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author | 2010-06-08 21:40:36 +0200 | |
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committer | 2010-06-08 21:40:36 +0200 | |
commit | 3a101d0548e925ab16ca6aaa8cf4f767d322ddb0 (patch) | |
tree | b90d8c5f2efe30fcfa49a00fdea037567c6cd46f /include/linux/cpuset.h | |
parent | sched: define and use CPU_PRI_* enums for cpu notifier priorities (diff) | |
download | linux-3a101d0548e925ab16ca6aaa8cf4f767d322ddb0.tar.gz linux-3a101d0548e925ab16ca6aaa8cf4f767d322ddb0.tar.bz2 linux-3a101d0548e925ab16ca6aaa8cf4f767d322ddb0.zip |
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.h | 6 |
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) { |