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authorLinus Torvalds <torvalds@linux-foundation.org>2012-01-06 08:33:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-06 08:44:54 -0800
commit0db49b72bce26341274b74fd968501489a361ae3 (patch)
treecdb076827aefb38d719d4c42f8ef291c36072fa8 /kernel/sched/idle_task.c
parent35b740e4662ef386f0c60e1b60aaf5b44db9914c (diff)
parent1ac9bc6943edf7d181b4b1cc734981350d4f6bae (diff)
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) sched/tracing: Add a new tracepoint for sleeptime sched: Disable scheduler warnings during oopses sched: Fix cgroup movement of waking process sched: Fix cgroup movement of newly created process sched: Fix cgroup movement of forking process sched: Remove cfs bandwidth period check in tg_set_cfs_period() sched: Fix load-balance lock-breaking sched: Replace all_pinned with a generic flags field sched: Only queue remote wakeups when crossing cache boundaries sched: Add missing rcu_dereference() around ->real_parent usage [S390] fix cputime overflow in uptime_proc_show [S390] cputime: add sparse checking and cleanup sched: Mark parent and real_parent as __rcu sched, nohz: Fix missing RCU read lock sched, nohz: Set the NOHZ_BALANCE_KICK flag for idle load balancer sched, nohz: Fix the idle cpu check in nohz_idle_balance sched: Use jump_labels for sched_feat sched/accounting: Fix parameter passing in task_group_account_field sched/accounting: Fix user/system tick double accounting sched/accounting: Re-use scheduler statistics for the root cgroup ... Fix up conflicts in - arch/ia64/include/asm/cputime.h, include/asm-generic/cputime.h usecs_to_cputime64() vs the sparse cleanups - kernel/sched/fair.c, kernel/time/tick-sched.c scheduler changes in multiple branches
Diffstat (limited to 'kernel/sched/idle_task.c')
-rw-r--r--kernel/sched/idle_task.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/kernel/sched/idle_task.c b/kernel/sched/idle_task.c
new file mode 100644
index 000000000000..91b4c957f289
--- /dev/null
+++ b/kernel/sched/idle_task.c
@@ -0,0 +1,99 @@
+#include "sched.h"
+
+/*
+ * idle-task scheduling class.
+ *
+ * (NOTE: these are not related to SCHED_IDLE tasks which are
+ * handled in sched_fair.c)
+ */
+
+#ifdef CONFIG_SMP
+static int
+select_task_rq_idle(struct task_struct *p, int sd_flag, int flags)
+{
+ return task_cpu(p); /* IDLE tasks as never migrated */
+}
+#endif /* CONFIG_SMP */
+/*
+ * Idle tasks are unconditionally rescheduled:
+ */
+static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
+{
+ resched_task(rq->idle);
+}
+
+static struct task_struct *pick_next_task_idle(struct rq *rq)
+{
+ schedstat_inc(rq, sched_goidle);
+ calc_load_account_idle(rq);
+ return rq->idle;
+}
+
+/*
+ * It is not legal to sleep in the idle task - print a warning
+ * message if some code attempts to do it:
+ */
+static void
+dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
+{
+ raw_spin_unlock_irq(&rq->lock);
+ printk(KERN_ERR "bad: scheduling from the idle thread!\n");
+ dump_stack();
+ raw_spin_lock_irq(&rq->lock);
+}
+
+static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
+{
+}
+
+static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
+{
+}
+
+static void set_curr_task_idle(struct rq *rq)
+{
+}
+
+static void switched_to_idle(struct rq *rq, struct task_struct *p)
+{
+ BUG();
+}
+
+static void
+prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
+{
+ BUG();
+}
+
+static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task)
+{
+ return 0;
+}
+
+/*
+ * Simple, special scheduling class for the per-CPU idle tasks:
+ */
+const struct sched_class idle_sched_class = {
+ /* .next is NULL */
+ /* no enqueue/yield_task for idle tasks */
+
+ /* dequeue is not valid, we print a debug message there: */
+ .dequeue_task = dequeue_task_idle,
+
+ .check_preempt_curr = check_preempt_curr_idle,
+
+ .pick_next_task = pick_next_task_idle,
+ .put_prev_task = put_prev_task_idle,
+
+#ifdef CONFIG_SMP
+ .select_task_rq = select_task_rq_idle,
+#endif
+
+ .set_curr_task = set_curr_task_idle,
+ .task_tick = task_tick_idle,
+
+ .get_rr_interval = get_rr_interval_idle,
+
+ .prio_changed = prio_changed_idle,
+ .switched_to = switched_to_idle,
+};