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authorJoel Fernandes <joelaf@google.com>2017-06-26 19:01:55 -0700
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-06-27 13:30:28 -0400
commitd914ba37d7145acb9fd3bb23075c2d56e5a44eb6 (patch)
treeedb1e6c1bfa0f0a92e13e9f891be524a31b23cea /kernel/trace/trace_events.c
parent83dd14933e33a45e9b366c572e15505982b46845 (diff)
downloadlinux-d914ba37d7145acb9fd3bb23075c2d56e5a44eb6.tar.bz2
tracing: Add support for recording tgid of tasks
Inorder to support recording of tgid, the following changes are made: * Introduce a new API (tracing_record_taskinfo) to additionally record the tgid along with the task's comm at the same time. This has has the benefit of not setting trace_cmdline_save before all the information for a task is saved. * Add a new API tracing_record_taskinfo_sched_switch to record task information for 2 tasks at a time (previous and next) and use it from sched_switch probe. * Preserve the old API (tracing_record_cmdline) and create it as a wrapper around the new one so that existing callers aren't affected. * Reuse the existing sched_switch and sched_wakeup probes to record tgid information and add a new option 'record-tgid' to enable recording of tgid When record-tgid option isn't enabled to being with, we take care to make sure that there's isn't memory or runtime overhead. Link: http://lkml.kernel.org/r/20170627020155.5139-1-joelaf@google.com Cc: kernel-team@android.com Cc: Ingo Molnar <mingo@redhat.com> Tested-by: Michael Sartain <mikesart@gmail.com> Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_events.c')
-rw-r--r--kernel/trace/trace_events.c42
1 files changed, 41 insertions, 1 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 83dfd0dbbbfe..36132f9280e6 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -343,6 +343,28 @@ void trace_event_enable_cmd_record(bool enable)
mutex_unlock(&event_mutex);
}
+void trace_event_enable_tgid_record(bool enable)
+{
+ struct trace_event_file *file;
+ struct trace_array *tr;
+
+ mutex_lock(&event_mutex);
+ do_for_each_event_file(tr, file) {
+ if (!(file->flags & EVENT_FILE_FL_ENABLED))
+ continue;
+
+ if (enable) {
+ tracing_start_tgid_record();
+ set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
+ } else {
+ tracing_stop_tgid_record();
+ clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
+ &file->flags);
+ }
+ } while_for_each_event_file();
+ mutex_unlock(&event_mutex);
+}
+
static int __ftrace_event_enable_disable(struct trace_event_file *file,
int enable, int soft_disable)
{
@@ -381,6 +403,12 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
tracing_stop_cmdline_record();
clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
}
+
+ if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
+ tracing_stop_tgid_record();
+ clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
+ }
+
call->class->reg(call, TRACE_REG_UNREGISTER, file);
}
/* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
@@ -407,18 +435,30 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
}
if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
+ bool cmd = false, tgid = false;
/* Keep the event disabled, when going to SOFT_MODE. */
if (soft_disable)
set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
+ cmd = true;
tracing_start_cmdline_record();
set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
}
+
+ if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
+ tgid = true;
+ tracing_start_tgid_record();
+ set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
+ }
+
ret = call->class->reg(call, TRACE_REG_REGISTER, file);
if (ret) {
- tracing_stop_cmdline_record();
+ if (cmd)
+ tracing_stop_cmdline_record();
+ if (tgid)
+ tracing_stop_tgid_record();
pr_info("event trace: Could not enable event "
"%s\n", trace_event_name(call));
break;