Impact: api and pipe waiting change

Currently, the waiting used in tracing_read_pipe() is done through a
100 msecs schedule_timeout() loop which periodically check if there
are traces on the buffer.

This can cause small latencies for programs which are reading the incoming
events.

This patch makes the reader waiting for the trace_wait waitqueue except
for few tracers such as the sched and functions tracers which might be
already hold the runqueue lock while waking up the reader.

This is performed through a new callback wait_pipe() on struct tracer.
If none is implemented on a specific tracer, the default waiting for
trace_wait queue is attached.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace

When the function graph tracer is activated, it iterates over the task_list
to allocate a stack to store the return addresses.

But the per cpu idle tasks are not iterated by using
do_each_thread / while_each_thread.

So we have to iterate on them manually.

This fixes somes weirdness in the traces and many losses of traces.
Examples on two cpus:

 0)   Xorg-4287    |   2.906 us    |              }
 0)   Xorg-4287    |   3.965 us    |            }
 0)   Xorg-4287    |   5.302 us    |          }
 ------------------------------------------
 0)   Xorg-4287    =>    <idle>-0
 ------------------------------------------

 0)    <idle>-0    |   2.861 us    |                        }
 0)    <idle>-0    |   0.526 us    |                        set_normalized_timespec();
 0)    <idle>-0    |   7.201 us    |                      }
 0)    <idle>-0    |   8.214 us    |                    }
 0)    <idle>-0    |               |                    clockevents_program_event() {
 0)    <idle>-0    |               |                      lapic_next_event() {
 0)    <idle>-0    |   0.510 us    |                        native_apic_mem_write();
 0)    <idle>-0    |   1.546 us    |                      }
 0)    <idle>-0    |   2.583 us    |                    }
 0)    <idle>-0    | + 12.435 us   |                  }
 0)    <idle>-0    | + 13.470 us   |                }
 0)    <idle>-0    |   0.608 us    |                _spin_unlock_irqrestore();
 0)    <idle>-0    | + 23.270 us   |              }
 0)    <idle>-0    | + 24.336 us   |            }
 0)    <idle>-0    | + 25.417 us   |          }
 0)    <idle>-0    |   0.593 us    |          _spin_unlock();
 0)    <idle>-0    | + 41.869 us   |        }
 0)    <idle>-0    | + 42.906 us   |      }
 0)    <idle>-0    | + 95.035 us   |    }
 0)    <idle>-0    |   0.540 us    |    menu_reflect();
 0)    <idle>-0    | ! 100.404 us  |  }
 0)    <idle>-0    |   0.564 us    |  mce_idle_callback();
 0)    <idle>-0    |               |  enter_idle() {
 0)    <idle>-0    |   0.526 us    |    mce_idle_callback();
 0)    <idle>-0    |   1.757 us    |  }
 0)    <idle>-0    |               |  cpuidle_idle_call() {
 0)    <idle>-0    |               |    menu_select() {
 0)    <idle>-0    |   0.525 us    |      pm_qos_requirement();
 0)    <idle>-0    |   0.518 us    |      tick_nohz_get_sleep_length();
 0)    <idle>-0    |   2.621 us    |    }
[...]
 1)    <idle>-0    |   0.518 us    |              touch_softlockup_watchdog();
 1)    <idle>-0    | + 14.355 us   |            }
 1)    <idle>-0    | + 22.840 us   |          }
 1)    <idle>-0    | + 25.949 us   |        }
 1)    <idle>-0    |               |        handle_irq() {
 1)    <idle>-0    |   0.511 us    |          irq_to_desc();
 1)    <idle>-0    |               |          handle_edge_irq() {
 1)    <idle>-0    |   0.638 us    |            _spin_lock();
 1)    <idle>-0    |               |            ack_apic_edge() {
 1)    <idle>-0    |   0.510 us    |              irq_to_desc();
 1)    <idle>-0    |               |              move_native_irq() {
 1)    <idle>-0    |   0.510 us    |                irq_to_desc();
 1)    <idle>-0    |   1.532 us    |              }
 1)    <idle>-0    |   0.511 us    |              native_apic_mem_write();
 ------------------------------------------
 1)    <idle>-0    =>    cat-5073
 ------------------------------------------

 1)    cat-5073    |   3.731 us    |                    }
 1)    cat-5073    |               |                    run_local_timers() {
 1)    cat-5073    |   0.533 us    |                      hrtimer_run_queues();
 1)    cat-5073    |               |                      raise_softirq() {
 1)    cat-5073    |               |                        __raise_softirq_irqoff() {
 1)    cat-5073    |               |                          /* nr: 1 */
 1)    cat-5073    |   2.718 us    |                        }
 1)    cat-5073    |   3.814 us    |                      }
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: clean up

The traceon and traceoff function probes are confusing to developers
to what happens when a counter is not specified. This should help
clear things up.

