Certain IA-32 applications which do mmap/munmaps which are not
PAGE_SIZE aligned could see temporary (recovered at process exit time)
memory leaks, because the kernel didn't have enough data to decide if
the complete page could be unmapped. This patch adds a new data
structure called the "partial page list" which helps the kernel keep
track of precisely which 4k pages are in use by the IA-32 application.

Armed with this data, the kernel can make better decisions at munmap
and mprotect time. No significant performance degradation was observed
in the workloads we tested and in some cases, the performance actually
improved!  This is possibly due to the reduced length of the vma list.
Signed-off-by: Arun Sharma <arun.sharma@intel.com>
Signed-off-by: Gordon Jin <gordon.jin@intel.com>
Signed-off-by: David Mosberger <davidm@hpl.hp.com>