You can inspect individual objects with Devel::Peek but you might find GTop more useful. If installed on a system that has libgtop, it can report the total memory for any process. Calling it like so:

use Gtop;
my $gtop = GTop->new();
my $mem = $gtop->proc_mem($$);

# Now you can use $mem->share / $mem->rss / $mem->vsize
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You could monitor these before creating new objects and check if your script is using more than a "sane" amount and quit if the threshold is reached.