percpu: add tracepoint support for percpu memory

Add support for tracepoints to the following events: chunk allocation,
chunk free, area allocation, area free, and area allocation failure.
This should let us replay percpu memory requests and evaluate
corresponding decisions.

Signed-off-by: Dennis Zhou <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
4 files changed