Commit Graph

1252 Commits

Author SHA1 Message Date
Li Zefan
c16de8fd7a tracing: fix F_printk() typos
I found some typos in F_printk(), so I wrote compile-time check
for it, and triggered some compile errors and warnings.

I've fixed them on x86_32, but I have no x86_64 in my hand, so there
may still be some compile warnings on 64bits.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AADF60B.5070407@cn.fujitsu.com>

[ tested on x86_64, and works fine ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-14 11:40:59 -04:00
Steven Rostedt
ec827c7ece tracing: add static to generated TRACE_EVENT functions
Some of the generated functions used in the TRACE_EVENT macros are
not declared static, but they are not global.

Discovered by sparse.

Reported-by: Jaswinder Singh Rajput <jaswinder@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-14 10:50:23 -04:00
Steven Rostedt
08a4081617 ring-buffer: typecast cmpxchg to fix PowerPC warning
The cmpxchg used by PowerPC does the following:

  ({									 \
     __typeof__(*(ptr)) _o_ = (o);					 \
     __typeof__(*(ptr)) _n_ = (n);					 \
     (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,		 \
				    (unsigned long)_n_, sizeof(*(ptr))); \
  })

This does a type check of *ptr to both o and n.

Unfortunately, the code in ring-buffer.c assigns longs to pointers
and pointers to longs and causes a warning on PowerPC:

ring_buffer.c: In function 'rb_head_page_set':
ring_buffer.c:704: warning: initialization makes pointer from integer without a cast
ring_buffer.c:704: warning: initialization makes pointer from integer without a cast
ring_buffer.c: In function 'rb_head_page_replace':
ring_buffer.c:797: warning: initialization makes integer from pointer without a cast

This patch adds the typecasts inside cmpxchg to annotate that a long is
being cast to a pointer and a pointer is being casted to a long and this
removes the PowerPC warnings.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-14 09:41:57 -04:00
Steven Rostedt
60ba770227 tracing: add filter event logic to special, mmiotrace and boot tracers
Now that the pluging tracers use macros to create the structures and
automate the exporting of their formats to the format files, they also
automatically get a filter file.

This patch adds the code to implement the filter logic in the trace
recordings.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 23:34:04 -04:00
Steven Rostedt
51df5fcbc1 tracing: remove trace_event_types.h
The macros in trace_entries.h have made the code in trace_event_types.h
obsolete. The file is no longer used, so this patch removes it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 23:08:11 -04:00
Steven Rostedt
4e5292ea1a tracing: use the new trace_entries.h to create format files
This patch changes the way the format files in

  debugfs/tracing/events/ftrace/*/format

are created. It uses the new trace_entries.h file to automate the
creation of the format files to ensure that they are always in sync
with the actual structures. This is the same methodology used to
create the format files for the TRACE_EVENT macro.

This also updates the filter creation that was built on the creation
of the format files.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 23:08:10 -04:00
Steven Rostedt
d73150943c tracing: show details of structures within the ftrace structures
Some of the internal ftrace structures use structures within. The
output of a field saying it is just a structure is useless for a format
file. A binary reader of the ring buffer needs to know more about
how the fields are broken up.

This patch adds to the ftrace structure macros new fields to
describe the structures inside a structure.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 23:08:07 -04:00
Steven Rostedt
0a1c49db8d tracing: use macros to create internal ftrace entry ring buffer structures
The entries used by ftrace internal code (plugins) currently have their
formats manually exported to userspace. That is, the format files in
debugfs/tracing/events/ftrace/*/format are currently created by hand.
This is a maintenance nightmare, and can easily become out of sync
with what is actually shown.

This patch uses the methodology of the TRACE_EVENT macros to build
the structures so that their formats can be automated and this
will keep the structures in sync with what users can see.

This patch only changes the way the structures are created. Further
patches will build off of this to automate the format files.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 23:08:06 -04:00
Li Zefan
558e6547e4 tracing/profile: fix profile_disable vs module_unload
If the correspoding module is unloaded before ftrace_profile_disable()
is called, event->profile_disable() won't be called, which can
cause oops:

  # insmod trace-events-sample.ko
  # perf record -f -a -e sample:foo_bar sleep 3 &
  # sleep 1
  # rmmod trace_events_sample
  # insmod trace-events-sample.ko
  OOPS!

