Commit Graph

546790 Commits

Author SHA1 Message Date
libin c84da8b9ad recordmcount: Fix endianness handling bug for nop_mcount
In nop_mcount, shdr->sh_offset and welp->r_offset should handle
endianness properly, otherwise it will trigger Segmentation fault
if the recordmcount main and file.o have different endianness.

Link: http://lkml.kernel.org/r/563806C7.7070606@huawei.com

Cc: <stable@vger.kernel.org> # 3.0+
Signed-off-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-03 10:45:26 -05:00
Mathieu Desnoyers a15920bea0 tracepoints: Fix documentation of RCU lockdep checks
The documentation on top of __DECLARE_TRACE() does not match its
implementation since the condition check has been added to the
RCU lockdep checks. Update the documentation to match its
implementation.

Link: http://lkml.kernel.org/r/1446504164-21563-1-git-send-email-mathieu.desnoyers@efficios.com

CC: Dave Hansen <dave@sr71.net>
Fixes: a05d59a567 "tracing: Add condition check to RCU lockdep checks"
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 17:52:49 -05:00
Yaowei Bai c6650b2e57 tracing: ftrace_event_is_function() can return boolean
Make ftrace_event_is_function() return bool to improve readability
due to this particular function only using either one or zero as its
return value.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-9-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:28:05 -05:00
Yaowei Bai 907bff917a tracing: is_legal_op() can return boolean
Make is_legal_op() return bool to improve readability due to this particular
function only using either one or zero as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-8-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:26:51 -05:00
Yaowei Bai cdb2a0a915 ring-buffer: rb_event_is_commit() can return boolean
Make rb_event_is_commit() return bool to improve readability
due to this particular function only using either one or zero as its
return value.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-7-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:25:29 -05:00
Yaowei Bai da58834cf2 ring-buffer: rb_per_cpu_empty() can return boolean
Makes rb_per_cpu_empty() return bool to improve readability.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-6-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:24:27 -05:00
Yaowei Bai 3d4e204d81 ring_buffer: ring_buffer_empty{cpu}() can return boolean
Make ring_buffer_empty() and ring_buffer_empty_cpu() return bool.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-5-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:23:38 -05:00
Yaowei Bai 06ca320952 ring-buffer: rb_is_reader_page() can return boolean
Make rb_is_reader_page() return bool to improve readability due to this
particular function only using either true or false as its return value.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-4-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:23:20 -05:00
Yaowei Bai 79851821b2 tracing: report_latency() in trace_irqsoff.c can return boolean
This patch makes report_latency return bool due to this
particular function only using either one or zero as its
return value.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-3-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:20:19 -05:00
Yaowei Bai 26ab2ef451 tracing: report_latency() in trace_sched_wakeup.c can return boolean
This patch makes report_latency return bool to improve readability,
indicating whether this new latency should be reported/recorded.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-2-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:20:06 -05:00
Chunyan Zhang 67aedeb857 Sample: Trace_event: Correct the comments
The commit 889204278c ("tracing: Update trace-event-sample with
TRACE_SYSTEM_VAR documentation") changed TRACE_SYSTEM to 'sample-trace',
but didn't make the according change of its name in the comments.

Link: http://lkml.kernel.org/r/1443599650-23680-1-git-send-email-zhang.chunyan@linaro.org

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 14:09:15 -05:00
Jiaxing Wang 681a4a2f45 tracing: Update instance_rmdir() to use tracefs_remove_recursive
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: 8434dc9340 ("tracing: Convert the tracing facility over to use tracefs")
Signed-off-by: Jiaxing Wang <hello.wjx@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 13:59:06 -05:00
Chunyan Zhang bdb5d0f904 tracing: Only benchmark the time tracepoints take if tracing is on
There's no need to record the time tracepoints take when tracing is off.
This is because:
1) We cannot see these records since ring_buffer record is off at that
moment.
2) If tracing is off and benchmark tracepoint is enabled, the time
tracepoint takes is fewer than the same situation when tracing is on,
since the tracepoints need to be wrote into ring_buffer, it would
take more time. If turn on tracing at this moment, the average and
standard deviation cannot exactly present the time that tracepoints
take to write data into ring_buffer.

