[for-next][PATCH 18/30] tracing: Add hist trigger support for stacktraces as keys

From: Tom Zanussi It's often useful to be able to use a stacktrace as a hash key, for keeping a count of the number of times a particular call path resulted in a trace event, for instance. Add a special key named 'stacktrace' which can be used as key in a 'keys='

[for-next][PATCH 18/30] tracing: Add hist trigger support for stacktraces as keys

From: Tom Zanussi It's often useful to be able to use a stacktrace as a hash key, for keeping a count of the number of times a particular call path resulted in a trace event, for instance. Add a special key named 'stacktrace' which can be used as key in a 'keys=' param for this purpose: #