The lowmemorykiller driver lets user-space specify a set of memory thresholds
where processes with a range of oom_adj values will get killed. Specify the
minimum oom_adj values in /sys/module/lowmemorykiller/parameters/adj and the
number of free pages in /sys/module/lowmemorykiller/parameters/minfree. Both
files take a comma separated list of numbers in ascending order.

For example, write "0,8" to /sys/module/lowmemorykiller/parameters/adj and
"1024,4096" to /sys/module/lowmemorykiller/parameters/minfree to kill processes
with a oom_adj value of 8 or higher when the free memory drops below 4096 pages
and kill processes with a oom_adj value of 0 or higher when the free memory
drops below 1024 pages.

The driver considers memory used for caches to be free, but if a large
percentage of the cached memory is locked this can be very inaccurate
and processes may not get killed until the normal oom killer is triggered.