[GIT PULL] tracing: make signal tracepoints more useful

From: Oleg Nesterov
Date: Fri Jan 13 2012 - 13:26:11 EST


Hello,

Please pull from

git://github.com/utrace/linux sigtrace


Another (4th) attempt to push these simple changes, now in the form
of a pull request (yes, github, I still can't restore my korg account).

2/2 looks like a bugfix to me, but 1/2 changes the output from
trace_signal_generate() and removes trace_signal_overflow_fail.
In essence the change is:

- TP_printk("sig=%d errno=%d code=%d comm=%s pid=%d",
+ TP_printk("sig=%d errno=%d code=%d comm=%s pid=%d grp=%d res=%d",

where
- grp=0/1 means private or shared

- res is enum {
TRACE_SIGNAL_DELIVERED,
TRACE_SIGNAL_IGNORED,
TRACE_SIGNAL_ALREADY_PENDING,
TRACE_SIGNAL_OVERFLOW_FAIL,
TRACE_SIGNAL_LOSE_INFO,
};

Obviously this is the user visible change. But personally I do
agree with Seiji who requested this feature. Currently
trace_signal_generate() just records the fact that __send_signal()
was called, you can't know whether the signal was actually sent
or not.

Steven Rostedt says:

Adding more to a tracepoint is never an issue, even without a library to
parse the data correctly (which we still need in the distros). Thus this
change should have no issues.



Oleg Nesterov (2):
tracing: let trace_signal_generate() report more info, kill overflow_fail/lose_info
tracing: send_sigqueue() needs trace_signal_generate() too

include/trace/events/signal.h | 85 +++++++++++------------------------------
kernel/signal.c | 28 +++++++++----
2 files changed, 41 insertions(+), 72 deletions(-)

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