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* [Patch v1] ACPI, x86: fix bug in associating hot-added CPUs with corresponding NUMA node
@ 2014-01-20  2:31 ` Jiang Liu
  0 siblings, 0 replies; 13+ messages in thread
From: Jiang Liu @ 2014-01-20  2:31 UTC (permalink / raw)
  To: Rafael J . Wysocki, Toshi Kani, Yinghai Lu, Yijing Wang,
	Len Brown, Pavel Machek, Rafael J. Wysocki, Thomas Gleixner,
	Ingo Molnar, H. Peter Anvin, x86
  Cc: Jiang Liu, linux-acpi, linux-hotplug, linux-kernel, linux-pm

Current ACPI cpu hotplug driver fails to associate hot-added CPUs with
corresponding NUMA node when doing socket online. The code path to
associate CPU with NUMA node is as below:
acpi_processor_add()
    ->acpi_processor_get_info()
	->acpi_processor_hotadd_init()
	    ->acpi_map_lsapic()
		->_acpi_map_lsapic()
		    ->acpi_map_cpu2node()
cpu_subsys_online()
    ->try_online_node()
	->node_set_online()

When doing socket online, a new NUMA node is introduced in addition to
hot-added CPU and memory device. And the new NUMA node is marked as
online when onlining hot-added CPUs through sysfs interface
/sys/devices/system/cpu/cpuxx/online.

On the other hand, acpi_map_cpu2node() will only build the CPU to node
map if corresponding NUMA node is already online, so it always fails
to associate hot-added CPUs with corresponding NUMA node because the
NUMA node is still in offline state.

For the fix, we could safely remove the "node_online(node)" check in
function acpi_map_cpu2node() because it's only called for hot-added CPUs
by acpi_processor_hotadd_init().

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 arch/x86/kernel/acpi/boot.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 6c0b43b..7625de9 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -614,10 +614,10 @@ static void acpi_map_cpu2node(acpi_handle handle, int cpu, int physid)
 	int nid;
 
 	nid = acpi_get_node(handle);
-	if (nid == -1 || !node_online(nid))
-		return;
-	set_apicid_to_node(physid, nid);
-	numa_set_node(cpu, nid);
+	if (nid != -1) {
+		set_apicid_to_node(physid, nid);
+		numa_set_node(cpu, nid);
+	}
 #endif
 }
 
-- 
1.7.10.4


^ permalink raw reply related	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2014-02-21  3:04 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-01-20  2:31 [Patch v1] ACPI, x86: fix bug in associating hot-added CPUs with corresponding NUMA node Jiang Liu
2014-01-20  2:31 ` Jiang Liu
2014-02-05  0:14 ` Rafael J. Wysocki
2014-02-05  0:14   ` Rafael J. Wysocki
2014-02-07  9:17   ` Jiang Liu
2014-02-07  9:17     ` Jiang Liu
2014-02-07 12:03     ` Rafael J. Wysocki
2014-02-07 12:03       ` Rafael J. Wysocki
2014-02-13  2:32       ` Jiang Liu
2014-02-13  2:32         ` Jiang Liu
2014-02-13  3:37         ` H. Peter Anvin
2014-02-13  3:37           ` H. Peter Anvin
2014-02-21  3:03 ` [tip:x86/acpi] x86, acpi: Fix " tip-bot for Jiang Liu

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