oom-killer on RHEL5.2

[ram_sen]

Hi

We are running RHEL 5.2 with PAE kernel.
Make: HP DL360
Hard Drive Type:Smart Array controller
MemTotal: 16633136 kB
SwapTotal: 33551744 kB
Intel(R) Xeon(R) CPU 5140 @ 2.33GHz; 2 Dual Core
RedHat Version: Linux 2.6.18-92.el5PAE #1 SMP i686 i686 i386 GNU/Linux
Oracle 10G

We are facing the oom-killer problem recently on our DB server
(conf:mention above).
Error: Out of memory: Killed process 30700 kernel: oracle invoked oom-killer: gfp_mask=0xd0, order=0, oomkilladj=0

i) the oom-killer process invoked and it kills the process one-by-one it includes oracle, ssh, bash login etc. its because of low memory value

ii) the LOW MEM value gets reduces rapidly when i run Oracle

iii)swap memory is not at all utilised even low memeory is fully drained

work arround we done:
i) set the following parameters
vm.overcommit_memory=2
vm.overcommit_ratio=70
To debug the issue as recommended by some forums but it is not at all solved.
ii)some other suggestion is to set the "vm.lower_zone_protection=100"
But there is no kernel parameter as such in RHEL 5.2. Is there any other alternative param in RHEL5.2 to this param.

If anyone have the idea to solve this issue, pls help us.
Thanks in advance

-Ram

[ram_sen]

Please help me friends and we are counting for production environment