory_resource(), which
adds memory corresponding to a pre-constructed resource. This allows
callers to use allocate_resource() to allocate a suitable chunk of
address space for the new memory (as well as cosmetic details, like a
descriptive name).
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
---
include/linux/memory_hotplug.h | 3 +++
mm/memory_hotplug.c | 20 ++++++++++++++++----
2 files changed, 19 insertions(+), 4 deletions(-)
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -171,7 +171,10 @@
#endif /* ! CONFIG_MEMORY_HOTPLUG */
+struct resource;
+
extern int add_memory(int nid, u64 start, u64 size);
+extern int add_memory_resource(int nid, struct resource *res);
extern int arch_add_memory(int nid, u64 start, u64 size);
extern int remove_memory(u64 start, u64 size);
extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -278,14 +278,28 @@
int add_memory(int nid, u64 start, u64 size)
{
- pg_data_t *pgdat = NULL;
- int new_pgdat = 0;
struct resource *res;
int ret;
res = register_memory_resource(start, size);
if (!res)
return -EEXIST;
+
+ ret = add_memory_resource(nid, res);
+
+ if (ret)
+ release_memory_resource(res);
+
+ return ret;
+}
+
+int add_memory_resource(int nid, struct resource *res)
+{
+ pg_data_t *pgdat = NULL;
+ int new_pgdat = 0;
+ int ret;
+ u64 start = res->start;
+ u64 size = res->end - res->start + 1;
if (!node_online(nid)) {
pgdat = hotadd_new_pgdat(nid, start);
@@ -320,8 +334,6 @@
/* rollback pgdat allocation and others */
if (new_pgdat)
rollback_node_hotadd(nid, pgdat);
- if (res)
- release_memory_resource(res);
return ret;
}
--
