Received: by 10.192.165.148 with SMTP id m20csp895137imm; Fri, 27 Apr 2018 09:11:20 -0700 (PDT) X-Google-Smtp-Source: AB8JxZod8MY2eHXdEoa3Opq17NT32faMBqeuXaai2tNsxEqZKyh83fZh7+jMSr5E7xt9AY3yE5dg X-Received: by 2002:a63:3688:: with SMTP id d130-v6mr2652903pga.228.1524845480564; Fri, 27 Apr 2018 09:11:20 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1524845480; cv=none; d=google.com; s=arc-20160816; b=E0MKIh5r63OpUExJQzUAkJLsjbl0wCU0PCsmlH3NI2VDLYW5pMBU/Q4463kSwMPVO0 rBm4sjt779ojbFyF4UaSVcbQSxmdsJK5I2ref8t40wy7+kafbVrQBkC1Odw8hlrovGCx a3k6vosgKqcwd5Odw7e2vAwmUu+MuXjNpCVa/+GgIPAwJYZIYlnH4lLIY4z3B/LNGnZw FLUH2JWmab36SoYXZCYBp8cGe1qeXwQ8vwQek5+2mNtPJRKnMTvqmZEef3T0sVhClTaz tzqo6XHC30kDLqD0zhgdfiCbYudVGsJzxZ/d0EVBnIaCIC5krccoEGUUllY6G2He22cT +Cgw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date :dmarc-filter:arc-authentication-results; bh=urStN65anwNZrdkWovcTOkA4tsMwIaQ6v1BL2BwbdHI=; b=cIZPBjGCvdRRR/d2fZa+0YtxknDK3bJ24WfjxK8IdTfsb7y2zJZssJ0zcc3q73PbiF ZnRMancH+1JzKsKVXeJB8z/zQJND6zoyg2nxabj4a6uQrM3rKPZlpIB1rIhEO5mYqp2D Qq0gnTRswIXPphoE2Ppudyq7hVhX5dzrqDsf7fY0bE8YIVc1ybE8BRQ0GkrWsNWNxOso azp2g7Sz7wiDPbzi79cFKYiw6dfdObKINJXk21GjZdHgwcLujl+4gmBya+aTt1gciqqF OIAk7O73wfKNl0egrkjDPIjHiVcM02cfo6mKZVp9ROTmwpiQ1/UqzJ3Budo88Vu7iz9s oCwA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id j185-v6si1443620pgc.606.2018.04.27.09.11.06; Fri, 27 Apr 2018 09:11:20 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758763AbeD0QJG (ORCPT + 99 others); Fri, 27 Apr 2018 12:09:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:51338 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758276AbeD0QJC (ORCPT ); Fri, 27 Apr 2018 12:09:02 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6562F2184E; Fri, 27 Apr 2018 16:09:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6562F2184E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Fri, 27 Apr 2018 12:08:58 -0400 From: Steven Rostedt To: Mathieu Desnoyers Cc: "Paul E. McKenney" , Joel Fernandes , linux-kernel , Peter Zijlstra , Ingo Molnar , Tom Zanussi , Namhyung Kim , Thomas Gleixner , Boqun Feng , fweisbec , Randy Dunlap , Masami Hiramatsu , kbuild test robot , baohong liu , vedang patel , kernel-team Subject: Re: [PATCH RFC] tracepoint: Introduce tracepoint callbacks executing with preempt on Message-ID: <20180427120858.1357f1e0@gandalf.local.home> In-Reply-To: <1953337577.5844.1524843821731.JavaMail.zimbra@efficios.com> References: <20180427042656.190746-1-joelaf@google.com> <1169911546.5820.1524839189395.JavaMail.zimbra@efficios.com> <20180427104747.2d965925@gandalf.local.home> <20180427153826.GK26088@linux.vnet.ibm.com> <20180427114005.31d1e8ab@gandalf.local.home> <1953337577.5844.1524843821731.JavaMail.zimbra@efficios.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 27 Apr 2018 11:43:41 -0400 (EDT) Mathieu Desnoyers wrote: > It does so by disabling preemption in the callbacks, even when it's > redundant with the guarantees already provided by tracepoint-sched-rcu > and by kprobes. It's not that great for a fast-path. Really, preempt_disable() is not bad for a fast path. It's far better than a local_irq_disable(). -- Steve