 # echo "*:traceoff" > set_ftrace_filter
 # cat /debug/tracing/set_ftrace_filter

  #### all functions enabled ####
  do_fork:traceoff:unlimited
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: cleanup

Fix incorrect hint message in code and typos in comments.
Signed-off-by: NWenji Huang <wenji.huang@oracle.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

This patch is to fix the return value of trace_selftest_startup_sysprof
and trace_selftest_startup_branch on failure.
Signed-off-by: NWenji Huang <wenji.huang@oracle.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Pass tsk to tracing_record_cmdline instead of current.
Signed-off-by: NWenji Huang <wenji.huang@oracle.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: clean up

Ingo Molnar did not like the _hook naming convention used by the
select function tracer. Luis Claudio R. Goncalves suggested using
the "_probe" extension. This patch implements the change of
calling the functions and variables "_hook" and replacing them
with "_probe".
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Ingo Molnar pointed out some coding style issues with the recent ftrace
updates. This patch cleans them up.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: build fix
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: build fix
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace

This patch adds a pretty print version of traceon and traceoff
output for set_ftrace_filter.

  # echo 'sys_open:traceon:4' > set_ftrace_filter
  # cat set_ftrace_filter

 #### all functions enabled ####
 sys_open:traceon:count=4
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

This patch adds a call back for the tracers that have hooks to
selected functions. This allows the tracer to show better output
in the set_ftrace_filter file.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

This patch adds output to show what functions have tracer hooks
attached to them.

  # echo 'sys_open:traceon:4' > /debug/tracing/set_ftrace_filter
  # cat set_ftrace_filter

 #### all functions enabled ####
 sys_open:ftrace_traceon:0000000000000004

  # echo 'do_fork:traceoff:' > set_ftrace_filter
  # cat set_ftrace_filter

 #### all functions enabled ####
 sys_open:ftrace_traceon:0000000000000002
 do_fork:ftrace_traceoff:ffffffffffffffff

Note the 4 changed to a 2. This is because The code was executed twice
since the traceoff was added. If a cat is done again:

 #### all functions enabled ####
 sys_open:ftrace_traceon
 do_fork:ftrace_traceoff:ffffffffffffffff

The number disappears. That is because it will not print a NULL.

Callbacks to allow the tracer to pretty print will be implemented soon.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

This patch adds the new function selection commands traceon and
traceoff. traceon sets the function to enable the ring buffers
while traceoff disables the ring buffers.  You can pass in the
number of times you want the command to be executed when the function
is hit. It will only execute if the state of the buffers are not
already in that state.

Example:

 # echo do_fork:traceon:4

Will enable the ring buffers if they are disabled every time it
hits do_fork, up to 4 times.

 # echo sys_close:traceoff

This will disable the ring buffers every time (unlimited) when
sys_close is called.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

This patch adds the tracing_is_on() interface to tell if the ring
buffer is turned on or not.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: new feature

Currently, the function tracer only gives you an ability to hook
a tracer to all functions being traced. The dynamic function trace
allows you to pick and choose which of those functions will be
traced, but all functions being traced will call all tracers that
registered with the function tracer.

This patch adds a new feature that allows a tracer to hook to specific
functions, even when all functions are being traced. It allows for
different functions to call different tracer hooks.

The way this is accomplished is by a special function that will hook
to the function tracer and will set up a hash table knowing which
tracer hook to call with which function. This is the most general
and easiest method to accomplish this. Later, an arch may choose
to supply their own method in changing the mcount call of a function
to call a different tracer. But that will be an exercise for the
future.

To register a function:

 struct ftrace_hook_ops {
	void			(*func)(unsigned long ip,
					unsigned long parent_ip,
					void **data);
	int			(*callback)(unsigned long ip, void **data);
	void			(*free)(void **data);
 };

 int register_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops,
				  void *data);

glob is a simple glob to search for the functions to hook.
ops is a pointer to the operations (listed below)
data is the default data to be passed to the hook functions when traced

ops:
 func is the hook function to call when the functions are traced
 callback is a callback function that is called when setting up the hash.
   That is, if the tracer needs to do something special for each
   function, that is being traced, and wants to give each function
   its own data. The address of the entry data is passed to this
   callback, so that the callback may wish to update the entry to
   whatever it would like.
 free is a callback for when the entry is freed. In case the tracer
   allocated any data, it is give the chance to free it.

