[ Upstream commit 2a1b02bcba78f8498ab00d6142e1238d85b01591 ]
Currently, worker ID formatting is open coded in create_worker(),
init_rescuer() and worker_thread() (for %WORKER_DIE case). The formatted ID
is saved into task->comm and wq_worker_comm() uses it as the base name to
append extra information to when generating the name to be shown to
userspace.
However, TASK_COMM_LEN is only 16 leading to badly truncated names for
rescuers. For example, the rescuer for the inet_frag_wq workqueue becomes:
$ ps -ef | grep '[k]worker/R-inet'
root 483 2 0 Apr26 ? 00:00:00 [kworker/R-inet_]
Even for non-rescue workers, it's easy to run over 15 characters on
moderately large machines.
Fit it by consolidating worker ID formatting into a new helper
format_worker_id() and calling it from wq_worker_comm() to obtain the
untruncated worker ID string.
$ ps -ef | grep '[k]worker/R-inet'
root 60 2 0 12:10 ? 00:00:00 [kworker/R-inet_frag_wq]
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Jan Engelhardt <jengelh@inai.de>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
f3d73b877a