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numa, cpu hotplug: change links of CPU and node when changing node number by onlining CPU

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When booting x86 system contains memoryless node, node numbers of CPUs
on memoryless node were changed to nearest online node number by
init_cpu_to_node() because the node is not online.

In my system, node numbers of cpu#30-44 and 75-89 were changed from 2 to
0 as follows:

  $ numactl --hardware
  available: 2 nodes (0-1)
  node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 30 31 32 33 34 35 36 37 38 39 40
  41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 75 76 77 78 79 80 81 82
  83 84 85 86 87 88 89
  node 0 size: 32394 MB
  node 0 free: 27898 MB
  node 1 cpus: 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 60 61 62 63 64 65 66
  67 68 69 70 71 72 73 74
  node 1 size: 32768 MB
  node 1 free: 30335 MB

If we hot add memory to memoryless node and offine/online all CPUs on
the node, node numbers of these CPUs are changed to correct node numbers
by srat_detect_node() because the node become online.

In this case, node numbers of cpu#30-44 and 75-89 were changed from 0 to
2 in my system as follows:

  $ numactl --hardware
  available: 3 nodes (0-2)
  node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 45 46 47 48 49 50 51 52 53 54 55
  56 57 58 59
  node 0 size: 32394 MB
  node 0 free: 27218 MB
  node 1 cpus: 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 60 61 62 63 64 65 66
  67 68 69 70 71 72 73 74
  node 1 size: 32768 MB
  node 1 free: 30014 MB
  node 2 cpus: 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 75 76 77 78 79 80 81
  82 83 84 85 86 87 88 89
  node 2 size: 16384 MB
  node 2 free: 16384 MB

But "cpu to node" and "node to cpu" links were not changed as follows:

  $ ls /sys/devices/system/cpu/cpu30/|grep node
  node0
  $ ls /sys/devices/system/node/node0/|grep cpu30
  cpu30

"numactl --hardware" shows that cpu30 belongs to node 2.  But sysfs
links does not change.

This patch changes "cpu to node" and "node to cpu" links when node
number changed by onlining CPU.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yasuaki Ishimatsu 2013-04-29 15:08:50 -07:00 committed by Linus Torvalds
parent 349daa0f93
commit 3464046824
1 changed files with 23 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/base/cpu.c
View File

@ -25,6 +25,15 @@ EXPORT_SYMBOL_GPL(cpu_subsys);
static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
#ifdef CONFIG_HOTPLUG_CPU
static void change_cpu_under_node(struct cpu *cpu,
unsigned int from_nid, unsigned int to_nid)
{
int cpuid = cpu->dev.id;
unregister_cpu_under_node(cpuid, from_nid);
register_cpu_under_node(cpuid, to_nid);
cpu->node_id = to_nid;
}
static ssize_t show_online(struct device *dev,
struct device_attribute *attr,
char *buf)
@ -39,17 +48,29 @@ static ssize_t __ref store_online(struct device *dev,
const char *buf, size_t count)
{
struct cpu *cpu = container_of(dev, struct cpu, dev);
int cpuid = cpu->dev.id;
int from_nid, to_nid;
ssize_t ret;
cpu_hotplug_driver_lock();
switch (buf[0]) {
case '0':
ret = cpu_down(cpu->dev.id);
ret = cpu_down(cpuid);
if (!ret)
kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
break;
case '1':
ret = cpu_up(cpu->dev.id);
from_nid = cpu_to_node(cpuid);
ret = cpu_up(cpuid);
/*
* When hot adding memory to memoryless node and enabling a cpu
* on the node, node number of the cpu may internally change.
*/
to_nid = cpu_to_node(cpuid);
if (from_nid != to_nid)
change_cpu_under_node(cpu, from_nid, to_nid);
if (!ret)
kobject_uevent(&dev->kobj, KOBJ_ONLINE);
break;