At 07/27/2012 06:45 PM, Yasuaki Ishimatsu Wrote:

Hi Wen,

2012/07/27 19:36, Wen Congyang wrote:

quoted

From: Yasuaki Ishimatsu <redacted>

The patch adds node_set_offline() and unregister_one_node() to
remove_memory()
for removing sysfs file of node.

CC: David Rientjes <rientjes@google.com>
CC: Jiang Liu <redacted>
CC: Len Brown <redacted>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <redacted>
CC: Christoph Lameter <redacted>
Cc: Minchan Kim <redacted>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <redacted>
CC: Wen Congyang <redacted>
Signed-off-by: Yasuaki Ishimatsu <redacted>
---
  mm/memory_hotplug.c |    5 +++++
  1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 5ac035f..5681968 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c

@@ -1267,6 +1267,11 @@ int __ref remove_memory(int nid, u64 start, u64

size)
      /* remove memmap entry */
      firmware_map_remove(start, start + size, "System RAM");

+    if (!node_present_pages(nid)) {

Applying [PATCH v5 17/19], pgdat->node_spanned_pages can become 0 when
all memory of the pgdat is removed. When pgdat->node_spanned_pages is 0,
it means the pgdat has no memory. So I think node_spanned_pages() is
better.

Hmm, if the node contains cpu, and the cpu is onlined, can we offline
this node?

Thanks
Wen Congyang

Thanks,
Yasuaki Ishimatsu

quoted

+        node_set_offline(nid);
+        unregister_one_node(nid);
+    }
+
      arch_remove_memory(start, size);
  out:
      unlock_memory_hotplug();