Re: [PATCH] Replace completions with semaphores

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To: Peter Zijlstra <peterz@...>
Cc: Andi Kleen <andi@...>, Roland Dreier <rdreier@...>, Ingo Molnar <mingo@...>, Matthew Wilcox <matthew@...>, Ingo Oeser <ioe-lkml@...>, Daniel Walker <dwalker@...>, <linux-kernel@...>, Linus Torvalds <torvalds@...>
Date: Tuesday, April 15, 2008 - 3:17 am

On Tue, Apr 15, 2008 at 8:46 AM, Peter Zijlstra <peterz@infradead.org> wrote:

Regarding semaphores and priority inversion: I have never recommended
the use of semaphores over mutexes, all I recommended is to keep the
name "semaphore" for something that behaves like a semaphore. There
might be better ways to discourage the use of the semaphore API, e.g.
letting the compiler print a warning every time a semaphore function
is called unless one or another #define has been enabled.

Regarding priority inheritance: does the above mean that you consider
priority inheritance as an optimal solution for realizing real-time
behavior in the kernel ? Are you aware of the fundamental problems
associated with priority inheritance ? These issues are well explained
in Victor Yodaiken's paper "Against priority inheritance". See also
http://www.linuxdevices.com/files/misc/yodaiken-july02.pdf .

Bart.
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Messages in current thread:
[PATCH] Replace completions with semaphores, Matthew Wilcox, (Fri Apr 11, 5:00 pm)
Re: [PATCH] Replace completions with semaphores, Peter Zijlstra, (Sat Apr 12, 8:24 am)
Re: [PATCH] Replace completions with semaphores, Ingo Molnar, (Sun Apr 13, 3:05 am)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Sun Apr 13, 8:52 am)
Re: [PATCH] Replace completions with semaphores, Jens Axboe, (Mon Apr 14, 12:54 pm)
Re: [PATCH] Replace completions with semaphores, Ingo Molnar, (Mon Apr 14, 11:41 am)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Mon Apr 14, 1:46 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Sat Apr 12, 1:26 pm)
Re: [PATCH] Replace completions with semaphores, Roland Dreier, (Sat Apr 12, 3:53 pm)
Re: [PATCH] Replace completions with semaphores, Bart Van Assche, (Sun Apr 13, 9:55 am)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Sun Apr 13, 10:22 am)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Sat Apr 12, 4:47 pm)
Re: [PATCH] Replace completions with semaphores, Ingo Molnar, (Sun Apr 13, 3:08 am)
Re: [PATCH] Replace completions with semaphores, Bart Van Assche, (Sun Apr 13, 10:55 am)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Sun Apr 13, 8:57 am)
Re: [PATCH] Replace completions with semaphores, Ingo Molnar, (Mon Apr 14, 11:39 am)
Re: [PATCH] Replace completions with semaphores, Roland Dreier, (Mon Apr 14, 11:58 am)
Re: [PATCH] Replace completions with semaphores, Peter Zijlstra, (Mon Apr 14, 12:32 pm)
Re: [PATCH] Replace completions with semaphores, Andi Kleen, (Mon Apr 14, 1:46 pm)
Re: [PATCH] Replace completions with semaphores, Peter Zijlstra, (Mon Apr 14, 1:54 pm)
Re: [PATCH] Replace completions with semaphores, Alan Cox, (Mon Apr 14, 3:16 pm)
Re: [PATCH] Replace completions with semaphores, Andi Kleen, (Mon Apr 14, 3:16 pm)
Re: [PATCH] Replace completions with semaphores, Bart Van Assche, (Tue Apr 15, 2:18 am)
Re: [PATCH] Replace completions with semaphores, Peter Zijlstra, (Tue Apr 15, 2:46 am)
Re: [PATCH] Replace completions with semaphores, Bart Van Assche, (Tue Apr 15, 3:17 am)
Re: [PATCH] Replace completions with semaphores, Peter Zijlstra, (Tue Apr 15, 4:44 am)
Re: [PATCH] Replace completions with semaphores, Linus Torvalds, (Tue Apr 15, 12:09 pm)
Re: [PATCH] Replace completions with semaphores, Andi Kleen, (Tue Apr 15, 12:27 pm)
Re: [PATCH] Replace completions with semaphores, Linus Torvalds, (Tue Apr 15, 12:57 pm)
Re: [PATCH] Replace completions with semaphores, Andi Kleen, (Tue Apr 15, 1:15 pm)
Re: [PATCH] Replace completions with semaphores, Linus Torvalds, (Tue Apr 15, 1:26 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Tue Apr 15, 1:41 pm)
Re: [PATCH] Replace completions with semaphores, Linus Torvalds, (Tue Apr 15, 2:14 pm)
Re: [PATCH] Replace completions with semaphores, Ingo Oeser, (Wed Apr 16, 12:07 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Wed Apr 16, 12:16 pm)
Re: [PATCH] Replace completions with semaphores, Oliver Neukum, (Wed Apr 16, 12:31 pm)
Re: [PATCH] Replace completions with semaphores, Arjan van de Ven, (Wed Apr 16, 12:50 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Wed Apr 16, 12:58 pm)
Re: [PATCH] Replace completions with semaphores, Arjan van de Ven, (Wed Apr 16, 1:08 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Wed Apr 16, 2:10 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Wed Apr 16, 1:12 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Wed Apr 16, 12:34 pm)
Re: [PATCH] Replace completions with semaphores, Oliver Neukum, (Wed Apr 16, 12:42 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Wed Apr 16, 12:44 pm)
Re: [PATCH] Replace completions with semaphores, Roland Dreier, (Wed Apr 16, 12:47 pm)
Re: [PATCH] Replace completions with semaphores, Ingo Molnar, (Tue Apr 15, 1:05 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Tue Apr 15, 2:50 pm)
Re: [PATCH] Replace completions with semaphores, Ingo Molnar, (Wed Apr 16, 8:37 am)
Re: [PATCH] Replace completions with semaphores, Andi Kleen, (Wed Apr 16, 8:50 am)
Killable stat/readdir, Matthew Wilcox, (Wed Apr 16, 8:59 am)
Re: [PATCH] Replace completions with semaphores, Bart Van Assche, (Tue Apr 15, 9:15 am)
Re: [PATCH] Replace completions with semaphores, Daniel Walker, (Mon Apr 14, 2:09 pm)
Re: [PATCH] Replace completions with semaphores, Arjan van de Ven, (Mon Apr 14, 12:56 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Mon Apr 14, 1:50 pm)
Re: [PATCH] Replace completions with semaphores, Peter Zijlstra, (Sat Apr 12, 2:05 pm)
Re: [PATCH] Replace completions with semaphores, Matthew Wilcox, (Sat Apr 12, 3:04 pm)
Re: [PATCH] Replace completions with semaphores, Peter Zijlstra, (Sat Apr 12, 3:16 pm)
Re: [PATCH] Replace completions with semaphores, Daniel Walker, (Sat Apr 12, 2:01 pm)
Re: [PATCH] Replace completions with semaphores, Daniel Walker, (Sat Apr 12, 2:43 am)
Re: [PATCH] Replace completions with semaphores, Ingo Oeser, (Sat Apr 12, 6:31 am)