Replace the NR_CPUS array of buffer_iter from the trace_iterator
with an allocated array. This will just create an array of
possible CPUS instead of the max number specified.

The use of NR_CPUS in that array caused allocation failures for
machines that were tight on memory. This did not cause any failures
to the system itself (no crashes), but caused unnecessary failures
for reading the trace files.

Added a helper function called 'trace_buffer_iter()' that returns
the buffer_iter item or NULL if it is not defined or the array was
not allocated. Some routines do not require the array
(tracing_open_pipe() for one).
Reported-by: NDave Jones <davej@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

If a function is set to be traced by the set_graph_function, but the
option funcgraph-irqs is zero, and the traced function happens to be
called from a interrupt, it will not be traced.

The point of funcgraph-irqs is to not trace interrupts when we are
preempted by an irq, not to not trace functions we want to trace that
happen to be *in* a irq.

Luckily the current->trace_recursion element is perfect to add a flag
to help us be able to trace functions within an interrupt even when
we are not tracing interrupts that preempt the trace.
Reported-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The function_graph tracer does not follow global context-info option.
Adding TRACE_ITER_CONTEXT_INFO trace_flags check to enable it.

With following commands:
	# echo function_graph > ./current_tracer
	# echo 0 > options/context-info
	# cat trace

This is what it looked like before:
# tracer: function_graph
#
#     TIME        CPU  DURATION                  FUNCTION CALLS
#      |          |     |   |                     |   |   |   |
 1)   0.079 us    |          } /* __vma_link_rb */
 1)   0.056 us    |          copy_page_range();
 1)               |          security_vm_enough_memory() {
...

This is what it looks like now:
# tracer: function_graph
#
  } /* update_ts_time_stats */
  timekeeping_max_deferment();
...
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-6-git-send-email-jolsa@redhat.comSigned-off-by: NSteven Rostedt <rostedt@goodmis.org>

The lock_depth was removed in commit
e6e1e259 tracing: Remove lock_depth from event entry

Removing the lock_depth info from function_graph latency header.

With following commands:
	# echo function_graph > ./current_tracer
	# echo 1 > options/latency-format
	# cat trace

This is what it looked like before:
# tracer: function_graph
#
# function_graph latency trace v1.1.5 on 3.0.0-rc1-tip+
# --------------------------------------------------------------------
# latency: 0 us, #59756/311298, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
#    -----------------
#    | task: -0 (uid:0 nice:0 policy:0 rt_prio:0)
#    -----------------
#
#      _-----=> irqs-off
#     / _----=> need-resched
#    | / _---=> hardirq/softirq
#    || / _--=> preempt-depth
#    ||| / _-=> lock-depth
#    |||| /
# CPU|||||  DURATION                  FUNCTION CALLS
# |  |||||   |   |                     |   |   |   |
 0)  ....  0.068 us    |    } /* __rcu_read_unlock */
...

This is what it looks like now:
# tracer: function_graph
#
# function_graph latency trace v1.1.5 on 3.0.0-rc1-tip+
# --------------------------------------------------------------------
# latency: 0 us, #59747/1744610, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2)
#    -----------------
#    | task: -0 (uid:0 nice:0 policy:0 rt_prio:0)
#    -----------------
#
#      _-----=> irqs-off
#     / _----=> need-resched
#    | / _---=> hardirq/softirq
#    || / _--=> preempt-depth
#    ||| /
# CPU||||  DURATION                  FUNCTION CALLS
# |  ||||   |   |                     |   |   |   |
 0)  ..s.  1.641 us    |  } /* __rcu_process_callbacks */
...
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-5-git-send-email-jolsa@redhat.comSigned-off-by: NSteven Rostedt <rostedt@goodmis.org>

Functions print_graph_overhead() and print_graph_duration() displays
data for one field - DURATION.

I merged them into single function print_graph_duration(),
and added a way to display the empty parts of the field.

This way the print_graph_irq() function can use this column to display
the IRQ signs if needed and the DURATION field details stays inside
the print_graph_duration() function.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-3-git-send-email-jolsa@redhat.comSigned-off-by: NSteven Rostedt <rostedt@goodmis.org>

The display of absolute time and duration fields is based on the
latency field. This was added during the irqsoff/wakeup tracers
graph support changes.

