linux-toradex.git/include/linux/tracepoint.h, branch v2.6.34

rcu: Fix tracepoints & lockdep false positive

2010-03-16T09:10:40+00:00

tracepoint.h uses rcu_dereference(), which triggers this warning:

[    0.701161] ===================================================
[    0.702211] [ INFO: suspicious rcu_dereference_check() usage. ]
[    0.702716] ---------------------------------------------------
[    0.703203] include/trace/events/workqueue.h:68 invoked rcu_dereference_check() without protection!
[    0.703971] [ 0.703990] other info that might help us debug this:
[    0.703993]
[    0.705590]
[    0.705604] rcu_scheduler_active = 1, debug_locks = 0
[    0.706712] 1 lock held by swapper/1:
[    0.707229]  #0:  (cpu_add_remove_lock){+.+.+.}, at: [] cpu_maps_update_begin+0x14/0x20
[    0.710097]
[    0.710106] stack backtrace:
[    0.712602] Pid: 1, comm: swapper Not tainted 2.6.34-rc1-tip-01613-g72662bb #168
[    0.713231] Call Trace:
[    0.713997]  [] lockdep_rcu_dereference+0x9d/0xb0
[    0.714746]  [] create_workqueue_thread+0x107/0x110
[    0.715353]  [] ? worker_thread+0x0/0x340
[    0.715845]  [] __create_workqueue_key+0x138/0x240
[    0.716427]  [] ? cpu_maps_update_done+0x12/0x20
[    0.717012]  [] init_workqueues+0x6f/0x80
[    0.717530]  [] kernel_init+0x102/0x1f0
[    0.717570]  [] ? kernel_init+0x0/0x1f0
[    0.718944]  [] kernel_thread_helper+0x6/0x10

Signed-off-by: Lai Jiangshan 
Cc: Paul E. McKenney 
Cc: Mathieu Desnoyers 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
LKML-Reference: <4B9F48AD.4000404@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

events: Rename TRACE_EVENT_TEMPLATE() to DECLARE_EVENT_CLASS()

2009-11-26T08:04:55+00:00

It is not quite obvious at first sight what TRACE_EVENT_TEMPLATE
does: does it define an event as well beyond defining a template?

To clarify this, rename it to DECLARE_EVENT_CLASS, which follows
the various 'DECLARE_*()' idioms we already have in the kernel:

  DECLARE_EVENT_CLASS(class)

    DEFINE_EVENT(class, event1)
    DEFINE_EVENT(class, event2)
    DEFINE_EVENT(class, event3)

To complete this logic we should also rename TRACE_EVENT() to:

  DEFINE_SINGLE_EVENT(single_event)

... but in a more quiet moment of the kernel cycle.

Cc: Pekka Enberg 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
LKML-Reference: <4B0E286A.2000405@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

tracing: Create new DEFINE_EVENT_PRINT

2009-11-24T23:23:53+00:00

After creating the TRACE_EVENT_TEMPLATE I started to look at other
trace points to see what duplication was made. I noticed that there
are several trace points where they are almost identical except for
the name and the output format. Since TRACE_EVENT_TEMPLATE was successful
in bringing down the size of trace events, I added a DEFINE_EVENT_PRINT.

DEFINE_EVENT_PRINT is used just like DEFINE_EVENT is. That is, the
DEFINE_EVENT_PRINT also uses a TRACE_EVENT_TEMPLATE, but it allows the
developer to overwrite the print format. If there are two or more
TRACE_EVENTS that are identical except for the name and print, then
they can be converted to use a TRACE_EVENT_TEMPLATE. Since the
TRACE_EVENT_TEMPLATE already does the print output, the first trace event
would have its print format held in the TRACE_EVENT_TEMPLATE and
be defined with a DEFINE_EVENT. The rest will use the DEFINE_EVENT_PRINT
and override the print format.

Converting the sched trace points to both DEFINE_EVENT and
DEFINE_EVENT_PRINT. Five were converted to DEFINE_EVENT and two were
converted to DEFINE_EVENT_PRINT.

I was able to get the following:

$ size kernel/sched.o-*
   text	   data	    bss	    dec	    hex	filename
  79299	   6776	   2520	  88595	  15a13	kernel/sched.o-notrace
 101941	  11896	   2584	 116421	  1c6c5	kernel/sched.o-templ
 104779	  11896	   2584	 119259	  1d1db	kernel/sched.o-trace

sched.o-notrace is the scheduler compiled with no trace points.
sched.o-templ is with the use of DEFINE_EVENT and DEFINE_EVENT_PRINT
sched.o-trace is the current trace events.

Signed-off-by: Steven Rostedt

tracing: Create new TRACE_EVENT_TEMPLATE

2009-11-24T22:52:11+00:00

There are some places in the kernel that define several tracepoints and
they are all identical besides the name. The code to enable, disable and
record is created for every trace point even if most of the code is
identical.

This patch adds TRACE_EVENT_TEMPLATE that lets the developer create
a template TRACE_EVENT and create trace points with DEFINE_EVENT, which
is based off of a given template. Each trace point used by this
will share most of the code, and bring down the size of the kernel
when there are several duplicate events.

