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author | Ingo Molnar <mingo@elte.hu> | 2007-07-09 18:51:58 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2007-07-09 18:51:58 +0200 |
commit | fa72e9e484c16f0c9aee23981917d8c8c03f0482 (patch) | |
tree | 2bcf45d83b9738af2b3455df0e3ada975a100306 /kernel/sched_idletask.c | |
parent | sched: cfs core, kernel/sched_rt.c (diff) | |
download | linux-fa72e9e484c16f0c9aee23981917d8c8c03f0482.tar.xz linux-fa72e9e484c16f0c9aee23981917d8c8c03f0482.zip |
sched: cfs core, kernel/sched_idletask.c
add kernel/sched_idletask.c - which implements the idle thread
scheduling class. This further simplifies sched.c (under CFS),
for example a number of 'if (p == rq->idle)' type of special-cases
can be removed from sched.c, and schedule() gets simpler too.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_idletask.c')
-rw-r--r-- | kernel/sched_idletask.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c new file mode 100644 index 000000000000..41841e741c4a --- /dev/null +++ b/kernel/sched_idletask.c @@ -0,0 +1,71 @@ +/* + * idle-task scheduling class. + * + * (NOTE: these are not related to SCHED_IDLE tasks which are + * handled in sched_fair.c) + */ + +/* + * Idle tasks are unconditionally rescheduled: + */ +static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p) +{ + resched_task(rq->idle); +} + +static struct task_struct *pick_next_task_idle(struct rq *rq, u64 now) +{ + schedstat_inc(rq, sched_goidle); + + 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 sleep, u64 now) +{ + spin_unlock_irq(&rq->lock); + printk(KERN_ERR "bad: scheduling from the idle thread!\n"); + dump_stack(); + spin_lock_irq(&rq->lock); +} + +static void put_prev_task_idle(struct rq *rq, struct task_struct *prev, u64 now) +{ +} + +static int +load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_nr_move, unsigned long max_load_move, + struct sched_domain *sd, enum cpu_idle_type idle, + int *all_pinned, unsigned long *total_load_moved) +{ + return 0; +} + +static void task_tick_idle(struct rq *rq, struct task_struct *curr) +{ +} + +/* + * Simple, special scheduling class for the per-CPU idle tasks: + */ +static struct sched_class idle_sched_class __read_mostly = { + /* 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, + + .load_balance = load_balance_idle, + + .task_tick = task_tick_idle, + /* no .task_new for idle tasks */ +}; |