RE: changing kernel thread priority created using kernel_thread()?

[Parav Pandit <paravpandit@xxxxxxxxx>]

Hi,

Threads are executed in the context of process, which
are created in the user space.

Other threads are created by the kernel drivers too.
Those I believe falls in init process, even though
they are created after kernel get booted and when
drivers are get loaded. (I am not sure about the
parent of these kernel_thread)

Now one process can have more than one thread.
So we should be able to set the priority for all the
threads present in one process.

So I expect an API which takes thread pid_t as an
argument and not task_t.

Any idea whether task_t type of instance is created
for the kernel_thread also or that is for the process?

Regards,
Parav Pandit


--- Manjunath_Naik <Manjunath_Naik@xxxxxxxxxx> wrote:

> 
> Hi Pavan,
> 
> I think in Linux the kernel thread will be getting
> executed in the
> context of the current process. I don't think these
> threads have its own
> task struct.
> 
> Thanks
> Manjunath Naik
> 
> 
> -----Original Message-----
> From: Parav Pandit [mailto:paravpandit@xxxxxxxxx] 
> Sent: Monday, June 05, 2006 2:57 PM
> To: Manjunath_Naik; kernelnewbies@xxxxxxxxxxxx
> Subject: RE: changing kernel thread priority created
> using
> kernel_thread()?
> 
> Hi Manjunath,
> 
> As per my understanding, nice command and
> set_user_nice() are for process and not for the
> threads inside the process and kernel level threads.
> 
> process are created using fork() and has huge
> task_struct.
> While kernel_threads are created using,
> kernel_thread.
> 
> I couldn't figure out which structure is for kernel
> threads, as architecture specific assembly code in
> arch_kernel_thread() function has in it.
> 
> Regards,
> Parav Pandit
> 
> 
> --- Manjunath_Naik <Manjunath_Naik@xxxxxxxxxx>
> wrote:
> 
> > 
> > I think the priority of the kernel thread can be
> > changed using
> > "set_user_nice" function. I had found this in
> > following mailing list.
> > 
> >
>
http://www.ussg.iu.edu/hypermail/linux/kernel/0510.2/1027.html
> > 
> > 
> > set_user_nice(current, -19);
> > 
> > Older kernels required:
> > 
> > task_lock(current);
> > current->nice = -19;
> > task_unlock(current);
> > 
> > The kernel thread can set this up when it is first
> > started.
> > 
> > 
> > Thanks
> > Manjunath Naik
> > 
> > -----Original Message-----
> > From: kernelnewbies-bounce@xxxxxxxxxxxx
> > [mailto:kernelnewbies-bounce@xxxxxxxxxxxx] On
> Behalf
> > Of Parav Pandit
> > Sent: Monday, June 05, 2006 1:53 AM
> > To: kernelnewbies@xxxxxxxxxxxx
> > Subject: changing kernel thread priority created
> > using kernel_thread()?
> > 
> > Hi,
> > 
> > 1. How to change the priority of the kernel
> threads
> > created using kernel_thread() API?
> > 
> > 2. What is the default priority of the threads
> > created
> > using kernel_thread() API?
> > 
> > 3. In latest 2.4 kernel and 2.6 kernel,
> > do we have one-to-one mapping for user space
> process
> > and POSIX threads to kernel_thread or we have
> M-to-N
> > mapping?
> > 
> > Regards,
> > Parav Pandit
> > 
> > 
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