It's causing confusion in what fields will be displayed for the
function_graph tracer itself. So I'm removing this depency, and
adding absolute time and duration fields to the preemptirqsoff
preemptoff irqsoff wakeup tracers.

With following commands:
	# echo function_graph > ./current_tracer
	# cat trace

This is what it looked like before:
# tracer: function_graph
#
#     TIME        CPU  DURATION                  FUNCTION CALLS
#      |          |     |   |                     |   |   |   |
 0)   0.068 us    |          } /* page_add_file_rmap */
 0)               |          _raw_spin_unlock() {
...

This is what it looks like now:
# tracer: function_graph
#
# CPU  DURATION                  FUNCTION CALLS
# |     |   |                     |   |   |   |
 0)   0.068 us    |                } /* add_preempt_count */
 0)   0.993 us    |              } /* vfsmount_lock_local_lock */
...

For preemptirqsoff preemptoff irqsoff wakeup tracers,
this is what it looked like before:
SNIP
#                       _-----=> irqs-off
#                      / _----=> need-resched
#                     | / _---=> hardirq/softirq
#                     || / _--=> preempt-depth
#                     ||| / _-=> lock-depth
#                     |||| /
# CPU  TASK/PID       |||||  DURATION                  FUNCTION CALLS
# |     |    |        |||||   |   |                     |   |   |   |
 1)    <idle>-0    |  d..1  0.000 us    |  acpi_idle_enter_simple();
...

This is what it looks like now:
SNIP
#
#                                       _-----=> irqs-off
#                                      / _----=> need-resched
#                                     | / _---=> hardirq/softirq
#                                     || / _--=> preempt-depth
#                                     ||| /
#     TIME        CPU  TASK/PID       ||||  DURATION                  FUNCTION CALLS
#      |          |     |    |        ||||   |   |                     |   |   |   |
   19.847735 |   1)    <idle>-0    |  d..1  0.000 us    |  acpi_idle_enter_simple();
...
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1307113131-10045-2-git-send-email-jolsa@redhat.comSigned-off-by: NSteven Rostedt <rostedt@goodmis.org>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

Even though the parent is recorded with the normal function tracing
of the latency tracers (irqsoff and wakeup), the function graph
recording is bogus.

This is due to the function graph messing with the return stack.
The latency tracers pass in as the parent CALLER_ADDR0, which
works fine for plain function tracing. But this causes bogus output
with the graph tracer:

 3)    <idle>-0    |  d.s3.  0.000 us    |  return_to_handler();
 3)    <idle>-0    |  d.s3.  0.000 us    |  _raw_spin_unlock_irqrestore();
 3)    <idle>-0    |  d.s3.  0.000 us    |  return_to_handler();
 3)    <idle>-0    |  d.s3.  0.000 us    |  trace_hardirqs_on();

The "return_to_handle()" call is the trampoline of the
function graph tracer, and is meaningless in this context.

Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Move trace_graph_function() and print_graph_headers_flags() functions
to the trace_function_graph.c to be globaly available.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
LKML-Reference: <1285243253-7372-3-git-send-email-jolsa@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The check_irq_entry and check_irq_return could be called
from graph event context. In such case there's no graph
private data allocated. Adding checks to handle this case.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
LKML-Reference: <20100924154102.GB1818@jolsa.brq.redhat.com>

[ Fixed some grammar in the comments ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Fix

kernel/trace/trace_functions_graph.c: In function ‘trace_print_graph_duration’:
kernel/trace/trace_functions_graph.c:652: warning: comparison of distinct pointer types lacks a cast

when building 36-rc6 on a 32-bit due to the strict type check failing
in the min() macro.
Signed-off-by: NBorislav Petkov <bp@alien8.de>
Cc: Chase Douglas <chase.douglas@canonical.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20100929080823.GA13595@liondog.tnic>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

When the function graph tracer funcgraph-irq option is zero, disable
tracing in IRQs. This makes the option have two effects.

