From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755359AbZHDMNV (ORCPT ); Tue, 4 Aug 2009 08:13:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755322AbZHDMNU (ORCPT ); Tue, 4 Aug 2009 08:13:20 -0400 Received: from hera.kernel.org ([140.211.167.34]:46081 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755267AbZHDMNR (ORCPT ); Tue, 4 Aug 2009 08:13:17 -0400 Date: Tue, 4 Aug 2009 12:12:50 GMT From: tip-bot for Lai Jiangshan To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, fweisbec@gmail.com, rostedt@goodmis.org, tglx@linutronix.de, laijs@cn.fujitsu.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, fweisbec@gmail.com, rostedt@goodmis.org, tglx@linutronix.de, laijs@cn.fujitsu.com In-Reply-To: <4A6EEC52.90704@cn.fujitsu.com> References: <4A6EEC52.90704@cn.fujitsu.com> Subject: [tip:tracing/urgent] tracing: Fix missing function_graph events when we splice_read from trace_pipe Message-ID: Git-Commit-ID: 74e7ff8c50b6b022e6ffaa736b16a4dc161d3eaf X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Tue, 04 Aug 2009 12:12:50 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 74e7ff8c50b6b022e6ffaa736b16a4dc161d3eaf Gitweb: http://git.kernel.org/tip/74e7ff8c50b6b022e6ffaa736b16a4dc161d3eaf Author: Lai Jiangshan AuthorDate: Tue, 28 Jul 2009 20:17:22 +0800 Committer: Frederic Weisbecker CommitDate: Tue, 28 Jul 2009 23:17:23 +0200 tracing: Fix missing function_graph events when we splice_read from trace_pipe About a half events are missing when we splice_read from trace_pipe. They are unexpectedly consumed because we ignore the TRACE_TYPE_NO_CONSUME return value used by the function graph tracer when it needs to consume the events by itself to walk on the ring buffer. The same problem appears with ftrace_dump() Example of an output before this patch: 1) | ktime_get_real() { 1) 2.846 us | read_hpet(); 1) 4.558 us | } 1) 6.195 us | } After this patch: 0) | ktime_get_real() { 0) | getnstimeofday() { 0) 1.960 us | read_hpet(); 0) 3.597 us | } 0) 5.196 us | } The fix also applies on 2.6.30 Signed-off-by: Lai Jiangshan Cc: Steven Rostedt Cc: stable@kernel.org LKML-Reference: <4A6EEC52.90704@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 8bc8d8a..da984ad 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3085,7 +3085,8 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter) break; } - trace_consume(iter); + if (ret != TRACE_TYPE_NO_CONSUME) + trace_consume(iter); rem -= count; if (!find_next_entry_inc(iter)) { rem = 0; @@ -4233,8 +4234,11 @@ static void __ftrace_dump(bool disable_tracing) iter.pos = -1; if (find_next_entry_inc(&iter) != NULL) { - print_trace_line(&iter); - trace_consume(&iter); + int ret; + + ret = print_trace_line(&iter); + if (ret != TRACE_TYPE_NO_CONSUME) + trace_consume(&iter); } trace_printk_seq(&iter.seq);