From 055a00865dcfc8e61f3cbefbb879c9577bd36ae5 Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Thu, 12 Nov 2009 11:07:44 +0100 Subject: [PATCH] sched: Fix/add missing update_rq_clock() calls kthread_bind(), migrate_task() and sched_fork were missing updates, and try_to_wake_up() was updating after having already used the stale clock. Aside from preventing potential latency hits, there' a side benefit in that early boot printk time stamps become monotonic. Signed-off-by: Mike Galbraith Acked-by: Peter Zijlstra LKML-Reference: <1258020464.6491.2.camel@marge.simson.net> Signed-off-by: Ingo Molnar LKML-Reference: --- kernel/sched.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 3c11ae0a948d..701eca4958a2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2017,6 +2017,7 @@ void kthread_bind(struct task_struct *p, unsigned int cpu) } spin_lock_irqsave(&rq->lock, flags); + update_rq_clock(rq); set_task_cpu(p, cpu); p->cpus_allowed = cpumask_of_cpu(cpu); p->rt.nr_cpus_allowed = 1; @@ -2115,6 +2116,7 @@ migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) * it is sufficient to simply update the task's cpu field. */ if (!p->se.on_rq && !task_running(rq, p)) { + update_rq_clock(rq); set_task_cpu(p, dest_cpu); return 0; } @@ -2376,14 +2378,15 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, task_rq_unlock(rq, &flags); cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, wake_flags); - if (cpu != orig_cpu) + if (cpu != orig_cpu) { + local_irq_save(flags); + rq = cpu_rq(cpu); + update_rq_clock(rq); set_task_cpu(p, cpu); - + local_irq_restore(flags); + } rq = task_rq_lock(p, &flags); - if (rq != orig_rq) - update_rq_clock(rq); - WARN_ON(p->state != TASK_WAKING); cpu = task_cpu(p); @@ -2545,6 +2548,7 @@ 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); @@ -2581,7 +2585,10 @@ void sched_fork(struct task_struct *p, int clone_flags) #ifdef CONFIG_SMP cpu = p->sched_class->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())) -- GitLab