From: Tang Chen <tangchen@cn.fujitsu.com>
To: peterz@infradead.org, srivatsa.bhat@linux.vnet.ibm.com,
mingo@kernel.org, tglx@linutronix.de,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-numa@vger.kernel.org
Cc: Tang Chen <tangchen@cn.fujitsu.com>, Wen Congyang <wency@cn.fujitsu.com>
Subject: [PATCH v2 2/2] Update sched_domains_numa_masks when new cpus are onlined.
Date: Tue, 25 Sep 2012 21:12:31 +0800 [thread overview]
Message-ID: <1348578751-16904-3-git-send-email-tangchen@cn.fujitsu.com> (raw)
In-Reply-To: <1348578751-16904-1-git-send-email-tangchen@cn.fujitsu.com>
Once array sched_domains_numa_masks is defined, it is never updated.
When a new cpu on a new node is onlined, the coincident member in
sched_domains_numa_masks is not initialized, and all the masks are 0.
As a result, the build_overlap_sched_groups() will initialize a NULL
sched_group for the new cpu on the new node, which will lead to kernel panic.
[ 3189.403280] Call Trace:
[ 3189.403286] [<ffffffff8106c36f>] warn_slowpath_common+0x7f/0xc0
[ 3189.403289] [<ffffffff8106c3ca>] warn_slowpath_null+0x1a/0x20
[ 3189.403292] [<ffffffff810b1d57>] build_sched_domains+0x467/0x470
[ 3189.403296] [<ffffffff810b2067>] partition_sched_domains+0x307/0x510
[ 3189.403299] [<ffffffff810b1ea2>] ? partition_sched_domains+0x142/0x510
[ 3189.403305] [<ffffffff810fcc93>] cpuset_update_active_cpus+0x83/0x90
[ 3189.403308] [<ffffffff810b22a8>] cpuset_cpu_active+0x38/0x70
[ 3189.403316] [<ffffffff81674b87>] notifier_call_chain+0x67/0x150
[ 3189.403320] [<ffffffff81664647>] ? native_cpu_up+0x18a/0x1b5
[ 3189.403328] [<ffffffff810a044e>] __raw_notifier_call_chain+0xe/0x10
[ 3189.403333] [<ffffffff81070470>] __cpu_notify+0x20/0x40
[ 3189.403337] [<ffffffff8166663e>] _cpu_up+0xe9/0x131
[ 3189.403340] [<ffffffff81666761>] cpu_up+0xdb/0xee
[ 3189.403348] [<ffffffff8165667c>] store_online+0x9c/0xd0
[ 3189.403355] [<ffffffff81437640>] dev_attr_store+0x20/0x30
[ 3189.403361] [<ffffffff8124aa63>] sysfs_write_file+0xa3/0x100
[ 3189.403368] [<ffffffff811ccbe0>] vfs_write+0xd0/0x1a0
[ 3189.403371] [<ffffffff811ccdb4>] sys_write+0x54/0xa0
[ 3189.403375] [<ffffffff81679c69>] system_call_fastpath+0x16/0x1b
[ 3189.403377] ---[ end trace 1e6cf85d0859c941 ]---
[ 3189.403398] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
This patch registers a new notifier for cpu hotplug notify chain, and
updates sched_domains_numa_masks every time a new cpu is onlined or offlined.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
kernel/sched/core.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3aa306a..fffc751 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6728,10 +6728,65 @@ static void sched_init_numa(void)
sched_domains_numa_levels = level;
}
+
+static void sched_domains_numa_masks_set(int cpu)
+{
+ int i, j;
+ int node = cpu_to_node(cpu);
+
+ for (i = 0; i < sched_domains_numa_levels; i++) {
+ for (j = 0; j < nr_node_ids; j++) {
+ if (node_distance(j, node) <= sched_domains_numa_distance[i])
+ cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]);
+ }
+ }
+}
+
+static void sched_domains_numa_masks_clear(int cpu)
+{
+ int i, j;
+ for (i = 0; i < sched_domains_numa_levels; i++) {
+ for (j = 0; j < nr_node_ids; j++)
+ cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
+ }
+}
+
+/*
+ * Update sched_domains_numa_masks[level][node] array when new cpus
+ * are onlined.
+ */
+static int sched_domains_numa_masks_update(struct notifier_block *nfb,
+ unsigned long action,
+ void *hcpu)
+{
+ int cpu = (int)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ sched_domains_numa_masks_set(cpu);
+ break;
+
+ case CPU_DEAD:
+ sched_domains_numa_masks_clear(cpu);
+ break;
+
+ default:
+ return NOTIFY_DONE;
+ }
+
+ return NOTIFY_OK;
+}
#else
static inline void sched_init_numa(void)
{
}
+
+static int sched_domains_numa_masks_update(struct notifier_block *nfb,
+ unsigned long action,
+ void *hcpu)
+{
+ return 0;
+}
#endif /* CONFIG_NUMA */
static int __sdt_alloc(const struct cpumask *cpu_map)
@@ -7180,6 +7235,7 @@ void __init sched_init_smp(void)
mutex_unlock(&sched_domains_mutex);
put_online_cpus();
+ hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
--
1.7.10.1
next prev parent reply other threads:[~2012-09-25 13:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-25 13:12 [PATCH v2 0/2] Update sched_domains_numa_masks when new cpus are onlined Tang Chen
2012-09-25 13:12 ` [PATCH v2 1/2] Ensure sched_domains_numa_levels safe in other functions Tang Chen
2012-10-05 13:01 ` [tip:sched/urgent] sched: Ensure 'sched_domains_numa_levels' is safe to use " tip-bot for Tang Chen
2012-09-25 13:12 ` Tang Chen [this message]
2012-10-04 12:30 ` [PATCH v2 2/2] Update sched_domains_numa_masks when new cpus are onlined Peter Zijlstra
2012-10-05 13:02 ` [tip:sched/urgent] sched: Update sched_domains_numa_masks[][] " tip-bot for Tang Chen
2012-10-02 11:33 ` [PATCH v2 0/2] Update sched_domains_numa_masks " Peter Zijlstra
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