[PATCH v3 11/12] memory-hotplug: remove sysfs file of node

Wen Congyang
2012-11-01T09:40:43Z

This patch introduces a new function try_offline_node() to
remove sysfs file of node when all memory sections of this
node are removed. If some memory sections of this node are
not removed, this function does nothing.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
drivers/acpi/acpi_memhotplug.c | 8 +++++-
include/linux/memory_hotplug.h | 2 +-
mm/memory_hotplug.c | 58 ++++++++++++++++++++++++++++++++++++++++--
3 files changed, 64 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 24c807f..0780f99 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -310,7 +310,9 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
{
int result;
struct acpi_memory_info *info, *n;
+ int node;

+ node = acpi_get_node(mem_device->device->handle);

/*
* Ask the VM to offline this memory range.
@@ -318,7 +320,11 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
*/
list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
if (info->enabled) {
- result = remove_memory(info->start_addr, info->length);
+ if (node < 0)
+ node = memory_add_physaddr_to_nid(
+ info->start_addr);
+ result = remove_memory(node, info->start_addr,
+ info->length);
if (result)
return result;
}
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index d4c4402..7b4cfe6 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -231,7 +231,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern int offline_memory_block(struct memory_block *mem);
extern bool is_memblock_offlined(struct memory_block *mem);
-extern int remove_memory(u64 start, u64 size);
+extern int remove_memory(int node, u64 start, u64 size);
extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
int nr_pages);
extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 7bcced0..d965da3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -29,6 +29,7 @@
#include <linux/suspend.h>
#include <linux/mm_inline.h>
#include <linux/firmware-map.h>
+#include <linux/stop_machine.h>

#include <asm/tlbflush.h>

@@ -1299,7 +1300,58 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
return ret;
}

-int __ref remove_memory(u64 start, u64 size)
+static int check_cpu_on_node(void *data)
+{
+ struct pglist_data *pgdat = data;
+ int cpu;
+
+ for_each_present_cpu(cpu) {
+ if (cpu_to_node(cpu) == pgdat->node_id)
+ /*
+ * the cpu on this node isn't removed, and we can't
+ * offline this node.
+ */
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+/* offline the node if all memory sections of this node are removed */
+static void try_offline_node(int nid)
+{
+ unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
+ unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
+ unsigned long pfn;
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ unsigned long section_nr = pfn_to_section_nr(pfn);
+
+ if (!present_section_nr(section_nr))
+ continue;
+
+ if (pfn_to_nid(pfn) != nid)
+ continue;
+
+ /*
+ * some memory sections of this node are not removed, and we
+ * can't offline node now.
+ */
+ return;
+ }
+
+ if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
+ return;
+
+ /*
+ * all memory/cpu of this node are removed, we can offline this
+ * node now.
+ */
+ node_set_offline(nid);
+ unregister_one_node(nid);
+}
+
+int __ref remove_memory(int nid, u64 start, u64 size)
{
unsigned long start_pfn, end_pfn;
int ret = 0;
@@ -1346,6 +1398,8 @@ repeat:

arch_remove_memory(start, size);

+ try_offline_node(nid);
+
unlock_memory_hotplug();

return 0;
@@ -1355,7 +1409,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
{
return -EINVAL;
}
-int remove_memory(u64 start, u64 size)
+int remove_memory(int nid, u64 start, u64 size)
{
return -EINVAL;
}
--
1.8.0