Commit graph

113723 commits

Author SHA1 Message Date
Steven Rostedt
d769041f86 ring_buffer: implement new locking
The old "lock always" scheme had issues with lockdep, and was not very
efficient anyways.

This patch does a new design to be partially lockless on writes.
Writes will add new entries to the per cpu pages by simply disabling
interrupts. When a write needs to go to another page than it will
grab the lock.

A new "read page" has been added so that the reader can pull out a page
from the ring buffer to read without worrying about the writer writing over
it. This allows us to not take the lock for all reads. The lock is
now only taken when a read needs to go to a new page.

This is far from lockless, and interrupts still need to be disabled,
but it is a step towards a more lockless solution, and it also
solves a lot of the issues that were noticed by the first conversion
of ftrace to the ring buffers.

Note: the ring_buffer_{un}lock API has been removed.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:05 +02:00
Steven Rostedt
70255b5e3f ring_buffer: remove raw from local_irq_save
The raw_local_irq_save causes issues with lockdep. We don't need it
so replace them with local_irq_save.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:04 +02:00
Frederic Weisbecker
9e9efffb78 tracing/ftrace: adapt the boot tracer to the new print_line type
This patch adapts the boot tracer to the new type of the
print_line callback.

It still relays entries it doesn't support to default output
functions.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:03 +02:00
Frederic Weisbecker
07f4e4f790 tracing/ftrace: adapt mmiotrace to the new type of print_line
Adapt mmiotrace to the new print_line type.
By default, it ignores (and consumes) types it doesn't support.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:02 +02:00
Pekka Paalanen
9ff4b9744c tracing/ftrace: fix pipe breaking
This patch fixes a bug which break the pipe when the seq is empty.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:01 +02:00
Frederic Weisbecker
2c4f035f6c tracing/ftrace: change the type of the print_line callback
We need a kind of disambiguation when a print_line callback
returns 0.

_There is not enough space to print all the entry.
 Please flush the seq and retry.
_I can't handle this type of entry

This patch changes the type of this callback for better information.

Also some changes have been made in this V2.

_ Only relay to default functions after the print_line callback fails.
_ This patch doesn't fix the issue with the broken pipe (see patch 2/4 for that)

Some things are still in discussion:

_ Find better names for the enum print_line_t values
_ Change the type of print_trace_line into boolean.

Patches to change that can be sent later.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:39:00 +02:00
Steven Rostedt
777e208d40 ftrace: take advantage of variable length entries
Now that the underlining ring buffer for ftrace now hold variable length
entries, we can take advantage of this by only storing the size of the
actual event into the buffer. This happens to increase the number of
entries in the buffer dramatically.

We can also get rid of the "trace_cont" operation, but I'm keeping that
until we have no more users. Some of the ftrace tracers can now change
their code to adapt to this new feature.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:59 +02:00
Steven Rostedt
3928a8a2d9 ftrace: make work with new ring buffer
This patch ports ftrace over to the new ring buffer.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:57 +02:00
Steven Rostedt
ed56829cb3 ring_buffer: reset buffer page when freeing
Mathieu Desnoyers pointed out that the freeing of the page frame needs
to be reset otherwise we might trigger BUG_ON in the page free code.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:56 +02:00
Steven Rostedt
a7b1374333 ring_buffer: add paranoid check for buffer page
If for some strange reason the buffer_page gets bigger, or the page struct
gets smaller, I want to know this ASAP.  The best way is to not let the
kernel compile.

This patch adds code to test the size of the struct buffer_page against the
page struct and will cause compile issues if the buffer_page ever gets bigger
than the page struct.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:55 +02:00
Steven Rostedt
7a8e76a382 tracing: unified trace buffer
This is a unified tracing buffer that implements a ring buffer that
hopefully everyone will eventually be able to use.

The events recorded into the buffer have the following structure:

  struct ring_buffer_event {
	u32 type:2, len:3, time_delta:27;
	u32 array[];
  };

The minimum size of an event is 8 bytes. All events are 4 byte
aligned inside the buffer.

There are 4 types (all internal use for the ring buffer, only
the data type is exported to the interface users).

 RINGBUF_TYPE_PADDING: this type is used to note extra space at the end
	of a buffer page.

