android: lowmemorykiller: add lmk parameters tunning code.

There are cases that LMK doesn't run, even when it must run.
It is due to LMK shrinker not considering memory status per zone.
So add LMK parameters(other_free, other_file) tunnig code to
consider target zone of LMK shrinker.

Change-Id: I6f1f8660d5da920a0e3af45a160499965032081d
Git-commit: 22d990a58fc17b3f0155e15eb2dc3efa037bea1c
Git-repo: https://android.googlesource.com/kernel/common/
[ohaugan@codeaurora.org: Fix compilation issues]
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
android/lowmemorykiller: Account for total_swapcache_pages

The lowmemorykiller relies on NR_FILE_PAGES when measureing
the amount of reclaimable memory in the system.
However when swap is enabled swap cache pages are counted
in NR_FILE_PAGES, and swap cache pages aren't as reclaimable
in low memory as file cache pages. Therefore a large swap
cache can result in the lowmemorykiller not running and
an OOM occuring.

In order to ensure the lowmemorykiller properly evaluates the
amount of reclaimable memory don't count the swap cache pages.

Change-Id: I38239283e572f814b277c718eaf6be7f92abacbb
Signed-off-by: Liam Mark <lmark@codeaurora.org>