diff options
Diffstat (limited to 'kernel/smpboot.c')
| -rw-r--r-- | kernel/smpboot.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/kernel/smpboot.c b/kernel/smpboot.c new file mode 100644 index 00000000000..98f60c5caa1 --- /dev/null +++ b/kernel/smpboot.c @@ -0,0 +1,67 @@ +/* + * Common SMP CPU bringup/teardown functions + */ +#include <linux/err.h> +#include <linux/smp.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/percpu.h> + +#include "smpboot.h" + +#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD +/* + * For the hotplug case we keep the task structs around and reuse + * them. + */ +static DEFINE_PER_CPU(struct task_struct *, idle_threads); + +struct task_struct * __cpuinit idle_thread_get(unsigned int cpu) +{ + struct task_struct *tsk = per_cpu(idle_threads, cpu); + + if (!tsk) + return ERR_PTR(-ENOMEM); + init_idle(tsk, cpu); + return tsk; +} + +void __init idle_thread_set_boot_cpu(void) +{ + per_cpu(idle_threads, smp_processor_id()) = current; +} + +/** + * idle_init - Initialize the idle thread for a cpu + * @cpu: The cpu for which the idle thread should be initialized + * + * Creates the thread if it does not exist. + */ +static inline void idle_init(unsigned int cpu) +{ + struct task_struct *tsk = per_cpu(idle_threads, cpu); + + if (!tsk) { + tsk = fork_idle(cpu); + if (IS_ERR(tsk)) + pr_err("SMP: fork_idle() failed for CPU %u\n", cpu); + else + per_cpu(idle_threads, cpu) = tsk; + } +} + +/** + * idle_threads_init - Initialize idle threads for all cpus + */ +void __init idle_threads_init(void) +{ + unsigned int cpu, boot_cpu; + + boot_cpu = smp_processor_id(); + + for_each_possible_cpu(cpu) { + if (cpu != boot_cpu) + idle_init(cpu); + } +} +#endif |