Commit-ID: 02404baf1b47123f1c88c9f9f1f3b00e1e2b10db
Gitweb: http://git.kernel.org/tip/02404baf1b47123f1c88c9f9f1f3b00e1e2b10db
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Thu, 1 Nov 2012 11:51:40 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Fri, 2 Nov 2012 10:21:51 -0400
tracing: Remove deprecated tracing_enabled file
The tracing_enabled file was used as a quick way to stop
tracers, and try to bring down overhead for things like
the latency tracers (irqsoff, wakeup, etc). But it didn't
work that well.
The tracing_on file was created as a really fast way to
stop recording into the ftrace ring buffer and can interact
with the kernel. That is a tracing_off() call in the kernel
can disable recording of events, and then from userspace one
could echo 1 into the tracing_on file to continue it. The
tracing_enabled function did too much to allow for this.
The tracing_on has taken over as a way to start and stop tracing
and the tracing_enabled file should not be used. But because of
its existance, it still confuses people. Over a year ago the
following commit was added:
commit 6752ab4a9c30d5411b2dfdb251a3f1cb18aae487
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
Date: Tue Feb 8 13:54:06 2011 -0500
tracing: Deprecate tracing_enabled for tracing_on
This commit added a WARN_ON() if the tracing_enabled file's variable
was changed. After this was added, only LatencyTop complained, and
they soon fixed their tool as there was no reason that LatencyTop
should touch this file as it was using the perf ring buffers which
this file does not interact with. But since that time no one else
has complained about this WARN_ON(). Thus it is safe to assume that
this file is no longer needed. Time to get rid of it.
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace.c | 3 ---
1 files changed, 0 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3c9b96a..d5cbc0d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4788,9 +4788,6 @@ static __init int tracer_init_debugfs(void)
d_tracer = tracing_init_dentry();
- trace_create_file("tracing_enabled", 0644, d_tracer,
- &global_trace, &rb_simple_fops);
-
trace_create_file("trace_options", 0644, d_tracer,
NULL, &tracing_iter_fops);
--
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