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A9214E3.2070807@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 22:28:38 -04:00
Carsten Emde
b5130b1e7d tracing: do not update tracing_max_latency when tracer is stopped
The state of the function pair tracing_stop()/tracing_start() is
correctly considered when tracer data are updated. However, the global
and externally accessible variable tracing_max_latency is always updated
- even when tracing is stopped.

The update should only occur, if tracing was not stopped.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 21:45:17 -04:00
Carsten Emde
41dfba4367 tracing: remove unused local variables in tracer probe functions
When the nsecs_to_usecs() conversion in probe_wakeup_sched_switch() and
check_critical_timing() was moved to a later stage in order to avoid
unnecessary computing, it was overlooked to remove the original
variables, assignments and comments..

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-12 21:44:13 -04:00
jolsa@redhat.com
689fd8b65d tracing: trace parser support for function and graph
Convert the writing to 'set_graph_function', 'set_ftrace_filter'
and 'set_ftrace_notrace' to use the generic trace_parser
'trace_get_user' function.

Removed FTRACE_ITER_CONT flag, since it's not needed after this change.

Minor fix in set_graph_function display - g_show function.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1252682969-3366-4-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-11 15:20:18 -04:00
jolsa@redhat.com
489663644c tracing: trace parser support for set_event
Convert the parsing of the file 'set_event' to use the generic
trace_praser 'trace_get_user' function.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1252682969-3366-3-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-11 14:47:11 -04:00
jolsa@redhat.com
b63f39ea50 tracing: create generic trace parser
Create a "trace_parser" that can parse the user space input for
separate words.

struct trace_parser is the descriptor.

Generic "trace_get_user" function that can be a helper to read multiple
words passed in by user space.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1252682969-3366-2-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-11 14:46:55 -04:00
Steven Rostedt
f81c972d27 tracing: consolidate code between trace_output.c and trace_function_graph.c
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: Steven Rostedt <rostedt@goodmis.org>
2009-09-11 14:24:13 -04:00
Steven Rostedt
637e7e8641 tracing: add lock depth to entries
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: Steven Rostedt <rostedt@goodmis.org>
2009-09-11 13:55:35 -04:00
Steven Rostedt
48659d3119 tracing: move tgid out of generic entry and into userstack
The userstack trace required the recording of the tgid entry.
Unfortunately, it was added to the generic entry where it wasted
4 bytes of every entry and was only used by one entry.

This patch moves it out of the generic field and moves it into the
only user (userstack_entry).

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-11 11:36:23 -04:00
Steven Rostedt
49ff590390 tracing: add latency format to function_graph tracer
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: Steven Rostedt <rostedt@goodmis.org>
2009-09-11 10:59:49 -04:00
Li Zefan
197e2eabc9 tracing: move PRED macros to trace_events_filter.c
Move DEFINE_COMPARISON_PRED() and DEFINE_EQUALITY_PRED()
  to kernel/trace/trace_events_filter.c

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AA8579B.4020706@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-09 23:54:11 -04:00
Li Zefan
a5921c6c37 tracing: remove stats from struct tracer
Remove unused field @stats from struct tracer.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AA8579B.4020706@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-09 23:54:09 -04:00
Li Zefan
bd9cfca9cb tracing: format clean ups
Fix white-space formatting.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AA8579B.4020706@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-09 23:54:07 -04:00
Li Zefan
e0ab5f2dae tracing: remove dead code
Removes unreachable code.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AA8579B.4020706@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-09 23:54:06 -04:00
Steven Rostedt
478142c39c tracing: do not grab lock in wakeup latency function tracing
The wakeup tracer, when enabled, has its own function tracer.
It only traces the functions on the CPU where the task it is following
is on. If a task is woken on one CPU but then migrates to another CPU
before it wakes up, the latency tracer will then start tracing functions
on the other CPU.

To find which CPU the task is on, the wakeup function tracer performs
a task_cpu(wakeup_task). But to make sure the task does not disappear
it grabs the wakeup_lock, which is also taken when the task wakes up.
By taking this lock, the function tracer does not need to worry about
the task being freed as it checks its cpu.

