On Sat, Dec 19, 2020 at 01:09:09AM +0800, Lai Jiangshan wrote: > From: Lai Jiangshan <[email protected]> > > 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. > > It doesn't handle for worker detachment. > It doesn't handle for worker attachement, mainly worker creation > which is handled by Valentin Schneider's patch [1]. > It doesn't handle for unbound workers which might be possible > per-cpu-kthread. > > 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]. The equivalent patch > is patch 10. > > Patch 1 fixes a flaw reported by Hillf Danton <[email protected]>. > 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. > > And TJ acked to route the series through tip. > > Changed from V1: > Add TJ's acked-by for the whole patchset > > Add more words to the comments and the changelog, mainly derived > from discussion with Peter. > > Update the comments as TJ suggested. > > Update a line of code as Valentin suggested. > > Add Valentin's ack for patch 10 because "Seems alright to me." and > add Valentin's comments to the changelog which is integral. > > [1]: > https://lore.kernel.org/r/[email protected] > [V1 patcheset]: > https://lore.kernel.org/lkml/[email protected]/ > > Cc: Hillf Danton <[email protected]> > Cc: Valentin Schneider <[email protected]> > Cc: Qian Cai <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Vincent Donnefort <[email protected]> > Cc: Tejun Heo <[email protected]>
And rcutorture hits this, so thank you for the fix! Tested-by: Paul E. McKenney <[email protected]> > 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 | 214 ++++++++++++++++++++++++++++----------------- > 1 file changed, 132 insertions(+), 82 deletions(-) > > -- > 2.19.1.6.gb485710b >
