From: Philippe Gerum <rpm@xenomai.org>
To: Jan Kiszka <jan.kiszka@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>
Subject: Re: [Xenomai-core] Fast native mutexes vs. RT_MUTEX_INFO.lockcnt
Date: Mon, 25 Aug 2008 18:43:01 +0200 [thread overview]
Message-ID: <48B2E115.4070107@domain.hid> (raw)
In-Reply-To: <48B2D1C4.5010306@domain.hid>
Jan Kiszka wrote:
> Hi,
>
> next issue on my way towards fast native mutexes: as mutexes are now
> mostly acquired in user space, the recursion counter lockcnt will only
> be maintained in the context of the owning thread (at best: its process)
> in user space. No update on the kernel-side lockcnt will take place
> anymore, thus rt_mutex_inquire can only return 0 or 1, no > 1. Is it OK
> to break the ABI here?
>
I think so, we might lose some debug information, but that's the price for much
better performances. I can't imagine any sane code iterating lockcnt-times
blindly to unlock a mutex it owns until it is free. Nah, of course not...
Btw, I guess that the /proc information about mutexes would have to be reworked
as well.
> Jan
>
--
Philippe.
next prev parent reply other threads:[~2008-08-25 16:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-25 15:37 [Xenomai-core] Fast native mutexes vs. RT_MUTEX_INFO.lockcnt Jan Kiszka
2008-08-25 16:43 ` Philippe Gerum [this message]
2008-08-25 16:45 ` Jan Kiszka
2008-08-25 16:53 ` Philippe Gerum
2008-08-25 16:55 ` Jan Kiszka
2008-08-25 16:51 ` Jan Kiszka
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