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authorTejun Heo <tj@kernel.org>2010-06-08 23:40:36 +0400
committerTejun Heo <tj@kernel.org>2010-06-08 23:40:36 +0400
commit3a101d0548e925ab16ca6aaa8cf4f767d322ddb0 (patch)
treeb90d8c5f2efe30fcfa49a00fdea037567c6cd46f /include/linux/cpuset.h
parent50a323b73069b169385a8ac65633dee837a7d13f (diff)
downloadlinux-3a101d0548e925ab16ca6aaa8cf4f767d322ddb0.tar.xz
sched: adjust when cpu_active and cpuset configurations are updated during cpu on/offlining
Currently, when a cpu goes down, cpu_active is cleared before CPU_DOWN_PREPARE starts and cpuset configuration is updated from a default priority cpu notifier. When a cpu is coming up, it's set before CPU_ONLINE but cpuset configuration again is updated from the same cpu notifier. For cpu notifiers, this presents an inconsistent state. Threads which a CPU_DOWN_PREPARE notifier expects to be bound to the CPU can be migrated to other cpus because the cpu is no more inactive. Fix it by updating cpu_active in the highest priority cpu notifier and cpuset configuration in the second highest when a cpu is coming up. Down path is updated similarly. This guarantees that all other cpu notifiers see consistent cpu_active and cpuset configuration. cpuset_track_online_cpus() notifier is converted to cpuset_update_active_cpus() which just updates the configuration and now called from cpuset_cpu_[in]active() notifiers registered from sched_init_smp(). If cpuset is disabled, cpuset_update_active_cpus() degenerates into partition_sched_domains() making separate notifier for !CONFIG_CPUSETS unnecessary. This problem is triggered by cmwq. During CPU_DOWN_PREPARE, hotplug callback creates a kthread and kthread_bind()s it to the target cpu, and the thread is expected to run on that cpu. * Ingo's test discovered __cpuinit/exit markups were incorrect. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Menage <menage@google.com>
Diffstat (limited to 'include/linux/cpuset.h')
-rw-r--r--include/linux/cpuset.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 457ed765a116..f20eb8f16025 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -20,6 +20,7 @@ extern int number_of_cpusets; /* How many cpusets are defined in system? */
extern int cpuset_init(void);
extern void cpuset_init_smp(void);
+extern void cpuset_update_active_cpus(void);
extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
extern int cpuset_cpus_allowed_fallback(struct task_struct *p);
extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
@@ -132,6 +133,11 @@ static inline void set_mems_allowed(nodemask_t nodemask)
static inline int cpuset_init(void) { return 0; }
static inline void cpuset_init_smp(void) {}
+static inline void cpuset_update_active_cpus(void)
+{
+ partition_sched_domains(1, NULL, NULL);
+}
+
static inline void cpuset_cpus_allowed(struct task_struct *p,
struct cpumask *mask)
{