Date: Thu, 22 Dec 2005 16:52:54 -0500 (EST)
From: Nicolas Pitre <nico@cam.org>
Subject: Re: [patch 00/10] mutex subsystem, -V5
In-reply-to: <20051222213902.GA32433@elte.hu>
To: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Lameter <clameter@engr.sgi.com>,
       Linus Torvalds <torvalds@osdl.org>, lkml <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@osdl.org>, Arjan van de Ven <arjanv@infradead.org>,
       Jes Sorensen <jes@trained-monkey.org>,
       Zwane Mwaikambo <zwane@arm.linux.org.uk>,
       Oleg Nesterov <oleg@tv-sign.ru>, David Howells <dhowells@redhat.com>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, Benjamin LaHaise <bcrl@kvack.org>,
       Steven Rostedt <rostedt@goodmis.org>,
       Christoph Hellwig <hch@infradead.org>, Andi Kleen <ak@suse.de>,
       Russell King <rmk+lkml@arm.linux.org.uk>
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On Thu, 22 Dec 2005, Ingo Molnar wrote:

> i definitely do not say that _everything_ should be generalized. That 
> would be micromanaging things. But i definitely think there's an 
> unhealthy amount of _under_ generalization in current Linux 
> architectures, and i dont want the mutex subsystem to fall into that 
> trap.

BTW, I strongly believe the semaphore implementation could go with the 
same model the mutex model I hope is heading for.

I.e., the only thing each architecture really have to implement is 
__sem_fast_down and __sem_fast _up, and incidentally they would have the 
exact same definition as your atomic_*_call_if_* functions (while a bit 
too restrictive for mutex semantics, they really are the minimum 
required for semaphores).  Then all the current per architecture 
semaphore code could be consolidated.


Nicolas
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