1) When reading the trace file, do not display the functions that
   happen in interrupt context (when detected)

2) [*new*] When recording a trace, skip those that are detected
   to be in interrupt by the 'in_irq()' function

Note, in_irq() is updated at irq_enter() and irq_exit(). There are
still functions that are recorded by the function graph tracer that
is in interrupt context but outside the irq_enter/exit() routines.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

It's handy to be able to disable the irq related output
and not to have to jump over each irq related code, when
you have no interrest in it.

The option is by default enabled, so there's no change to
current behaviour. It affects only the final output, so all
the irq related data stay in the ring buffer.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
LKML-Reference: <20100907145344.GC1912@jolsa.brq.redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

ftrace_event_call->perf_events, perf_trace_buf,
fgraph_data->cpu_data and some local variables are percpu pointers
missing __percpu markups. Add them.
Signed-off-by: NNamhyung Kim <namhyung@gmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <1281498479-28551-1-git-send-email-namhyung@gmail.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

With CONFIG_DEBUG_PAGEALLOC, I observed an unallocated memory access in
function_graph trace. It appears we find a small size entry in ring buffer,
but we access it as a big size entry. The access overflows the page size
and touches an unallocated page.

Cc: <stable@kernel.org>
Signed-off-by: NShaohua Li <shaohua.li@intel.com>
LKML-Reference: <1280217994.32400.76.camel@sli10-desk.sh.intel.com>
[ Added a comment to explain the problem - SDR ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The nsecs_str string is a local variable defined as:

char nsecs_str[5];

It is possible for the snprintf call to use a size value larger than the
size of the string. This should not cause a buffer overrun as it is
written now due to the value for the string format "%03lu" can not be
larger than 1000. However, this change makes it correct. By making the
size correct we guard against potential future changes that could actually
cause a buffer overrun.
Signed-off-by: NChase Douglas <chase.douglas@canonical.com>
LKML-Reference: <1276619355-18116-1-git-send-email-chase.douglas@canonical.com>

[ added 'UL' to number 8 to fix gcc warning comparing it to sizeof() ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Multiple events may use the same method to print their data.
Instead of having all events have a pointer to their print funtions,
the trace_event structure now points to a trace_event_functions structure
that will hold the way to print ouf the event.

The event itself is now passed to the print function to let the print
function know what kind of event it should print.

This opens the door to consolidating the way several events print
their output.

   text	   data	    bss	    dec	    hex	filename
4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
4900382	1048964	 861512	6810858	 67ecea	vmlinux.init
4900446	1049028	 861512	6810986	 67ed6a	vmlinux.preprint

This change slightly increases the size but is needed for the next change.

v3: Fix the branch tracer events to handle this change.

v2: Fix the new function graph tracer event calls to handle this change.
Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: NMasami Hiramatsu <mhiramat@redhat.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Add function graph output to irqsoff tracer.

The graph output is enabled by setting new 'display-graph' trace option.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
LKML-Reference: <1270227683-14631-4-git-send-email-jolsa@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Let the function graph tracer have custom flags passed to its
output functions.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
LKML-Reference: <1270227683-14631-3-git-send-email-jolsa@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Add ftrace events for graph tracer, so the graph output could be shared
with other tracers.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
LKML-Reference: <1270227683-14631-2-git-send-email-jolsa@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Currently, when the ring buffer drops events, it does not record
the fact that it did so. It does inform the writer that the event
was dropped by returning a NULL event, but it does not put in any
place holder where the event was dropped.

This is not a trivial thing to add because the ring buffer mostly
runs in overwrite (flight recorder) mode. That is, when the ring
buffer is full, new data will overwrite old data.

In a produce/consumer mode, where new data is simply dropped when
the ring buffer is full, it is trivial to add the placeholder
for dropped events. When there's more room to write new data, then
a special event can be added to notify the reader about the dropped
events.

But in overwrite mode, any new write can overwrite events. A place
holder can not be inserted into the ring buffer since there never
may be room. A reader could also come in at anytime and miss the
placeholder.

Luckily, the way the ring buffer works, the read side can find out
if events were lost or not, and how many events. Everytime a write
takes place, if it overwrites the header page (the next read) it
updates a "overrun" variable that keeps track of the number of
lost events. When a reader swaps out a page from the ring buffer,
it can record this number, perfom the swap, and then check to
see if the number changed, and take the diff if it has, which would be
the number of events dropped. This can be stored by the reader
and returned to callers of the reader.

