From patchwork Fri May 13 07:56:04 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 67728 Delivered-To: patch@linaro.org Received: by 10.140.92.199 with SMTP id b65csp135550qge; Fri, 13 May 2016 00:57:14 -0700 (PDT) X-Received: by 10.98.55.133 with SMTP id e127mr20212132pfa.81.1463126231574; Fri, 13 May 2016 00:57:11 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id q66si23008572pfb.190.2016.05.13.00.57.11; Fri, 13 May 2016 00:57:11 -0700 (PDT) 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 S1752651AbcEMH44 (ORCPT + 29 others); Fri, 13 May 2016 03:56:56 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:61982 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752455AbcEMH4t (ORCPT ); Fri, 13 May 2016 03:56:49 -0400 Received: from 172.24.1.137 (EHLO szxeml433-hub.china.huawei.com) ([172.24.1.137]) by szxrg01-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id DKL57612; Fri, 13 May 2016 15:56:41 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml433-hub.china.huawei.com (10.82.67.210) with Microsoft SMTP Server id 14.3.235.1; Fri, 13 May 2016 15:56:24 +0800 From: Wang Nan To: CC: , , Wang Nan , He Kuang , "Arnaldo Carvalho de Melo" , Jiri Olsa , Masami Hiramatsu , Namhyung Kim , "Zefan Li" , Subject: [PATCH 07/17] perf record: Don't read from and poll overwrite channel Date: Fri, 13 May 2016 07:56:04 +0000 Message-ID: <1463126174-119290-8-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1463126174-119290-1-git-send-email-wangnan0@huawei.com> References: <1463126174-119290-1-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=0001.0A020201.573588B9.0117, 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: ac9414ea88b442078929bbbf4e0dfaaf 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 such ring buffers 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 5e87602..d9a92e0 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -429,6 +429,19 @@ 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; @@ -439,7 +452,7 @@ 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;