From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752649AbcEMH44 (ORCPT ); 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 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 Content-Type: text/plain 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 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(-) 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; -- 1.8.3.4