tree ca9eca5fcbe93dc8a433d839221505ad8fba5296
parent 259032bfe379281bf7cba512b7705bdb4ce41db5
author Steven Rostedt <srostedt@redhat.com> 1310675813 -0400
committer Steven Rostedt <rostedt@goodmis.org> 1310675813 -0400

tracing: Have dynamic size event stack traces

Currently the stack trace per event in ftace is only 8 frames.
This can be quite limiting and sometimes useless. Especially when
the "ignore frames" is wrong and we also use up stack frames for
the event processing itself.

Change this to be dynamic by adding a percpu buffer that we can
write a large stack frame into and then copy into the ring buffer.

For interrupts and NMIs that come in while another event is being
process, will only get to use the 8 frame stack. That should be enough
as the task that it interrupted will have the full stack frame anyway.

Requested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>