 RINGBUF_TYPE_TIME_EXTENT: This type is used when the time between events
	is greater than the 27 bit delta can hold. We add another
	32 bits, and record that in its own event (8 byte size).

 RINGBUF_TYPE_TIME_STAMP: (Not implemented yet). This will hold data to
	help keep the buffer timestamps in sync.

RINGBUF_TYPE_DATA: The event actually holds user data.

The "len" field is only three bits. Since the data must be
4 byte aligned, this field is shifted left by 2, giving a
max length of 28 bytes. If the data load is greater than 28
bytes, the first array field holds the full length of the
data load and the len field is set to zero.

Example, data size of 7 bytes:

	type = RINGBUF_TYPE_DATA
	len = 2
	time_delta: <time-stamp> - <prev_event-time-stamp>
	array[0..1]: <7 bytes of data> <1 byte empty>

This event is saved in 12 bytes of the buffer.

An event with 82 bytes of data:

	type = RINGBUF_TYPE_DATA
	len = 0
	time_delta: <time-stamp> - <prev_event-time-stamp>
	array[0]: 84 (Note the alignment)
	array[1..14]: <82 bytes of data> <2 bytes empty>

The above event is saved in 92 bytes (if my math is correct).
82 bytes of data, 2 bytes empty, 4 byte header, 4 byte length.

Do not reference the above event struct directly. Use the following
functions to gain access to the event table, since the
ring_buffer_event structure may change in the future.

ring_buffer_event_length(event): get the length of the event.
	This is the size of the memory used to record this
	event, and not the size of the data pay load.

ring_buffer_time_delta(event): get the time delta of the event
	This returns the delta time stamp since the last event.
	Note: Even though this is in the header, there should
		be no reason to access this directly, accept
		for debugging.

ring_buffer_event_data(event): get the data from the event
	This is the function to use to get the actual data
	from the event. Note, it is only a pointer to the
	data inside the buffer. This data must be copied to
	another location otherwise you risk it being written
	over in the buffer.

ring_buffer_lock: A way to lock the entire buffer.
ring_buffer_unlock: unlock the buffer.

ring_buffer_alloc: create a new ring buffer. Can choose between
	overwrite or consumer/producer mode. Overwrite will
	overwrite old data, where as consumer producer will
	throw away new data if the consumer catches up with the
	producer.  The consumer/producer is the default.

ring_buffer_free: free the ring buffer.

ring_buffer_resize: resize the buffer. Changes the size of each cpu
	buffer. Note, it is up to the caller to provide that
	the buffer is not being used while this is happening.
	This requirement may go away but do not count on it.

ring_buffer_lock_reserve: locks the ring buffer and allocates an
	entry on the buffer to write to.
ring_buffer_unlock_commit: unlocks the ring buffer and commits it to
	the buffer.

ring_buffer_write: writes some data into the ring buffer.

ring_buffer_peek: Look at a next item in the cpu buffer.
ring_buffer_consume: get the next item in the cpu buffer and
	consume it. That is, this function increments the head
	pointer.

ring_buffer_read_start: Start an iterator of a cpu buffer.
	For now, this disables the cpu buffer, until you issue
	a finish. This is just because we do not want the iterator
	to be overwritten. This restriction may change in the future.
	But note, this is used for static reading of a buffer which
	is usually done "after" a trace. Live readings would want
	to use the ring_buffer_consume above, which will not
	disable the ring buffer.

ring_buffer_read_finish: Finishes the read iterator and reenables
	the ring buffer.

ring_buffer_iter_peek: Look at the next item in the cpu iterator.
ring_buffer_read: Read the iterator and increment it.
ring_buffer_iter_reset: Reset the iterator to point to the beginning
	of the cpu buffer.
ring_buffer_iter_empty: Returns true if the iterator is at the end
	of the cpu buffer.

ring_buffer_size: returns the size in bytes of each cpu buffer.
	Note, the real size is this times the number of CPUs.

ring_buffer_reset_cpu: Sets the cpu buffer to empty
ring_buffer_reset: sets all cpu buffers to empty

ring_buffer_swap_cpu: swaps a cpu buffer from one buffer with a
	cpu buffer of another buffer. This is handy when you
	want to take a snap shot of a running trace on just one
	cpu. Having a backup buffer, to swap with facilitates this.
	Ftrace max latencies use this.

