Tracing fixes for 6.9:

- Fix the buffer_percent accounting as it is dependent on three variables:
  1) pages_read - number of subbuffers read
  2) pages_lost - number of subbuffers lost due to overwrite
  3) pages_touched - number of pages that a writer entered
  These three counters only increment, and to know how many active pages
  there are on the buffer at any given time, the pages_read and
  pages_lost are subtracted from pages_touched. But the pages touched
  was incremented whenever any writer went to the next subbuffer even
  if it wasn't the only one, so it was incremented more than it should
  be causing the counter for how many subbuffers currently have content
  incorrect, which caused the buffer_percent that holds waiters until
  the ring buffer is filled to a given percentage to wake up early.

- Fix warning of unused functions when PERF_EVENTS is not configured in

- Replace bad tab with space in Kconfig for FTRACE_RECORD_RECURSION_SIZE

- Fix to some kerneldoc function comments in eventfs code.
-----BEGIN PGP SIGNATURE-----

iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCZhk+khQccm9zdGVkdEBn
b29kbWlzLm9yZwAKCRAp5XQQmuv6qvs0AP98c226UFU6Dha4wvgSulC/wKVvHN3X
jeclMTdn8RGs2gD/b9OULKNv1//6fP16ZRun7ntRQkotVhlNhf9Ee0smiwU=
=UYrk
-----END PGP SIGNATURE-----