Since the reader page swap will fail if the writer moved the head
page since the time the reader page set up the swap, this gives room
to record the overruns without worrying about races. If the reader
sets up the pages, records the overrun, than performs the swap,
if the swap succeeds, then the overrun variable has not been
updated since the setup before the swap.

For binary readers of the ring buffer, a flag is set in the header
of each sub page (sub buffer) of the ring buffer. This flag is embedded
in the size field of the data on the sub buffer, in the 31st bit (the size
can be 32 or 64 bits depending on the architecture), but only 27
bits needs to be used for the actual size (less actually).

We could add a new field in the sub buffer header to also record the
number of events dropped since the last read, but this will change the
format of the binary ring buffer a bit too much. Perhaps this change can
be made if the information on the number of events dropped is considered
important enough.

Note, the notification of dropped events is only used by consuming reads
or peeking at the ring buffer. Iterating over the ring buffer does not
keep this information because the necessary data is only available when
a page swap is made, and the iterator does not swap out pages.

Cc: Robert Richter <robert.richter@amd.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lclaudio@uudg.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Add support for tracing_thresh to the function_graph tracer.  This
version of this feature isolates the checks into new entry and
return functions, to avoid adding more conditional code into the
main function_graph paths.

When the tracing_thresh is set and the function graph tracer is
enabled, only the functions that took longer than the time in
microseconds that was set in tracing_thresh are recorded. To do this
efficiently, only the function exits are recorded:

 [tracing]# echo 100 > tracing_thresh
 [tracing]# echo function_graph > current_tracer
 [tracing]# cat trace
 # tracer: function_graph
 #
 # CPU  DURATION                  FUNCTION CALLS
 # |     |   |                     |   |   |   |
  1) ! 119.214 us  |  } /* smp_apic_timer_interrupt */
  1)   <========== |
  0) ! 101.527 us  |              } /* __rcu_process_callbacks */
  0) ! 126.461 us  |            } /* rcu_process_callbacks */
  0) ! 145.111 us  |          } /* __do_softirq */
  0) ! 149.667 us  |        } /* do_softirq */
  0) ! 168.817 us  |      } /* irq_exit */
  0) ! 248.254 us  |    } /* smp_apic_timer_interrupt */

Also, add support for specifying tracing_thresh on the kernel
command line.  When used like so: "tracing_thresh=200 ftrace=function_graph"
this can be used to analyse system startup.  It is important to disable
tracing soon after boot, in order to avoid losing the trace data.
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NTim Bird <tim.bird@am.sony.com>
LKML-Reference: <4B87098B.4040308@am.sony.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

When a '}' does not have a matching function start, the name is printed
within parenthesis. But this makes it confusing between ending '}'
and function starts. This patch makes the function name appear in C comment
notation.

Old view:
 3)   1.281 us    |            } (might_fault)
 3)   3.620 us    |          } (filldir)
 3)   5.251 us    |        } (call_filldir)
 3)               |        call_filldir() {
 3)               |          filldir() {

New view:
 3)   1.281 us    |            } /* might_fault */
 3)   3.620 us    |          } /* filldir */
 3)   5.251 us    |        } /* call_filldir */
 3)               |        call_filldir() {
 3)               |          filldir() {
Requested-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The function graph tracer is currently the most invasive tracer
in the ftrace family. It can easily overflow the buffer even with
10megs per CPU. This means that events can often be lost.

On start up, or after events are lost, if the function return is
recorded but the function enter was lost, all we get to see is the
exiting '}'.

Here is how a typical trace output starts:

 [tracing] cat trace
 # tracer: function_graph
 #
 # CPU  DURATION                  FUNCTION CALLS
 # |     |   |                     |   |   |   |
  0) + 91.897 us   |                  }
  0) ! 567.961 us  |                }
  0)   <========== |
  0) ! 579.083 us  |                _raw_spin_lock_irqsave();
  0)   4.694 us    |                _raw_spin_unlock_irqrestore();
  0) ! 594.862 us  |              }
  0) ! 603.361 us  |            }
  0) ! 613.574 us  |          }
  0) ! 623.554 us  |        }
  0)   3.653 us    |        fget_light();
  0)               |        sock_poll() {

There are a series of '}' with no matching "func() {". There's no information
to what functions these ending brackets belong to.