Jan Blunck found a problem with this approach on his 32 CPU box. When
a task is being traced by the wakeup tracer, all functions take this
lock. That means that on all 32 CPUs, each function call is taking
this one lock to see if the task is on that CPU. This lock has just
serialized all functions on all 32 CPUs. Needless to say, this caused
major issues on that box. It would even lockup.

This patch changes the wakeup latency to insert a probe on the migrate task
tracepoint. When a task changes its CPU that it will run on, the
probe will take note. Now the wakeup function tracer no longer needs
to take the lock. It only compares the current CPU with a variable that
holds the current CPU the task is on. We don't worry about races since
it is OK to add or miss a function trace.

Reported-by: Jan Blunck <jblunck@suse.de>
Tested-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-09 23:54:04 -04:00
Robert Richter
d8eeb2d3b2 ring-buffer: consolidate interface of rb_buffer_peek()
rb_buffer_peek() operates with struct ring_buffer_per_cpu *cpu_buffer
only. Thus, instead of passing variables buffer and cpu it is better
to use cpu_buffer directly. This also reduces the risk of races since
cpu_buffer is not calculated twice.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1249045084-3028-1-git-send-email-robert.richter@amd.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-09 23:54:02 -04:00
Ingo Molnar
d28daf923a Merge branch 'tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/core 2009-09-06 06:27:40 +02:00
Ingo Molnar
ed011b22ce Merge commit 'v2.6.31-rc9' into tracing/core
Merge reason: move from -rc5 to -rc9.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-06 06:11:42 +02:00
Steven Rostedt
85bac32c4a ring-buffer: only enable ring_buffer_swap_cpu when needed
Since the ability to swap the cpu buffers adds a small overhead to
the recording of a trace, we only want to add it when needed.

Only the irqsoff and preemptoff tracers use this feature, and both are
not recommended for production kernels. This patch disables its use
when neither irqsoff nor preemptoff is configured.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 19:42:22 -04:00
Steven Rostedt
62f0b3eb5c ring-buffer: check for swapped buffers in start of committing
Because the irqsoff tracer can swap an internal CPU buffer, it is possible
that a swap happens between the start of the write and before the committing
bit is set (the committing bit will disable swapping).

This patch adds a check for this and will fail the write if it detects it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 19:38:42 -04:00
Steven Rostedt
e8165dbb03 tracing: report error in trace if we fail to swap latency buffer
The irqsoff tracer will fail to swap the cpu buffer with the max
buffer if it preempts a commit. Instead of ignoring this, this patch
makes the tracer report it if the last max latency failed due to preempting
a current commit.

The output of the latency tracer will look like this:

 # tracer: irqsoff
 #
 # irqsoff latency trace v1.1.5 on 2.6.31-rc5
 # --------------------------------------------------------------------
 # latency: 112 us, #1/1, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4)
 #    -----------------
 #    | task: -4281 (uid:0 nice:0 policy:0 rt_prio:0)
 #    -----------------
 #  => started at: save_args
 #  => ended at:   __do_softirq
 #
 #
 #                  _------=> CPU#
 #                 / _-----=> irqs-off
 #                | / _----=> need-resched
 #                || / _---=> hardirq/softirq
 #                ||| / _--=> preempt-depth
 #                |||| /
 #                |||||     delay
 #  cmd     pid   ||||| time  |   caller
 #     \   /      |||||   \   |   /
    bash-4281    1d.s6  265us : update_max_tr_single: Failed to swap buffers due to commit in progress

Note the latency time and the functions that disabled the irqs or preemption
will still be listed.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 19:22:41 -04:00
Steven Rostedt
659372d3e4 tracing: add trace_array_printk for internal tracers to use
This patch adds a trace_array_printk to allow a tracer to use the
trace_printk on its own trace array.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 19:13:53 -04:00
Steven Rostedt
e77405ad80 tracing: pass around ring buffer instead of tracer
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: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 18:59:39 -04:00
Steven Rostedt
f633903af2 tracing: make tracing_reset safe for external use
Reseting the trace buffer without first disabling the buffer and
waiting for any writers to complete, can corrupt the ring buffer.

