Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756153Ab3DSFXz (ORCPT ); Fri, 19 Apr 2013 01:23:55 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:36054 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753429Ab3DSFXy (ORCPT ); Fri, 19 Apr 2013 01:23:54 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <5170D4CB.20900@jp.fujitsu.com> Date: Fri, 19 Apr 2013 14:23:23 +0900 From: Yasuaki Ishimatsu User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130328 Thunderbird/17.0.5 MIME-Version: 1.0 To: , , , , CC: , , Subject: [Bug fix PATCH v2] numa, cpu hotplug: Change links of CPU and node when changing node number by onlining CPU Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3859 Lines: 121 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 --- v2: Change argument's name from num to cpuid in store_online() Add comments for explaining why node number change --- drivers/base/cpu.c | 25 +++++++++++++++++++++++-- 1 files changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index fb10728..229d6e7 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/