FYI, the reason nothing is released in the first snippet is: 
{
    my $foo = 'X' x 100000000;       <-- a lexical var $foo
    getc;
}
undef $foo;                          <-- the package var $foo was
my $foo = "";                            already undef so does nothing
getc;

[download]

You would have wanted 

{
    my $foo = 'X' x 100000000;
    getc;
    undef $foo;
}
getc;

[download]

In reply to Re: Perl Garbage Collection, again by ikegami
in thread Perl Garbage Collection, again by pkirsch

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