[PATCH] lockdep: Add nr_save_trace_invocations counter

[John Kacur]

NOT FOR INCLUSION

I created this patch as a result of Peter Zilstra's request to get more 
info from lockdep. This patch is not for inclusion, at least in its 
present form, because it adds some redunant info to /proc/lockdep_stats

However, some of the fields are new, and it is worth examining, and / or 
applying if you are looking at the MAX_STACK_TRACE_ENTRIES too big 
problem.

I generated this patch against a recent tip/master but it applies without 
conflicts to the latest rt kernel as well. Comments are welcome, in fact 
they are appreciated.