I tried this code. It allocated 13% of my memory at the beginning, and it stayed at this level until the end, which means new invocation of the function does not increase the memory consumption.

sub test {
  my $size = 1000000;
  my %hash;
  @hash{1..$size} = (rand()) x $size;
  sleep 5;
  print keys %hash;
} 
test(),sleep 5 for 1..10;
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