Impact: cleanup

Use tracing_reset_online_cpus instead of open coding it.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Get rid of 'waited' stack variable.
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: build fix

Also mention in the help text that blktrace now can be used using
the ftrace interface.
Reported-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Also make sure sparse (make C=2 block/blktrace.o) is happy too.
Reported-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: New way of using the blktrace infrastructure

This drops the requirement of userspace utilities to use the blktrace
facility.

Configuration is done thru sysfs, adding a "trace" directory to the
partition directory where blktrace can be enabled for the associated
request_queue.

The same filters present in the IOCTL interface are present as sysfs
device attributes.

The /sys/block/sdX/sdXN/trace/enable file allows tracing without any
filters.

The other files in this directory: pid, act_mask, start_lba and end_lba
can be used with the same meaning as with the IOCTL interface.

Using the sysfs interface will only setup the request_queue->blk_trace
fields, tracing will only take place when the "blk" tracer is selected
via the ftrace interface, as in the following example:

To see the trace, one can use the /d/tracing/trace file or the
/d/tracign/trace_pipe file, with semantics defined in the ftrace
documentation in Documentation/ftrace.txt.

[root@f10-1 ~]# cat /t/trace
       kjournald-305   [000]  3046.491224:   8,1    A WBS 6367 + 8 <- (8,1) 6304
       kjournald-305   [000]  3046.491227:   8,1    Q   R 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491236:   8,1    G  RB 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491239:   8,1    P  NS [kjournald]
       kjournald-305   [000]  3046.491242:   8,1    I RBS 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491251:   8,1    D  WB 6367 + 8 [kjournald]
       kjournald-305   [000]  3046.491610:   8,1    U  WS [kjournald] 1
          <idle>-0     [000]  3046.511914:   8,1    C  RS 6367 + 8 [6367]
[root@f10-1 ~]#

The default line context (prefix) format is the one described in the ftrace
documentation, with the blktrace specific bits using its existing format,
described in blkparse(8).

If one wants to have the classic blktrace formatting, this is possible by
using:

[root@f10-1 ~]# echo blk_classic > /t/trace_options
[root@f10-1 ~]# cat /t/trace
  8,1    0  3046.491224   305  A WBS 6367 + 8 <- (8,1) 6304
  8,1    0  3046.491227   305  Q   R 6367 + 8 [kjournald]
  8,1    0  3046.491236   305  G  RB 6367 + 8 [kjournald]
  8,1    0  3046.491239   305  P  NS [kjournald]
  8,1    0  3046.491242   305  I RBS 6367 + 8 [kjournald]
  8,1    0  3046.491251   305  D  WB 6367 + 8 [kjournald]
  8,1    0  3046.491610   305  U  WS [kjournald] 1
  8,1    0  3046.511914     0  C  RS 6367 + 8 [6367]
[root@f10-1 ~]#

Using the ftrace standard format allows more flexibility, such
as the ability of asking for backtraces via trace_options:

[root@f10-1 ~]# echo noblk_classic > /t/trace_options
[root@f10-1 ~]# echo stacktrace > /t/trace_options

[root@f10-1 ~]# cat /t/trace
       kjournald-305   [000]  3318.826779:   8,1    A WBS 6375 + 8 <- (8,1) 6312
       kjournald-305   [000]  3318.826782:
 <= submit_bio
 <= submit_bh
 <= sync_dirty_buffer
 <= journal_commit_transaction
 <= kjournald
 <= kthread
 <= child_rip
       kjournald-305   [000]  3318.826836:   8,1    Q   R 6375 + 8 [kjournald]
       kjournald-305   [000]  3318.826837:
 <= generic_make_request
 <= submit_bio
 <= submit_bh
 <= sync_dirty_buffer
 <= journal_commit_transaction
 <= kjournald
 <= kthread

Please read the ftrace documentation to use aditional, standardized
tracing filters such as /d/tracing/trace_cpumask, etc.

See also /d/tracing/trace_mark to add comments in the trace stream,
that is equivalent to the /d/block/sdaN/msg interface.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: new helper function
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix kmemtrace printk warnings:

  kernel/trace/kmemtrace.c:142: warning: format '%4ld' expects type 'long int', but argument 3 has type 'size_t'
  kernel/trace/kmemtrace.c:147: warning: format '%4ld' expects type 'long int', but argument 3 has type 'size_t'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: NEduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch brings various bugfixes:

- Drop the first irrelevant task switch on the very beginning of a trace.

