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Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

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* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  work_on_cpu(): rewrite it to create a kernel thread on demand
  kthread: move sched-realeted initialization from kthreadd context
  kthread: Don't looking for a task in create_kthread() #2
This commit is contained in:
Linus Torvalds 2009-04-08 18:00:55 -07:00
commit f4efdd65b7
2 changed files with 30 additions and 30 deletions
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26
kernel/kthread.c
View file

@ -76,6 +76,7 @@ static int kthread(void *_create)
/* OK, tell user we're spawned, wait for stop or wakeup */
__set_current_state(TASK_UNINTERRUPTIBLE);
create->result = current;
complete(&create->started);
schedule();
@ -96,22 +97,10 @@ static void create_kthread(struct kthread_create_info *create)
/* We want our own signal handler (we take no signals by default). */
pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD);
if (pid < 0) {
if (pid < 0)
create->result = ERR_PTR(pid);
} else {
struct sched_param param = { .sched_priority = 0 };
else
wait_for_completion(&create->started);
read_lock(&tasklist_lock);
create->result = find_task_by_pid_ns(pid, &init_pid_ns);
read_unlock(&tasklist_lock);
/*
* root may have changed our (kthreadd's) priority or CPU mask.
* The kernel thread should not inherit these properties.
*/
sched_setscheduler(create->result, SCHED_NORMAL, &param);
set_user_nice(create->result, KTHREAD_NICE_LEVEL);
set_cpus_allowed_ptr(create->result, cpu_all_mask);
}
complete(&create->done);
}
@ -154,11 +143,20 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
wait_for_completion(&create.done);
if (!IS_ERR(create.result)) {
struct sched_param param = { .sched_priority = 0 };
va_list args;
va_start(args, namefmt);
vsnprintf(create.result->comm, sizeof(create.result->comm),
namefmt, args);
va_end(args);
/*
* root may have changed our (kthreadd's) priority or CPU mask.
* The kernel thread should not inherit these properties.
*/
sched_setscheduler_nocheck(create.result, SCHED_NORMAL, &param);
set_user_nice(create.result, KTHREAD_NICE_LEVEL);
set_cpus_allowed_ptr(create.result, cpu_all_mask);
}
return create.result;
}

34
kernel/workqueue.c
View file

@ -966,20 +966,20 @@ undo:
}
#ifdef CONFIG_SMP
static struct workqueue_struct *work_on_cpu_wq __read_mostly;
struct work_for_cpu {
struct work_struct work;
struct completion completion;
long (*fn)(void *);
void *arg;
long ret;
};
static void do_work_for_cpu(struct work_struct *w)
static int do_work_for_cpu(void *_wfc)
{
struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work);
struct work_for_cpu *wfc = _wfc;
wfc->ret = wfc->fn(wfc->arg);
complete(&wfc->completion);
return 0;
}
/**
@ -990,17 +990,23 @@ static void do_work_for_cpu(struct work_struct *w)
*
* This will return the value @fn returns.
* It is up to the caller to ensure that the cpu doesn't go offline.
* The caller must not hold any locks which would prevent @fn from completing.
*/
long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
{
struct work_for_cpu wfc;
INIT_WORK(&wfc.work, do_work_for_cpu);
wfc.fn = fn;
wfc.arg = arg;
queue_work_on(cpu, work_on_cpu_wq, &wfc.work);
flush_work(&wfc.work);
struct task_struct *sub_thread;
struct work_for_cpu wfc = {
.completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion),
.fn = fn,
.arg = arg,
};
sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu");
if (IS_ERR(sub_thread))
return PTR_ERR(sub_thread);
kthread_bind(sub_thread, cpu);
wake_up_process(sub_thread);
wait_for_completion(&wfc.completion);
return wfc.ret;
}
EXPORT_SYMBOL_GPL(work_on_cpu);
@ -1016,8 +1022,4 @@ void __init init_workqueues(void)
hotcpu_notifier(workqueue_cpu_callback, 0);
keventd_wq = create_workqueue("events");
BUG_ON(!keventd_wq);
#ifdef CONFIG_SMP
work_on_cpu_wq = create_workqueue("work_on_cpu");
BUG_ON(!work_on_cpu_wq);
#endif
}