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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2020-03-17 17:32:31 -0400
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-03-27 16:39:01 -0400
commit06e0a548bad0f43a21e036db018e4dadb501ce8b (patch)
tree7587fb20e56bbb7fecf55fb4c9f0c6729b55f67d /kernel/trace
parent1039221cc2787dee51a7ffbf9b0e79d192dadf76 (diff)
tracing: Do not disable tracing when reading the trace file
When opening the "trace" file, it is no longer necessary to disable tracing. Note, a new option is created called "pause-on-trace", when set, will cause the trace file to emulate its original behavior. Link: http://lkml.kernel.org/r/20200317213416.903351225@goodmis.org Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c9
-rw-r--r--kernel/trace/trace.h1
2 files changed, 7 insertions, 3 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 47889123be7f..650fa81fffe8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4273,8 +4273,11 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot)
if (trace_clocks[tr->clock_id].in_ns)
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
- /* stop the trace while dumping if we are not opening "snapshot" */
- if (!iter->snapshot)
+ /*
+ * If pause-on-trace is enabled, then stop the trace while
+ * dumping, unless this is the "snapshot" file
+ */
+ if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
tracing_stop_tr(tr);
if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
@@ -4371,7 +4374,7 @@ static int tracing_release(struct inode *inode, struct file *file)
if (iter->trace && iter->trace->close)
iter->trace->close(iter);
- if (!iter->snapshot)
+ if (!iter->snapshot && tr->stop_count)
/* reenable tracing if it was previously enabled */
tracing_start_tr(tr);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index c61e1b1c85a6..f37e05135986 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1302,6 +1302,7 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
C(IRQ_INFO, "irq-info"), \
C(MARKERS, "markers"), \
C(EVENT_FORK, "event-fork"), \
+ C(PAUSE_ON_TRACE, "pause-on-trace"), \
FUNCTION_FLAGS \
FGRAPH_FLAGS \
STACK_FLAGS \