ring_buffer_empty: Returns true if the ring buffer is empty.
ring_buffer_empty_cpu: Returns true if the cpu buffer is empty.

ring_buffer_record_disable: disable all cpu buffers (read only)
ring_buffer_record_disable_cpu: disable a single cpu buffer (read only)
ring_buffer_record_enable: enable all cpu buffers.
ring_buffer_record_enabl_cpu: enable a single cpu buffer.

ring_buffer_entries: The number of entries in a ring buffer.
ring_buffer_overruns: The number of entries removed due to writing wrap.

ring_buffer_time_stamp: Get the time stamp used by the ring buffer
ring_buffer_normalize_time_stamp: normalize the ring buffer time stamp
	into nanosecs.

I still need to implement the GTOD feature. But we need support from
the cpu frequency infrastructure.  But this can be done at a later
time without affecting the ring buffer interface.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:54 +02:00
Steven Rostedt
5aa60c6073 ftrace: give time for wakeup test to run
It is possible that the testing thread in the ftrace wakeup test does not
run before we stop the trace. This will cause the trace to fail since nothing
will be in the buffers.

This patch adds a small wait in the wakeup test to allow for the woken task
to run and be traced.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:53 +02:00
Frédéric Weisbecker
7c572ac0cf tracing/ftrace: don't consume unhandled entries by boot tracer
When the boot tracer can't handle an entry output, it returns 1.
It should return 0 to relay on other output functions.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:52 +02:00
Frédéric Weisbecker
3ce2b9200d ftrace/fastboot: disable tracers self-tests when boot tracer is selected
The tracing engine resets the ring buffer and the tracers touch it
too during self-tests. These self-tests happen during tracers registering
and work against boot tracing which is logging initcalls.

We have to disable tracing self-tests if the boot-tracer is selected.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:51 +02:00
Frédéric Weisbecker
3bf77af6e1 tracing/ftrace: launch boot tracing after pre-smp initcalls
Launch the boot tracing inside the initcall_debug area. Old printk
have not been removed to keep the old way of initcall tracing for
backward compatibility.

[ mingo@elte.hu: resolved conflicts ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:50 +02:00
Frédéric Weisbecker
1f5c2abbde tracing/ftrace: give an entry on the config for boot tracer
Bring the entry to choose the boot tracer on the kernel config.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:49 +02:00
Frédéric Weisbecker
b5ad384e79 tracing/ftrace: make tracing suitable to run the boot tracer
The tracing engine have now to be init in early_initcall to set the
boot tracer. Only the debugfs settings will be initialized at
fs_initcall time.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:48 +02:00
Frédéric Weisbecker
d13744cd6e tracing/ftrace: add the boot tracer
Add the boot/initcall tracer.

It's primary purpose is to be able to trace the initcalls.

It is intended to be used with scripts/bootgraph.pl after some small
improvements.

Note that it is not active after its init. To avoid tracing (and so
crashing) before the whole tracing engine init, you have to explicitly
call start_boot_trace() after do_pre_smp_initcalls() to enable it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:47 +02:00
Arjan van de Ven
aa5d9151f7 tracing/fastboot: add a script to visualize the kernel boot process / time
When optimizing the kernel boot time, it's very valuable to visualize
what is going on at which time. In addition, with the fastboot asynchronous
initcall level, it's very valuable to see which initcall gets run where
and when.

This patch adds a script to turn a dmesg into a SVG graph (that can be
shown with tools such as InkScape, Gimp or Firefox) and a small change
to the initcall code to print the PID of the thread calling the initcall
(so that the script can work out the parallelism).