This patch adds a stack on the per cpu structure used in outputting
the function graph tracer to keep track of what function was outputted.
Then on a function exit event, it checks the depth to see if the
function exit has a matching entry event. If it does, then it only
prints the '}', otherwise it adds the function name after the '}'.

This allows function exit events to show what function they belong to
at trace output startup, when the entry was lost due to ring buffer
overflow, or even after a new task is scheduled in.

Here is what the above trace will look like after this patch:

 [tracing] cat trace
 # tracer: function_graph
 #
 # CPU  DURATION                  FUNCTION CALLS
 # |     |   |                     |   |   |   |
  0) + 91.897 us   |                  } (irq_exit)
  0) ! 567.961 us  |                } (smp_apic_timer_interrupt)
  0)   <========== |
  0) ! 579.083 us  |                _raw_spin_lock_irqsave();
  0)   4.694 us    |                _raw_spin_unlock_irqrestore();
  0) ! 594.862 us  |              } (add_wait_queue)
  0) ! 603.361 us  |            } (__pollwait)
  0) ! 613.574 us  |          } (tcp_poll)
  0) ! 623.554 us  |        } (sock_poll)
  0)   3.653 us    |        fget_light();
  0)               |        sock_poll() {
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The "cpu" variable is declared at the start of the function and
also within a branch, with the exact same initialization.

Remove the local variable of the same name in the branch.
Signed-off-by: NWenji Huang <wenji.huang@oracle.com>
LKML-Reference: <1266997226-6833-3-git-send-email-wenji.huang@oracle.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

In the function graph tracer, a calling function is to be traced
only when it is enabled through the set_graph_function file,
or when it is nested in an enabled function.

Current code uses TSK_TRACE_FL_GRAPH to test whether it is nested
or not. Looking at the code, we can get this:
(trace->depth > 0) <==> (TSK_TRACE_FL_GRAPH is set)

trace->depth is more explicit to tell that it is nested.
So we use trace->depth directly and simplify the code.

No functionality is changed.
TSK_TRACE_FL_GRAPH is not removed yet, it is left for future usage.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B4DB0B6.7040607@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Each time we save a function entry from the function graph
tracer, we check if the trace array is set, which is wasteful
because it is set anyway before we start the tracer. All we need
is to ensure we have good read and write orderings. When we set
the trace array, we just need to guarantee it to be visible
before starting tracing.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
LKML-Reference: <1263453795-7496-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

There is a case where the graph tracer might get confused and omits
displaying of a single record.  This applies mostly with the trace_pipe
since it is unlikely that the trace_seq buffer will overflow with the
trace file.

As the function_graph tracer goes through the trace entries keeping a
pointer to the current record:

current ->  func1 ENTRY
            func2 ENTRY
            func2 RETURN
            func1 RETURN

When an function ENTRY is encountered, it moves the pointer to the
next entry to check if the function is a nested or leaf function.

            func1 ENTRY
current ->  func2 ENTRY
            func2 RETURN
            func1 RETURN

If the rest of the writing of the function fills the trace_seq buffer,
then the trace_pipe read will ignore this entry. The next read will
Now start at the current location, but the first entry (func1) will
be discarded.

This patch keeps a copy of the current entry in the iterator private
storage and will keep track of when the trace_seq buffer fills. When
the trace_seq buffer fills, it will reuse the copy of the entry in the
next iteration.

[
  This patch has been largely modified by Steven Rostedt in order to
  clean it up and simplify it. The original idea and concept was from
  Jirka and for that, this patch will go under his name to give him
  the credit he deserves. But because this was modify by Steven Rostedt
  anything wrong with the patch should be blamed on Steven.
]
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1259067458-27143-1-git-send-email-jolsa@redhat.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Now that the return from alloc_percpu is compatible with the address
of per-cpu vars, it makes sense to hand around the address of per-cpu
variables.  To make this sane, we remove the per_cpu__ prefix we used
created to stop people accidentally using these vars directly.

Now we have sparse, we can use that (next patch).

tj: * Updated to convert stuff which were missed by or added after the
      original patch.

