From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261390AbVA1CPF (ORCPT ); Thu, 27 Jan 2005 21:15:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261392AbVA1CPF (ORCPT ); Thu, 27 Jan 2005 21:15:05 -0500 Received: from omx3-ext.sgi.com ([192.48.171.20]:37343 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S261390AbVA1CPA (ORCPT ); Thu, 27 Jan 2005 21:15:00 -0500 Date: Thu, 27 Jan 2005 18:14:33 -0800 From: Paul Jackson To: Linus Torvalds Cc: mingo@elte.hu, pwil3058@bigpond.net.au, akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [patch, 2.6.10-rc2] sched: fix ->nr_uninterruptible handling bugs Message-Id: <20050127181433.0e63b463.pj@sgi.com> In-Reply-To: References: <20041116113209.GA1890@elte.hu> <419A7D09.4080001@bigpond.net.au> <20041116232827.GA842@elte.hu> <20050127165330.6f388054.pj@sgi.com> Organization: SGI X-Mailer: Sylpheed version 0.9.12 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org True - thanks - including the part about the cost of locking bugs. My question was poorly phrased - the code speaks the answer to the real question I had: $ grep define.atomic_ include/asm-ia64/atomic.h | head -2 #define atomic_read(v) ((v)->counter) #define atomic_set(v,i) (((v)->counter) = (i)) An atomic_read() of a one word counter on ia64 is just a load, and an atomic_set() is just a store. This is unlike the more difficult atomic_inc, atomic_dec, atomic_add, atomic_mutilate, ... calls that require something fancier, and I presume more painful for that CPUs innards. Good. Thanks. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.650.933.1373, 1.925.600.0401