From patchwork Fri Feb 5 14:02:08 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 61280 Delivered-To: patch@linaro.org Received: by 10.112.43.199 with SMTP id y7csp1110871lbl; Fri, 5 Feb 2016 06:05:28 -0800 (PST) X-Received: by 10.66.144.37 with SMTP id sj5mr19929201pab.69.1454681128527; Fri, 05 Feb 2016 06:05:28 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p16si24194182pfi.111.2016.02.05.06.05.28; Fri, 05 Feb 2016 06:05:28 -0800 (PST) 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 S1754378AbcBEOFU (ORCPT + 30 others); Fri, 5 Feb 2016 09:05:20 -0500 Received: from [119.145.14.65] ([119.145.14.65]:8011 "EHLO szxga02-in.huawei.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754336AbcBEOFP (ORCPT ); Fri, 5 Feb 2016 09:05:15 -0500 Received: from 172.24.1.49 (EHLO SZXEML429-HUB.china.huawei.com) ([172.24.1.49]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id DAZ55302; Fri, 05 Feb 2016 22:03:40 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by SZXEML429-HUB.china.huawei.com (10.82.67.184) with Microsoft SMTP Server id 14.3.235.1; Fri, 5 Feb 2016 22:03:32 +0800 From: Wang Nan To: Alexei Starovoitov , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Brendan Gregg CC: Adrian Hunter , Cody P Schafer , "David S. Miller" , He Kuang , =?UTF-8?q?J=C3=A9r=C3=A9mie=20Galarneau?= , Jiri Olsa , Kirill Smelkov , Li Zefan , Masami Hiramatsu , Namhyung Kim , Peter Zijlstra , , Wang Nan , Subject: [PATCH 43/54] perf record: Don't read from and poll overwrite channel Date: Fri, 5 Feb 2016 14:02:08 +0000 Message-ID: <1454680939-24963-44-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1454680939-24963-1-git-send-email-wangnan0@huawei.com> References: <1454680939-24963-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.193.248] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.56B4ABBC.01F9, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: ed3c5da7ef8e6abc39b22eb024ff40c0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Reading from overwritable ring buffer is unreliable. Introduce record__mmap_should_read() and prevent reading from overwrite ring buffer in 'perf record'. The rule in record__mmap_should_read() will be changed when perf support reading from backward writing ring buffer. Signed-off-by: Wang Nan Signed-off-by: He Kuang Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Zefan Li Cc: pi3orama@163.com --- tools/perf/builtin-record.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) -- 1.8.3.4 diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 53bfe55..503eee9 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -461,6 +461,19 @@ static struct perf_event_header finished_round_event = { .type = PERF_RECORD_FINISHED_ROUND, }; +static bool record__mmap_should_read(struct record *rec, int idx) +{ + int channel = -1; + + if (!rec->evlist->mmap[idx].base) + return false; + if (perf_evlist__channel_idx(rec->evlist, &channel, &idx)) + return false; + if (perf_evlist__channel_check(rec->evlist, channel, RDONLY)) + return false; + return true; +} + static int record__mmap_read_all(struct record *rec) { u64 bytes_written = rec->bytes_written; @@ -471,7 +484,7 @@ static int record__mmap_read_all(struct record *rec) for (i = 0; i < total_mmaps; i++) { struct auxtrace_mmap *mm = &rec->evlist->mmap[i].auxtrace_mmap; - if (rec->evlist->mmap[i].base) { + if (record__mmap_should_read(rec, i)) { if (record__mmap_read(rec, i) != 0) { rc = -1; goto out;