Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932519AbVLPVzz (ORCPT ); Fri, 16 Dec 2005 16:55:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932518AbVLPVzz (ORCPT ); Fri, 16 Dec 2005 16:55:55 -0500 Received: from 213-239-205-147.clients.your-server.de ([213.239.205.147]:19404 "EHLO mail.tglx.de") by vger.kernel.org with ESMTP id S932499AbVLPVzy (ORCPT ); Fri, 16 Dec 2005 16:55:54 -0500 Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation From: Thomas Gleixner Reply-To: tglx@linutronix.de To: Andrew Morton Cc: dhowells@redhat.com, lkml@rtr.ca, alan@lxorguk.ukuu.org.uk, pj@sgi.com, mingo@elte.hu, hch@infradead.org, torvalds@osdl.org, arjan@infradead.org, matthew@wil.cx, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org In-Reply-To: <20051215121817.2abb0166.akpm@osdl.org> References: <20051214155432.320f2950.akpm@osdl.org> <1134559121.25663.14.camel@localhost.localdomain> <13820.1134558138@warthog.cambridge.redhat.com> <20051213143147.d2a57fb3.pj@sgi.com> <20051213094053.33284360.pj@sgi.com> <20051212161944.3185a3f9.akpm@osdl.org> <20051213075441.GB6765@elte.hu> <20051213090219.GA27857@infradead.org> <20051213093949.GC26097@elte.hu> <20051213100015.GA32194@elte.hu> <6281.1134498864@warthog.cambridge.redhat.com> <14242.1134558772@warthog.cambridge.redhat.com> <16315.1134563707@warthog.cambridge.redhat.com> <1134568731.4275.4.camel@tglx.tec.linutronix.de> <43A0AD54.6050109@rtr.ca> <4336.1134661053@warthog.cambridge.redhat.com> <20051215112855.31669dc1.akpm@osdl.org> <20051215121817.2abb0166.akpm@osdl.org> Content-Type: text/plain Organization: linutronix Date: Fri, 16 Dec 2005 23:02:49 +0100 Message-Id: <1134770569.2806.27.camel@tglx.tec.linutronix.de> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 919 Lines: 26 On Thu, 2005-12-15 at 12:18 -0800, Andrew Morton wrote: > Look at it from the POV of major architectures: there's no way the new > mutex code will be faster than down() and up(), so we're adding a bunch of > new tricky locking code which bloats the kernel and has to be understood > and debugged for no gain. Look at it from the semantical POV first, which is the most important one. semaphores are semantically different from mutexes, so they require different APIs. When you have semantically different APIs, you can still implement them for whatever (e.g. peformance) reason on top of the same mechanism, but you can not make this work the other way round. tglx - 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/