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Date: Thu, 02 Feb 2012 10:15:58 +0100
From: Eric Dumazet <eric.dumazet@...il.com>
To: Dmitry Antipov <dmitry.antipov@...aro.org>
Cc: linux-kernel@...r.kernel.org
Subject: Re: Module/kthread/printk question/problem
Le jeudi 02 février 2012 à 10:13 +0400, Dmitry Antipov a écrit :
> On 02/01/2012 09:16 PM, Eric Dumazet wrote:
>
> >> I realize this, but there was a second part of the question: what's the
> >> better way to ensure that all test/X threads are really gone at some point of
> >> testmod_exit()?
> >>
> >
> > You could use kthread_stop()
> >
> > This way you can control all your kernel threads really exited before
> > module cleanup.
>
> Hm... if I try something like:
>
> static void __exit testmod_exit(void)
> {
> int i;
>
> wait_for_completion(&done);
> for (i = 0; i < nrthreads; i++)
> kthread_stop(threads[i]);
> kfree(threads);
> }
Try following code :
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/slab.h>
MODULE_LICENSE("GPL");
static int nrthreads = 128;
module_param(nrthreads, int, 0644);
static int loopcount = 1024;
module_param(loopcount, int, 0644);
static int usehrtime = 0;
module_param(usehrtime, int, 0644);
static int slack = 50000;
module_param(slack, int, 0644);
static int msecs = 1;
module_param(msecs, int, 0644);
static struct task_struct **threads;
static int test(void *unused)
{
int i;
ktime_t expires = ktime_set(0, msecs * NSEC_PER_MSEC);
for (i = 0; !kthread_should_stop() && i < loopcount; i++) {
if (usehrtime) {
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_hrtimeout_range(&expires, slack, HRTIMER_MODE_REL);
}
else
schedule_timeout_uninterruptible(msecs_to_jiffies(msecs));
}
return 0;
}
static int __init testmod_init(void)
{
int i;
printk("test begin\n");
threads = kmalloc(nrthreads * sizeof(struct task_struct *), GFP_KERNEL);
if (!threads)
return -ENOMEM;
for (i = 0; i < nrthreads; i++) {
threads[i] = kthread_create(test, NULL, "test/%d", i);
if (IS_ERR(threads[i])) {
int j, err = PTR_ERR(threads[i]);
for (j = 0; j < i; j++)
kthread_stop(threads[j]);
kfree(threads);
return err;
}
}
for (i = 0; i < nrthreads; i++) {
get_task_struct(threads[i]);
wake_up_process(threads[i]);
}
return 0;
}
static void __exit testmod_exit(void)
{
int i;
for (i = 0; i < nrthreads; i++) {
kthread_stop(threads[i]);
put_task_struct(threads[i]);
}
kfree(threads);
}
module_init(testmod_init);
module_exit(testmod_exit);
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