    * Kill per_cpu_var() macro.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NTejun Heo <tj@kernel.org>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>

ftrace_cpu_disabled usage in trace_functions_graph.c were left out
during this_cpu_xx conversion in commit 9288f99a causing compile
failure.  Convert them.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Lameter <cl@linux-foundation.org>

For direct function pointers (like what mcount provides) PowerPC64
requires the use of %ps, otherwise nothing is printed.

This patch converts all prints of functions retrieved through mcount
to use the %ps format from the %pf.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Both trace_output.c and trace_function_graph.c do basically the same
thing to handle the printing of the latency-format. This patch moves
the code into one function that both can use.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

This patch adds the lock depth of the big kernel lock to the generic
entry header. This way we can see the depth of the lock and help
in removing the BKL.

Example:

 #                  _------=> CPU#
 #                 / _-----=> irqs-off
 #                | / _----=> need-resched
 #                || / _---=> hardirq/softirq
 #                ||| / _--=> preempt-depth
 #                |||| /_--=> lock-depth
 #                |||||/     delay
 #  cmd     pid   |||||| time  |   caller
 #     \   /      ||||||   \   |   /
   <idle>-0       2.N..3 5902255250us+: lock_acquire: read rcu_read_lock
   <idle>-0       2.N..3 5902255253us+: lock_release: rcu_read_lock
   <idle>-0       2dN..3 5902255257us+: lock_acquire: xtime_lock
   <idle>-0       2dN..4 5902255259us : lock_acquire: clocksource_lock
   <idle>-0       2dN..4 5902255261us+: lock_release: clocksource_lock
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

While debugging something with the function_graph tracer, I found the
need to see the preempt count of the traces. Unfortunately, since
the function graph tracer has its own output formatting, it does not
honor the latency-format option.

This patch makes the function_graph tracer honor the latency-format
option, but still keeps control of the output. But now we have the
same details that the latency-format supplies.

 # tracer: function_graph
 #
 #      _-----=> irqs-off
 #     / _----=> need-resched
 #    | / _---=> hardirq/softirq
 #    || / _--=> preempt-depth
 #    ||| /
 #    ||||
 # CPU||||  DURATION                  FUNCTION CALLS
 # |  ||||   |   |                     |   |   |   |
  3)  d..1  1.333 us    |        idle_cpu();
  3)  d.h1              |        tick_check_idle() {
  3)  d.h1  0.550 us    |          tick_check_oneshot_broadcast();
  3)  d.h1              |          tick_nohz_stop_idle() {
  3)  d.h1              |            ktime_get() {
  3)  d.h1              |              ktime_get_ts() {
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The latency tracers (irqsoff and wakeup) can swap trace buffers
on the fly. If an event is happening and has reserved data on one of
the buffers, and the latency tracer swaps the global buffer with the
max buffer, the result is that the event may commit the data to the
wrong buffer.

This patch changes the API to the trace recording to be recieve the
buffer that was used to reserve a commit. Then this buffer can be passed
in to the commit.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The function graph events helpers which insert the function entry and
return events into the ring buffer currently reside in trace.c
But this file is quite overloaded and the right place for these helpers
is in the function graph tracer file.

Then move them to trace_functions_graph.c
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>

print_graph_cpu() is little over-designed.

And "log10_all" may be wrong when there are holes in cpu_online_mask:
the max online cpu id > cpumask_weight(cpu_online_mask)

So change it by using a static column length for the cpu matching
nr_cpu_ids number of decimal characters.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A6EEE5E.2000001@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

When print_graph_entry() computes a function call entry event, it needs
to also check the next entry to guess if it matches the return event of
the current function entry.
In order to look at this next event, it needs to consume the current
entry before going ahead in the ring buffer.

However, if the current event that gets consumed is the last one in the
ring buffer head page, the ring_buffer may reuse the page for writers.
The consumed entry will then become invalid because of possible
racy overwriting.

Me must then handle this entry by making a copy of it.

The fix also applies on 2.6.30
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: stable@kernel.org
LKML-Reference: <4A6EEAEC.3050508@cn.fujitsu.com>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>

Remove the obsolete seq_print_ip_sym() usage and replace it
by the %pf format in order to print function symbols.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <1247107590-6428-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>