From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH 03/12] ftrace: Do not bother checking per CPU "disabled" flag
Date: Fri, 02 May 2025 16:51:50 -0400 [thread overview]
Message-ID: <20250502205348.303564071@goodmis.org> (raw)
In-Reply-To: 20250502205147.283272733@goodmis.org
From: Steven Rostedt <rostedt@goodmis.org>
The per CPU "disabled" value was the original way to disable tracing when
the tracing subsystem was first created. Today, the ring buffer
infrastructure has its own way to disable tracing. In fact, things have
changed so much since 2008 that many things ignore the disable flag.
There's no reason for the function tracer to check it, if tracing is
disabled, the ring buffer will not record the event anyway.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace_functions.c | 16 +++-------------
1 file changed, 3 insertions(+), 13 deletions(-)
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 98ccf3f00c51..bd153219a712 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -209,7 +209,6 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
{
struct trace_array *tr = op->private;
- struct trace_array_cpu *data;
unsigned int trace_ctx;
int bit;
@@ -224,9 +223,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
trace_ctx = tracing_gen_ctx_dec();
- data = this_cpu_ptr(tr->array_buffer.data);
- if (!atomic_read(&data->disabled))
- trace_function(tr, ip, parent_ip, trace_ctx, NULL);
+ trace_function(tr, ip, parent_ip, trace_ctx, NULL);
ftrace_test_recursion_unlock(bit);
}
@@ -236,10 +233,8 @@ function_args_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct ftrace_regs *fregs)
{
struct trace_array *tr = op->private;
- struct trace_array_cpu *data;
unsigned int trace_ctx;
int bit;
- int cpu;
if (unlikely(!tr->function_enabled))
return;
@@ -250,10 +245,7 @@ function_args_trace_call(unsigned long ip, unsigned long parent_ip,
trace_ctx = tracing_gen_ctx();
- cpu = smp_processor_id();
- data = per_cpu_ptr(tr->array_buffer.data, cpu);
- if (!atomic_read(&data->disabled))
- trace_function(tr, ip, parent_ip, trace_ctx, fregs);
+ trace_function(tr, ip, parent_ip, trace_ctx, fregs);
ftrace_test_recursion_unlock(bit);
}
@@ -352,7 +344,6 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
{
struct trace_func_repeats *last_info;
struct trace_array *tr = op->private;
- struct trace_array_cpu *data;
unsigned int trace_ctx;
int bit;
@@ -364,8 +355,7 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
return;
parent_ip = function_get_true_parent_ip(parent_ip, fregs);
- data = this_cpu_ptr(tr->array_buffer.data);
- if (atomic_read(&data->disabled))
+ if (!tracer_tracing_is_on(tr))
goto out;
/*
--
2.47.2
next prev parent reply other threads:[~2025-05-02 20:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-02 20:51 [PATCH 00/12] tracing: Remove most uses of "disabled" field Steven Rostedt
2025-05-02 20:51 ` [PATCH 01/12] tracing/mmiotrace: Remove reference to unused per CPU data pointer Steven Rostedt
2025-05-02 20:51 ` [PATCH 02/12] tracing: Do not bother setting "disabled" field for ftrace_dump_one() Steven Rostedt
2025-05-02 20:51 ` Steven Rostedt [this message]
2025-05-02 20:51 ` [PATCH 04/12] tracing: Just use this_cpu_read() to access ignore_pid Steven Rostedt
2025-05-02 20:51 ` [PATCH 05/12] tracing: kdb: Use tracer_tracing_on/off() instead of setting per CPU disabled Steven Rostedt
2025-05-05 5:05 ` kernel test robot
2025-05-05 15:42 ` Doug Anderson
2025-05-05 15:59 ` Steven Rostedt
2025-05-02 20:51 ` [PATCH 06/12] ftrace: Do not disabled function graph based on "disabled" field Steven Rostedt
2025-05-02 20:51 ` [PATCH 07/12] tracing: Do not use per CPU array_buffer.data->disabled for cpumask Steven Rostedt
2025-05-02 20:51 ` [PATCH 08/12] ring-buffer: Add ring_buffer_record_is_on_cpu() Steven Rostedt
2025-05-02 20:51 ` [PATCH 09/12] tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field Steven Rostedt
2025-05-03 10:10 ` kernel test robot
2025-05-05 12:11 ` kernel test robot
2025-05-02 20:51 ` [PATCH 10/12] tracing: Convert the per CPU "disabled" counter to local from atomic Steven Rostedt
2025-05-02 20:51 ` [PATCH 11/12] tracing: Use atomic_inc_return() for updating "disabled" counter in irqsoff tracer Steven Rostedt
2025-05-02 20:51 ` [PATCH 12/12] tracing: Remove unused buffer_page field from trace_array_cpu structure Steven Rostedt
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