perf session: Cleanup __perf_session__process_events()

perf session: Cleanup __perf_session__process_events()

Replace the pseudo C++ self argument with session and give the mmap related
variables a sensible name. shift is a complete misnomer - it took me several
rounds of cursing to figure out that it's not a shift value.

Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
LKML-Reference: <20101130163820.029687218@linutronix.de>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>