To unregister we have three functions:

  void
  unregister_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops,
				void *data)

This will unregister all hooks that match glob, point to ops, and
have its data matching data. (note, if glob is NULL, blank or '*',
all functions will be tested).

  void
  unregister_ftrace_function_hook_func(char *glob,
				 struct ftrace_hook_ops *ops)

This will unregister all functions matching glob that has an entry
pointing to ops.

  void unregister_ftrace_function_hook_all(char *glob)

This simply unregisters all funcs.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: clean up

Now that ftrace_lock is a mutex, there is no reason to have three
different mutexes protecting similar data. All the mutex paths
are not in hot paths, so having a mutex to cover more data is
not a problem.

This patch removes the ftrace_sysctl_lock and ftrace_start_lock
and uses the ftrace_lock to protect the locations that were protected
by these locks. By doing so, this change also removes some of
the lock nesting that was taking place.

There are still more mutexes in ftrace.c that can probably be
consolidated, but they can be dealt with later. We need to be careful
about the way the locks are nested, and by consolidating, we can cause
a recursive deadlock.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: clean up

The older versions of ftrace required doing the ftrace list
search under atomic context. Now all the calls are in non-atomic
context. There is no reason to keep the ftrace_lock as a spinlock.

This patch converts it to a mutex.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Allow for other tracers to add their own commands for function
selection. This interface gives a trace the ability to name a
command for function selection. Right now it is pretty limited
in what it offers, but this is a building step for more features.

The :mod: command is converted to this interface and also serves
as a template for other implementations.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: fix to prevent empty set_ftrace_filter and no ftrace output

The function filter is used to only trace a given set of functions.
The filter is enabled when a function name is echoed into the
set_ftrace_filter file. But if the name has a typo and the function
is not found, the filter is enabled, but no function is listed.

This makes a confusing situation where set_ftrace_filter is empty
but no functions ever get enabled for tracing.

For example:

 # cat /debug/tracing/set_ftrace_filter

  #### all functions enabled ####

 # echo bad_name > set_ftrace_filter
 # cat /debug/tracing/set_ftrace_filter

 # echo function > current_tracer
 # cat trace

  # tracer: nop
  #
  #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
  #              | |       |          |         |

This patch changes that to only enable filtering if a function
is set to be filtered on. Now, the filter is not enabled if
a bad name is echoed into set_ftrace_filter.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

This patch adds a "command" syntax to the function filtering files:

  /debugfs/tracing/set_ftrace_filter
  /debugfs/tracing/set_ftrace_notrace

Of the format:  <function>:<command>:<parameter>

The command is optional, and dependent on the command, so are
the parameters.

 echo do_fork > set_ftrace_filter

Will only trace 'do_fork'.

 echo 'sched_*' > set_ftrace_filter

Will only trace functions starting with the letters 'sched_'.

 echo '*:mod:ext3' > set_ftrace_filter

Will trace only the ext3 module functions.

 echo '*write*:mod:ext3' > set_ftrace_notrace

Will prevent the ext3 functions with the letters 'write' in
the name from being traced.

 echo '!*_allocate:mod:ext3' > set_ftrace_filter

Will remove the functions in ext3 that end with the letters
'_allocate' from the ftrace filter.

Although this patch implements the 'command' format, only the
'mod' command is supported. More commands to follow.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: clean up

ftrace_match_records does a lot of things that other features
can use. This patch breaks up ftrace_match_records and pulls
out ftrace_setup_glob and ftrace_match_record.

ftrace_setup_glob prepares a simple glob expression for use with
ftrace_match_record. ftrace_match_record compares a single record
with a glob type.

Breaking this up will allow for more features to run on individual
records.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: clean up

ftrace_match is too generic of a name. What it really does is
search all records and matches the records with the given string,
and either sets or unsets the functions to be traced depending
on if the parameter 'enable' is set or not.

This allows us to make another function called ftrace_match that
can be used to test a single record.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: clean up

To iterate over all the functions that dynamic trace knows about
it requires two for loops. One to iterate over the pages and the
other to iterate over the records within the page.

There are several duplications of these loops in ftrace.c. This
patch creates the macros do_for_each_ftrace_rec and
while_for_each_ftrace_rec to handle this logic, and removes the
duplicate code.

While making this change, I also discovered and fixed a small
bug that one of the iterations should exit the loop after it found the
record it was searching for. This used a break when it should have
used a goto, since there were two loops it needed to break out
from.  No real harm was done by this bug since it would only continue
to search the other records, and the code was in a slow path anyway.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Impact: clean up, make set_ftrace_filter less confusing

The set_ftrace_filter shows only the functions that will be traced.
But when it is empty, it will trace all functions. This can be a bit
confusing.

This patch makes set_ftrace_filter show:

  #### all functions enabled ####

When all functions will be traced, and we do not filter only a select
few.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>

Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/power-tracer

The function bts_trace_init() references a variable
bts_hotcpu_notifier which is marked
as __cpuinitdata. Thus causes section mismatch. This patch fixes it.