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-10-14 10:38:46 +02:00
Lai Jiangshan
1b7ae37c03 markers: bit-field is not thread-safe nor smp-safe
bit-field is not thread-safe nor smp-safe.

struct marker_entry.rcu_pending is not protected by any lock
in rcu-callback free_old_closure().
so we must turn it into a safe type.

detail:

I suppose rcu_pending and ptype are store in struct marker_entry.tmp1

free_old_closure() side:           change ptype side:

                                |  load struct marker_entry.tmp1
--------------------------------|--------------------------------
                                |  change ptype bit in tmp1
load struct marker_entry.tmp1   |
change rcu_pending bit in tmp1  |
store tmp1                      |
--------------------------------|--------------------------------
                                |  store tmp1

now this result equals that free_old_closure() do not change rcu_pending
bit, bug! This bug will cause redundant rcu_barrier_sched() called.
not too harmful.

----- corresponding:

free_old_closure() side:           change ptype side:

load struct marker_entry.tmp1   |
--------------------------------|--------------------------------
                                |  load struct marker_entry.tmp1
change rcu_pending bit in tmp1  |
                                |  change ptype bit in tmp1
                                |  store tmp1
--------------------------------|--------------------------------
store tmp1                      |

now this result equals that change ptype side do not change ptype
bit, bug! this bug cause marker_probe_cb() access to invalid memory.
oops!

see also: http://en.wikipedia.org/wiki/Bit_field

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:45 +02:00
Lai Jiangshan
48043bcdf8 markers: fix unchecked format
when the second, third... probe is registered, its format is
not checked, this patch fixes it.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:42 +02:00
Mathieu Desnoyers
53c8c8fdfd markers: turn marker_synchronize_unregister() into an inline
Turn marker synchronize unregister into a static inline. There is no
reason to keep it as a macro over a static inline.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:40 +02:00
Mathieu Desnoyers
ed86a59071 markers: re-enable fast batch registration
Lai Jiangshan discovered a reentrancy issue with markers and fixed it by
adding synchronize_sched() calls at each registration/unregistraiton.

It works, but it removes the ability to do batch
registration/unregistration and can cause registration of ~100 markers
to take about 30 seconds on a loaded machine (synchronize_sched() is
much slower on such workloads).

This patch implements a version of the fix which won't slow down marker batch
registration/unregistration. It also go back to the original non-synchronized
reg/unreg.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:38 +02:00
Mathieu Desnoyers
5b9261d93e sputrace: use marker_synchronize_unregister()
We need a marker_synchronize_unregister() before the end of exit() to make sure
every probe callers have exited the non preemptible section and thus are not
executing the probe code anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:35 +02:00
Mathieu Desnoyers
91a8d46c47 markers: documentation fix for teardown
Document the need for a marker_synchronize_unregister() before the end of
exit() to make sure every probe callers have exited the non preemptible
section and thus are not executing the probe code anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:33 +02:00
Mathieu Desnoyers
531d297569 markers: probe example, fix teardown
Need a marker_synchronize_unregister() before the end of exit() to make sure
every probe callers have exited the non preemptible section and thus are not
executing the probe code anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:30 +02:00
Mathieu Desnoyers
e2d3b75dbc markers: fix unregister bug and reenter bug, cleanup
Use the new rcu_read_lock_sched/unlock_sched() in marker code around the call
site instead of preempt_disable/enable(). It helps reviewing the code more
easily.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:28 +02:00
Mathieu Desnoyers
e98d0eabef markers: marker_synchronize_unregister()
Create marker_synchronize_unregister() which must be called before the end of
exit() to make sure every probe callers have exited the non preemptible section
and thus are not executing the probe code anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:26 +02:00
Mathieu Desnoyers
9a1e9693f5 tracepoints: fix reentrancy
The tracepoints had the same problem markers did have wrt reentrancy. Apply a
similar fix using a rcu_barrier after each tracepoint mutex lock.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:23 +02:00
Mathieu Desnoyers
ca2db6cf30 tracepoints: use rcu sched
Make tracepoints use rcu sched. (cleanup)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:21 +02:00
Lai Jiangshan
d74185ed27 markers: fix unregister bug and reenter bug
unregister bug:

codes using makers are typically calling marker_probe_unregister()
and then destroying the data that marker_probe_func needs(or
unloading this module). This is bug when the corresponding
marker_probe_func is still running(on other cpus),
it is using the destroying/ed data.

we should call synchronize_sched() after marker_update_probes().

