Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754728AbZAZU0a (ORCPT ); Mon, 26 Jan 2009 15:26:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753558AbZAZU0S (ORCPT ); Mon, 26 Jan 2009 15:26:18 -0500 Received: from mx2.redhat.com ([66.187.237.31]:37872 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753376AbZAZU0S (ORCPT ); Mon, 26 Jan 2009 15:26:18 -0500 Date: Mon, 26 Jan 2009 18:25:50 -0200 From: Arnaldo Carvalho de Melo To: Jens Axboe Cc: Ingo Molnar , Linux Kernel Mailing List Subject: [PATCH tip 1/1] blktrace: the ftrace interface needs CONFIG_TRACING Message-ID: <20090126202549.GC11038@ghostprotocols.net> Mail-Followup-To: Arnaldo Carvalho de Melo , Jens Axboe , Ingo Molnar , Linux Kernel Mailing List MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Url: http://oops.ghostprotocols.net:81/blog User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1414 Lines: 45 Resend, the first time I forgot to add [PATCH tip 1/1]. Ingo, this fix that problem you reported me, where a .config didn't had CONFIG_TRACING selected. Impact: Fix Kconfig selection for blktrace Also mention in the help text that blktrace now can be used using the ftrace interface. Cc: Jens Axboe Reported-by: Ingo Molnar Signed-off-by: Arnaldo Carvalho de Melo diff --git a/block/Kconfig b/block/Kconfig index 0cbb3b8..7cdaa1d 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -50,6 +50,8 @@ config BLK_DEV_IO_TRACE select RELAY select DEBUG_FS select TRACEPOINTS + select TRACING + select STACKTRACE help Say Y here if you want to be able to trace the block layer actions on a given queue. Tracing allows you to see any traffic happening @@ -58,6 +60,12 @@ config BLK_DEV_IO_TRACE git://git.kernel.dk/blktrace.git + Tracing also is possible using the ftrace interface, e.g.: + + echo 1 > /sys/block/sda/sda1/trace/enable + echo blk > /sys/kernel/debug/tracing/current_tracer + cat /sys/kernel/debug/tracing/trace_pipe + If unsure, say N. config BLK_DEV_BSG -- 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/