Re: MAXACTION exceeded error while using systemtap

[Martin Hunt <hunt at redhat dot com>]

Frank and I have been discussing this in various PRs for a couple weeks.

What I would like to see is MAXACTION set to a very low value in kprobes
(or jprobes or djprobes). It would be equivalent to a couple of
milliseconds, at most.

It would prevent things like sorting and printing maps, no matter what
their size. Theoretically we could allow these for very small maps, but
why would we want to? Rather than attempt to calculate how much time a
potentially time-consuming function will really take, just set it to a
large fixed value assuming the worst.  It would be best to print errors
at compile time in scripts that attempt it. 

For timer events, MAXACTION would be very large. Large enough to sort
any size arrays and print maybe 1000 lines or so.

For begin and end probes, MAXACTION would be something less than
infinite so there are no infinite loops.