diff options
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 69 |
1 files changed, 0 insertions, 69 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index ae8f75a5ceb4..d1e8889872a1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c | |||
@@ -9131,72 +9131,3 @@ struct cgroup_subsys cpuacct_subsys = { | |||
9131 | }; | 9131 | }; |
9132 | #endif /* CONFIG_CGROUP_CPUACCT */ | 9132 | #endif /* CONFIG_CGROUP_CPUACCT */ |
9133 | 9133 | ||
9134 | #ifndef CONFIG_SMP | ||
9135 | |||
9136 | void synchronize_sched_expedited(void) | ||
9137 | { | ||
9138 | barrier(); | ||
9139 | } | ||
9140 | EXPORT_SYMBOL_GPL(synchronize_sched_expedited); | ||
9141 | |||
9142 | #else /* #ifndef CONFIG_SMP */ | ||
9143 | |||
9144 | static atomic_t synchronize_sched_expedited_count = ATOMIC_INIT(0); | ||
9145 | |||
9146 | static int synchronize_sched_expedited_cpu_stop(void *data) | ||
9147 | { | ||
9148 | /* | ||
9149 | * There must be a full memory barrier on each affected CPU | ||
9150 | * between the time that try_stop_cpus() is called and the | ||
9151 | * time that it returns. | ||
9152 | * | ||
9153 | * In the current initial implementation of cpu_stop, the | ||
9154 | * above condition is already met when the control reaches | ||
9155 | * this point and the following smp_mb() is not strictly | ||
9156 | * necessary. Do smp_mb() anyway for documentation and | ||
9157 | * robustness against future implementation changes. | ||
9158 | */ | ||
9159 | smp_mb(); /* See above comment block. */ | ||
9160 | return 0; | ||
9161 | } | ||
9162 | |||
9163 | /* | ||
9164 | * Wait for an rcu-sched grace period to elapse, but use "big hammer" | ||
9165 | * approach to force grace period to end quickly. This consumes | ||
9166 | * significant time on all CPUs, and is thus not recommended for | ||
9167 | * any sort of common-case code. | ||
9168 | * | ||
9169 | * Note that it is illegal to call this function while holding any | ||
9170 | * lock that is acquired by a CPU-hotplug notifier. Failing to | ||
9171 | * observe this restriction will result in deadlock. | ||
9172 | */ | ||
9173 | void synchronize_sched_expedited(void) | ||
9174 | { | ||
9175 | int snap, trycount = 0; | ||
9176 | |||
9177 | smp_mb(); /* ensure prior mod happens before capturing snap. */ | ||
9178 | snap = atomic_read(&synchronize_sched_expedited_count) + 1; | ||
9179 | get_online_cpus(); | ||
9180 | while (try_stop_cpus(cpu_online_mask, | ||
9181 | synchronize_sched_expedited_cpu_stop, | ||
9182 | NULL) == -EAGAIN) { | ||
9183 | put_online_cpus(); | ||
9184 | if (trycount++ < 10) | ||
9185 | udelay(trycount * num_online_cpus()); | ||
9186 | else { | ||
9187 | synchronize_sched(); | ||
9188 | return; | ||
9189 | } | ||
9190 | if (atomic_read(&synchronize_sched_expedited_count) - snap > 0) { | ||
9191 | smp_mb(); /* ensure test happens before caller kfree */ | ||
9192 | return; | ||
9193 | } | ||
9194 | get_online_cpus(); | ||
9195 | } | ||
9196 | atomic_inc(&synchronize_sched_expedited_count); | ||
9197 | smp_mb__after_atomic_inc(); /* ensure post-GP actions seen after GP. */ | ||
9198 | put_online_cpus(); | ||
9199 | } | ||
9200 | EXPORT_SYMBOL_GPL(synchronize_sched_expedited); | ||
9201 | |||
9202 | #endif /* #else #ifndef CONFIG_SMP */ | ||