The following patches add accounting for the delays seen by tasks in
a) waiting for a CPU (while being runnable)
b) completion of synchronous block I/O initiated by the task
c) swapping in pages (i.e. capacity misses).
Such delays provide feedback for a task's cpu priority, io priority and
rss limit values. Long delays, especially relative to other tasks, can
be a trigger for changing a task's cpu/io priorities and modifying its
rss usage (either directly through sys_getprlimit() that was proposed
earlier on lkml or by throttling cpu consumption or process calling
sys_setrlimit etc.)