| | 1 | /* |
| | 2 | * Common SMP CPU bringup/teardown functions |
| | 3 | */ |
| | 4 | #include <linux/err.h> |
| | 5 | #include <linux/smp.h> |
| | 6 | #include <linux/init.h> |
| | 7 | #include <linux/sched.h> |
| | 8 | #include <linux/percpu.h> |
| | 9 | |
| | 10 | #include "smpboot.h" |
| | 11 | |
| | 12 | #ifdef CONFIG_GENERIC_SMP_IDLE_THREAD |
| | 13 | /* |
| | 14 | * For the hotplug case we keep the task structs around and reuse |
| | 15 | * them. |
| | 16 | */ |
| | 17 | static DEFINE_PER_CPU(struct task_struct *, idle_threads); |
| | 18 | |
| | 19 | struct task_struct * __cpuinit idle_thread_get(unsigned int cpu) |
| | 20 | { |
| | 21 | struct task_struct *tsk = per_cpu(idle_threads, cpu); |
| | 22 | |
| | 23 | if (!tsk) |
| | 24 | return ERR_PTR(-ENOMEM); |
| | 25 | init_idle(tsk, cpu); |
| | 26 | return tsk; |
| | 27 | } |
| | 28 | |
| | 29 | void __init idle_thread_set_boot_cpu(void) |
| | 30 | { |
| | 31 | per_cpu(idle_threads, smp_processor_id()) = current; |
| | 32 | } |
| | 33 | |
| | 34 | /** |
| | 35 | * idle_init - Initialize the idle thread for a cpu |
| | 36 | * @cpu: The cpu for which the idle thread should be initialized |
| | 37 | * |
| | 38 | * Creates the thread if it does not exist. |
| | 39 | */ |
| | 40 | static inline void idle_init(unsigned int cpu) |
| | 41 | { |
| | 42 | struct task_struct *tsk = per_cpu(idle_threads, cpu); |
| | 43 | |
| | 44 | if (!tsk) { |
| | 45 | tsk = fork_idle(cpu); |
| | 46 | if (IS_ERR(tsk)) |
| | 47 | pr_err("SMP: fork_idle() failed for CPU %u\n", cpu); |
| | 48 | else |
| | 49 | per_cpu(idle_threads, cpu) = tsk; |
| | 50 | } |
| | 51 | } |
| | 52 | |
| | 53 | /** |
| | 54 | * idle_threads_init - Initialize idle threads for all cpus |
| | 55 | */ |
| | 56 | void __init idle_threads_init(void) |
| | 57 | { |
| | 58 | unsigned int cpu, boot_cpu; |
| | 59 | |
| | 60 | boot_cpu = smp_processor_id(); |
| | 61 | |
| | 62 | for_each_possible_cpu(cpu) { |
| | 63 | if (cpu != boot_cpu) |
| | 64 | idle_init(cpu); |
| | 65 | } |
| | 66 | } |
| | 67 | #endif |
projects / linux-2.6-block.git / blame_incremental