Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754688Ab0DAJnA (ORCPT ); Thu, 1 Apr 2010 05:43:00 -0400 Received: from mail2.shareable.org ([80.68.89.115]:34508 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209Ab0DAJmx (ORCPT ); Thu, 1 Apr 2010 05:42:53 -0400 Date: Thu, 1 Apr 2010 10:41:11 +0100 From: Jamie Lokier To: David Howells Cc: Russell King , Yinghai Lu , Andrew Morton , Rabin Vincent , lkml , hpa@zytor.com, penberg@cs.helsinki.fi, cl@linux-foundation.org, Benjamin Herrenschmidt , linux-arch@vger.kernel.org Subject: Re: start_kernel(): bug: interrupts were enabled early Message-ID: <20100401094111.GB29433@shareable.org> References: <20100331210555.GA17715@flint.arm.linux.org.uk> <20100325194100.GA2364@debian> <20100331134048.da4e35a7.akpm@linux-foundation.org> <4BB3B4DB.7040904@kernel.org> <19680.1270076318@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19680.1270076318@redhat.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 784 Lines: 19 David Howells wrote: > Russell King wrote: > > We use the standard generic kernel implementation. Is x86 different? ;) > > The optimised fast paths used on x86 rwsems don't disable interrupts. Any reason not to use the same technique for all the archs - plus the trick used in arch/armkernel/entry-armv.S:__kuser_cmpxchg for those archs which don't have atomic instructions or ll/sc? If the problem here is _only_ semaphores, and the above might make semaphores faster anyway, perhaps it's a solution. -- Jamie -- 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/