Re: [PATCH tip 1/1] trace: Call tracing_reset_online_cpus beforetracer->init()

From: Frederic Weisbecker
Date: Thu Feb 05 2009 - 18:12:55 EST

On Thu, Feb 05, 2009 at 06:02:00PM -0200, Arnaldo Carvalho de Melo wrote:
> Impact: cleanup
>
> To make it easy for ftrace plugin writers, as this was open coded in
> the existing plugins
>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Cc: Frédéric Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
> block/blktrace.c | 2 --
> kernel/trace/trace.c | 8 +++++++-
> kernel/trace/trace.h | 1 +
> kernel/trace/trace_branch.c | 1 -
> kernel/trace/trace_functions.c | 17 +++--------------
> kernel/trace/trace_functions_graph.c | 1 -
> kernel/trace/trace_hw_branches.c | 1 -
> kernel/trace/trace_nop.c | 1 -
> kernel/trace/trace_sched_switch.c | 8 +-------
> kernel/trace/trace_selftest.c | 18 +++++++++---------
> kernel/trace/trace_sysprof.c | 14 ++++----------
> 11 files changed, 25 insertions(+), 47 deletions(-)
>
> diff --git a/block/blktrace.c b/block/blktrace.c
> index 834cd84..ca6d320 100644
> --- a/block/blktrace.c
> +++ b/block/blktrace.c
> @@ -1086,8 +1086,6 @@ static void blk_tracer_print_header(struct seq_file *m)
>
> static void blk_tracer_start(struct trace_array *tr)
> {
> - tracing_reset_online_cpus(tr);
> -
> mutex_lock(&blk_probe_mutex);
> if (atomic_add_return(1, &blk_probes_ref) == 1)
> if (blk_register_tracepoints())
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 8fad377..ef4dbac 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -2171,6 +2171,12 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf,
> return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
> }
>
> +int tracer_init(struct tracer *t, struct trace_array *tr)
> +{
> + tracing_reset_online_cpus(tr);
> + return t->init(tr);
> +}
> +
> static int tracing_set_tracer(const char *buf)
> {
> struct trace_array *tr = &global_trace;
> @@ -2195,7 +2201,7 @@ static int tracing_set_tracer(const char *buf)
>
> current_trace = t;
> if (t->init) {
> - ret = t->init(tr);
> + ret = tracer_init(t, tr);
> if (ret)
> goto out;
> }
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index e03f157..f2742fb 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -395,6 +395,7 @@ struct trace_iterator {
> cpumask_var_t started;
> };
>
> +int tracer_init(struct tracer *t, struct trace_array *tr);
> int tracing_is_enabled(void);
> void trace_wake_up(void);
> void tracing_reset(struct trace_array *tr, int cpu);
> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
> index 48b2196..f8ae2c5 100644
> --- a/kernel/trace/trace_branch.c
> +++ b/kernel/trace/trace_branch.c
> @@ -131,7 +131,6 @@ static void stop_branch_trace(struct trace_array *tr)
>
> static int branch_trace_init(struct trace_array *tr)
> {
> - tracing_reset_online_cpus(tr);
> start_branch_trace(tr);
> return 0;
> }
> diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
> index d067cea..36bf956 100644
> --- a/kernel/trace/trace_functions.c
> +++ b/kernel/trace/trace_functions.c
> @@ -24,32 +24,21 @@ static struct trace_array *func_trace;
> static void tracing_start_function_trace(void);
> static void tracing_stop_function_trace(void);
>
> -static void start_function_trace(struct trace_array *tr)
> +static int function_trace_init(struct trace_array *tr)
> {
> func_trace = tr;
> tr->cpu = get_cpu();
> - tracing_reset_online_cpus(tr);
> put_cpu();
>
> tracing_start_cmdline_record();
> tracing_start_function_trace();
> -}
> -
> -static void stop_function_trace(struct trace_array *tr)
> -{
> - tracing_stop_function_trace();
> - tracing_stop_cmdline_record();
> -}
> -
> -static int function_trace_init(struct trace_array *tr)
> -{
> - start_function_trace(tr);
> return 0;
> }
>
> static void function_trace_reset(struct trace_array *tr)
> {
> - stop_function_trace(tr);
> + tracing_stop_function_trace();
> + tracing_stop_cmdline_record();
> }
>
> static void function_trace_start(struct trace_array *tr)
> diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
> index c97594d..222f97d 100644
> --- a/kernel/trace/trace_functions_graph.c
> +++ b/kernel/trace/trace_functions_graph.c
> @@ -56,7 +56,6 @@ static int graph_trace_init(struct trace_array *tr)
> &trace_graph_entry);
> if (ret)
> return ret;
> - tracing_reset_online_cpus(tr);
> tracing_start_cmdline_record();
>
> return 0;
> diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