This patch makes the external version of tracing_reset safe from
corruption by disabling the ring buffer and calling synchronize_sched.

This version can no longer be called from interrupt context. But all those
callers have been removed.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 18:46:51 -04:00
Steven Rostedt
2f26ebd549 tracing: use timestamp to determine start of latency traces
Currently the latency tracers reset the ring buffer. Unfortunately
if a commit is in process (due to a trace event), this can corrupt
the ring buffer. When this happens, the ring buffer will detect
the corruption and then permanently disable the ring buffer.

The bug does not crash the system, but it does prevent further tracing
after the bug is hit.

Instead of reseting the trace buffers, the timestamp of the start of
the trace is used instead. The buffers will still contain the previous
data, but the output will not count any data that is before the
timestamp of the trace.

Note, this only affects the static trace output (trace) and not the
runtime trace output (trace_pipe). The runtime trace output does not
make sense for the latency tracers anyway.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 18:44:22 -04:00
Li Zefan
c58b43218c tracing/filters: Defer pred allocation, fix memory leak
The predicates of an event and their filter structure are allocated
when we create an event filter for the first time.

These objects must be created once but each time we come with a new
filter, we overwrite such pre-existing allocation, if any.

Thus, this patch checks if the filter has already been allocated
before going ahead.

Spotted-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4A9CB1BA.3060402@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-04 23:22:33 +02:00
Steven Rostedt
76f0d07376 tracing: remove users of tracing_reset
The function tracing_reset is deprecated for outside use of trace.c.

The new function to reset the the buffers is tracing_reset_online_cpus.

The reason for this is that resetting the buffers while the event
trace points are active can corrupt the buffers, because they may
be writing at the time of reset. The tracing_reset_online_cpus disables
writes and waits for current writers to finish.

This patch replaces all users of tracing_reset except for the latency
tracers. Those changes require more work and will be removed in the
following patches.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 12:12:39 -04:00
Steven Rostedt
621968cdb2 tracing: disable buffers and synchronize_sched before resetting
Resetting the ring buffers while traces are happening can corrupt
the ring buffer and disable it (no kernel crash to worry about).

The safest thing to do is disable the ring buffers, call synchronize_sched()
to wait for all current writers to finish and then reset the buffer.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 12:02:35 -04:00
Steven Rostedt
b8de7bd168 tracing: disable update max tracer while reading trace
When reading the tracer from the trace file, updating the max latency
may corrupt the output. This patch disables the tracing of the max
latency while reading the trace file.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:52:24 -04:00
Steven Rostedt
8248ac052d tracing: print out start and stop in latency traces
During development of the tracer, we would copy information from
the live tracer to the max tracer with one memcpy. Since then we
added a generic ring buffer and we handle the copies differently now.
Unfortunately, we never copied the critical section information, and
we lost the output:

 #  => started at: kmem_cache_alloc
 #  => ended at:   kmem_cache_alloc

This patch adds back the critical start and end copying as well as
removes the unused "trace_idx" and "overrun" fields of the
trace_array_cpu structure.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:48:12 -04:00
Steven Rostedt
077c5407cd ring-buffer: disable all cpu buffers when one finds a problem
Currently the way RB_WARN_ON works, is to disable either the current
CPU buffer or all CPU buffers, depending on whether a ring_buffer or
ring_buffer_per_cpu struct was passed into the macro.

Most users of the RB_WARN_ON pass in the CPU buffer, so only the one
CPU buffer gets disabled but the rest are still active. This may
confuse users even though a warning is sent to the console.

This patch changes the macro to disable the entire buffer even if
the CPU buffer is passed in.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:46:25 -04:00
Steven Rostedt
a1863c212b ring-buffer: do not count discarded events
The latency tracers report the number of items in the trace buffer.
This uses the ring buffer data to calculate this. Because discarded
events are also counted, the numbers do not match the number of items
that are printed. The ring buffer also adds a "padding" item to the
end of each buffer page which also gets counted as a discarded item.

This patch decrements the counter to the page entries on a discard.
This allows us to ignore discarded entries while reading the buffer.

