From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752133AbdCAQmV (ORCPT ); Wed, 1 Mar 2017 11:42:21 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:40337 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751565AbdCAQmT (ORCPT ); Wed, 1 Mar 2017 11:42:19 -0500 Date: Wed, 1 Mar 2017 20:41:05 +0530 From: "Naveen N. Rao" To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Steven Rostedt , Arnaldo Carvalho de Melo , linuxppc-dev@lists.ozlabs.org, Ingo Molnar Subject: Re: [PATCH v3 2/2] perf: kretprobes: offset from reloc_sym if kernel supports it References: <2f4181ecccf794d05065cb10648badc290aa4c28.1487849577.git.naveen.n.rao@linux.vnet.ibm.com> <20170225021208.3bb8f7810ae1c5644df3ae6a@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170225021208.3bb8f7810ae1c5644df3ae6a@kernel.org> User-Agent: Mutt/1.6.2 (2016-07-01) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17030115-0016-0000-0000-000003EBDAD7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17030115-0017-0000-0000-000028D1DFA0 Message-Id: <20170301151105.GL4212@naverao1-tp.localdomain> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-03-01_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1703010140 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/02/25 02:12AM, Masami Hiramatsu wrote: > On Thu, 23 Feb 2017 17:07:24 +0530 > "Naveen N. Rao" wrote: > > > We indicate support for accepting sym+offset with kretprobes through a > > line in ftrace README. Parse the same to identify support and choose the > > appropriate format for kprobe_events. > > > > Signed-off-by: Naveen N. Rao > > --- > > tools/perf/util/probe-event.c | 49 ++++++++++++++++++++++++++++++++++++------- > > tools/perf/util/probe-event.h | 2 ++ > > 2 files changed, 44 insertions(+), 7 deletions(-) > > > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > > index 35f5b7b7715c..dd6b9ce0eef3 100644 > > --- a/tools/perf/util/probe-event.c > > +++ b/tools/perf/util/probe-event.c > > @@ -737,6 +737,43 @@ post_process_module_probe_trace_events(struct probe_trace_event *tevs, > > return ret; > > } > > > > +bool is_kretprobe_offset_supported(void) > > +{ > > + FILE *fp; > > + char *buf = NULL; > > + size_t len = 0; > > + bool target_line = false; > > + static int supported = -1; > > + int fd; > > + > > + if (supported >= 0) > > + return !!supported; > > + > > + fd = open_trace_file("README", false); > > + if (fd < 0) > > + return false; > > + > > + fp = fdopen(fd, "r"); > > + if (!fp) { > > + close(fd); > > + return false; > > + } > > + > > + while (getline(&buf, &len, fp) > 0) { > > + target_line = !!strstr(buf, "place (kretprobe): "); > > + if (!target_line) > > + continue; > > + supported = 1; > > + } > > + if (supported == -1) > > + supported = 0; > > + > > + fclose(fp); > > + free(buf); > > + > > + return !!supported; > > +} > > Hmm, I think you can do more than that. > Can you reuse probe_type_is_available() to scan README? > I think we can have something like scan_ftrace_readme() in probe-file.c > to scan all the options and cache the results. > > probe_type_is_available() and kreprobe_offset_is_available() > just returns cached result or scan it in first call.(I would like to > ask you to do it in probe-file.c too) Ok sure, that makes sense. I see that we only ever care about support for hex type, so I will add a separate routine to only look for that and the newly added kretprobe offset support. - Naveen