Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750832AbVLTIDM (ORCPT ); Tue, 20 Dec 2005 03:03:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750833AbVLTIDM (ORCPT ); Tue, 20 Dec 2005 03:03:12 -0500 Received: from smtp103.plus.mail.mud.yahoo.com ([68.142.206.236]:62884 "HELO smtp103.plus.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1750832AbVLTIDL (ORCPT ); Tue, 20 Dec 2005 03:03:11 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=kbmuyYA8J8G2NOpCcMG9In+w5I1lcdb2e6vXhFInfFiJt48ETgUP29BfyjbAwMsS5Q/ye5Mi6R/ZlnKaVgCszIkTTEa9vWNXXhOAyv6SdcLSW2/fuWqISi7eYhDb8oSeXh3O9ekWZtfhB16g7HYrJ1Yt7lncXkhkr71aZIgCjhY= ; Message-ID: <43A7BAB5.7020201@yahoo.com.au> Date: Tue, 20 Dec 2005 19:03:01 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Linus Torvalds CC: Ingo Molnar , Andi Kleen , Linux Kernel Mailing List , Andrew Morton , Arjan van de Ven , Steven Rostedt , Alan Cox , Christoph Hellwig , David Howells , Alexander Viro , Oleg Nesterov , Benjamin LaHaise Subject: Re: [patch 00/15] Generic Mutex Subsystem References: <20051219013415.GA27658@elte.hu> <20051219042248.GG23384@wotan.suse.de> <20051219155010.GA7790@elte.hu> <20051219195553.GA14155@elte.hu> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1514 Lines: 38 Linus Torvalds wrote: > And don't get me wrong: if it's easier to just ignore the performance bug, > and introduce a new "struct mutex" that just doesn't have it, I'm all for > it. However, if so, I do NOT want to do the unnecessary renaming. "struct > semaphore" should stay as "struct semaphore", and we should not affect old > code in the _least_. > It would still be good to look at a fair mutex implementation first IMO before making a choice to use unfair mutexes. They'll often be held for longer than spinlocks so fairness may be more important. > Then code can switch to "struct mutex" if people want to. And if one > reason for it ends up being that the code avoids a performance bug in the > process, all the better ;) > Is this a good idea? Then we will have for a long time different bits of code with exactly the same synchronisation requirements using two different constructs that are slightly different. Not to mention code specifically requiring semaphores would get confusing. If we agree mutex is a good idea at all (and I think it is), then wouldn't it be better to aim for a wholesale conversion rather than "if people want to"? -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/