----- On Apr 19, 2016, at 10:34 AM, rostedt [email protected] wrote: > From: Steven Rostedt <[email protected]> > > Add the infrastructure needed to have the PIDs in set_event_pid to > automatically add PIDs of the children of the tasks that have their PIDs in > set_event_pid. This will also remove PIDs from set_event_pid when a task > exits > > This is implemented by adding hooks into the fork and exit tracepoints. On > fork, the PIDs are added to the list, and on exit, they are removed. > > Add a new option called event_fork that when set, PIDs in set_event_pid will > automatically get their children PIDs added when they fork, as well as any > task that exits will have its PID removed from set_event_pid.
Just out of curiosity: how does it deal with multi-process and multi-thread ? What events are expected in each case ? Thanks, Mathieu > > This works for instances as well. > > Signed-off-by: Steven Rostedt <[email protected]> > --- > kernel/trace/trace.c | 3 ++ > kernel/trace/trace.h | 2 ++ > kernel/trace/trace_events.c | 84 +++++++++++++++++++++++++++++++++++++++------ > 3 files changed, 79 insertions(+), 10 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index a2f0b9f33e9b..0d12dbde8399 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -3571,6 +3571,9 @@ int set_tracer_flag(struct trace_array *tr, unsigned int > mask, int enabled) > if (mask == TRACE_ITER_RECORD_CMD) > trace_event_enable_cmd_record(enabled); > > + if (mask == TRACE_ITER_EVENT_FORK) > + trace_event_follow_fork(tr, enabled); > + > if (mask == TRACE_ITER_OVERWRITE) { > ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled); > #ifdef CONFIG_TRACER_MAX_TRACE > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 68cbb8e10aea..2525042760e6 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -655,6 +655,7 @@ static inline void __trace_stack(struct trace_array *tr, > unsigned long flags, > extern cycle_t ftrace_now(int cpu); > > extern void trace_find_cmdline(int pid, char comm[]); > +extern void trace_event_follow_fork(struct trace_array *tr, bool enable); > > #ifdef CONFIG_DYNAMIC_FTRACE > extern unsigned long ftrace_update_tot_cnt; > @@ -966,6 +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(EVENT_FORK, "event-fork"), \ > FUNCTION_FLAGS \ > FGRAPH_FLAGS \ > STACK_FLAGS \ > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 45f7cc72bf25..add81dff7520 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -474,11 +474,23 @@ static void ftrace_clear_events(struct trace_array *tr) > /* Shouldn't this be in a header? */ > extern int pid_max; > > +/* Returns true if found in filter */ > static bool > -ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct > *task) > +find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid) > { > - pid_t pid; > + /* > + * If pid_max changed after filtered_pids was created, we > + * by default ignore all pids greater than the previous pid_max. > + */ > + if (search_pid >= filtered_pids->pid_max) > + return false; > + > + return test_bit(search_pid, filtered_pids->pids); > +} > > +static bool > +ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct > *task) > +{ > /* > * Return false, because if filtered_pids does not exist, > * all pids are good to trace. > @@ -486,16 +498,68 @@ ignore_this_task(struct trace_pid_list *filtered_pids, > struct task_struct *task) > if (!filtered_pids) > return false; > > - pid = task->pid; > + return !find_filtered_pid(filtered_pids, task->pid); > +} > > - /* > - * If pid_max changed after filtered_pids was created, we > - * by default ignore all pids greater than the previous pid_max. > - */ > - if (task->pid >= filtered_pids->pid_max) > - return true; > +static void filter_add_remove_task(struct trace_pid_list *pid_list, > + struct task_struct *self, > + struct task_struct *task) > +{ > + if (!pid_list) > + return; > + > + /* For forks, we only add if the forking task is listed */ > + if (self) { > + if (!find_filtered_pid(pid_list, self->pid)) > + return; > + } > + > + /* Sorry, but we don't support pid_max changing after setting */ > + if (task->pid >= pid_list->pid_max) > + return; > + > + /* "self" is set for forks, and NULL for exits */ > + if (self) > + set_bit(task->pid, pid_list->pids); > + else > + clear_bit(task->pid, pid_list->pids); > +} > + > +static void > +event_filter_pid_sched_process_exit(void *data, struct task_struct *task) > +{ > + struct trace_pid_list *pid_list; > + struct trace_array *tr = data; > + > + pid_list = rcu_dereference_sched(tr->filtered_pids); > + filter_add_remove_task(pid_list, NULL, task); > +} > > - return !test_bit(task->pid, filtered_pids->pids); > +static void > +event_filter_pid_sched_process_fork(void *data, > + struct task_struct *self, > + struct task_struct *task) > +{ > + struct trace_pid_list *pid_list; > + struct trace_array *tr = data; > + > + pid_list = rcu_dereference_sched(tr->filtered_pids); > + filter_add_remove_task(pid_list, self, task); > +} > + > +void trace_event_follow_fork(struct trace_array *tr, bool enable) > +{ > + if (enable) { > + > register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork, > + tr, INT_MIN); > + > register_trace_prio_sched_process_exit(event_filter_pid_sched_process_exit, > + tr, INT_MAX); > + } else { > + > unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork, > + tr); > + > unregister_trace_sched_process_exit(event_filter_pid_sched_process_exit, > + tr); > + } > } > > static void > -- > 2.8.0.rc3 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-trace-users" > in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
