[PATCH 00/10] workqueue: break affinity initiatively

[Lai Jiangshan]

From: Lai Jiangshan <laijs@xxxxxxxxxxxxxxxxx>

06249738a41a ("workqueue: Manually break affinity on hotplug")
said that scheduler will not force break affinity for us.

But workqueue highly depends on the old behavior. Many parts of the codes
relies on it, 06249738a41a ("workqueue: Manually break affinity on hotplug")
is not enough to change it, and the commit has flaws in itself too.

We need to thoroughly update the way workqueue handles affinity
in cpu hot[un]plug, what is this patchset intends to do and
replace the Valentin Schneider's patch [1].

Patch 1 fixes a flaw reported by Hillf Danton <hdanton@xxxxxxxx>.
I have to include this fix because later patches depends on it.

The patchset is based on tip/master rather than workqueue tree,
because the patchset is a complement for 06249738a41a ("workqueue:
Manually break affinity on hotplug") which is only in tip/master by now.

[1]: https://lore.kernel.org/r/ff62e3ee994efb3620177bf7b19fab16f4866845.camel@xxxxxxxxxx

Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Valentin Schneider <valentin.schneider@xxxxxxx>
Cc: Qian Cai <cai@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Vincent Donnefort <vincent.donnefort@xxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>

Lai Jiangshan (10):
  workqueue: restore unbound_workers' cpumask correctly
  workqueue: use cpu_possible_mask instead of cpu_active_mask to break
    affinity
  workqueue: Manually break affinity on pool detachment
  workqueue: don't set the worker's cpumask when kthread_bind_mask()
  workqueue: introduce wq_online_cpumask
  workqueue: use wq_online_cpumask in restore_unbound_workers_cpumask()
  workqueue: Manually break affinity on hotplug for unbound pool
  workqueue: reorganize workqueue_online_cpu()
  workqueue: reorganize workqueue_offline_cpu() unbind_workers()
  workqueue: Fix affinity of kworkers when attaching into pool

 kernel/workqueue.c | 212 +++++++++++++++++++++++++++------------------
 1 file changed, 130 insertions(+), 82 deletions(-)

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2.19.1.6.gb485710b