- Drop the OVERHEAD word from the headers, the DURATION word is sufficient
  and will not overlap other columns.

- Make the headers fit well their respective columns whatever the
  selected options.

Ie, default options:

 # tracer: function_graph
 #
 # CPU  DURATION                  FUNCTION CALLS
 # |     |   |                     |   |   |   |

  1)   0.646 us    |                    }
  1)               |                    mem_cgroup_del_lru_list() {
  1)   0.624 us    |                      lookup_page_cgroup();
  1)   1.970 us    |                    }

 echo funcgraph-proc > trace_options

 # tracer: function_graph
 #
 # CPU  TASK/PID        DURATION                  FUNCTION CALLS
 # |    |    |           |   |                     |   |   |   |

  0)   bash-2937    |   0.895 us    |                }
  0)   bash-2937    |   0.888 us    |                __rcu_read_unlock();
  0)   bash-2937    |   0.864 us    |                conv_uni_to_pc();
  0)   bash-2937    |   1.015 us    |                __rcu_read_lock();

 echo nofuncgraph-cpu > trace_options
 echo nofuncgraph-proc > trace_options

 # tracer: function_graph
 #
 #   DURATION                  FUNCTION CALLS
 #    |   |                     |   |   |   |

   3.752 us    |                  native_pud_val();
   0.616 us    |                  native_pud_val();
   0.624 us    |                  native_pmd_val();

About features, one can now disable the duration (this will hide the
overhead too for convenient reasons and because on  doesn't need
overhead if it hasn't the duration):

 echo nofuncgraph-duration > trace_options

 # tracer: function_graph
 #
 #                FUNCTION CALLS
 #                |   |   |   |

           cap_vm_enough_memory() {
             __vm_enough_memory() {
               vm_acct_memory();
             }
           }
         }

And at last, an option to print the absolute time:

 //Restart from default options
 echo funcgraph-abstime > trace_options

 # tracer: function_graph
 #
 #      TIME       CPU  DURATION                  FUNCTION CALLS
 #       |         |     |   |                     |   |   |   |

   261.339774 |   1) + 42.823 us   |    }
   261.339775 |   1)   1.045 us    |    _spin_lock_irq();
   261.339777 |   1)   0.940 us    |    _spin_lock_irqsave();
   261.339778 |   1)   0.752 us    |    _spin_unlock_irqrestore();
   261.339780 |   1)   0.857 us    |    _spin_unlock_irq();
   261.339782 |   1)               |    flush_to_ldisc() {
   261.339783 |   1)               |      tty_ldisc_ref() {
   261.339783 |   1)               |        tty_ldisc_try() {
   261.339784 |   1)   1.075 us    |          _spin_lock_irqsave();
   261.339786 |   1)   0.842 us    |          _spin_unlock_irqrestore();
   261.339788 |   1)   4.211 us    |        }
   261.339788 |   1)   5.662 us    |      }

The format is seconds.usecs.

I guess no one needs the nanosec precision here, the main goal is to have
an overview about the general timings of events, and to see the place when
the trace switches from one cpu to another.

ie:

   274.874760 |   1)   0.676 us    |      _spin_unlock();
   274.874762 |   1)   0.609 us    |      native_load_sp0();
   274.874763 |   1)   0.602 us    |      native_load_tls();
   274.878739 |   0)   0.722 us    |                  }
   274.878740 |   0)   0.714 us    |                  native_pmd_val();
   274.878741 |   0)   0.730 us    |                  native_pmd_val();

Here there is a 4000 usecs difference when we switch the cpu.

Changes in V2:

- Completely fix the first pointless task switch.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix to preempt trace triggering lockdep check_flag failure

In local_bh_disable, the use of add_preempt_count causes the
preempt tracer to start recording the time preemption is off.
But because it already modified the preempt_count to show
softirqs disabled, and before it called the lockdep code to
handle this, it causes a state that lockdep can not handle.

The preempt tracer will reset the ring buffer on start of a trace,
and the ring buffer reset code does a spin_lock_irqsave. This
calls into lockdep and lockdep will fail when it detects the
invalid state of having softirqs disabled but the internal
current->softirqs_enabled is still set.

The fix is to manually add the SOFTIRQ_OFFSET to preempt count
and call the preempt tracer code outside the lockdep critical
area.

Thanks to Peter Zijlstra for suggesting this solution.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The logic in the tracing_start/stop code prevents the WARN_ON
from ever detecting if a start/stop pair was mismatched.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup of duplicate features

The trace output disables the ring buffer and prevents tracing to
occur. The code in irqsoff to do the same thing is no longer needed.
This patch removes it.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Cleanup the cpuid check for DS configuration.