Link: http://lkml.kernel.org/r/1445947933-27955-1-git-send-email-zhang.chunyan@linaro.org

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 13:34:58 -05:00
Li Bin 46a2b61ecb recordmcount: x86: Assign a meaningful value to rel_type_nop
Although, the default value of rel_type_nop is zero, and the value
of R_386_NONE/R_X86_64_NONE is zero too, but it should be assigned
a meaningful value explicitly, otherwise it looks confused.

Assign R_386_NONE to rel_type_nop for 386, assign R_X86_64_NONE
to rel_type_nop for x86_64.

Link: http://lkml.kernel.org/r/1446020606-16352-1-git-send-email-huawei.libin@huawei.com

Signed-off-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 13:34:32 -05:00
Steven Rostedt (Red Hat) 799fd44cf5 tracing: Call on_each_cpu() when adding or removing single pids from set_event_pid
For the case where pids are already in set_event_pid, and one is added or
removed then each CPU should be checked to make sure that the new or old pid
is on or not on a CPU.

 For example:

 # echo 123 >> set_event_pid

or

 # echo '!123' >> set_event_pid

Link: http://lkml.kernel.org/r/20151030061643.GA19480@cac

Suggested-by: Jiaxing Wang <hello.wjx@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-11-02 13:08:26 -05:00
Steven Rostedt (Red Hat) fb66228828 tracing: Fix sparse RCU warning
p_start() and p_stop() are seq_file functions that match. Teach sparse to
know that rcu_read_lock_sched() that is taken by p_start() is released by
p_stop.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-26 03:51:32 -04:00
Steven Rostedt (Red Hat) 8ca532ad2b tracing: Check all tasks on each CPU when filtering pids
My tests found that if a task is running but not filtered when set_event_pid
is modified, then it can still be traced.

Call on_each_cpu() to check if the current running task should be filtered
and update the per cpu flags of tr->data appropriately.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-25 21:33:56 -04:00
Steven Rostedt (Red Hat) 3fdaf80f4a tracing: Implement event pid filtering
Add the necessary hooks to use the pids loaded in set_event_pid to filter
all the events enabled in the tracing instance that match the pids listed.

Two probes are added to both sched_switch and sched_wakeup tracepoints to be
called before other probes are called and after the other probes are called.
The first is used to set the necessary flags to let the probes know to test
if they should be traced or not.

The sched_switch pre probe will set the "ignore_pid" flag if neither the
previous or next task has a matching pid.

The sched_switch probe will set the "ignore_pid" flag if the next task
does not match the matching pid.

The pre probe allows for probes tracing sched_switch to be traced if
necessary.

The sched_wakeup pre probe will set the "ignore_pid" flag if neither the
current task nor the wakee task has a matching pid.

The sched_wakeup post probe will set the "ignore_pid" flag if the current
task does not have a matching pid.

Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-25 21:33:56 -04:00
Steven Rostedt (Red Hat) 4909010788 tracing: Add set_event_pid directory for future use
Create a tracing directory called set_event_pid, which currently has no
function, but will be used to filter all events for the tracing instance or
the pids that are added to the file.

The reason no functionality is added with this commit is that this commit
focuses on the creation and removal of the pids in a safe manner. And tests
can be made against this change to make sure things are correct before
hooking features to the list of pids.

Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-25 21:33:55 -04:00
Steven Rostedt (Red Hat) 7904b5c498 tracepoint: Give priority to probes of tracepoints
In order to guarantee that a probe will be called before other probes that
are attached to a tracepoint, there needs to be a mechanism to provide
priority of one probe over the others.

Adding a prio field to the struct tracepoint_func, which lets the probes be
sorted by the priority set in the structure. If no priority is specified,
then a priority of 10 is given (this is a macro, and perhaps may be changed
in the future).

Now probes may be added to affect other probes that are attached to a
tracepoint with a guaranteed order.

