Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 12 Jul 2002 10:34:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 12 Jul 2002 10:34:07 -0400 Received: from mail.clsp.jhu.edu ([128.220.34.27]:22521 "EHLO mail.clsp.jhu.edu") by vger.kernel.org with ESMTP id ; Fri, 12 Jul 2002 10:34:06 -0400 Date: Fri, 12 Jul 2002 14:39:15 +0200 From: Pavel Machek To: Ingo Molnar Cc: Erich Focht , linux-kernel , linux-ia64 Subject: Re: O(1) scheduler "complex" macros Message-ID: <20020712123915.GA108@elf.ucw.cz> References:

Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.28i X-Warning: Reading this can be dangerous to your mental health. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 881 Lines: 21 Hi! > > #define task_running(rq, p) \ > > ((rq)->curr == (p)) && !spin_is_locked(&(p)->switch_lock) > > one more implementational note: the above test is not 'sharp' in the sense > that on SMP it's only correct (the test has no barriers) if the runqueue > lock is held. This is true for all the critical task_running() uses in > sched.c - and the cases that use it outside the runqueue lock are > optimizations so they dont need an exact test. I believe this is worth a *big fat* comment. Pavel -- Worst form of spam? Adding advertisment signatures ala sourceforge.net. What goes next? Inserting advertisment *into* email? - 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/