I am using Parallel::ForkManager in the file1.pl, btw.

file1.pl

use Parallel::ForkManager;
my $pm = new Parallel::ForkManager(4);
foreach my $base_dir (@base_dirs) {

    my $storable_file = $storable_dir.$f;
    $pm->start and next; # do the fork

    `/home/qiang/file2.pl $storable_file $base_dir`;

    $pm->finish;
}
$pm->wait_all_children;
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file2.pl

use File::Find;
use Storable qw(store retrieve);

my $storable_file = shift;
my $base_dir = shift;
my @usr_dirs = map {chomp;$base_dir."/".$_} `/bin/ls $base_dir`;
my $mbox = {};

find(\&wanted,@usr_dirs);
store $mbox, $storable_file or die "Can't store !\n";
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How are you determining that memory is being used?

Also, looking at your file1.pl, I think you probably want an exec here rather than using the back tick.

exec('/home/qiang/file2.pl', $storable_file, $base_dir);
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Because, from the docs, backticks does a fork and exec. So I would think you're probably doing fork from the ForkManager, Fork from backticks, then an exec from backticks. If that makes any sense.

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"Look, Shiny Things!" is not a better business strategy than compatibility and reuse.