reenter bug:

marker_probe_register(), marker_probe_unregister() and
marker_probe_unregister_private_data() are not reentrant safe
functions. these 3 functions release markers_mutex and then
require it again and do "entry->oldptr = old; ...", but entry->oldptr
maybe is using now for these 3 functions may reenter when markers_mutex
is released.

we use synchronize_sched() instead of call_rcu_sched() to fix
this bug. actually we can do:
"
if (entry->rcu_pending)
		rcu_barrier_sched();
"
after require markers_mutex again. but synchronize_sched()
is better and simpler. For these 3 functions are not critical path.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:19 +02:00
Frédéric Weisbecker
ac2b86fdef x86/ftrace: use uaccess in atomic context
With latest -tip I get this bug:

[   49.439988] in_atomic():0, irqs_disabled():1
[   49.440118] INFO: lockdep is turned off.
[   49.440118] Pid: 2814, comm: modprobe Tainted: G        W 2.6.27-rc7 #4
[   49.440118]  [<c01215e1>] __might_sleep+0xe1/0x120
[   49.440118]  [<c01148ea>] ftrace_modify_code+0x2a/0xd0
[   49.440118]  [<c01148a2>] ? ftrace_test_p6nop+0x0/0xa
[   49.440118]  [<c016e80e>] __ftrace_update_code+0xfe/0x2f0
[   49.440118]  [<c01148a2>] ? ftrace_test_p6nop+0x0/0xa
[   49.440118]  [<c016f190>] ftrace_convert_nops+0x50/0x80
[   49.440118]  [<c016f1d6>] ftrace_init_module+0x16/0x20
[   49.440118]  [<c015498b>] load_module+0x185b/0x1d30
[   49.440118]  [<c01767a0>] ? find_get_page+0x0/0xf0
[   49.440118]  [<c02463c0>] ? sprintf+0x0/0x30
[   49.440118]  [<c034e012>] ? mutex_lock_interruptible_nested+0x1f2/0x350
[   49.440118]  [<c0154eb3>] sys_init_module+0x53/0x1b0
[   49.440118]  [<c0352340>] ? do_page_fault+0x0/0x740
[   49.440118]  [<c0104012>] syscall_call+0x7/0xb
[   49.440118]  =======================

It is because ftrace_modify_code() calls copy_to_user and
copy_from_user.
These functions have been inserted after guessing that there
couldn't be any race condition but copy_[to/from]_user might
sleep and __ftrace_update_code is called with local_irq_saved.

These function have been inserted since this commit:
d5e92e8978fd2574e415dc2792c5eb592978243d:
"ftrace: x86 use copy from user function"

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:16 +02:00
Harvey Harrison
37a52f5ef1 x86: suppress trivial sparse signedness warnings
Could just as easily change the three casts to cast to the correct
type...this patch changes the type of ftrace_nop instead.

Supresses sparse warnings:

 arch/x86/kernel/ftrace.c:157:14: warning: incorrect type in assignment (different signedness)
 arch/x86/kernel/ftrace.c:157:14:    expected long *static [toplevel] ftrace_nop
 arch/x86/kernel/ftrace.c:157:14:    got unsigned long *<noident>
 arch/x86/kernel/ftrace.c:161:14: warning: incorrect type in assignment (different signedness)
 arch/x86/kernel/ftrace.c:161:14:    expected long *static [toplevel] ftrace_nop
 arch/x86/kernel/ftrace.c:161:14:    got unsigned long *<noident>
 arch/x86/kernel/ftrace.c:165:14: warning: incorrect type in assignment (different signedness)
 arch/x86/kernel/ftrace.c:165:14:    expected long *static [toplevel] ftrace_nop
 arch/x86/kernel/ftrace.c:165:14:    got unsigned long *<noident>

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:14 +02:00
Steven Rostedt
05736a427f ftrace: warn on failure to disable mcount callers
With the recent updates to ftrace, there should not be any failures when
modifying the code. If there is, then we need to warn about it.

This patch has a cleaned up version of the code that I used to discover
that the weak symbols were causing failures.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:11 +02:00
Frédéric Weisbecker
43a15386c4 tracing/ftrace: replace none tracer by nop tracer
Replace "none" tracer by the recently created "nop" tracer.
Both are pretty similar except that nop accepts TRACE_PRINT
or TRACE_SPECIAL entries.

