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()

10 files changed, 13 insertions, 13 deletions

diff --git a/drivers/gpu/drm/drm_vblank_work.c b/drivers/gpu/drm/drm_vblank_work.c
index 1752ffb44e1d..9cc71120246f 100644
--- a/drivers/gpu/drm/drm_vblank_work.c
+++ b/drivers/gpu/drm/drm_vblank_work.c
@@ -277,7 +277,7 @@ int drm_vblank_worker_init(struct drm_vblank_crtc *vblank)
 
 	INIT_LIST_HEAD(&vblank->pending_work);
 	init_waitqueue_head(&vblank->work_wait_queue);
-	worker = kthread_create_worker(0, "card%d-crtc%d",
+	worker = kthread_run_worker(0, "card%d-crtc%d",
 				       vblank->dev->primary->index,
 				       vblank->pipe);
 	if (IS_ERR(worker))
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
index 89d4dc8b60c6..eb0158e43417 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c
@@ -369,7 +369,7 @@ static int live_parallel_switch(void *arg)
 		if (!data[n].ce[0])
 			continue;
 
-		worker = kthread_create_worker(0, "igt/parallel:%s",
+		worker = kthread_run_worker(0, "igt/parallel:%s",
 					       data[n].ce[0]->engine->name);
 		if (IS_ERR(worker)) {
 			err = PTR_ERR(worker);
diff --git a/drivers/gpu/drm/i915/gt/selftest_execlists.c b/drivers/gpu/drm/i915/gt/selftest_execlists.c
index 222ca7c44951..81c31396eceb 100644
--- a/drivers/gpu/drm/i915/gt/selftest_execlists.c
+++ b/drivers/gpu/drm/i915/gt/selftest_execlists.c
@@ -3574,7 +3574,7 @@ static int smoke_crescendo(struct preempt_smoke *smoke, unsigned int flags)
 			arg[id].batch = NULL;
 		arg[id].count = 0;
 
-		worker[id] = kthread_create_worker(0, "igt/smoke:%d", id);
+		worker[id] = kthread_run_worker(0, "igt/smoke:%d", id);
 		if (IS_ERR(worker[id])) {
 			err = PTR_ERR(worker[id]);
 			break;
diff --git a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
index 9ce8ff1c04fe..9d3aeb237295 100644
--- a/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
+++ b/drivers/gpu/drm/i915/gt/selftest_hangcheck.c
@@ -1025,7 +1025,7 @@ static int __igt_reset_engines(struct intel_gt *gt,
 			threads[tmp].engine = other;
 			threads[tmp].flags = flags;
 
-			worker = kthread_create_worker(0, "igt/%s",
+			worker = kthread_run_worker(0, "igt/%s",
 						       other->name);
 			if (IS_ERR(worker)) {
 				err = PTR_ERR(worker);
diff --git a/drivers/gpu/drm/i915/gt/selftest_slpc.c b/drivers/gpu/drm/i915/gt/selftest_slpc.c
index 4ecc4ae74a54..e218b229681f 100644
--- a/drivers/gpu/drm/i915/gt/selftest_slpc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_slpc.c
@@ -489,7 +489,7 @@ static int live_slpc_tile_interaction(void *arg)
 		return -ENOMEM;
 
 	for_each_gt(gt, i915, i) {
-		threads[i].worker = kthread_create_worker(0, "igt/slpc_parallel:%d", gt->info.id);
+		threads[i].worker = kthread_run_worker(0, "igt/slpc_parallel:%d", gt->info.id);
 
 		if (IS_ERR(threads[i].worker)) {
 			ret = PTR_ERR(threads[i].worker);
diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
index acae30a04a94..88870844b5bd 100644
--- a/drivers/gpu/drm/i915/selftests/i915_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_request.c
@@ -492,7 +492,7 @@ static int mock_breadcrumbs_smoketest(void *arg)
 	for (n = 0; n < ncpus; n++) {
 		struct kthread_worker *worker;
 
-		worker = kthread_create_worker(0, "igt/%d", n);
+		worker = kthread_run_worker(0, "igt/%d", n);
 		if (IS_ERR(worker)) {
 			ret = PTR_ERR(worker);
 			ncpus = n;
@@ -1645,7 +1645,7 @@ static int live_parallel_engines(void *arg)
 		for_each_uabi_engine(engine, i915) {
 			struct kthread_worker *worker;
 
