lkml.org 
[lkml]   [2012]   [Sep]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC v9 PATCH 19/21] memory-hotplug: remove sysfs file of node
Date
From: Wen Congyang <wency@cn.fujitsu.com>

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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
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>
---
mm/memory_hotplug.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 54 insertions(+), 0 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index afda7e9..270c249 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>

@@ -1285,6 +1286,57 @@ int offline_memory(u64 start, u64 size)
return 0;
}

+static int check_cpu_on_node(void *data)
+{
+ struct pglist_data *pgdat = data;
+ int cpu;
+
+ for_each_online_cpu(cpu) {
+ if (cpu_to_node(cpu) == pgdat->node_id)
+ /*
+ * the cpu on this node is onlined, 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 sections 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)
{
int ret = 0;
@@ -1305,6 +1357,8 @@ int __ref remove_memory(int nid, u64 start, u64 size)
firmware_map_remove(start, start + size, "System RAM");

arch_remove_memory(start, size);
+
+ try_offline_node(nid);
out:
unlock_memory_hotplug();
return ret;
--
1.7.1


\
 
 \ /
  Last update: 2012-09-05 12:22    [W:1.981 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site