* Unbound workqueues now support more flexible affinity scopes. The default
behavior is to soft-affine according to last level cache boundaries. A
work item queued from a given LLC is executed by a worker running on the
same LLC but the worker may be moved across cache boundaries as the
scheduler sees fit. On machines which multiple L3 caches, which are
becoming more popular along with chiplet designs, this improves cache
locality while not harming work conservation too much.
Unbound workqueues are now also a lot more flexible in terms of execution
affinity. Differeing levels of affinity scopes are supported and both the
default and per-workqueue affinity settings can be modified dynamically.
This should help working around amny of sub-optimal behaviors observed
recently with asymmetric ARM CPUs.
This involved signficant restructuring of workqueue code. Nothing was
reported yet but there's some risk of subtle regressions. Should keep an
eye out.
* Rescuer workers now has more identifiable comms.
* workqueue.unbound_cpus added so that CPUs which can be used by workqueue
can be constrained early during boot.
* Now that all the in-tree users have been flushed out, trigger warning if
system-wide workqueues are flushed.
* One pull commit from for-6.5-fixes to avoid cascading conflicts in the
affinity scope patchset.
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Merge tag 'wq-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo:
- Unbound workqueues now support more flexible affinity scopes.
The default behavior is to soft-affine according to last level cache
boundaries. A work item queued from a given LLC is executed by a
worker running on the same LLC but the worker may be moved across
cache boundaries as the scheduler sees fit. On machines which
multiple L3 caches, which are becoming more popular along with
chiplet designs, this improves cache locality while not harming work
conservation too much.
Unbound workqueues are now also a lot more flexible in terms of
execution affinity. Differeing levels of affinity scopes are
supported and both the default and per-workqueue affinity settings
can be modified dynamically. This should help working around amny of
sub-optimal behaviors observed recently with asymmetric ARM CPUs.
This involved signficant restructuring of workqueue code. Nothing was
reported yet but there's some risk of subtle regressions. Should keep
an eye out.
- Rescuer workers now has more identifiable comms.
- workqueue.unbound_cpus added so that CPUs which can be used by
workqueue can be constrained early during boot.
- Now that all the in-tree users have been flushed out, trigger warning
if system-wide workqueues are flushed.
* tag 'wq-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (31 commits)
workqueue: fix data race with the pwq->stats[] increment
workqueue: Rename rescuer kworker
workqueue: Make default affinity_scope dynamically updatable
workqueue: Add "Affinity Scopes and Performance" section to documentation
workqueue: Implement non-strict affinity scope for unbound workqueues
workqueue: Add workqueue_attrs->__pod_cpumask
workqueue: Factor out need_more_worker() check and worker wake-up
workqueue: Factor out work to worker assignment and collision handling
workqueue: Add multiple affinity scopes and interface to select them
workqueue: Modularize wq_pod_type initialization
workqueue: Add tools/workqueue/wq_dump.py which prints out workqueue configuration
workqueue: Generalize unbound CPU pods
workqueue: Factor out clearing of workqueue-only attrs fields
workqueue: Factor out actual cpumask calculation to reduce subtlety in wq_update_pod()
workqueue: Initialize unbound CPU pods later in the boot
workqueue: Move wq_pod_init() below workqueue_init()
workqueue: Rename NUMA related names to use pod instead
workqueue: Rename workqueue_attrs->no_numa to ->ordered
workqueue: Make unbound workqueues to use per-cpu pool_workqueues
workqueue: Call wq_update_unbound_numa() on all CPUs in NUMA node on CPU hotplug
...
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