This also fixes a Corei7 CPUID enumeration bug.
Signed-off-by: NMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix bad times of recent resets

The ring buffer needs to reset its timestamps when reseting of the
buffer, otherwise the timestamps are stale and might be used to
calculate times in the buffer causing funny timestamps to appear.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix bad times of recent resets

The ring buffer needs to reset its timestamps when reseting of the
buffer, otherwise the timestamps are stale and might be used to
calculate times in the buffer causing funny timestamps to appear.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: better data for wakeup tracer

This patch adds the wakeup and schedule calls that are used by
the scheduler tracer to make the wakeup tracer more readable.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: add option to trace all tasks or just RT tasks

The current wakeup tracer only traces RT task wakeups. This is
fine for those interested in wake up timings of RT tasks, but
it is useless for those that are interested in the causes
of long wakeups for non RT tasks.

This patch creates a "wakeup_rt" to implement the tracing of just
RT tasks (as the current "wakeup" does). And makes "wakeup" now
trace all tasks as an average developer would expect.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

If the ring buffer recording has been disabled. Do not let
swapping of ring buffers occur. Simply return -EAGAIN.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix to erased trace output

To try not to have the outputing of a trace interfere with the wakeup
tracer, it would disable tracing while the output was printing. But
if a trace had started when it was disabled, it can show a partial
trace. To try to solve this, on closing of the tracer, it would
clear the trace buffer.

The latency tracers (wakeup and irqsoff) have two buffers. One for
recording and one for holding the max trace that is printed. The
clearing of the trace above should only affect the recording buffer.
But for some reason it would move the erased trace to the print
buffer. Probably due to a race with the closing of the trace and
the saving ofhe max race.

The above is all pretty useless, and if the user does not want the
printing of the trace to be traced itself, then the user can manual
disable tracing. This patch removes all the code that tries to keep
the output of the tracer from modifying the trace.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: trace max latencies on start of latency tracing

This patch sets the max latency to zero whenever one of the
irq variant tracers or the wakeup tracer is set to current tracer.

Most developers expect to see output when starting up a latency
tracer. But since the max_latency is already set to max, and
it takes a latency greater than max_latency to be recorded, there
is no trace. This is not the expected behavior and has even confused
myself.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: limit ftrace dump output

Currently ftrace_dump only calls ftrace_kill that is a fast way
to prevent the function tracer functions from being called (just sets
a flag and clears the function to call, nothing else). It is better
to also turn off any recording to the ring buffers as well.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix to print out ftrace_dump when expected

I was debugging a hard race condition to only find out that
after I hit the race, my log level was not at level to show
KERN_INFO. The time it took to trigger the race was wasted because
I did not capture the trace.

Since ftrace_dump is only called from kernel oops (and only when
it is set in the kernel command line to do so), or when a
developer adds it to their own local tree, the log level of
the print should be at KERN_EMERG to make sure the print appears.

ftrace_dump is not called by a normal user setup, and will not
add extra unwanted print out to the console. There is no reason
it should be at KERN_INFO.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: reset struct buffer_page.write when interrupt storm

if struct buffer_page.write is not reset, any succedent committing
will corrupted ring_buffer:

static inline void
rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
{
	......
		cpu_buffer->commit_page->commit =
			cpu_buffer->commit_page->write;
	......
}

when "if (RB_WARN_ON(cpu_buffer, next_page == reader_page))", ring_buffer
is disabled, but some reserved buffers may haven't been committed.
we need reset struct buffer_page.write.

when "if (unlikely(next_page == cpu_buffer->commit_page))", ring_buffer
is still available, we should not corrupt it.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix a crash while kernel image restore

When the function graph tracer is running and while suspend to disk, some racy
and dangerous things happen against this tracer.

The current task will save its registers including the stack pointer which
contains the return address hooked by the tracer. But the current task will
continue to enter other functions after that to save the memory, and then
it will store other return addresses, and finally loose the old depth which
matches the return address saved in the old stack (during the registers saving).

So on image restore, the code will return to wrong addresses.
And there are other things: on restore, the task will have it's "current"
pointer overwritten during registers restoring....switching from one task to
another... That would be insane to try to trace function graphs at these
stages.

This patch makes the function graph tracer listening on power events, making
it's tracing disabled for the current task (the one that performs the
hibernation work) while suspend/resume to disk, making the tracing safe
during hibernation.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix to allow some archs to use the ring buffer

Commits in the ring buffer are checked by pointer arithmetic.
If the calculation is incorrect, then the commits will never take
place and the buffer will simply fill up and report an error.

