PGA Allocation for an Oracle Process

Query help to find out how much PGA allocated for an Oracle Process.

SELECT
  s.sid,
  p.spid,
  DECODE(s.program, NULL, p.program, s.program) AS "Program",
  pga_used_mem,
  pga_alloc_mem,
  pga_max_mem
FROM gv$process p, gv$session s
WHERE s.paddr = p.addr
ORDER BY s.sid;

Thanks,
Jyothish