From patchwork Fri Feb 26 09:32:23 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 63009 Delivered-To: patch@linaro.org Received: by 10.112.199.169 with SMTP id jl9csp613813lbc; Fri, 26 Feb 2016 01:43:31 -0800 (PST) X-Received: by 10.98.64.26 with SMTP id n26mr699929pfa.149.1456479811253; Fri, 26 Feb 2016 01:43:31 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t62si18831258pfa.211.2016.02.26.01.43.28; Fri, 26 Feb 2016 01:43:31 -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 S1753593AbcBZJnM (ORCPT + 30 others); Fri, 26 Feb 2016 04:43:12 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:9041 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752700AbcBZJdz (ORCPT ); Fri, 26 Feb 2016 04:33:55 -0500 Received: from 172.24.1.49 (EHLO szxeml422-hub.china.huawei.com) ([172.24.1.49]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id BWR34449; Fri, 26 Feb 2016 17:33:17 +0800 (CST) Received: from linux-4hy3.site (10.107.193.248) by szxeml422-hub.china.huawei.com (10.82.67.152) with Microsoft SMTP Server id 14.3.235.1; Fri, 26 Feb 2016 17:33:09 +0800 From: Wang Nan To: Alexei Starovoitov , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo CC: Jiri Olsa , Li Zefan , "Peter Zijlstra" , , Wang Nan , , He Kuang , Masami Hiramatsu , Namhyung Kim Subject: [PATCH 35/46] perf record: Don't read from and poll overwrite channel Date: Fri, 26 Feb 2016 09:32:23 +0000 Message-ID: <1456479154-136027-36-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1456479154-136027-1-git-send-email-wangnan0@huawei.com> References: <1456479154-136027-1-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=0001.0A090201.56D01BFF.007F, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: b649635266d0d7b017ab56cbe28089b3 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 92eccf1..120b3bb 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -462,6 +462,19 @@ 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; @@ -472,7 +485,7 @@ 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;