Merge tag 'kthread-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks

Pull kthread updates from Frederic Weisbecker:
 "Kthreads affinity follow either of 4 existing different patterns:

   1) Per-CPU kthreads must stay affine to a single CPU and never
      execute relevant code on any other CPU. This is currently handled
      by smpboot code which takes care of CPU-hotplug operations.
      Affinity here is a correctness constraint.

   2) Some kthreads _have_ to be affine to a specific set of CPUs and
      can't run anywhere else. The affinity is set through
      kthread_bind_mask() and the subsystem takes care by itself to
      handle CPU-hotplug operations. Affinity here is assumed to be a
      correctness constraint.

   3) Per-node kthreads _prefer_ to be affine to a specific NUMA node.
      This is not a correctness constraint but merely a preference in
      terms of memory locality. kswapd and kcompactd both fall into this
      category. The affinity is set manually like for any other task and
      CPU-hotplug is supposed to be handled by the relevant subsystem so
      that the task is properly reaffined whenever a given CPU from the
      node comes up. Also care should be taken so that the node affinity
      doesn't cross isolated (nohz_full) cpumask boundaries.

   4) Similar to the previous point except kthreads have a _preferred_
      affinity different than a node. Both RCU boost kthreads and RCU
      exp kworkers fall into this category as they refer to "RCU nodes"
      from a distinctly distributed tree.

  Currently the preferred affinity patterns (3 and 4) have at least 4
  identified users, with more or less success when it comes to handle
  CPU-hotplug operations and CPU isolation. Each of which do it in its
  own ad-hoc way.

  This is an infrastructure proposal to handle this with the following
  API changes:

   - kthread_create_on_node() automatically affines the created kthread
     to its target node unless it has been set as per-cpu or bound with
     kthread_bind[_mask]() before the first wake-up.

   - kthread_affine_preferred() is a new function that can be called
     right after kthread_create_on_node() to specify a preferred
     affinity different than the specified node.

  When the preferred affinity can't be applied because the possible
  targets are offline or isolated (nohz_full), the kthread is affine to
  the housekeeping CPUs (which means to all online CPUs most of the time
  or only the non-nohz_full CPUs when nohz_full= is set).

  kswapd, kcompactd, RCU boost kthreads and RCU exp kworkers have been
  converted, along with a few old drivers.

  Summary of the changes:

   - Consolidate a bunch of ad-hoc implementations of
     kthread_run_on_cpu()

   - Introduce task_cpu_fallback_mask() that defines the default last
     resort affinity of a task to become nohz_full aware

   - Add some correctness check to ensure kthread_bind() is always
     called before the first kthread wake up.

   - Default affine kthread to its preferred node.

   - Convert kswapd / kcompactd and remove their halfway working ad-hoc
     affinity implementation

   - Implement kthreads preferred affinity

   - Unify kthread worker and kthread API's style

   - Convert RCU kthreads to the new API and remove the ad-hoc affinity
     implementation"

* tag 'kthread-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks:
  kthread: modify kernel-doc function name to match code
  rcu: Use kthread preferred affinity for RCU exp kworkers
  treewide: Introduce kthread_run_worker[_on_cpu]()
  kthread: Unify kthread_create_on_cpu() and kthread_create_worker_on_cpu() automatic format
  rcu: Use kthread preferred affinity for RCU boost
  kthread: Implement preferred affinity
  mm: Create/affine kswapd to its preferred node
  mm: Create/affine kcompactd to its preferred node
  kthread: Default affine kthread to its preferred NUMA node
  kthread: Make sure kthread hasn't started while binding it
  sched,arm64: Handle CPU isolation on last resort fallback rq selection
  arm64: Exclude nohz_full CPUs from 32bits el0 support
  lib: test_objpool: Use kthread_run_on_cpu()
  kallsyms: Use kthread_run_on_cpu()
  soc/qman: test: Use kthread_run_on_cpu()
  arm/bL_switcher: Use kthread_run_on_cpu()

3 files changed, 3 insertions, 3 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_dpll.c b/drivers/net/ethernet/intel/ice/ice_dpll.c
index 38e151c7ea23..8d806d8ad761 100644
--- a/drivers/net/ethernet/intel/ice/ice_dpll.c
+++ b/drivers/net/ethernet/intel/ice/ice_dpll.c
@@ -2053,7 +2053,7 @@ static int ice_dpll_init_worker(struct ice_pf *pf)
 	struct kthread_worker *kworker;
 
 	kthread_init_delayed_work(&d->work, ice_dpll_periodic_work);
-	kworker = kthread_create_worker(0, "ice-dplls-%s",
+	kworker = kthread_run_worker(0, "ice-dplls-%s",
 					dev_name(ice_pf_to_dev(pf)));
 	if (IS_ERR(kworker))
 		return PTR_ERR(kworker);
diff --git a/drivers/net/ethernet/intel/ice/ice_gnss.c b/drivers/net/ethernet/intel/ice/ice_gnss.c
index f02e8ca55375..b2148dbe49b2 100644
--- a/drivers/net/ethernet/intel/ice/ice_gnss.c
+++ b/drivers/net/ethernet/intel/ice/ice_gnss.c
@@ -182,7 +182,7 @@ static struct gnss_serial *ice_gnss_struct_init(struct ice_pf *pf)
 	pf->gnss_serial = gnss;
 
 	kthread_init_delayed_work(&gnss->read_work, ice_gnss_read);
-	kworker = kthread_create_worker(0, "ice-gnss-%s", dev_name(dev));
+	kworker = kthread_run_worker(0, "ice-gnss-%s", dev_name(dev));
 	if (IS_ERR(kworker)) {
 		kfree(gnss);
 		return NULL;
diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
index efd770dfec44..12b4eef84b77 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
@@ -3072,7 +3072,7 @@ static int ice_ptp_init_work(struct ice_pf *pf, struct ice_ptp *ptp)
 	/* Allocate a kworker for handling work required for the ports
 	 * connected to the PTP hardware clock.
 	 */
-	kworker = kthread_create_worker(0, "ice-ptp-%s",
+	kworker = kthread_run_worker(0, "ice-ptp-%s",
 					dev_name(ice_pf_to_dev(pf)));
 	if (IS_ERR(kworker))
 		return PTR_ERR(kworker);