Date: Tue, 7 Jun 2011 10:43:43 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Monica Puig-Pey <puigpeym@unican.es>
cc: hannes_bauer@aon.at, Peter Zijlstra <peterz@infradead.org>,
        Rolando Martins <rolando.martins@gmail.com>,
        linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Changing Kernel thread priorities
In-Reply-To: <4DEDE232.4090007@unican.es>
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On Tue, 7 Jun 2011, Monica Puig-Pey wrote:
> El 07/06/11 10:27, Johannes Bauer escribió:
> > There's a reason all RT irq threads are started at 50, its plain
> > impossible to do better.
> > 
> 
> That's it!
> If I work with embedded system where I know all my tasks running and there is
> not a user how could I do it?

init scripts run from user space and you can adjust the priority there.
 
> What I tried is create the kernel thread in my init_module using:
> 
> 	#include <linux/kthread.h>
> 
> 	struct task_struct *kthread_create(int (*threadfn)(void *data),
> 				   void *data,
> 				   const char namefmt[], ...)
> and then running it with:
> 
> 	#include <linux/sched.h>
> 	
> 	extern int wake_up_process(struct task_struct *tsk);
> 
> These functions stars a Kthread which has a NON RT priority. I can see this
> using the ps command from user space.
> Because it's not a real time thread is why I want, better need, to change its
> priority, to have only real time threads running in my driver. I want to use
> the Kthread as a bottom half for the interrupts.

Use threaded interrupt handlers. That's what they are made for.

Thanks,

	tglx
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