Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264359AbUAFQVJ (ORCPT ); Tue, 6 Jan 2004 11:21:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264442AbUAFQVJ (ORCPT ); Tue, 6 Jan 2004 11:21:09 -0500 Received: from fw.osdl.org ([65.172.181.6]:54488 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S264359AbUAFQVE (ORCPT ); Tue, 6 Jan 2004 11:21:04 -0500 Date: Tue, 6 Jan 2004 08:19:47 -0800 From: Andrew Morton To: James Bottomley Cc: johnstultz@us.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fix get_jiffies_64 to work on voyager Message-Id: <20040106081947.3d51a1d5.akpm@osdl.org> In-Reply-To: <1073405053.2047.28.camel@mulgrave> References: <1073405053.2047.28.camel@mulgrave> X-Mailer: Sylpheed version 0.9.4 (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 Content-Length: 1630 Lines: 44 James Bottomley wrote: > > This patch > > > ChangeSet@1.1534.5.2, 2003-12-30 15:40:23-08:00, akpm@osdl.org > [PATCH] ia32 jiffy wrapping fixes > > Causes the voyager boot to hang. The problem is this change: > > --- a/arch/i386/kernel/timers/timer_tsc.c Tue Jan 6 09:57:34 2004 > +++ b/arch/i386/kernel/timers/timer_tsc.c Tue Jan 6 09:57:34 2004 > @@ -141,7 +140,7 @@ > #ifndef CONFIG_NUMA > if (!use_tsc) > #endif > - return (unsigned long long)jiffies * (1000000000 / HZ); > + return (unsigned long long)get_jiffies_64() * > (1000000000 / HZ); Hm, OK. I hit the same deadlock when running with the "don't require TSCs to be synchronised in sched_clock()" patch from -mm. The fix for that is below. I shall accelerate it. --- 25/arch/i386/kernel/timers/timer_tsc.c~sched_clock-2.6.0-A1-deadlock-fix 2003-12-30 00:45:09.000000000 -0800 +++ 25-akpm/arch/i386/kernel/timers/timer_tsc.c 2003-12-30 00:45:09.000000000 -0800 @@ -140,7 +140,8 @@ unsigned long long sched_clock(void) #ifndef CONFIG_NUMA if (!use_tsc) #endif - return (unsigned long long)get_jiffies_64() * (1000000000 / HZ); + /* jiffies might overflow but this is not a big deal here */ + return (unsigned long long)jiffies * (1000000000 / HZ); /* Read the Time Stamp Counter */ rdtscll(this_offset); _ - 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/