One use case would be to allow tracing of tracepoints be able to filter by
pid. A special (higher priority probe) may be added to the sched_switch
tracepoint and set the necessary flags of the other tracepoints to notify
them if they should be traced or not. In case a tracepoint is enabled at the
sched_switch tracepoint too, the order of the two are not random.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-25 21:33:54 -04:00
Minfei Huang 883a1e867e ftrace: Calculate the correct dyn_ftrace number to report to the userspace
Now, ftrace only calculate the dyn_ftrace number in the adding
breakpoint loop, not in adding update and finish update loop.

Calculate the correct dyn_ftrace, once ftrace reports the failure message
to the userspace.

Link: http://lkml.kernel.org/r/1442420382-13130-1-git-send-email-mnfhuang@gmail.com

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-22 15:44:24 -04:00
Dmitry Safonov 3061692921 tracing: Remove {start,stop}_branch_trace
Both start_branch_trace() and stop_branch_trace() are used in only one
location, and are both static. As they are small functions there is no
need to keep them separated out.

Link: http://lkml.kernel.org/r/1445000689-32596-1-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-21 10:10:09 -04:00
Tal Shorer ddd70280bf tracing: gpio: Add Kconfig option for enabling/disabling trace events
Add a new options to trace Kconfig, CONFIG_TRACING_EVENTS_GPIO, that is
used for enabling/disabling compilation of gpio function trace events.

Link: http://lkml.kernel.org/r/1438432079-11704-4-git-send-email-tal.shorer@gmail.com

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tal Shorer <tal.shorer@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-20 21:56:10 -04:00
Tal Shorer c63b7682b6 tracing: Allow disabling compilation of specific trace systems
Allow a trace events header file to disable compilation of its
trace events by defining the preprocessor macro NOTRACE.

This could be done, for example, according to a Kconfig option.

Link: http://lkml.kernel.org/r/1438432079-11704-3-git-send-email-tal.shorer@gmail.com

Signed-off-by: Tal Shorer <tal.shorer@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-20 21:55:44 -04:00
Dmitry Safonov b86d9371be Documentation: ftrace: Module globbing usage
Link: http://lkml.kernel.org/r/1443545176-3215-5-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-20 20:04:14 -04:00
Dmitry Safonov 0b507e1ed1 ftrace: add module globbing
Extend module command for function filter selection with globbing.
It uses the same globbing as function filter.

  sh# echo '*alloc*:mod:*' > set_ftrace_filter

Will trace any function with the letters 'alloc' in the name in any
module but not in kernel.

  sh# echo '!*alloc*:mod:ipv6' >> set_ftrace_filter

Will prevent from tracing functions with 'alloc' in the name from module
ipv6 (do not forget to append to set_ftrace_filter file).

  sh# echo '*alloc*:mod:!ipv6' > set_ftrace_filter

Will trace functions with 'alloc' in the name from kernel and any
module except ipv6.

  sh# echo '*alloc*:mod:!*' > set_ftrace_filter

Will trace any function with the letters 'alloc' in the name only from
kernel, but not from any module.

  sh# echo '*:mod:!*' > set_ftrace_filter
or
  sh# echo ':mod:!' > set_ftrace_filter

Will trace every function in the kernel, but will not trace functions
from any module.

  sh# echo '*:mod:*' > set_ftrace_filter
or
  sh# echo ':mod:' > set_ftrace_filter

As the opposite will trace all functions from all modules, but not from
kernel.

  sh# echo '*:mod:*snd*' > set_ftrace_filter

Will trace your sound drivers only (if any).

Link: http://lkml.kernel.org/r/1443545176-3215-4-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
[ Made format changes ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-20 20:02:03 -04:00
Dmitry Safonov 3ba0092971 ftrace: Introduce ftrace_glob structure
ftrace_match parameters are very related and I reduce the number of local
variables & parameters with it.
This is also preparation for module globbing as it would introduce more
realated variables & parameters.