Decrementing the counter is still safe since it can only happen while
the committing flag is still set.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:43:36 -04:00
Steven Rostedt
dc892f7339 ring-buffer: remove ring_buffer_event_discard
The function ring_buffer_event_discard can be used on any item in the
ring buffer, even after the item was committed. This function provides
no safety nets and is very race prone.

An item may be safely removed from the ring buffer before it is committed
with the ring_buffer_discard_commit.

Since there are currently no users of this function, and because this
function is racey and error prone, this patch removes it altogether.

Note, removing this function also allows the counters to ignore
all discarded events (patches will follow).

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:36:19 -04:00
Steven Rostedt
7e9391cfed ring-buffer: fix ring_buffer_read crossing pages
When the ring buffer uses an iterator (static read mode, not on the
fly reading), when it crosses a page boundery, it will skip the first
entry on the next page. The reason is that the last entry of a page
is usually padding if the page is not full. The padding will not be
returned to the user.

The problem arises on ring_buffer_read because it also increments the
iterator. Because both the read and peek use the same rb_iter_peek,
the rb_iter_peak will return the padding but also increment to the next
item. This is because the ring_buffer_peek will not incerment it
itself.

The ring_buffer_read will increment it again and then call rb_iter_peek
again to get the next item. But that will be the second item, not the
first one on the page.

The reason this never showed up before, is because the ftrace utility
always calls ring_buffer_peek first and only uses ring_buffer_read
to increment to the next item. The ring_buffer_peek will always keep
the pointer to a valid item and not padding. This just hid the bug.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:28:39 -04:00
Steven Rostedt
1b959e18c4 ring-buffer: remove unnecessary cpu_relax
The loops in the ring buffer that use cpu_relax are not dependent on
other CPUs. They simply came across some padding in the ring buffer and
are skipping over them. It is a normal loop and does not require a
cpu_relax.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:25:27 -04:00
Steven Rostedt
98277991a9 ring-buffer: do not swap buffers during a commit
If a commit is taking place on a CPU ring buffer, do not allow it to
be swapped. Return -EBUSY when this is detected instead.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:22:47 -04:00
Steven Rostedt
41b6a95d69 ring-buffer: do not reset while in a commit
The callers of reset must ensure that no commit can be taking place
at the time of the reset. If it does then we may corrupt the ring buffer.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 11:15:08 -04:00
Li Zefan
8e254c1d18 tracing/filters: Defer pred allocation
init_preds() allocates about 5392 bytes of memory (on x86_32) for
a TRACE_EVENT. With my config, at system boot total memory occupied
is:

	5392 * (642 + 15) == 3459KB

642 == cat available_events | wc -l
15 == number of dirs in events/ftrace

That's quite a lot, so we'd better defer memory allocation util
it's needed, that's when filter is used.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4A9B8EA5.6020700@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-31 10:58:08 +02:00
Ingo Molnar
73222acf96 Merge branch 'tip/tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/core 2009-08-29 13:06:05 +02:00
Steven Rostedt
5d4a9dba2d tracing: only show tracing_max_latency when latency tracer configured
The tracing_max_latency file should only be present when one of the
latency tracers ({preempt|irqs}off, wakeup*) are enabled.

This patch also removes tracing_thresh when latency tracers are not
enabled, as well as compiles out code that is only used for latency
tracers.

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-27 16:58:05 -04:00
Steven Rostedt
c0729be99c tracing: remove legacy select of MARKERS by context switch tracing
The context switch tracer was made before tracepoints were mature, and
the original version used markers. This is no longer true and this
patch removes the select.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-27 16:58:03 -04:00
Jason Baron
57421dbbdc tracing: Convert event tracing code to use NR_syscalls
Convert the syscalls event tracing code to use NR_syscalls, instead of
FTRACE_SYSCALL_MAX. NR_syscalls is standard accross most arches, and
reduces code confusion/complexity.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Josh Stone <jistone@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anwin <hpa@zytor.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
LKML-Reference: <9b4f1a84ecae57cc6599412772efa36f0d2b815b.1251146513.git.jbaron@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26 21:30:02 +02:00