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=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI 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 0B2777DE74 for ; Tue, 17 Apr 2018 04:34:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752672AbeDQEeO (ORCPT ); Tue, 17 Apr 2018 00:34:14 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:33378 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752619AbeDQEeK (ORCPT ); Tue, 17 Apr 2018 00:34:10 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w3H4XwDH010910 for ; Tue, 17 Apr 2018 00:34:10 -0400 Received: from e06smtp12.uk.ibm.com (e06smtp12.uk.ibm.com [195.75.94.108]) by mx0a-001b2d01.pphosted.com with ESMTP id 2hd4m8kh80-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Tue, 17 Apr 2018 00:34:10 -0400 Received: from localhost by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 17 Apr 2018 05:34:07 +0100 Received: from b06cxnps4075.portsmouth.uk.ibm.com (9.149.109.197) by e06smtp12.uk.ibm.com (192.168.101.142) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 17 Apr 2018 05:34:00 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w3H4Xxnt50397392; Tue, 17 Apr 2018 04:33:59 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2E018AE057; Tue, 17 Apr 2018 05:23:50 +0100 (BST) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 96C67AE04D; Tue, 17 Apr 2018 05:23:45 +0100 (BST) Received: from bangoria.in.ibm.com (unknown [9.124.31.151]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 17 Apr 2018 05:23:45 +0100 (BST) From: Ravi Bangoria To: mhiramat@kernel.org, oleg@redhat.com, peterz@infradead.org, srikar@linux.vnet.ibm.com, rostedt@goodmis.org Cc: 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: [PATCH v3 8/9] trace_uprobe/sdt: Document about reference counter Date: Tue, 17 Apr 2018 10:02:43 +0530 X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180417043244.7501-1-ravi.bangoria@linux.vnet.ibm.com> References: <20180417043244.7501-1-ravi.bangoria@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18041704-0008-0000-0000-000004EC167E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041704-0009-0000-0000-00001E8017E6 Message-Id: <20180417043244.7501-9-ravi.bangoria@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-17_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804170042 Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org 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 --- 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 -- 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