-			worker = kthread_create_worker(0, "igt/parallel:%s",
+			worker = kthread_run_worker(0, "igt/parallel:%s",
 						       engine->name);
 			if (IS_ERR(worker)) {
 				err = PTR_ERR(worker);
@@ -1806,7 +1806,7 @@ static int live_breadcrumbs_smoketest(void *arg)
 			unsigned int i = idx * ncpus + n;
 			struct kthread_worker *worker;
 
-			worker = kthread_create_worker(0, "igt/%d.%d", idx, n);
+			worker = kthread_run_worker(0, "igt/%d.%d", idx, n);
 			if (IS_ERR(worker)) {
 				ret = PTR_ERR(worker);
 				goto out_flush;
@@ -3219,7 +3219,7 @@ static int perf_parallel_engines(void *arg)
 
 			memset(&engines[idx].p, 0, sizeof(engines[idx].p));
 
-			worker = kthread_create_worker(0, "igt:%s",
+			worker = kthread_run_worker(0, "igt:%s",
 						       engine->name);
 			if (IS_ERR(worker)) {
 				err = PTR_ERR(worker);
diff --git a/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c b/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
index e75b97127c0d..2be00b11e557 100644
--- a/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
+++ b/drivers/gpu/drm/msm/disp/msm_disp_snapshot.c
@@ -109,7 +109,7 @@ int msm_disp_snapshot_init(struct drm_device *drm_dev)
 
 	mutex_init(&kms->dump_mutex);
 
-	kms->dump_worker = kthread_create_worker(0, "%s", "disp_snapshot");
+	kms->dump_worker = kthread_run_worker(0, "%s", "disp_snapshot");
 	if (IS_ERR(kms->dump_worker))
 		DRM_ERROR("failed to create disp state task\n");
 
diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c
index 9c45d641b521..a7a2384044ff 100644
--- a/drivers/gpu/drm/msm/msm_atomic.c
+++ b/drivers/gpu/drm/msm/msm_atomic.c
@@ -115,7 +115,7 @@ int msm_atomic_init_pending_timer(struct msm_pending_timer *timer,
 	timer->kms = kms;
 	timer->crtc_idx = crtc_idx;
 
-	timer->worker = kthread_create_worker(0, "atomic-worker-%d", crtc_idx);
+	timer->worker = kthread_run_worker(0, "atomic-worker-%d", crtc_idx);
 	if (IS_ERR(timer->worker)) {
 		int ret = PTR_ERR(timer->worker);
 		timer->worker = NULL;
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 0d4a3744cfcb..8557998e0c92 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -859,7 +859,7 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 	gpu->funcs = funcs;
 	gpu->name = name;
 
-	gpu->worker = kthread_create_worker(0, "gpu-worker");
+	gpu->worker = kthread_run_worker(0, "gpu-worker");
 	if (IS_ERR(gpu->worker)) {
 		ret = PTR_ERR(gpu->worker);
 		gpu->worker = NULL;
diff --git a/drivers/gpu/drm/msm/msm_kms.c b/drivers/gpu/drm/msm/msm_kms.c
index 4cfad12f4dc1..38965e12a6bf 100644
--- a/drivers/gpu/drm/msm/msm_kms.c
+++ b/drivers/gpu/drm/msm/msm_kms.c
@@ -268,7 +268,7 @@ int msm_drm_kms_init(struct device *dev, const struct drm_driver *drv)
 		/* initialize event thread */
 		ev_thread = &priv->event_thread[drm_crtc_index(crtc)];
 		ev_thread->dev = ddev;
-		ev_thread->worker = kthread_create_worker(0, "crtc_event:%d", crtc->base.id);
+		ev_thread->worker = kthread_run_worker(0, "crtc_event:%d", crtc->base.id);
 		if (IS_ERR(ev_thread->worker)) {
 			ret = PTR_ERR(ev_thread->worker);
 			DRM_DEV_ERROR(dev, "failed to create crtc_event kthread\n");