And as a consequence, changing the size of the ring buffer now
requires that tracing has already been disabled.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:09 +02:00
Frédéric Weisbecker
2a3a4f669d tracing/ftrace: tracing engine depends on Nop Tracer
Now that the nop tracer is used as the default tracer by
replacing the "none" tracer, tracing engine depends on it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:06 +02:00
Frédéric Weisbecker
35cb5ed012 tracing/ftrace: make nop tracer reset previous entries
If nop tracer is selected, some old entries from the previous tracer
could still be enqueued. Tracing have to be reset.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:04 +02:00
Steven Noonan
8925b394ec trace: remove pointless ifdefs
The functions are already 'extern' anyway, so there's no problem
with linkage. Removing these ifdefs also helps find any potential
compiler errors.

Suggested by Andrew Morton.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:38:01 +02:00
Steven Noonan
71c67d58b5 ftrace: mcount_addr defined but not used
When CONFIG_DYNAMIC_FTRACE isn't used, neither is mcount_addr. This
patch eliminates that warning.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:58 +02:00
Steven Noonan
fb1b6d8b51 ftrace: add nop tracer
A no-op tracer which can serve two purposes:

 1. A template for development of a new tracer.
 2. A convenient way to see ftrace_printk() calls without
    an irrelevant trace making the output messy.

[ mingo@elte.hu: resolved conflicts ]
Signed-off-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:43 +02:00
Pekka Paalanen
5bf9a1ee35 ftrace: inject markers via trace_marker file
Allow a user to inject a marker (TRACE_PRINT entry) into the trace ring
buffer. The related file operations are derived from code by Frédéric
Weisbecker <fweisbec@gmail.com>.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:20 +02:00
Pekka Paalanen
4427414170 mmiotrace: remove left-over marker cruft
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:17 +02:00
Pekka Paalanen
fc5e27ae4b mmiotrace: handle TRACE_PRINT entries
Also make trace_seq_print_cont() non-static, and add a newline if the
seq buffer can't hold all data.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:14 +02:00
Pekka Paalanen
9e57fb35d7 x86 mmiotrace: implement mmiotrace_printk()
Offer mmiotrace users a function to inject markers from inside the kernel.
This depends on the trace_vprintk() patch.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:11 +02:00
Pekka Paalanen
801fe40001 ftrace: add trace_vprintk()
trace_vprintk() for easier implementation of tracer specific *_printk
functions. Add check check for no_tracer, and implement
__ftrace_printk() as a wrapper.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:07 +02:00
Pekka Paalanen
45dcd8b8a8 ftrace: move mmiotrace functions out of trace.c
Moves the mmiotrace specific functions from trace.c to
trace_mmiotrace.c. Functions trace_wake_up(), tracing_get_trace_entry(),
and tracing_generic_entry_update() are therefore made available outside
trace.c.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:04 +02:00
Pekka Paalanen
bbe5c7830c x86 mmiotrace: fix a rare memory leak
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:37:01 +02:00
Steven Rostedt
644f991d4b ftrace: fix unlocking of hash
This must be brown paper bag week for Steven Rostedt!

While working on ftrace for PPC, I discovered that the hash locking done
when CONFIG_FTRACE_MCOUNT_RECORD is not set, is totally incorrect.

With a cut and paste error, I had the hash lock macro to lock for both
hash_lock _and_ hash_unlock!

This bug did not affect x86 since this bug was introduced when
CONFIG_FTRACE_MCOUNT_RECORD was added to x86.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:36:58 +02:00
Steven Rostedt
c0719e5a4b ftrace: use ftrace_release for all dynamic ftrace functions
ftrace_release is necessary for all uses of dynamic ftrace and not just
the archs that have CONFIG_FTRACE_MCOUNT_RECORD defined.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:36:55 +02:00
Ingo Molnar
d3ee6d9928 ftrace: make it depend on DEBUG_KERNEL
make most of the tracers depend on DEBUG_KERNEL - that's their intended
purpose. (most distributions have DEBUG_KERNEL enabled anyway so this is
not a practical limitation - but it simplifies the tracing menu in the
normal case)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14 10:36:51 +02:00