mm: oom_kill: add trace logs in process_mrelease() system call

mm: oom_kill: add trace logs in process_mrelease() system call

The process_mrelease() system call is used to release the memory of a
dying process from the context of the caller, which is similar to and uses
the functions of the oom reaper logic.  There exist trace logs for a
process when reaped by the oom reaper.  Just extend the same to when done
by the process_mrelease() system call.

This patch provides information on how much memory is freed from a process
which is being reaped.  Adding trace events in the process_mrelease() path
when process is being reaped would enable more holistic debug as it
happens in oom_reap_task_mm() currently.

This extends the debug functionality for the events as described in [1] to
the process_mrelease() system call.  Now the coverage of trace events is
complete.

[1] https://lore.kernel.org/all/20170530185231.GA13412@castle/T/#u

Link: https://lkml.kernel.org/r/20220816060017.17996-1-pbrahma@qti.qualcomm.com
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Signed-off-by: Pratyush Brahma <quic_pbrahma@quicinc.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>