From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753802AbbLEKWs (ORCPT ); Sat, 5 Dec 2015 05:22:48 -0500 Received: from mail.efficios.com ([78.47.125.74]:36680 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753505AbbLEKWr (ORCPT ); Sat, 5 Dec 2015 05:22:47 -0500 From: Mathieu Desnoyers To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Thomas Gleixner , Ingo Molnar , Peter Zijlstra Subject: [RFC PATCH 1/2] ftrace: add quiet option to trace_irqsoff Date: Sat, 5 Dec 2015 11:22:27 +0100 Message-Id: <1449310948-3799-1-git-send-email-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow irqsoff and preemptoff tracers to be used by perf and lttng without always having ftrace writing into its own ring buffers. Add this "quiet" option to allow using those tracers without actively tracing into the ftrace ring buffer. Signed-off-by: Mathieu Desnoyers CC: Thomas Gleixner CC: Steven Rostedt CC: Ingo Molnar CC: Peter Zijlstra --- kernel/trace/trace.h | 1 + kernel/trace/trace_irqsoff.c | 19 +++++++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 919d9d0..490413c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -967,6 +967,7 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf, C(STOP_ON_FREE, "disable_on_free"), \ C(IRQ_INFO, "irq-info"), \ C(MARKERS, "markers"), \ + C(QUIET, "quiet"), \ FUNCTION_FLAGS \ FGRAPH_FLAGS \ STACK_FLAGS \ diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index e4e5658..4ed348a 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -67,6 +67,8 @@ static inline int irqsoff_display_graph(struct trace_array *tr, int set) # define is_graph(tr) false #endif +#define is_quiet(tr) ((tr)->trace_flags & TRACE_ITER_QUIET) + /* * Sequence count - we record it when starting a measurement and * skip the latency if the sequence has changed - some other section @@ -321,9 +323,11 @@ check_critical_timing(struct trace_array *tr, if (!report_latency(tr, delta)) goto out_unlock; - __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); - /* Skip 5 functions to get to the irq/preempt enable function */ - __trace_stack(tr, flags, 5, pc); + if (!is_quiet(tr)) { + __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); + /* Skip 5 functions to get to the irq/preempt enable function */ + __trace_stack(tr, flags, 5, pc); + } if (data->critical_sequence != max_sequence) goto out_unlock; @@ -343,7 +347,8 @@ out_unlock: out: data->critical_sequence = max_sequence; data->preempt_timestamp = ftrace_now(cpu); - __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); + if (!is_quiet(tr)) + __trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc); } static inline void @@ -375,7 +380,8 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip) local_save_flags(flags); - __trace_function(tr, ip, parent_ip, flags, preempt_count()); + if (!is_quiet(tr)) + __trace_function(tr, ip, parent_ip, flags, preempt_count()); per_cpu(tracing_cpu, cpu) = 1; @@ -409,7 +415,8 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) atomic_inc(&data->disabled); local_save_flags(flags); - __trace_function(tr, ip, parent_ip, flags, preempt_count()); + if (!is_quiet(tr)) + __trace_function(tr, ip, parent_ip, flags, preempt_count()); check_critical_timing(tr, data, parent_ip ? : ip, cpu); data->critical_start = 0; atomic_dec(&data->disabled); -- 2.1.4