Usage is:

TRACE_EVENT_TEMPLATE(name, proto, args, tstruct, assign, print);

Which would be the same as defining a normal TRACE_EVENT.

To create the trace events that the trace points will use:

DEFINE_EVENT(template, name, proto, args) is done. The template
is the name of the TRACE_EVENT_TEMPLATE to use. The name is the
name of the trace point. The parameters proto and args must be the same
as the proto and args of the template. If they are not the same,
then a compile error will result. I tried hard removing this duplication
but the C preprocessor is not powerful enough (or my CPP magic
experience points is not at a high enough level) to not need them.

A lot of trace events are coming in with new XFS development. Most of
the trace points are identical except for the name. The following shows
the advantage of having TRACE_EVENT_TEMPLATE:

$ size fs/xfs/xfs.o.*
    text          data     bss     dec     hex filename
  452114          2788    3520  458422   6feb6 fs/xfs/xfs.o.old
  638482         38116    3744  680342   a6196 fs/xfs/xfs.o.template
  996954         38116    4480 1039550   fdcbe fs/xfs/xfs.o.trace

xfs.o.old is without any tracepoints.
xfs.o.template uses the new TRACE_EVENT_TEMPLATE.
xfs.o.trace uses the current TRACE_EVENT macros.

Requested-by: Christoph Hellwig 
Signed-off-by: Steven Rostedt

tracing: Fix a comment and a trivial format issue in tracepoint.h

2009-09-22T21:14:58+00:00

Fix the tracepoint documentation path in tracepoints headers and
a misaligned tabulation.

Signed-off-by: Li Hong 
Cc: Steven Rostedt 
Cc: Ingo Molnar 
LKML-Reference: <3a3680030909220300h7cf18849q4d4702b9d4feaa67@mail.gmail.com>
Signed-off-by: Frederic Weisbecker

Merge branch 'tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/core

2009-08-26T06:29:02+00:00

Conflicts:
	include/linux/tracepoint.h

Signed-off-by: Ingo Molnar

tracing: add comments to explain TRACE_EVENT out of protection

2009-08-26T04:32:37+00:00

The commit:
  commit 5ac35daa9343936038a3c9c4f4d6d3fe6a2a7bd8
  Author: Xiao Guangrong 
  tracing/events: fix the include file dependencies

Moved the TRACE_EVENT out of the ifdef protection of tracepoints.h
but uses the define of TRACE_EVENT itself as protection. This patch
adds comments to explain why.

Signed-off-by: Steven Rostedt

tracing/events: fix the include file dependencies

2009-08-26T04:32:09+00:00

The TRACE_EVENT depends on the include/linux/tracepoint.h first
and include/trace/ftrace.h later, if we include the ftrace.h early,
a building error will occur.

Both define TRACE_EVENT in trace_a.h and trace_b.h, if we include
those in .c file, like this:

#define CREATE_TRACE_POINTS
include 
include 

The above will not work, because the TRACE_EVENT was re-defined by
the previous .h file.

Reported-by: Wei Yongjun 
Signed-off-by: Xiao Guangrong 
LKML-Reference: <4A937F5E.3020802@cn.fujitsu.com>
Signed-off-by: Steven Rostedt

tracing: Move tracepoint callbacks from declaration to definition

2009-08-25T22:36:41+00:00

It's not strictly correct for the tracepoint reg/unreg callbacks to
occur when a client is hooking up, because the actual tracepoint may not
be present yet.  This happens to be fine for syscall, since that's in
the core kernel, but it would cause problems for tracepoints defined in
a module that hasn't been loaded yet.  It also means the reg/unreg has
to be EXPORTed for any modules to use the tracepoint (as in SystemTap).

This patch removes DECLARE_TRACE_WITH_CALLBACK, and instead introduces
DEFINE_TRACE_FN which stores the callbacks in struct tracepoint.  The
callbacks are used now when the active state of the tracepoint changes
in set_tracepoint & disable_tracepoint.

This also introduces TRACE_EVENT_FN, so ftrace events can also provide
registration callbacks if needed.

Signed-off-by: Josh Stone 
Cc: Jason Baron 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Li Zefan 
Cc: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Mathieu Desnoyers 
Cc: Jiaying Zhang 
Cc: Martin Bligh 
Cc: Lai Jiangshan 
Cc: Paul Mundt 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
LKML-Reference: <1251150194-1713-4-git-send-email-jistone@redhat.com>
Signed-off-by: Frederic Weisbecker

tracing: Add DECLARE_TRACE_WITH_CALLBACK() macro

2009-08-11T18:35:26+00:00

Introduce a new 'DECLARE_TRACE_WITH_CALLBACK()' macro, so that
tracepoints can associate an external register/unregister function.

This prepares for the syscalls tracer conversion to trace events. We
will need to perform arch level operations once a syscall event is
turned on/off, such as TIF flags setting, hence the need of such
specific callbacks.

Signed-off-by: Jason Baron 
Cc: Lai Jiangshan 
Cc: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Mathieu Desnoyers 
Cc: Jiaying Zhang 
Cc: Martin Bligh 
Cc: Li Zefan 
Cc: Masami Hiramatsu 
Signed-off-by: Frederic Weisbecker