> index 2aa1c9f..ca4bbcf 100644
> --- a/kernel/trace/trace_hw_branches.c
> +++ b/kernel/trace/trace_hw_branches.c
> @@ -132,7 +132,6 @@ static int bts_trace_init(struct trace_array *tr)
> hw_branch_trace = tr;
>
> register_hotcpu_notifier(&bts_hotcpu_notifier);
> - tracing_reset_online_cpus(tr);
> bts_trace_start(tr);
>
> return 0;
> diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
> index 087b6cb..9aa84bd 100644
> --- a/kernel/trace/trace_nop.c
> +++ b/kernel/trace/trace_nop.c
> @@ -48,7 +48,6 @@ static void stop_nop_trace(struct trace_array *tr)
> static int nop_trace_init(struct trace_array *tr)
> {
> ctx_trace = tr;
> - tracing_reset_online_cpus(tr);
> start_nop_trace(tr);
> return 0;
> }
> diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
> index c4f9add..30e14fe 100644
> --- a/kernel/trace/trace_sched_switch.c
> +++ b/kernel/trace/trace_sched_switch.c
> @@ -185,12 +185,6 @@ void tracing_sched_switch_assign_trace(struct trace_array *tr)
> ctx_trace = tr;
> }
>
> -static void start_sched_trace(struct trace_array *tr)
> -{
> - tracing_reset_online_cpus(tr);
> - tracing_start_sched_switch_record();
> -}
> -
> static void stop_sched_trace(struct trace_array *tr)
> {
> tracing_stop_sched_switch_record();
> @@ -199,7 +193,7 @@ static void stop_sched_trace(struct trace_array *tr)
> static int sched_switch_trace_init(struct trace_array *tr)
> {
> ctx_trace = tr;
> - start_sched_trace(tr);
> + tracing_start_sched_switch_record();
> return 0;
> }
>
> diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
> index 5013812..445700e 100644
> --- a/kernel/trace/trace_selftest.c
> +++ b/kernel/trace/trace_selftest.c
> @@ -115,7 +115,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
> ftrace_set_filter(func_name, strlen(func_name), 1);
>
> /* enable tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> goto out;
> @@ -189,7 +189,7 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
> ftrace_enabled = 1;
> tracer_enabled = 1;
>
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> goto out;
> @@ -236,7 +236,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
> int ret;
>
> /* start the tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> return ret;
> @@ -290,7 +290,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
> }
>
> /* start the tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> return ret;
> @@ -344,7 +344,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
> }
>
> /* start the tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> goto out;
> @@ -476,7 +476,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
> wait_for_completion(&isrt);
>
> /* start the tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> return ret;
> @@ -537,7 +537,7 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr
> int ret;
>
> /* start the tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> return ret;
> @@ -569,7 +569,7 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
> int ret;
>
> /* start the tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> return 0;
> @@ -596,7 +596,7 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
> int ret;
>
> /* start the tracing */
> - ret = trace->init(tr);
> + ret = tracer_init(trace, tr);
> if (ret) {
> warn_failed_init_tracer(trace, ret);
> return ret;
> diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
> index eaca5ad..84ca9d8 100644
> --- a/kernel/trace/trace_sysprof.c
> +++ b/kernel/trace/trace_sysprof.c
> @@ -226,15 +226,6 @@ static void stop_stack_timers(void)
> stop_stack_timer(cpu);
> }
>
> -static void start_stack_trace(struct trace_array *tr)
> -{
> - mutex_lock(&sample_timer_lock);
> - tracing_reset_online_cpus(tr);
> - start_stack_timers();
> - tracer_enabled = 1;
> - mutex_unlock(&sample_timer_lock);
> -}
> -
> static void stop_stack_trace(struct trace_array *tr)
> {
> mutex_lock(&sample_timer_lock);
> @@ -247,7 +238,10 @@ static int stack_trace_init(struct trace_array *tr)
> {
> sysprof_trace = tr;
>
> - start_stack_trace(tr);
> + mutex_lock(&sample_timer_lock);
> + start_stack_timers();
> + tracer_enabled = 1;
> + mutex_unlock(&sample_timer_lock);
> return 0;
> }
>
> --
> 1.6.0.6
>

Heh, I will have to manage an "arnaldo" topic in my local git tree
if I want to stay synced :-)

Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>

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