Messages in this thread | | | From | Waiman Long <> | Subject | [PATCH wq/for-6.9 v5 0/4] workqueue: Enable unbound cpumask update on ordered workqueues | Date | Thu, 8 Feb 2024 11:10:10 -0500 |
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v5: - [v4] https://lore.kernel.org/lkml/20240207011911.975608-1-longman@redhat.com/ - Streamline patch 2 by simplifying unplug_oldest_pwq() and calling it only in pwq_release_workfn().
v4: - [v3] https://lore.kernel.org/lkml/20240205194602.871505-1-longman@redhat.com/ - Rebase on the latest for-6.9 branch again & discard the use of __WQ_ORDERED_EXPLICIT and resetting of __WQ_ORDERED. - Add a new patch 1 to change the ordering of pwq's in wq->pwqs from oldest to newest. - Change the terminalogy from freeze/thaw to plug/unplug. - Allow more than 2 pwq's in wq->pwqs of ordered workqueue but only the oldest one is unplugged. This eliminates the need to wait for the draining of extra pwq in workqueue_apply_unbound_cpumask().
v3: - [v2] https://lore.kernel.org/lkml/20240203154334.791910-1-longman@redhat.com/ - Drop patch 1 as it has been merged into the for-6.9 branch. - Use rcu_access_pointer() to access wq->dfl_pwq. - Use RCU protection instead of acquiring wq->mutex in apply_wqattrs_cleanup().
Ordered workqueues does not currently follow changes made to the global unbound cpumask because per-pool workqueue changes may break the ordering guarantee. IOW, a work function in an ordered workqueue may run on a cpuset isolated CPU.
This series enables ordered workqueues to follow changes made to the global unbound cpumask by temporaily suspending (plugging) the execution of work items in the newly allocated pool_workqueue until the old pwq has been properly drained.
The cpumask of the rescuer task of each workqueue is also made to follow changes in workqueue unbound cpumask as well as its sysfs cpumask, if available.
Juri Lelli (1): kernel/workqueue: Let rescuers follow unbound wq cpumask changes
Waiman Long (3): workqueue: Link pwq's into wq->pwqs from oldest to newest workqueue: Enable unbound cpumask update on ordered workqueues workqueue: Bind unbound workqueue rescuer to wq_unbound_cpumask
kernel/workqueue.c | 81 +++++++++++++++++++++++++++++++++++++++------- 1 file changed, 69 insertions(+), 12 deletions(-)
-- 2.39.3
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