Link: http://lkml.kernel.org/r/1443545176-3215-3-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
[ Made some formatting changes ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-20 18:23:07 -04:00
Dmitry Safonov f0a3b154bd ftrace: Clarify code for mod command
"Not" is too abstract variable name - changed to clear_filter.
Removed ftrace_match_module_records function: comparison with !* or *
not does the general code in filter_parse_regex() as it works without
mod command for
  sh# echo '!*' > /sys/kernel/debug/tracing/set_ftrace_filter

Link: http://lkml.kernel.org/r/1443545176-3215-2-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-16 10:29:53 -04:00
Dmitry Safonov 5e3949f0ac ftrace: Remove redundant strsep in mod_callback
By now there isn't any subcommand for mod.

Before:
	sh$ echo '*:mod:ipv6:a' > set_ftrace_filter
	sh$ echo '*:mod:ipv6' > set_ftrace_filter
had the same results, but now first will result in:
	sh$ echo '*:mod:ipv6:a' > set_ftrace_filter
	-bash: echo: write error: Invalid argument

Also, I clarified ftrace_mod_callback code a little.

Link: http://lkml.kernel.org/r/1443545176-3215-1-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
[ converted 'if (ret == 0)' to 'if (!ret)' ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-13 20:59:24 -04:00
Rasmus Villemoes 6db0290322 ftrace: Remove redundant swap function
To cover the common case of sorting an array of pointers, Daniel
Wagner recently modified the library sort() to use a specific swap
function for size==8, in addition to the size==4 case which was
already handled. Since sizeof(long) is either 4 or 8,
ftrace_swap_ips() is redundant and we can just let sort() pick an
appropriate and fast swap callback.

Link: http://lkml.kernel.org/r/1441834023-13130-1-git-send-email-linux@rasmusvillemoes.dk

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-01 09:32:20 -04:00
Rasmus Villemoes 79ac6ef521 tracing: Use kstrdup_const instead of private implementation
The kernel now has kstrdup_const/kfree_const for reusing .rodata
(typically string literals) when possible; there's no reason to
duplicate that logic in the tracing system. Moreover, as the comment
above core_kernel_data states, it may not always return true for
.rodata - that is for example the case on x86_64, where we thus end up
kstrdup'ing all the passed-in strings.

Arguably, testing for .rodata explicitly (as kstrdup_const does) is
also more correct: I don't think one is supposed to be able to change
the name after creating the event_subsystem by passing the address of
a static char (but non-const) array.

Link: http://lkml.kernel.org/r/1441833841-12955-1-git-send-email-linux@rasmusvillemoes.dk

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-10-01 09:05:17 -04:00
Steven Rostedt (Red Hat) 37aea98b84 tracing: Add trace options for tracer options to instances
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 <rostedt@goodmis.org>
2015-09-30 15:22:58 -04:00
Steven Rostedt (Red Hat) 16270145ce tracing: Add trace options for core options to instances
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 <rostedt@goodmis.org>
2015-09-30 15:22:57 -04:00
Steven Rostedt (Red Hat) 2d34f48955 tracing: Make ftrace_trace_stack() depend on general trace_array flag
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 <rostedt@goodmis.org>
2015-09-30 15:22:57 -04:00
Steven Rostedt (Red Hat) 9a38a8856f tracing: Add a method to pass in trace_array descriptor to option files
In preparation of having the multi buffer instances having their own trace
option flags, the trace option files needs a way to not only pass in the
flag they represent, but also the trace_array descriptor.

A new field is added to the trace_array descriptor called trace_flags_index,
which is a 32 byte character array representing a bit. This array is simply
filled with the index of the array, where

  index_array[n] = n;

Then the address of this array is passed to the file callbacks instead of
the index of the flag index. Then to retrieve both the flag index and the
trace_array descriptor:

  data is the passed in argument.

  index = *(unsigned char *)data;

  data -= index;

  /* Now data points to the address of the array in the trace_array */

  tr = container_of(data, struct trace_array, trace_flags_index);

Suggested-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-30 15:22:56 -04:00
Steven Rostedt (Red Hat) 983f938ae6 tracing: Move trace_flags from global to a trace_array field
In preparation to make trace options per instance, the global trace_flags
needs to be moved from being a global variable to a field within the trace
instance trace_array structure.

