Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760751Ab3GSOU1 (ORCPT ); Fri, 19 Jul 2013 10:20:27 -0400 Received: from mail-qa0-f53.google.com ([209.85.216.53]:60012 "EHLO mail-qa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755243Ab3GSOUW (ORCPT ); Fri, 19 Jul 2013 10:20:22 -0400 Date: Fri, 19 Jul 2013 10:20:19 -0400 (EDT) From: Nicolas Pitre To: Will Deacon cc: Stephen Boyd , John Stultz , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Thomas Gleixner , Russell King , Catalin Marinas , Christopher Covington Subject: Re: [PATCH v4 02/17] sched_clock: Use seqcount instead of rolling our own In-Reply-To: <20130719090328.GA18139@mudshark.cambridge.arm.com> Message-ID: References: <1374189690-10810-1-git-send-email-sboyd@codeaurora.org> <1374189690-10810-3-git-send-email-sboyd@codeaurora.org> <20130719090328.GA18139@mudshark.cambridge.arm.com> User-Agent: Alpine 2.03 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 599 Lines: 17 On Fri, 19 Jul 2013, Will Deacon wrote: > Looks good to me. The current scheme would be very fiddly to extend to > 64-bit values on 32-bit architectures without cheap atomic doubleword > accesses. You should have a look at include/linux/cnt32_to_63.h. This could be applied to pure software counters if the low part is atomically increased. Nicolas -- 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/