Package qos contains helper functions for quality of service. For each resource (memory, CPU) Kubelet supports three classes of containers. Memory guaranteed containers will receive the highest priority and will get all the resources they need. Burstable containers will be guaranteed their request and can "burst" and use more resources when available. Best-Effort containers, which don't specify a request, can use resources only if not being used by other pods.
GetContainerOOMScoreAdjust returns the amount by which the OOM score of all processes in the container should be adjusted. The OOM score of a process is the percentage of memory it consumes multiplied by 10 (barring exceptional cases) + a configurable quantity which is between -1000 and 1000. Containers with higher OOM scores are killed if the system runs out of memory. See https://lwn.net/Articles/391222/ for more information.