diff options
author | Oleg Nesterov <oleg@redhat.com> | 2009-06-18 03:27:45 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-19 00:03:54 +0400 |
commit | 371cbb387e33651b4c1326457116568ff01ac422 (patch) | |
tree | 4678d02d44fc9764f316e5d84e5d307cc14a0923 | |
parent | 63706172f332fd3f6e7458ebfb35fa6de9c21dc5 (diff) | |
download | linux-371cbb387e33651b4c1326457116568ff01ac422.tar.xz |
kthreads: simplify migration_thread() exit path
Now that kthread_stop() can be used even if the task has already exited,
we can kill the "wait_to_die:" loop in migration_thread(). But we must
pin rq->migration_thread after creation.
Actually, I don't think CPU_UP_CANCELED or CPU_DEAD should wait for
->migration_thread exit. Perhaps we can simplify this code a bit more.
migration_call() can set ->should_stop and forget about this thread. But
we need a new helper in kthred.c for that.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Vitaliy Gusev <vgusev@openvz.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | kernel/sched.c | 14 |
1 files changed, 4 insertions, 10 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 8fb88a906aaa..247fd0fedd0b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7045,7 +7045,7 @@ static int migration_thread(void *data) if (cpu_is_offline(cpu)) { spin_unlock_irq(&rq->lock); - goto wait_to_die; + break; } if (rq->active_balance) { @@ -7071,16 +7071,7 @@ static int migration_thread(void *data) complete(&req->done); } __set_current_state(TASK_RUNNING); - return 0; -wait_to_die: - /* Wait for kthread_stop */ - set_current_state(TASK_INTERRUPTIBLE); - while (!kthread_should_stop()) { - schedule(); - set_current_state(TASK_INTERRUPTIBLE); - } - __set_current_state(TASK_RUNNING); return 0; } @@ -7494,6 +7485,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) rq = task_rq_lock(p, &flags); __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); task_rq_unlock(rq, &flags); + get_task_struct(p); cpu_rq(cpu)->migration_thread = p; break; @@ -7524,6 +7516,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) kthread_bind(cpu_rq(cpu)->migration_thread, cpumask_any(cpu_online_mask)); kthread_stop(cpu_rq(cpu)->migration_thread); + put_task_struct(cpu_rq(cpu)->migration_thread); cpu_rq(cpu)->migration_thread = NULL; break; @@ -7533,6 +7526,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) migrate_live_tasks(cpu); rq = cpu_rq(cpu); kthread_stop(rq->migration_thread); + put_task_struct(rq->migration_thread); rq->migration_thread = NULL; /* Idle task back to normal (off runqueue, low prio) */ spin_lock_irq(&rq->lock); |