   LD      kernel/trace/built-in.o
 WARNING: kernel/trace/built-in.o(.text+0xc90c): Section mismatch in
 reference from the function bts_trace_init() to the variable
 .cpuinit.data:bts_hotcpu_notifier
 The function bts_trace_init() references
 the variable __cpuinitdata bts_hotcpu_notifier.
 This is often because bts_trace_init lacks a __cpuinitdata
 annotation or the annotation of bts_hotcpu_notifier is wrong.

 WARNING: kernel/trace/built-in.o(.text+0xc92a): Section mismatch in
 reference from the function bts_trace_reset() to the variable
 .cpuinit.data:bts_hotcpu_notifier
 The function bts_trace_reset() references
 the variable __cpuinitdata bts_hotcpu_notifier.
 This is often because bts_trace_reset lacks a __cpuinitdata
 annotation or the annotation of bts_hotcpu_notifier is wrong.
Signed-off-by: NRakib Mullick <rakib.mullick@gmail.com>
Cc: markus.t.metzger@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Conflicts:
	kernel/trace/trace_mmiotrace.c

Impact: prevents confusing the user when buffer size is inadequate

The tracing framework offers a resizeable buffer, which mmiotrace uses
to record events. If the buffer is full, the following events will be
lost. Events should not be lost, so the documentation instructs the user
to increase the buffer size. The buffer size is set via a debugfs file.

Mmiotrace documentation was not updated the same time the debugfs file
was changed. The old file was tracing/trace_entries and first contained
the number of entries the buffer had space for, per cpu. Nowadays this
file is replaced with the file tracing/buffer_size_kb, which tells the
amount of memory reserved for the buffer, per cpu, in kilobytes.

Previously, a flag had to be toggled via the debugfs file
tracing/tracing_enabled when the buffer size was changed. This is no
longer necessary.

The mmiotrace documentation is updated to reflect the current state of
the tracing framework.
Signed-off-by: NPekka Paalanen <pq@iki.fi>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cosmetic change in Kconfig menu layout

This patch was originally suggested by Peter Zijlstra, but seems it
was forgotten.

CONFIG_MMIOTRACE and CONFIG_MMIOTRACE_TEST were selectable
directly under the Kernel hacking / debugging menu in the kernel
configuration system. They were present only for x86 and x86_64.

Other tracers that use the ftrace tracing framework are in their own
sub-menu. This patch moves the mmiotrace configuration options there.
Since the Kconfig file, where the tracer menu is, is not architecture
specific, HAVE_MMIOTRACE_SUPPORT is introduced and provided only by
x86/x86_64. CONFIG_MMIOTRACE now depends on it.
Signed-off-by: NPekka Paalanen <pq@iki.fi>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: enhances lost events counting in mmiotrace

The tracing framework, or the ring buffer facility it uses, has a switch
to stop recording data. When recording is off, the trace events will be
lost. The framework does not count these, so mmiotrace has to count them
itself.
Signed-off-by: NPekka Paalanen <pq@iki.fi>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ASoC: Only register AC97 bus if it's not done already
  ALSA: hda - Add snd_hda_multi_out_dig_cleanup()
  ALSA: hda - Add missing terminator in slave dig-out array
  ALSA: hda - Change HP dv7 (103c:30f4) quirk from hp-m4 to hp-dv5 model
  ALSA: hda - Register (new) devices at reconfig
  ALSA: mtpav - Fix initial value for input hwport
  ALSA: hda - add id for Intel IbexPeak integrated HDMI codec
  ALSA: hda - compute checksum in HDMI audio infoframe
  ALSA: hda - enable HDMI audio pin out at module loading time
  ALSA: hda - allow multi-channel HDMI audio playback when ELD is not present
  ASoC: Update SDP3430 machine driver for snd_soc_card
  ALSA: hda - Add quirk for Asus z37e (1043:8284)
  sound: Remove OSSlib stuff from linux/soundcard.h
  ASoC: WM8990: Fix kcontrol's private value use in put callback
  ASoC: TLV320AIC3X: Fix kcontrol's private value use in put callback

uids in namespaces other than init don't get a sysfs entry.

For those in the init namespace, while we're waiting to remove
the sysfs entry for the uid the uid is still hashed, and
alloc_uid() may re-grab that uid without getting a new
reference to the user_ns, which we've already put in free_user
before scheduling remove_user_sysfs_dir().
Reported-and-tested-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert the c/p state "power" tracer to use tracepoints. Avoids a
function call when the tracer is disabled.
Signed-off-by: NJason Baron <jbaron@redhat.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>