[RFC PATCH 0/2] tracing - signal tracer, support multiple pids in set_pid_ftrace

[jolsa@redhat.com]

I was debugging some ptrace applications and got to the idea of 
tracing signals - signal tracer. There's probably possibility to 
trace more info than just signal delivery info (like ignored 
signals deliveries, queue status...).

While doing this I realized it might be worth to have ability to trace 
more independent processes via set_pid_ftrace file.

Althought I'm sending this as RFC, attached patches work for me. 
I'm open to any suggestions/comments/ideas.

1/2 - signal trace
2/2 - multiple pids support for set_pid_ftrace file

thanks,
jirka

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
 include/linux/signaltrace.h |   22 ++++
 include/linux/tracehook.h   |   14 +++
 kernel/signal.c             |    3 +
 kernel/trace/Kconfig        |   11 ++
 kernel/trace/Makefile       |    1 +
 kernel/trace/ftrace.c       |  226 +++++++++++++++++++++++++++++++------------
 kernel/trace/trace.h        |   13 ++-
 kernel/trace/trace_signal.c |  132 +++++++++++++++++++++++++
 8 files changed, 356 insertions(+), 66 deletions(-)