From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751874AbeDII3g (ORCPT ); Mon, 9 Apr 2018 04:29:36 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:42976 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750952AbeDII3f (ORCPT ); Mon, 9 Apr 2018 04:29:35 -0400 Subject: Re: [PATCH v2 9/9] perf probe: Support SDT markers having reference counter (semaphore) To: Masami Hiramatsu 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 References: <20180404083110.18647-1-ravi.bangoria@linux.vnet.ibm.com> <20180404083110.18647-10-ravi.bangoria@linux.vnet.ibm.com> <20180409162856.df4c32b840eb5f2ef8c028f1@kernel.org> From: Ravi Bangoria Date: Mon, 9 Apr 2018 13:59:16 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180409162856.df4c32b840eb5f2ef8c028f1@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18040908-0020-0000-0000-0000040F982C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18040908-0021-0000-0000-000042A3B794 Message-Id: <643a8fb2-fb96-8dbe-9f36-2540bd8a1de5@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-09_03:,, 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=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804090093 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Masami, On 04/09/2018 12:58 PM, Masami Hiramatsu wrote: > Hi Ravi, > > On Wed, 4 Apr 2018 14:01:10 +0530 > Ravi Bangoria wrote: > >> @@ -2054,15 +2060,21 @@ char *synthesize_probe_trace_command(struct probe_trace_event *tev) >> } >> >> /* Use the tp->address for uprobes */ >> - if (tev->uprobes) >> + if (tev->uprobes) { >> err = strbuf_addf(&buf, "%s:0x%lx", tp->module, tp->address); >> - else if (!strncmp(tp->symbol, "0x", 2)) >> + if (uprobe_ref_ctr_is_supported() && >> + tp->ref_ctr_offset && >> + err >= 0) >> + err = strbuf_addf(&buf, "(0x%lx)", tp->ref_ctr_offset); > If the kernel doesn't support uprobe_ref_ctr but the event requires > to increment uprobe_ref_ctr, I think we should (at least) warn user here. pr_debug("A semaphore is associated with %s:%s and seems your kernel doesn't support it.\n"          tev->group, tev->event); Looks good? >> @@ -776,14 +784,21 @@ static char *synthesize_sdt_probe_command(struct sdt_note *note, >> { >> struct strbuf buf; >> char *ret = NULL, **args; >> - int i, args_count; >> + int i, args_count, err; >> + unsigned long long ref_ctr_offset; >> >> if (strbuf_init(&buf, 32) < 0) >> return NULL; >> >> - if (strbuf_addf(&buf, "p:%s/%s %s:0x%llx", >> - sdtgrp, note->name, pathname, >> - sdt_note__get_addr(note)) < 0) >> + err = strbuf_addf(&buf, "p:%s/%s %s:0x%llx", >> + sdtgrp, note->name, pathname, >> + sdt_note__get_addr(note)); >> + >> + ref_ctr_offset = sdt_note__get_ref_ctr_offset(note); >> + if (uprobe_ref_ctr_is_supported() && ref_ctr_offset && err >= 0) >> + err = strbuf_addf(&buf, "(0x%llx)", ref_ctr_offset); > We don't have to care about uprobe_ref_ctr support here, because > this information will be just cached, not directly written to > uprobe_events. Sure, will remove the check. Thanks for the review :). Ravi