tracing: Always use canonical ftrace path

The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

  Before 4.1, all ftrace tracing control files were within the debugfs
  file system, which is typically located at /sys/kernel/debug/tracing.
  For backward compatibility, when mounting the debugfs file system,
  the tracefs file system will be automatically mounted at:

  /sys/kernel/debug/tracing

Many comments and Kconfig help messages in the tracing code still refer
to this older debugfs path, so let's update them to avoid confusion.

Link: https://lore.kernel.org/linux-trace-kernel/20230215223350.2658616-2-zwisler@google.com
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index fe6efb2..40bce74 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -297,7 +297,7 @@ bool mac_pton(const char *s, u8 *mac);
  *
  * Use tracing_on/tracing_off when you want to quickly turn on or off
  * tracing. It simply enables or disables the recording of the trace events.
- * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
+ * This also corresponds to the user space /sys/kernel/tracing/tracing_on
  * file, which gives a means for the kernel and userspace to interact.
  * Place a tracing_off() in the kernel where you want tracing to end.
  * From user space, examine the trace, and then echo 1 > tracing_on

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 4b33b95..fa1004f 100644 (file)
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -471,7 +471,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
  *     * This is how the trace record is structured and will
  *     * be saved into the ring buffer. These are the fields
  *     * that will be exposed to user-space in
- *     * /sys/kernel/debug/tracing/events/<*>/format.
+ *     * /sys/kernel/tracing/events/<*>/format.
  *     *
  *     * The declared 'local variable' is called '__entry'
  *     *
@@ -531,7 +531,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
  * tracepoint callback (this is used by programmatic plugins and
  * can also by used by generic instrumentation like SystemTap), and
  * it is also used to expose a structured trace record in
- * /sys/kernel/debug/tracing/events/.
+ * /sys/kernel/tracing/events/.
  *
  * A set of (un)registration functions can be passed to the variant
  * TRACE_EVENT_FN to perform any (un)registration work.

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d704304..5f5e64f 100644 (file)
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -239,7 +239,7 @@ config DYNAMIC_FTRACE
          enabled, and the functions not enabled will not affect
          performance of the system.
 
-         See the files in /sys/kernel/debug/tracing:
+         See the files in /sys/kernel/tracing:
            available_filter_functions
            set_ftrace_filter
            set_ftrace_notrace
@@ -299,7 +299,7 @@ config STACK_TRACER
        select KALLSYMS
        help
          This special tracer records the maximum stack footprint of the
-         kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
+         kernel and displays it in /sys/kernel/tracing/stack_trace.
 
          This tracer works by hooking into every function call that the
          kernel executes, and keeping a maximum stack depth value and
@@ -339,7 +339,7 @@ config IRQSOFF_TRACER
          disabled by default and can be runtime (re-)started
          via:
 
-             echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
+             echo 0 > /sys/kernel/tracing/tracing_max_latency
 
          (Note that kernel size and overhead increase with this option
          enabled. This option and the preempt-off timing option can be
@@ -363,7 +363,7 @@ config PREEMPT_TRACER
          disabled by default and can be runtime (re-)started
          via:
 
-             echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
+             echo 0 > /sys/kernel/tracing/tracing_max_latency
 
          (Note that kernel size and overhead increase with this option
          enabled. This option and the irqs-off timing option can be
@@ -515,7 +515,7 @@ config TRACER_SNAPSHOT
          Allow tracing users to take snapshot of the current buffer using the
          ftrace interface, e.g.:
 
-             echo 1 > /sys/kernel/debug/tracing/snapshot
+             echo 1 > /sys/kernel/tracing/snapshot
              cat snapshot
 
 config TRACER_SNAPSHOT_PER_CPU_SWAP
@@ -527,7 +527,7 @@ config TRACER_SNAPSHOT_PER_CPU_SWAP
          full swap (all buffers). If this is set, then the following is
          allowed:
 
-             echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
+             echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot
 
          After which, only the tracing buffer for CPU 2 was swapped with
          the main tracing buffer, and the other CPU buffers remain the same.
@@ -574,7 +574,7 @@ config PROFILE_ANNOTATED_BRANCHES
          This tracer profiles all likely and unlikely macros
          in the kernel. It will display the results in:
 
-         /sys/kernel/debug/tracing/trace_stat/branch_annotated
+         /sys/kernel/tracing/trace_stat/branch_annotated
 
          Note: this will add a significant overhead; only turn this
          on if you need to profile the system's use of these macros.
@@ -587,7 +587,7 @@ config PROFILE_ALL_BRANCHES
          taken in the kernel is recorded whether it hit or miss.
          The results will be displayed in:
 
-         /sys/kernel/debug/tracing/trace_stat/branch_all
+         /sys/kernel/tracing/trace_stat/branch_all
 
          This option also enables the likely/unlikely profiler.
 
@@ -638,8 +638,8 @@ config BLK_DEV_IO_TRACE
          Tracing also is possible using the ftrace interface, e.g.:
 
            echo 1 > /sys/block/sda/sda1/trace/enable
-           echo blk > /sys/kernel/debug/tracing/current_tracer
-           cat /sys/kernel/debug/tracing/trace_pipe
+           echo blk > /sys/kernel/tracing/current_tracer
+           cat /sys/kernel/tracing/trace_pipe
 
          If unsure, say N.
 

diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
index c736487..4850fdf 100644 (file)
--- a/kernel/trace/kprobe_event_gen_test.c
+++ b/kernel/trace/kprobe_event_gen_test.c
@@ -21,7 +21,7 @@
  * Then:
  *
  * # insmod kernel/trace/kprobe_event_gen_test.ko
- * # cat /sys/kernel/debug/tracing/trace
+ * # cat /sys/kernel/tracing/trace
  *
  * You should see many instances of the "gen_kprobe_test" and
  * "gen_kretprobe_test" events in the trace buffer.

