staging: android: lowmemorykiller: Don't count reserved free memory

The amount of reserved memory varies between devices. Subtract it
here to reduce the amount of devices specific tuning needed for the
minfree values.

Change-Id: I466ae8b18f5972f6f6d8b5a7d8c4ae69660de53a
Signed-off-by: Arve Hjønnevåg <arve@android.com>
staging: android: lowmemorykiller: Change default debug_level to 1

The select...to kill messages are not very useful when not debugging
the lowmemorykiller itself. After the change to check TIF_MEMDIE
instead of using a task notifer this message can also get very
noisy.

Change-Id: Ice171c25801d6faa454b885a23b24b002423b754
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Revert "staging: android: lowmemorykiller: Don't count reserved free memory"

This reverts commit 4971f84bfce8bd180287c8cb94136ac89d328f1d

Change-Id: I6c51caef9c6bdf0ec86d2c155aab0313c54272e8
android/lowmemorykiller: Check all tasks for death pending

The lowmemorykiller uses the TIF_MEMDIE flag to help ensure it doesn't
kill another task until the memory from the previously killed task has
been returned to the system.

However the lowmemorykiller does not currently look at tasks who do not
have a tasks->mm, but just because a process doesn't have a tasks->mm
does not mean that the task's memory has been fully returned to the
system yet.

In order to prevent the lowmemorykiller from unnecessarily killing
multiple applications in a row the lowmemorykiller has been changed to
ensure that previous killed tasks are no longer in the process list
before attempting to kill another task.

Change-Id: I7d8a8fd39ca5625e6448ed2efebfb621f6e93845
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>

Conflicts:
	drivers/staging/android/lowmemorykiller.c