PGA Allocated memoery

hi
i query the v$process and it is showing me that one process is using
757600845 bytes of memory as i see it in PGA_ALLOC_MEM column and almost same value is in PGA_USED_MEM column,
when i mapped this process ID to the session in V$SESSION view, it was an application running through my application server 9i (A web base application written in PL/SQL web toolkit and is run using DADs from oracle application server 9i running on windows 2000)
I dont understand how this session is using this much PGA memory and my workarea_size_policy is AUTO and pga_aggregate_target is
293601280.

When i see many sessions eating up memory as their PGA is of same size i mentioned above, Server begins to slowdown and then i see "kswapd0" process on the top of all processes in my "top" command's window. what does it do?

Can you please explain?

Second thing is that my this application is a web base and in username column i only see OS User name by which i logged into my application server(windows based) machine and started the application server instance and in machine name column, it displayas the application server name.
Is it possible that i coould actually see that from which client machinet his application was called?
Regards

With regard to your second issue, OEM (which I'm assuming is what you're using at the moment) is showing the Application Server because as far as the database is concerned that's where the request has come from. If you log in to the database directly (e.g. using SQLPlus) then your machine name will show.

I believe that TOAD will show you the machine name.

Well the thing is that v$session can show the cliend, operating system user, and other information about the user process whose procesing is eating up memory as PGA is increasing, i want to know that why PGA is increasing this much that my server hangs as no memory is left on server. PGA_AGGRIGATE_TARGET is almost 300 M
Regards