There's still more work to do, as there's some functions that use
trace_flags without passing in a way to get to the current_trace array. For
those, the global_trace is used directly (from trace.c). This includes
setting and clearing the trace_flags. This means that when a new instance is
created, it just gets the trace_flags of the global_trace and will not be
able to modify them. Depending on the functions that have access to the
trace_array, the flags of an instance may not affect parts of its trace,
where the global_trace is used. These will be fixed in future changes.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-30 15:22:55 -04:00
Steven Rostedt (Red Hat) 5557720415 tracing: Move sleep-time and graph-time options out of the core trace_flags
The sleep-time and graph-time options are only for the function graph tracer
and are not used by anything else. As tracer options are now visible when
the tracer is not activated, its better to move the function graph specific
tracer options into the function graph tracer.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-30 15:22:42 -04:00
Steven Rostedt (Red Hat) b9f9108cad tracing: Remove access to trace_flags in trace_printk.c
In the effort to move the global trace_flags to the tracing instances, the
direct access to trace_flags must be removed from trace_printk.c

Instead, add a new trace_printk_enabled boolean that is set by a new access
function trace_printk_control(), that will enable or disable trace_printk.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-30 04:35:18 -04:00
Steven Rostedt (Red Hat) b5e87c0581 tracing: Add build bug if we have more trace_flags than bits
Add a enum that denotes the last bit of the trace_flags and have a
BUILD_BUG_ON(last_bit > 32).

If we add more bits than we have in trace_flags, the kernel wont build.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-30 04:35:18 -04:00
Steven Rostedt (Red Hat) 41d9c0becc tracing: Always show all tracer options in the options directory
There are options that are unique to a specific tracer (like function and
function graph). Currently, these options are only visible in the options
directory when the tracer is enabled.

This has been a pain, especially for something like the func_stack_trace
option that if used inappropriately, could bring the system to a crawl. But
the only way to see it, is to enable the function tracer.

For example, if one had done:

 # cd /sys/kernel/tracing
 # echo __schedule > set_ftrace_filter
 # echo 1 > options/func_stack_trace
 # echo function > current_tracer

The __schedule call will be traced and a stack trace will also be recorded
there. Now when you were done, you may do...

 # echo nop > current_tracer
 # echo > set_ftrace_filter

But you forgot to disable the func_stack_trace. The only way to disable it
is to re-enable function tracing first. If you do not add a filter to
set_ftrace_filter and just do:

 # echo function > current_tracer

Now you would be performing a stack trace on *every* function! On some
systems, that causes a live lock. Others may take a few minutes to fix your
mistake.

Having the func_stack_trace option visible allows you to check it and
disable it before enabling the funtion tracer.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-30 04:34:54 -04:00
Steven Rostedt (Red Hat) 73dddbb57b tracing: Only create stacktrace option when STACKTRACE is configured
Only create the stacktrace trace option when CONFIG_STACKTRACE is
configured.

Cleaned up the ftrace_trace_stack() function call a little to allow better
encapsulation of the stacktrace trace flag.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 15:38:55 -04:00
Steven Rostedt (Red Hat) 8179e8a15b tracing: Do not create function tracer options when not compiled in
When the function tracer is not compiled in, do not create the option files
for it.

Fix up both the sched_wakeup and irqsoff tracers to handle the change.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 15:01:34 -04:00
Steven Rostedt (Red Hat) 4ee4301c4b tracing: Only create branch tracer options when compiled in
When the branch tracer is not compiled in, do not create the option files
associated to it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 13:23:59 -04:00
Steven Rostedt (Red Hat) 729358da95 tracing: Only create function graph options when it is compiled in
Do not create fuction graph tracer options when function graph tracer is not
even compiled in.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 13:23:58 -04:00
Steven Rostedt (Red Hat) a3418a364e tracing: Use TRACE_FLAGS macro to keep enums and strings matched
Use a cute little macro trick to keep the names of the trace flags file
guaranteed to match the corresponding masks.

