What is causing memory to continuously rise perl?

Question

Problem

I have created a simple perl script to read log files and process the data asynchronously.

The problem i am facing is that the script appears to continuously use more memory the longer it runs. This seems to be affected by the amount of data it processes. The problem I have is that i am unable to identify what exactly is using all this memory, and whether it is a leak or something is just holding onto it.

Question

How can i modify the below script so that it no longer continuously consumes memory ?

Code

#Multithreaded to read multiple log files at the same time.

use strict;
use warnings;

use threads;
use Thread::Queue;
use threads::shared;

my $logq = Thread::Queue->new();
my %Servers :shared;
my %servername :shared;

sub csvsplit {
        my $line = shift;
        my $sep = (shift or ',');

        return () unless $line;

        my @cells;
        my $re = qr/(?:^|$sep)(?:"([^"]*)"|([^$sep]*))/;

        while($line =~ /$re/g) {
                my $value = defined $1 ? $1 : $2;
                push @cells, (defined $value ? $value : '');
        }

        return @cells;
}


sub process_data
{
        while(sleep(1)){

                if ($logq->pending())
                {
                        my %sites;
                        my %returns;
                        while($logq->pending() > 0){
                                my $data = $logq->dequeue();
                                my @fields = csvsplit($data);
                                $returns{$fields[$#fields - 1]}++;
                                $sites{$fields[$#fields]}++;
                        }
                print "counter:$_, value=\"$sites{$_}\" />
" for (keys%sites);
                print "counter:$_, value=\"$returns{$_}\" />
" for (keys%returns);
                
                }
        }

}

sub read_file
{
        my $myFile=$_[0];
        open(my $logfile,'<',$myFile) || die "error";
        my $Inode=(stat($logfile))[1];
        my $fileSize=(stat($logfile))[7];
        seek $logfile, 0, 2;
        for (;;) {
                while (<$logfile>) {
                        chomp( $_ );
                        $logq->enqueue( $_ );
                }
                sleep 5;
                if($Inode != (stat($myFile))[1] || (stat($myFile))[7] < $fileSize){
                        close($logfile);
                        while (! -e $myFile){
                                sleep 2;
                        }
                        open($logfile,'<',$myFile) || die "error";
                        $Inode=(stat($logfile))[1];
                        $fileSize=(stat($logfile))[7];
                }
                seek $logfile, 0, 1;
        }

}


my $thr1 = threads->create(\&read_file,"log");
my $thr4 = threads->create(\&process_data);
$thr1->join();
$thr4->join();

Obeservations and relevant info

The memory only seems to increase when the program has data to process, if i just leave it, it maintains the current memory usage.

Memory only appears to increase for larger throughput and increase about half a Mb per 5 seconds for around 2000 lines in the same time.

I have not included the csv as i do not think it is relevant. If you do and want me to add it please give a valid reason.

Specs

GNU bash, version 3.2.57(1)-release (s390x-ibm-linux-gnu)
perl, v5.10.0

I have looked through other questions but cannot find much of relevance. If this is a duplicate or the relevant info is in another question, feel free to mark as a dupe and ill check it out.

Any more info needed just ask.