Commit-ID: b8de7bd168fa54d059b16d3057b2f8a32cc5bdc3
Gitweb: http://git.kernel.org/tip/b8de7bd168fa54d059b16d3057b2f8a32cc5bdc3
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Mon, 31 Aug 2009 22:32:27 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Fri, 4 Sep 2009 11:52:24 -0400
tracing: disable update max tracer while reading trace
When reading the tracer from the trace file, updating the max latency
may corrupt the output. This patch disables the tracing of the max
latency while reading the trace file.
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace.c | 12 +++++++++---
1 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index df2c9f7..e521f1e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -263,6 +263,9 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
TRACE_ITER_GRAPH_TIME;
+static int trace_stop_count;
+static DEFINE_SPINLOCK(tracing_start_lock);
+
/**
* trace_wake_up - wake up tasks waiting for trace input
*
@@ -442,6 +445,9 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
struct ring_buffer *buf = tr->buffer;
+ if (trace_stop_count)
+ return;
+
WARN_ON_ONCE(!irqs_disabled());
__raw_spin_lock(&ftrace_max_lock);
@@ -469,6 +475,9 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
int ret;
+ if (trace_stop_count)
+ return;
+
WARN_ON_ONCE(!irqs_disabled());
__raw_spin_lock(&ftrace_max_lock);
@@ -685,9 +694,6 @@ static void trace_init_cmdlines(void)
cmdline_idx = 0;
}
-static int trace_stop_count;
-static DEFINE_SPINLOCK(tracing_start_lock);
-
/**
* ftrace_off_permanent - disable all ftrace code permanently
*
--
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