The macro TRACE_FLAGS is defined as a serious of enum names followed by
the string name of the file that matches it. For example:

 #define TRACE_FLAGS						\
		C(PRINT_PARENT,		"print-parent"),	\
		C(SYM_OFFSET,		"sym-offset"),		\
		C(SYM_ADDR,		"sym-addr"),		\
		C(VERBOSE,		"verbose"),

Now we can define the following:

 #undef C
 #define C(a, b) TRACE_ITER_##a##_BIT
 enum trace_iterator_bits { TRACE_FLAGS };

The above creates:

 enum trace_iterator_bits {
	TRACE_ITER_PRINT_PARENT_BIT,
	TRACE_ITER_SYM_OFFSET_BIT,
	TRACE_ITER_SYM_ADDR_BIT,
	TRACE_ITER_VERBOSE_BIT,
 };

Then we can redefine C as:

 #undef C
 #define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT)
 enum trace_iterator_flags { TRACE_FLAGS };

Which creates:

 enum trace_iterator_flags {
	TRACE_ITER_PRINT_PARENT	= (1 << TRACE_ITER_PRINT_PARENT_BIT),
	TRACE_ITER_SYM_OFFSET	= (1 << TRACE_ITER_SYM_OFFSET_BIT),
	TRACE_ITER_SYM_ADDR	= (1 << TRACE_ITER_SYM_ADDR_BIT),
	TRACE_ITER_VERBOSE	= (1 << TRACE_ITER_VERBOSE_BIT),
 };

Then finally we can create the list of file names:

 #undef C
 #define C(a, b) b
 static const char *trace_options[] = {
	TRACE_FLAGS
	NULL
 };

Which creates:
 static const char *trace_options[] = {
	"print-parent",
	"sym-offset",
	"sym-addr",
	"verbose",
	NULL
 };

The importance of this is that the strings match the bit index.

	trace_options[TRACE_ITER_SYM_ADDR_BIT] == "sym-addr"

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 13:23:57 -04:00
Steven Rostedt (Red Hat) ce3fed628e tracing: Use enums instead of hard coded bitmasks for TRACE_ITER flags
Using enums with FLAG_BIT and then defining a FLAG = (1 << FLAG_BIT), is a
bit more robust as we require that there are no bits out of order or skipped
to match the file names that represent the bits.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 13:23:56 -04:00
Steven Rostedt (Red Hat) 938db5f569 tracing: Remove unused tracing option "ftrace_preempt"
There was a time where the function tracing would disable interrupts unless
specifically told not to, where it would only disable preemption. With the
new lockless code, the function tracing never disalbes interrupts and just
uses disabling of preemption. Remove the option "ftrace_preempt" as it does
nothing anyway.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 13:23:54 -04:00
Steven Rostedt (Red Hat) 03905582fd tracing: Move "display-graph" option to main options
In order to facilitate making all tracer options visible even when the
tracer is not active, we need to get rid of duplicate options. Any option
that is shared between multiple tracers really should be a main option.

As the wakeup and irqsoff tracers both use the "display-graph" option, and
use it exactly the same way, move that option from the tracer options to the
main options and consolidate them.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-29 12:56:40 -04:00
Steven Rostedt (Red Hat) ef92480a58 tracing: Turn seq_print_user_ip() into a static function
seq_print_user_ip() is used in only one location in one file. Turn it into a
static function. We could inject its code into the caller, but that would
make the code a bit too complex. Keep the code separate.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-28 10:16:12 -04:00
Steven Rostedt (Red Hat) 6b1032d53c tracing: Inject seq_print_userip_objs() into its only user
seq_print_userip_objs() is used only in one location, in one file. Instead
of having it as an external function, go one further than making it static,
but inject is code into its only user. It doesn't make the calling function
much more complex.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-09-28 10:11:44 -04:00