[RFC PATCH 0/2] Add queue_*() functions and prefer per-cpu workqueue and flag

[Marco Crivellari <marco.crivellari@suse.com>]

Hi,

The following is part of the Workqueue refactoring, and a first RFC about
the rename of the schedule_*() interfaces along with the introduction of
the "wq prefer per-cpu" workqueue and workqueue flag.

Any feedback is more then welcome!

~~~

More information about the reasons behind the workqueue refactoring can
be found at:

  https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/

Actually schedule_work() and schedule_work_on() enqueue works using
system_percpu_wq. The function name doesn't suggest it, on top of that,
only the per-cpu version is present.

Because of that, the following changes are introduced:

- queue_{bound|unbound}_work() as future replacement of schedule_work()

- queue_bound_work_on() as future replacement of schedule_work_on()

- queue_bound_delayed_work() as future replacement of
  schedule_delayed_work()

- queue_unbound_delayed_work() to offer the unbound version

- queue_bound_delayed_work_on() as future replacement of
  schedule_delayed_work_on()

The addition of queue_unbound_delayed_work() is because "delayed" functions
make use of a global timer and that means the work will be executed on the
CPU where the timer fired.

The Workqueue API currently do not distinguish between use case where
locality is important for correctness and where is important for
efficiency. So introduce WQ_PREFER_PERCPU and wq_prefer_percpu_wq, so
that works who need to be per-cpu but don't strictly require it, can
use such workqueue / workqueue flag.


Thanks!

Marco Crivellari (2):
  workqueue: Add queue_*() functions, future schedule_*() replacement
  workqueue: Add WQ_PREFER_PERCPU and system_prefer_percpu_wq

 include/linux/workqueue.h | 108 ++++++++++++++++++++++++++++++++++++++
 kernel/workqueue.c        |   6 ++-
 2 files changed, 113 insertions(+), 1 deletion(-)

-- 
2.53.0