Each page in the ring buffer has a small header:

struct buffer_data_page {
	u64		time_stamp;
	local_t		commit;
	unsigned char	data[];
};

Unfortuntely, some of the calculations used sizeof(struct buffer_data_page)
to know the size of the header. But this is incorrect on some archs,
where sizeof(struct buffer_data_page) does not equal
offsetof(struct buffer_data_page, data), and on those archs, the commits
are never processed.

This patch replaces the sizeof with offsetof.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: use percpu data instead of a global structure

Use:

   static DEFINE_PER_CPU(struct workqueue_global_stats, all_workqueue_stat);

instead of allocating a global structure.

percpu data also works well on NUMA.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Cleanup the cpuid check for DS configuration.
Signed-off-by: NMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Document the hw-branch-tracer in the ftrace documentation.
Signed-off-by: NMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Change the hw-branch-tracer format to be more readable.
Signed-off-by: NMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Reset the ftrace buffer on close. Since we use cyclic buffers, the
trace is not contiguous, anyway.
Signed-off-by: NMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Dump the branch trace on an oops (based on ftrace_dump_on_oops).
Signed-off-by: NMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Support hotplug cpus.
Reported-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NMarkus Metzger <markus.t.metzger@intel.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix failure of dynamic function tracer selftest

In a course of development, a developer does several makes on their
kernel. Sometimes, the make might do something abnormal. In the
case of running the recordmcount.pl script on an object twice,
the script will duplicate all the calls to mcount in the __mcount_loc
section.

On boot up, the dynamic function tracer is careful when it modifies
code, and performs several consistency checks. One is to not modify
the call site if it is not what it expects it to be. If a function
call site is listed twice, the first entry will convert the site
to a nop, and the second will fail because it expected to see a
call to mcount, but instead it sees a nop. Thus, the function tracer
is disabled.

Eric Sesterhenn reported seeing:

[    1.055440] ftrace: converting mcount calls to 0f 1f 44 00 00
[    1.055568] ftrace: allocating 29418 entries in 116 pages
[    1.061000] ------------[ cut here ]------------
[    1.061000] WARNING: at kernel/trace/ftrace.c:441

 [...]

[    1.060000] ---[ end trace 4eaa2a86a8e2da23 ]---
[    1.060000] ftrace failed to modify [<c0118072>] check_corruption+0x3/0x2d
[    1.060000]  actual: 0f:1f:44:00:00

This warning shows that check_corruption+0x3 already had a nop in
its place (0x0f1f440000). After compiling another kernel the problem
went away.

Later Eric Paris notice the same type of issue. Luckily, he saved
the vmlinux file that caused it. In the file we found a bunch of
duplicate mcount call site records, which lead us to the script.

Perhaps this problem only happens to people named Eric.

This patch changes the script to test if the __mcount_loc already
exists in the object file, and if it does, it will print out
an error message and kill the compile.
Reported-by: NEric Sesterhenn <snakebyte@gmx.de>
Reported-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (23 commits)
  ACPI PCI hotplug: harden against panic regression
  ACPI: rename main.c to sleep.c
  dell-laptop: move to drivers/platform/x86/ from drivers/misc/
  eeepc-laptop: enable Bluetooth ACPI details
  ACPI: fix ACPI_FADT_S4_RTC_WAKE comment
  kprobes: check CONFIG_FREEZER instead of CONFIG_PM
  PM: Fix freezer compilation if PM_SLEEP is unset
  thermal fixup for broken BIOS which has invalid trip points.
  ACPI: EC: Don't trust ECDT tables from ASUS
  ACPI: EC: Limit workaround for ASUS notebooks even more
  ACPI: thinkpad-acpi: bump up version to 0.22
  ACPI: thinkpad-acpi: handle HKEY event 6030
  ACPI: thinkpad-acpi: clean-up fan subdriver quirk
  ACPI: thinkpad-acpi: start the event hunt season
  ACPI: thinkpad-acpi: handle HKEY thermal and battery alarms
  ACPI: thinkpad-acpi: clean up hotkey_notify()
  ACPI: thinkpad-acpi: use killable instead of interruptible mutexes
  ACPI: thinkpad-acpi: add UWB radio support
  ACPI: thinkpad-acpi: preserve radio state across shutdown
  ACPI: thinkpad-acpi: resume with radios disabled
  ...