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 45d4a23..0711843 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2886,7 +2886,7 @@ rb_check_timestamp(struct ring_buffer_per_cpu *cpu_buffer,
                  sched_clock_stable() ? "" :
                  "If you just came from a suspend/resume,\n"
                  "please switch to the trace global clock:\n"
-                 "  echo global > /sys/kernel/debug/tracing/trace_clock\n"
+                 "  echo global > /sys/kernel/tracing/trace_clock\n"
                  "or add trace_clock=global to the kernel command line\n");
 }
 

diff --git a/kernel/trace/synth_event_gen_test.c b/kernel/trace/synth_event_gen_test.c
index 8d77526..8dfe854 100644 (file)
--- a/kernel/trace/synth_event_gen_test.c
+++ b/kernel/trace/synth_event_gen_test.c
@@ -22,7 +22,7 @@
  * Then:
  *
  * # insmod kernel/trace/synth_event_gen_test.ko
- * # cat /sys/kernel/debug/tracing/trace
+ * # cat /sys/kernel/tracing/trace
  *
  * You should see several events in the trace buffer -
  * "create_synth_test", "empty_synth_test", and several instances of

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 97c8871..fbb602a 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1187,7 +1187,7 @@ void tracing_snapshot_instance(struct trace_array *tr)
  *
  * Note, make sure to allocate the snapshot with either
  * a tracing_snapshot_alloc(), or by doing it manually
- * with: echo 1 > /sys/kernel/debug/tracing/snapshot
+ * with: echo 1 > /sys/kernel/tracing/snapshot
  *
  * If the snapshot buffer is not allocated, it will stop tracing.
  * Basically making a permanent snapshot.

diff --git a/samples/user_events/example.c b/samples/user_events/example.c
index d06dc24..18e34c9 100644 (file)
--- a/samples/user_events/example.c
+++ b/samples/user_events/example.c
@@ -23,8 +23,8 @@
 #endif
 
 /* Assumes debugfs is mounted */
-const char *data_file = "/sys/kernel/debug/tracing/user_events_data";
-const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
+const char *data_file = "/sys/kernel/tracing/user_events_data";
+const char *status_file = "/sys/kernel/tracing/user_events_status";
 
 static int event_status(long **status)
 {

diff --git a/scripts/tracing/draw_functrace.py b/scripts/tracing/draw_functrace.py
index 438516b..42fa873 100755 (executable)
--- a/scripts/tracing/draw_functrace.py
+++ b/scripts/tracing/draw_functrace.py
@@ -12,9 +12,9 @@ calls. Only the functions's names and the call time are provided.
 
 Usage:
        Be sure that you have CONFIG_FUNCTION_TRACER
-       # mount -t debugfs nodev /sys/kernel/debug
-       # echo function > /sys/kernel/debug/tracing/current_tracer
-       $ cat /sys/kernel/debug/tracing/trace_pipe > ~/raw_trace_func
+       # mount -t tracefs nodev /sys/kernel/tracing
+       # echo function > /sys/kernel/tracing/current_tracer
+       $ cat /sys/kernel/tracing/trace_pipe > ~/raw_trace_func
        Wait some times but not too much, the script is a bit slow.
        Break the pipe (Ctrl + Z)
        $ scripts/tracing/draw_functrace.py < ~/raw_trace_func > draw_functrace

diff --git a/tools/lib/api/fs/tracing_path.c b/tools/lib/api/fs/tracing_path.c
index b8e457c..7ba3e81 100644 (file)
--- a/tools/lib/api/fs/tracing_path.c
+++ b/tools/lib/api/fs/tracing_path.c
@@ -14,8 +14,8 @@
 #include "tracing_path.h"
 
 static char tracing_mnt[PATH_MAX]  = "/sys/kernel/debug";
-static char tracing_path[PATH_MAX]        = "/sys/kernel/debug/tracing";
-static char tracing_events_path[PATH_MAX] = "/sys/kernel/debug/tracing/events";
+static char tracing_path[PATH_MAX]        = "/sys/kernel/tracing";
+static char tracing_events_path[PATH_MAX] = "/sys/kernel/tracing/events";
 
 static void __tracing_path_set(const char *tracing, const char *mountpoint)
 {

diff --git a/tools/tracing/latency/latency-collector.c b/tools/tracing/latency/latency-collector.c
index 59a7f23..0fd9c74 100644 (file)
--- a/tools/tracing/latency/latency-collector.c
+++ b/tools/tracing/latency/latency-collector.c
@@ -1584,7 +1584,7 @@ static void *do_printloop(void *arg)
                /*
                 * Toss a coin to decide if we want to sleep before printing
                 * out the backtrace. The reason for this is that opening
-                * /sys/kernel/debug/tracing/trace will cause a blackout of
+                * /sys/kernel/tracing/trace will cause a blackout of
                 * hundreds of ms, where no latencies will be noted by the
                 * latency tracer. Thus by randomly sleeping we try to avoid
                 * missing traces systematically due to this. With this option