[GIT PULL] scheduler fixes

Ingo Molnar
2012-10-12T09:11:33Z

Linus,

Please pull the latest sched-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-for-linus

HEAD: 301a5cba2887d1f640e6d5184b05a6d7132017d5 sched: Update sched_domains_numa_masks[][] when new cpus are onlined

A CPU hotplug related crash fix and a nohz accounting fixlet.

Thanks,

Ingo

------------------>
Frederic Weisbecker (1):
nohz: Fix one jiffy count too far in idle cputime

Tang Chen (2):
sched: Ensure 'sched_domains_numa_levels' is safe to use in other functions
sched: Update sched_domains_numa_masks[][] when new cpus are onlined

kernel/sched/core.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++
kernel/time/tick-sched.c | 2 +-
2 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c177472..8322d73 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6122,6 +6122,17 @@ static void sched_init_numa(void)
* numbers.
*/

+ /*
+ * Here, we should temporarily reset sched_domains_numa_levels to 0.
+ * If it fails to allocate memory for array sched_domains_numa_masks[][],
+ * the array will contain less then 'level' members. This could be
+ * dangerous when we use it to iterate array sched_domains_numa_masks[][]
+ * in other functions.
+ *
+ * We reset it to 'level' at the end of this function.
+ */
+ sched_domains_numa_levels = 0;
+
sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL);
if (!sched_domains_numa_masks)
return;
@@ -6176,11 +6187,68 @@ static void sched_init_numa(void)
}

sched_domain_topology = tl;
+
+ 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 = (long)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)
@@ -6629,6 +6697,7 @@ 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);

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index f423bdd..a402608 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -835,7 +835,7 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
*/
if (ts->tick_stopped) {
touch_softlockup_watchdog();
- if (idle_cpu(cpu))
+ if (is_idle_task(current))
ts->idle_jiffies++;
}
update_process_times(user_mode(regs));