From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.9 required=5.0 tests=DKIM_SIGNED, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id EB7407DE78 for ; Thu, 3 May 2018 14:57:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751166AbeECO5b (ORCPT ); Thu, 3 May 2018 10:57:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:34644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750947AbeECO52 (ORCPT ); Thu, 3 May 2018 10:57:28 -0400 Received: from devbox (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 B3CA721775; Thu, 3 May 2018 14:57:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1525359446; bh=kWGtCkSxHO+SW65fH0QPjo8YE6SSAE1be7Q6Q9dEh60=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=kNNRhQG/SYnEBUfiosadp2jhrHCjiCXrLtuhSifp5nn7Z79z3tqWDmdLWZFVhcE+5 Aoox52wpeO6Etb1Ytf/7fqxqABKRmXTk61h978FD4ml6af9COH8rs3kr094zP/sEch JV299CrqYBAki5eB0/Rqz+JAAm/3SDr/MKkl84XU= Date: Thu, 3 May 2018 23:57:21 +0900 From: Masami Hiramatsu To: Ravi Bangoria Cc: oleg@redhat.com, peterz@infradead.org, srikar@linux.vnet.ibm.com, rostedt@goodmis.org, acme@kernel.org, ananth@linux.vnet.ibm.com, akpm@linux-foundation.org, alexander.shishkin@linux.intel.com, alexis.berlemont@gmail.com, corbet@lwn.net, dan.j.williams@intel.com, jolsa@redhat.com, kan.liang@intel.com, kjlx@templeofstupid.com, kstewart@linuxfoundation.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, milian.wolff@kdab.com, mingo@redhat.com, namhyung@kernel.org, naveen.n.rao@linux.vnet.ibm.com, pc@us.ibm.com, tglx@linutronix.de, yao.jin@linux.intel.com, fengguang.wu@intel.com, jglisse@redhat.com, Ravi Bangoria Subject: Re: [PATCH v3 8/9] trace_uprobe/sdt: Document about reference counter Message-Id: <20180503235721.d1dbc6f5bfdfc97e6200b7de@kernel.org> In-Reply-To: <20180417043244.7501-9-ravi.bangoria@linux.vnet.ibm.com> References: <20180417043244.7501-1-ravi.bangoria@linux.vnet.ibm.com> <20180417043244.7501-9-ravi.bangoria@linux.vnet.ibm.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Tue, 17 Apr 2018 10:02:43 +0530 Ravi Bangoria wrote: > From: Ravi Bangoria > > Reference counter gate the invocation of probe. If present, > by default reference count is 0. Kernel needs to increment > it before tracing the probe and decrement it when done. This > is identical to semaphore in Userspace Statically Defined > Tracepoints (USDT). > > Document usage of reference counter. > > Signed-off-by: Ravi Bangoria Looks good to me. Acked-by: Masami Hiramatsu Thanks! > --- > Documentation/trace/uprobetracer.txt | 16 +++++++++++++--- > kernel/trace/trace.c | 2 +- > 2 files changed, 14 insertions(+), 4 deletions(-) > > diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt > index bf526a7c..cb6751d 100644 > --- a/Documentation/trace/uprobetracer.txt > +++ b/Documentation/trace/uprobetracer.txt > @@ -19,15 +19,25 @@ user to calculate the offset of the probepoint in the object. > > Synopsis of uprobe_tracer > ------------------------- > - p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe > - r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe) > - -:[GRP/]EVENT : Clear uprobe or uretprobe event > + p[:[GRP/]EVENT] PATH:OFFSET[(REF_CTR_OFFSET)] [FETCHARGS] > + r[:[GRP/]EVENT] PATH:OFFSET[(REF_CTR_OFFSET)] [FETCHARGS] > + -:[GRP/]EVENT > + > + p : Set a uprobe > + r : Set a return uprobe (uretprobe) > + - : Clear uprobe or uretprobe event > > GRP : Group name. If omitted, "uprobes" is the default value. > EVENT : Event name. If omitted, the event name is generated based > on PATH+OFFSET. > PATH : Path to an executable or a library. > OFFSET : Offset where the probe is inserted. > + REF_CTR_OFFSET: Reference counter offset. Optional field. Reference count > + gate the invocation of probe. If present, by default > + reference count is 0. Kernel needs to increment it before > + tracing the probe and decrement it when done. This is > + identical to semaphore in Userspace Statically Defined > + Tracepoints (USDT). > > FETCHARGS : Arguments. Each probe can have up to 128 args. > %REG : Fetch register REG > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 300f4ea..d211937 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -4604,7 +4604,7 @@ static int tracing_trace_options_open(struct inode *inode, struct file *file) > "place (kretprobe): [:][+]|\n" > #endif > #ifdef CONFIG_UPROBE_EVENTS > - "\t place: :\n" > + " place (uprobe): :[(ref_ctr_offset)]\n" > #endif > "\t args: =fetcharg[:type]\n" > "\t fetcharg: %, @
, @[+|-],\n" > -- > 1.8.3.1 > -- Masami Hiramatsu -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html