linux-toradex.git/kernel/trace/trace_output.c, branch tegra-10.9.9

tracing: Fix trace_seq_printf() return value

2009-10-24T09:07:50+00:00

trace_seq_printf() return value is a little ambiguous. It
currently returns the length of the space available in the
buffer. printf usually returns the amount written. This is not
adequate here, because:

  trace_seq_printf(s, "");

is perfectly legal, and returning 0 would indicate that it
failed.

We can always see the amount written by looking at the before
and after values of s->len. This is not quite the same use as
printf. We only care if the string was successfully written to
the buffer or not.

Make trace_seq_printf() return 0 if the trace oversizes the
buffer's free space, 1 otherwise.

Signed-off-by: Jiri Olsa 
Signed-off-by: Steven Rostedt 
Cc: Frederic Weisbecker 
LKML-Reference: <20091023233646.631787612@goodmis.org>
Signed-off-by: Ingo Molnar

tracing: fix transposed numbers of lock_depth and preempt_count

2009-10-07T18:05:04+00:00

The lock_depth and preempt_count numbers in the latency format is
transposed.

Signed-off-by: Steven Rostedt

trace: Fix missing assignment in trace_ctxwake_*

2009-10-06T12:28:24+00:00

The state char variable S should be reassigned, if S == 0.

We are missing the state of the task that is going to sleep for the
context switch events (in the raw mode).

Fortunately the problem arises with the sched_switch/wake_up
tracers, not the sched trace events.

The formers are legacy now. But still, that was buggy.

Signed-off-by: Hiroshi Shimamoto 
Cc: Steven Rostedt 
Acked-by: Frederic Weisbecker 
LKML-Reference: <4AC43118.6050409@ct.jp.nec.com>
Signed-off-by: Ingo Molnar

tracing: consolidate code between trace_output.c and trace_function_graph.c

2009-09-11T18:24:13+00:00

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

tracing: add lock depth to entries

2009-09-11T17:55:35+00:00

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
 #     \   /      ||||||   \   |   /
   -0       2.N..3 5902255250us+: lock_acquire: read rcu_read_lock
   -0       2.N..3 5902255253us+: lock_release: rcu_read_lock
   -0       2dN..3 5902255257us+: lock_acquire: xtime_lock
   -0       2dN..4 5902255259us : lock_acquire: clocksource_lock
   -0       2dN..4 5902255261us+: lock_release: clocksource_lock

Signed-off-by: Steven Rostedt

tracing: move tgid out of generic entry and into userstack

2009-09-11T15:36:23+00:00

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

tracing: Fix trace_print_seq()

2009-07-02T06:51:13+00:00

We will lose something if trace_seq->buffer[0] is 0, because the copy length
is calculated by strlen() in seq_puts(), so using seq_write() instead of
seq_puts().

There have a example:
after reboot:

 # echo kmemtrace > current_tracer
 # echo 0 > options/kmem_minimalistic
 # cat trace
 # tracer: kmemtrace
 #
 #

Nothing is exported, because the first byte of trace_seq->buffer[ ]
is KMEMTRACE_USER_ALLOC.

( the value of KMEMTRACE_USER_ALLOC is zero, seeing
  kmemtrace_print_alloc_user() in kernel/trace/kmemtrace.c)

Signed-off-by: Xiao Guangrong 
Acked-by: Frederic Weisbecker 
Acked-by: Pekka Enberg 
Acked-by: Eduard - Gabriel Munteanu 
Cc: Steven Rostedt 
LKML-Reference: <4A4B2351.5010300@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

tracing: add protection around module events unload

2009-06-09T21:29:07+00:00

When reading the trace buffer, there is a race that when a module
is unloaded it removes events that is stilled referenced in the buffers.
This patch adds the protection around the unloading of the events
from modules and the reading of the trace buffers.

Signed-off-by: Steven Rostedt

tracing: add trace_seq_vprint interface

2009-06-09T19:17:32+00:00

The code to update the print formats for events requires a vprintf
format in the trace_seq. This patch adds that interface.

Signed-off-by: Steven Rostedt

tracing: add annotation to what type of stack trace is recorded

2009-06-03T15:10:44+00:00

The current method of printing out a stack trace is to add a new line
and print out the trace:

    yum-updatesd-3120  [002]   573.691303:
 => do_softirq
 => irq_exit
 => smp_apic_timer_interrupt
 => apic_timer_interrupt

This looks a bit awkward, and if we have both stack and user stack traces
running, it would be nice to have a title to tell them apart, although
it is easy to tell by the output.

This patch adds an annotation to the start of the stack traces:

            init-1     [003]   929.304979: 
 => user_path_at
 => vfs_fstatat
 => vfs_stat
 => sys_newstat
 => system_call_fastpath

             cat-3459  [002]  1016.824040: 
 =>  <0000003aae6c0250>
 =>  <00007ffff4b06ae4>
 =>  <69636172742f6775>

Signed-off-by: Steven Rostedt