Android users make heavy use of the displays on their devices for almost
all of their interaction; good display performance is thus critical for a
satisfactory user experience. Achieving that performance is not always
easy; there are a lot of pieces that need to work together, and the kernel
does not always support this collaboration as well as one might like. The
Android team is currently considering a number of combinations of existing
kernel features and possible enhancements in its efforts to provide the
best display experience possible.

Source: LWN.net – [$] Scheduling for the Android display pipeline