From mboxrd@z Thu Jan  1 00:00:00 1970
Subject: Re: [Xenomai-help] Standard linux assignment of processes to CPUs
	depends on Xenomai Config
From: Philippe Gerum <rpm@xenomai.org>
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Date: Mon, 19 Feb 2007 12:23:21 +0100
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To: Dmitry Adamushko <dmitry.adamushko@domain.hid>
Cc: Xenomai help <xenomai@xenomai.org>, Jan Kiszka <jan.kiszka@domain.hid>

On Mon, 2007-02-19 at 12:01 +0100, Dmitry Adamushko wrote:
> Hi,
> 
> I suppose, that's what happens.
> 
> __xeno_sys_init() (./ksrc/nucleus/module.c) which is module_init() and
> when compiled in -> initcall()
> 
> calls xnarch_init() (./include/asm-i386/bits/init.h)
> 
> This one amongst other things does
> 
> ...
> #ifdef CONFIG_SMP
>         /* Make sure the init sequence is kept on the same CPU when
>            running as a module. */
>         set_cpus_allowed(current, cpumask_of_cpu(0));
> #endif /* CONFIG_SMP */
> 
> In fact, "running as a module" seems to be a bit
> misleading here.  Then another macro should be used in addition,
> MODULE or how it's called.
> 
> Now guess who is a "current" here? It's "init" (pid 0).
> 
> init() -> do_basic_setup() -> do_initcalls() -> ... ->
> __xeno_sys_init() -> xnarch_init()
> 
> "init" is a first process to run and all the rest will inherit its
> "cpus_allowed" field.
> 
> That's it.
> 

Eh, that's what I call a nice one Dmitry. This is the perfect example of
legacy code stabbing us in the back. We should indeed definitely check
for MODULE && SMP.

-- 
Philippe.