From patchwork Fri Sep 21 16:13:29 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Walmsley X-Patchwork-Id: 1492611 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 62893400ED for ; Fri, 21 Sep 2012 16:14:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756232Ab2IUQNd (ORCPT ); Fri, 21 Sep 2012 12:13:33 -0400 Received: from utopia.booyaka.com ([74.50.51.50]:34234 "EHLO utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756217Ab2IUQNa (ORCPT ); Fri, 21 Sep 2012 12:13:30 -0400 Received: (qmail 2791 invoked by uid 1019); 21 Sep 2012 16:13:29 -0000 Date: Fri, 21 Sep 2012 16:13:29 +0000 (UTC) From: Paul Walmsley To: "Paul E. McKenney" , Dipankar Sarma cc: linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, "Bruce, Becky" , "Hilman, Kevin" , "Shilimkar, Santosh" , "Hunter, Jon" , snijsure@grid-net.com Subject: [PATCH] Documentation: RCU: update the stall warning message "timer=-1" to match reality Message-ID: User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org The CONFIG_RCU_FAST_NO_HZ stall warning messages can never emit "timer=-1". This is because the printf() format specifier to generate that number is '%lu'. So, update the documentation to use the unsigned long equivalent instead, "timer=4294967295". This is what actually shows up in traces. Signed-off-by: Paul Walmsley Cc: Paul E. McKenney Cc: Dipankar Sarma --- Documentation/RCU/stallwarn.txt | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index 523364e..fe3379e 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -99,7 +99,7 @@ In kernels with CONFIG_RCU_FAST_NO_HZ, even more information is printed: INFO: rcu_preempt detected stall on CPU - 0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 drain=0 . timer=-1 + 0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 drain=0 . timer=4294967295 (t=65000 jiffies) The "(64628 ticks this GP)" indicates that this CPU has taken more @@ -119,10 +119,10 @@ number (as shown above) otherwise. For CONFIG_RCU_FAST_NO_HZ kernels, the "drain=0" indicates that the CPU is not in the process of trying to force itself into dyntick-idle state, the "." indicates that the CPU has not given up forcing RCU -into dyntick-idle mode (it would be "H" otherwise), and the "timer=-1" -indicates that the CPU has not recented forced RCU into dyntick-idle -mode (it would otherwise indicate the number of microseconds remaining -in this forced state). +into dyntick-idle mode (it would be "H" otherwise), and the +"timer=4294967295" (the magic number (2^32)-1) indicates that the CPU +has not recently forced RCU into dyntick-idle mode (it would otherwise +indicate the number of microseconds remaining in this forced state). Multiple Warnings From One Stall