High Memory Usage - Cpanel Server

for the last few days, i am facing high memory usage up to 90%.

Memory usage get's high, even if i don't have many visitors online. I have to restart httpd to get the memory to normal. some times, server loads, get's high aswell.

In error logs (only unusual things i see):

Code:
[Sat Jan 6 10:37:04 2007] [error] mod_gzip: TRANSMIT_ERROR:ISMEM:104
[Sat Jan 6 10:37:25 2007] [error] mod_gzip: TRANSMIT_ERROR:ISMEM:104

# top:

Code:
top - 10:42:19 up 10:35, 1 user, load average: 22.95, 10.67, 9.79
Tasks: 318 total, 1 running, 317 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.7% us, 1.3% sy, 0.0% ni, 0.0% id, 61.9% wa, 36.1% hi, 0.0% si
Mem: 2009652k total, 1220736k used, 788916k free, 28756k buffers
Swap: 6224564k total, 135212k used, 6089352k free, 389768k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6365 root 0 -20 0 0 0 D 40 0.0 3:01.33 loop0
4553 root 16 0 3112 1108 760 R 1 0.1 0:00.30 top
327 root 15 0 0 0 0 S 0 0.0 6:33.15 kjournald
3743 nobody 15 0 18592 7260 2320 S 0 0.4 0:00.21 httpd
3833 nobody 15 0 21664 10m 2780 D 0 0.5 0:00.94 httpd
3838 nobody 15 0 20472 9400 2664 S 0 0.5 0:00.18 httpd
3858 nobody 15 0 18876 7616 2388 S 0 0.4 0:00.82 httpd
3919 nobody 16 0 21492 10m 2432 D 0 0.5 0:00.82 httpd
3931 nobody 15 0 18976 8016 2716 D 0 0.4 0:00.45 httpd
4439 nobody 15 0 18892 7612 2368 S 0 0.4 0:00.16 httpd
4913 root 18 0 2512 292 244 D 0 0.0 0:00.24 sync
1 root 16 0 2484 488 456 S 0 0.0 0:06.16 init
2 root RT 0 0 0 0 S 0 0.0 0:00.11 migration/0
3 root 34 19 0 0 0 S 0 0.0 0:06.66 ksoftirqd/0
4 root RT 0 0 0 0 S 0 0.0 0:00.16 migration/1
5 root 34 19 0 0 0 S 0 0.0 0:00.71 ksoftirqd/1
6 root 5 -10 0 0 0 S 0 0.0 0:14.59 events/0
7 root 5 -10 0 0 0 S 0 0.0 0:42.07 events/1
this looks suspisous to me:
6365 root 0 -20 0 0 0 D 40 0.0 3:01.33 loop0

as it's taking alot of memory. i don't see this before.