From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH 1/3] acpi: add real mutex function calls Date: Mon, 21 Jul 2008 11:17:25 +0200 Message-ID: <48845425.9000607@linux.intel.com> References: <1216491411-24080-1-git-send-email-dwalker@mvista.com> <1216491411-24080-2-git-send-email-dwalker@mvista.com> <1216605078.4135.23.camel@yakui_zhao.sh.intel.com> <1216631698.7257.29.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com ([134.134.136.24]:39447 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754640AbYGUJR0 (ORCPT ); Mon, 21 Jul 2008 05:17:26 -0400 In-Reply-To: <1216631698.7257.29.camel@twins> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Peter Zijlstra Cc: Zhao Yakui , Daniel Walker , linux-acpi@vger.kernel.org, Ingo Molnar , len.brown@intel.com Peter Zijlstra wrote: > On Mon, 2008-07-21 at 09:51 +0800, Zhao Yakui wrote: >> On Sat, 2008-07-19 at 11:16 -0700, Daniel Walker wrote: >>> Instead of re-using semaphores for the mutex operation, I've >>> added usage of the kernel mutex for the os mutex implementation. >>> >> What is the advantage that the kernel mutex is used for the ACPI mutex >> implementation instead of using semaphore? >> And it seems that too much ACPICA source code is touched. > > You get help from lockdep, and also our goal is to fully eradicate > semaphore usage. Issue is that ACPICA is shared with other OS source code and to replace a major interface like this would mean replacing it for everyone. It might end up with ACPICA just reimplementing a semaphore like wrapper if semaphores really go away, but I don't really see that coming anyways. -Andi