diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2026-02-07 22:24:18 -0500 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2026-02-08 21:01:11 -0500 |
| commit | 64dee86ad7de3d59bae041e0d8f80ef89ddc4cf6 (patch) | |
| tree | 8b691f4171f08d07a342a5baa90593236b79b2db /kernel/trace/trace.c | |
| parent | ba73713da50e5c24499ca8941171593466ea34f7 (diff) | |
tracing: Make tracing_disabled global for tracing system
The tracing_disabled variable is set to one on boot up to prevent some
parts of tracing to access the tracing infrastructure before it is set up.
It also can be set after boot if an anomaly is discovered.
It is currently a static variable in trace.c and can be accessed via a
function call trace_is_disabled(). There's really no reason to use a
function call as the tracing subsystem should be able to access it
directly.
By making the variable accessed directly, code can be moved out of trace.c
without adding overhead of a function call to see if tracing is disabled
or not.
Make tracing_disabled global and remove the tracing_is_disabled() helper
function. Also add some "unlikely()"s around tracing_disabled where it's
checked in hot paths.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://patch.msgid.link/20260208032449.483690153@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d02c4004c718..1ff40c88e75c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -114,7 +114,7 @@ DEFINE_PER_CPU(bool, trace_taskinfo_save); * of the tracer is successful. But that is the only place that sets * this back to zero. */ -static int tracing_disabled = 1; +int tracing_disabled = 1; cpumask_var_t __read_mostly tracing_buffer_mask; @@ -3423,7 +3423,7 @@ int __trace_array_vprintk(struct trace_buffer *buffer, unsigned int trace_ctx; char *tbuffer; - if (tracing_disabled) + if (unlikely(tracing_disabled)) return 0; /* Don't pollute graph traces with trace_vprintk internals */ @@ -4765,11 +4765,6 @@ int tracing_open_generic(struct inode *inode, struct file *filp) return 0; } -bool tracing_is_disabled(void) -{ - return (tracing_disabled) ? true: false; -} - /* * Open and update trace_array ref count. * Must have the current trace_array passed to it. @@ -7609,7 +7604,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, unsigned long ip; char *buf; - if (tracing_disabled) + if (unlikely(tracing_disabled)) return -EINVAL; if (!(tr->trace_flags & TRACE_ITER(MARKERS))) @@ -7689,7 +7684,7 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, ssize_t written = -ENODEV; char *buf; - if (tracing_disabled) + if (unlikely(tracing_disabled)) return -EINVAL; if (!(tr->trace_flags & TRACE_ITER(MARKERS))) |