From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB900C433DF for ; Fri, 19 Jun 2020 01:01:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C60A320771 for ; Fri, 19 Jun 2020 01:01:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="fcIyB9vp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729853AbgFSBBs (ORCPT ); Thu, 18 Jun 2020 21:01:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729302AbgFSBBq (ORCPT ); Thu, 18 Jun 2020 21:01:46 -0400 Received: from mail-qv1-xf42.google.com (mail-qv1-xf42.google.com [IPv6:2607:f8b0:4864:20::f42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C39CEC06174E for ; Thu, 18 Jun 2020 18:01:46 -0700 (PDT) Received: by mail-qv1-xf42.google.com with SMTP id ec10so3721277qvb.5 for ; Thu, 18 Jun 2020 18:01:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=MJ6veFyzxDt135BoIfRzKOs9xaQDu2Yqf6GKe1z5Eo0=; b=fcIyB9vpbknZC/CmQAv0sRfKuQtGTX2dBJV+aATVZfItZbLJPnfF6DDJg7psKdn1mO g2Qf5hC7mdTHAMNeTwKiLiEI/gK80VSljz33bbvO8dcxcoZ+lRb9BXYoadKBIh6TKveV hTv/Za8X7gzAd8G5Tlo9cz2HTWg8KDU9nqWlc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=MJ6veFyzxDt135BoIfRzKOs9xaQDu2Yqf6GKe1z5Eo0=; b=NEF5cdrrxLP7HuZVJTLRuL2nDEH2nnXnH6r2b1fk4kPqNdB8H5CbqTNuwLiVm+s3Mj mSBqomXGFBrQanQjuv68fP/JBL+QD4oUVi7/ESvsidhhruCygX2BO/RgQnzW1A8VnG3O igyIWPnNu7qfi+GgGN1wOzgLXqeHyK3bzgXjuAFwsUDC61QPcqzEmVXn4un9dTJPQSwI MJ91I/qDLdbj3TZw8UC4pon2BxIPKJ94Be+WeRT0+q6xxUzouFuJDMDI/qlZDCOKd9RS dteBEWZ8L8p8vb2lhduXaleHWqKUQvuHzvusMnsalYJ48Bi1tLnCOlNNiChucM7EwDI7 eFrQ== X-Gm-Message-State: AOAM531Hyq4dkbosIAdquvLNI41Ri5pt4KEsifE9Yr0g4o7lBaVbXJcN Sj8YQLjnQnMnedG/1zThQM7lNA== X-Google-Smtp-Source: ABdhPJyPbwMv7xmOR0zrhGfawXpUfQc9CBRHap72QZBY41qY/2j9nrXNnzCAiZX4nU/81eVpTlvC6A== X-Received: by 2002:ad4:56e3:: with SMTP id cr3mr6499327qvb.175.1592528505164; Thu, 18 Jun 2020 18:01:45 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id o62sm4601391qkd.53.2020.06.18.18.01.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Jun 2020 18:01:44 -0700 (PDT) Date: Thu, 18 Jun 2020 21:01:44 -0400 From: Joel Fernandes To: Steven Rostedt Cc: "Paul E. McKenney" , linux-kernel@vger.kernel.org, Davidlohr Bueso , Ingo Molnar , Josh Triplett , Lai Jiangshan , Marco Elver , Mathieu Desnoyers , rcu@vger.kernel.org, "Uladzislau Rezki (Sony)" Subject: Re: [PATCH 3/7] rcu/trace: Add name of the source for gp_seq Message-ID: <20200619010144.GH40119@google.com> References: <20200618202955.4024-1-joel@joelfernandes.org> <20200618202955.4024-3-joel@joelfernandes.org> <20200618221901.GZ2723@paulmck-ThinkPad-P72> <20200618200138.500b20cb@oasis.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200618200138.500b20cb@oasis.local.home> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 18, 2020 at 08:01:38PM -0400, Steven Rostedt wrote: > On Thu, 18 Jun 2020 15:19:01 -0700 > "Paul E. McKenney" wrote: > > > For future reference, the TPS() around strings is not optional. Without > > it, trace messages from crash dumps are garbled, if I remember correctly. > > When you pass in a string like this, only the pointer to the string is > saved in the ring buffer. User space tools have no idea what those > pointers are. The TPS() around strings maps those pointers to the > string and shows them in the /sys/kernel/tracing/printk_formats file, > such that perf and trace-cmd know how to make sense of those strings. Makes sense. Quite a valuable feature! thanks, - Joel