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Date: Mon, 13 Oct 2008 14:17:19 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-core] Fast mutexes vs. automatic mode switch
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To: Jan Kiszka <jan.kiszka@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

Jan Kiszka wrote:
> As we are already fighting hard to avoid new explicit mode-switch use
> cases, rather get rid of old ones, I thought it would be better to keep
> existing semantic across the fast mutex changes.
> 
> Regarding those shared maps: they are per process, aren't they? But here
> we need per thread memory. I'm currently thinking of a memory piece that
> the caller of xeno_set_current provides (or some service that is called
> together with the latter one, or some extended services - to keep APIs
> clean). Then, on mode switches, the kernel will carefully
> (xn_copy_to_user) update it.

We can allocate a piece of memory on the shared heap, and attach it to a
thread using a pthread_key.

-- 
                                                 Gilles.