linux-toradex.git/kernel/trace/trace.c, branch v4.4-rc6

tracing: #ifdef out uses of max trace when CONFIG_TRACER_MAX_TRACE is not set

2015-11-10T15:16:05+00:00

tracing_max_lat_fops is used only when TRACER_MAX_TRACE enabled, so also
swith the related code. The related warning with defconfig under x86_64:

    CC      kernel/trace/trace.o
  kernel/trace/trace.c:5466:37: warning: ‘tracing_max_lat_fops’ defined but not used [-Wunused-const-variable]
   static const struct file_operations tracing_max_lat_fops = {

Signed-off-by: Chen Gang 
Signed-off-by: Steven Rostedt

tracing: Remove unused ftrace_cpu_disabled per cpu variable

2015-11-07T18:25:14+00:00

Since the ring buffer is lockless, there is no need to disable ftrace on
CPU. And no one doing so: after commit 68179686ac67cb ("tracing: Remove
ftrace_disable/enable_cpu()") ftrace_cpu_disabled stays the same after
initialization, nothing changes it.
ftrace_cpu_disabled shouldn't be used by any external module since it
disables only function and graph_function tracers but not any other
tracer.

Link: http://lkml.kernel.org/r/1446836846-22239-1-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steven Rostedt

tracing: Make tracing work when debugfs is not configured in

2015-11-06T15:02:33+00:00

Currently tracing_init_dentry() returns -ENODEV when debugfs is not
configured in, which causes tracefs not populated with tracing files and
directories, so we will get an empty directory even after we manually
mount tracefs.

We can make tracing_init_dentry() return NULL if debugfs is not
configured in and can manually mount tracefs. But return -ENODEV
if debugfs is configured in but not initialized or failed to create
automount point as that would break backward compatibility with older
tools.

Link: http://lkml.kernel.org/r/1446797056-11683-1-git-send-email-hello.wjx@gmail.com

Signed-off-by: Jiaxing Wang 
Signed-off-by: Steven Rostedt

tracing: Put back comma for empty fields in boot string parsing

2015-11-04T03:15:14+00:00

Both early_enable_events() and apply_trace_boot_options() parse a boot
string that may get parsed later on. They both use strsep() which converts a
comma into a nul character. To still allow the boot string to be parsed
again the same way, the nul character gets converted back to a comma after
the token is processed.

The problem is that these two functions check for an empty parameter (two
commas in a row ",,"), and continue the loop if the parameter is empty, but
fails to place the comma back. In this case, the second parsing will end at
this blank field, and not process fields afterward.

In most cases, users should not have an empty field, but if its going to be
checked, the code might as well be correct.

Signed-off-by: Steven Rostedt

tracing: Apply tracer specific options from kernel command line.

2015-11-04T02:51:43+00:00

Currently, the trace_options parameter is only applied in
tracer_alloc_buffers() when global_trace.current_trace is nop_trace,
so a tracer specific option will not be applied even when the specific
tracer is also enabled from kernel command line. For example, the
'func_stack_trace' option can't be enabled with the following kernel
parameter:

  ftrace=function ftrace_filter=kfree trace_options=func_stack_trace

We can enable tracer specific options by simply apply the options again
if the specific tracer is also supplied from command line and started
in register_tracer().

To make trace_boot_options_buf can be parsed again, a comma and a space
is put back if they were replaced by strsep and strstrip respectively.

Also make register_tracer() be __init to access the __init data, and
in fact register_tracer is only called from __init code.

Link: http://lkml.kernel.org/r/1446599669-9294-1-git-send-email-hello.wjx@gmail.com

Signed-off-by: Jiaxing Wang 
Signed-off-by: Steven Rostedt

tracing: Allow dumping traces without tracking trace started cpus

2015-11-03T21:10:08+00:00

We don't init iter->started when dumping the ftrace buffer, and there's no
real need to do so - so allow skipping that check if the iter doesn't have
an initialized ->started cpumask.

Link: http://lkml.kernel.org/r/1441385156-27279-1-git-send-email-sasha.levin@oracle.com

Signed-off-by: Sasha Levin 
Signed-off-by: Steven Rostedt

tracing: Update instance_rmdir() to use tracefs_remove_recursive

2015-11-02T18:59:06+00:00

Update instancd_rmdir to use tracefs_remove_recursive instead of
debugfs_remove_recursive.This was left in the transition from debugfs
to tracefs.

Link: http://lkml.kernel.org/r/1445169490-18315-2-git-send-email-hello.wjx@gmail.com

Cc: stable@vger.kernel.org # 4.1+
Fixes: 8434dc9340cd2 ("tracing: Convert the tracing facility over to use tracefs")
Signed-off-by: Jiaxing Wang 
Signed-off-by: Steven Rostedt

tracing: Add trace options for tracer options to instances

2015-09-30T19:22:58+00:00

Add the tracer options to instances options directory as well. Only add the
options for tracers that are allowed to be enabled by an instance. But note,
that tracer options are global. That is, tracer options enabled in an
instance, also take affect at the top level and in other instances.

Signed-off-by: Steven Rostedt

tracing: Add trace options for core options to instances

2015-09-30T19:22:57+00:00

Allow instances to have their own options, at least for the core options
(non tracer specific ones). There are a few global options that should not
be added to instances, like enabling of trace_printk, and the sched comm
recording, which do not have a specific trace instance associated to them.

Signed-off-by: Steven Rostedt

tracing: Make ftrace_trace_stack() depend on general trace_array flag

2015-09-30T19:22:57+00:00

In preparation for the multi buffer instances to have their own trace_flags,
the check in ftrace_trace_stack() needs to test the trace_array descriptor
flag that is for the current event, not the global_trace descriptor.

Signed-off-by: Steven Rostedt