diff options
author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-11-27 17:32:46 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-12-09 10:03:05 +0100 |
commit | cd29fe6f2637cc2ccbda5ac65f5332d6bf5fa3c6 (patch) | |
tree | b4206012d424a8c0bce1f260d042c678db0602a2 /kernel/sched.c | |
parent | ab19cb23313733c55e0517607844b86720b35f5f (diff) |
sched: Sanitize fork() handling
Currently we try to do task placement in wake_up_new_task() after we do
the load-balance pass in sched_fork(). This yields complicated semantics
in that we have to deal with tasks on different RQs and the
set_task_cpu() calls in copy_process() and sched_fork()
Rename ->task_new() to ->task_fork() and call it from sched_fork()
before the balancing, this gives the policy a clear point to place the
task.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 47 |
1 files changed, 18 insertions, 29 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index c92670f8e09..33c90357313 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1811,6 +1811,20 @@ static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) static void calc_load_account_active(struct rq *this_rq); +static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) +{ + set_task_rq(p, cpu); +#ifdef CONFIG_SMP + /* + * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be + * successfuly executed on another CPU. We must ensure that updates of + * per-task data have been completed by this moment. + */ + smp_wmb(); + task_thread_info(p)->cpu = cpu; +#endif +} + #include "sched_stats.h" #include "sched_idletask.c" #include "sched_fair.c" @@ -1967,20 +1981,6 @@ inline int task_curr(const struct task_struct *p) return cpu_curr(task_cpu(p)) == p; } -static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) -{ - set_task_rq(p, cpu); -#ifdef CONFIG_SMP - /* - * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be - * successfuly executed on another CPU. We must ensure that updates of - * per-task data have been completed by this moment. - */ - smp_wmb(); - task_thread_info(p)->cpu = cpu; -#endif -} - static inline void check_class_changed(struct rq *rq, struct task_struct *p, const struct sched_class *prev_class, int oldprio, int running) @@ -2552,7 +2552,6 @@ static void __sched_fork(struct task_struct *p) void sched_fork(struct task_struct *p, int clone_flags) { int cpu = get_cpu(); - unsigned long flags; __sched_fork(p); @@ -2586,13 +2585,13 @@ void sched_fork(struct task_struct *p, int clone_flags) if (!rt_prio(p->prio)) p->sched_class = &fair_sched_class; + if (p->sched_class->task_fork) + p->sched_class->task_fork(p); + #ifdef CONFIG_SMP cpu = select_task_rq(p, SD_BALANCE_FORK, 0); #endif - local_irq_save(flags); - update_rq_clock(cpu_rq(cpu)); set_task_cpu(p, cpu); - local_irq_restore(flags); #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) if (likely(sched_info_on())) @@ -2625,17 +2624,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) rq = task_rq_lock(p, &flags); BUG_ON(p->state != TASK_RUNNING); update_rq_clock(rq); - - if (!p->sched_class->task_new || !current->se.on_rq) { - activate_task(rq, p, 0); - } else { - /* - * Let the scheduling class do new task startup - * management (if any): - */ - p->sched_class->task_new(rq, p); - inc_nr_running(rq); - } + activate_task(rq, p, 0); trace_sched_wakeup_new(rq, p, 1); check_preempt_curr(rq, p, WF_FORK); #ifdef CONFIG_SMP |