1 files changed, 77 insertions, 141 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 9f4341885f60..48208888aee0 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -321,8 +321,7 @@ struct workqueue_struct {
 
 	/* hot fields used during command issue, aligned to cacheline */
 	unsigned int		flags ____cacheline_aligned; /* WQ: WQ_* flags */
-	struct pool_workqueue __percpu **cpu_pwq; /* I: per-cpu pwqs */
-	struct pool_workqueue __rcu *numa_pwq_tbl[]; /* PWR: unbound pwqs indexed by node */
+	struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */
 };
 
 static struct kmem_cache *pwq_cache;
@@ -608,35 +607,6 @@ static int worker_pool_assign_id(struct worker_pool *pool)
 	return ret;
 }
 
-/**
- * unbound_pwq_by_node - return the unbound pool_workqueue for the given node
- * @wq: the target workqueue
- * @node: the node ID
- *
- * This must be called with any of wq_pool_mutex, wq->mutex or RCU
- * read locked.
- * If the pwq needs to be used beyond the locking in effect, the caller is
- * responsible for guaranteeing that the pwq stays online.
- *
- * Return: The unbound pool_workqueue for @node.
- */
-static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq,
-						  int node)
-{
-	assert_rcu_or_wq_mutex_or_pool_mutex(wq);
-
-	/*
-	 * XXX: @node can be NUMA_NO_NODE if CPU goes offline while a
-	 * delayed item is pending.  The plan is to keep CPU -> NODE
-	 * mapping valid and stable across CPU on/offlines.  Once that
-	 * happens, this workaround can be removed.
-	 */
-	if (unlikely(node == NUMA_NO_NODE))
-		return wq->dfl_pwq;
-
-	return rcu_dereference_raw(wq->numa_pwq_tbl[node]);
-}
-
 static unsigned int work_color_to_flags(int color)
 {
 	return color << WORK_STRUCT_COLOR_SHIFT;
@@ -1676,16 +1646,14 @@ static void __queue_work(int cpu, struct workqueue_struct *wq,
 	rcu_read_lock();
 retry:
 	/* pwq which will be used unless @work is executing elsewhere */
-	if (wq->flags & WQ_UNBOUND) {
-		if (req_cpu == WORK_CPU_UNBOUND)
+	if (req_cpu == WORK_CPU_UNBOUND) {
+		if (wq->flags & WQ_UNBOUND)
 			cpu = wq_select_unbound_cpu(raw_smp_processor_id());
-		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
-	} else {
-		if (req_cpu == WORK_CPU_UNBOUND)
+		else
 			cpu = raw_smp_processor_id();
-		pwq = *per_cpu_ptr(wq->cpu_pwq, cpu);
 	}
 
+	pwq = rcu_dereference(*per_cpu_ptr(wq->cpu_pwq, cpu));
 	pool = pwq->pool;
 
 	/*
@@ -1715,12 +1683,11 @@ retry:
 	}
 
 	/*
-	 * pwq is determined and locked.  For unbound pools, we could have
-	 * raced with pwq release and it could already be dead.  If its
-	 * refcnt is zero, repeat pwq selection.  Note that pwqs never die
-	 * without another pwq replacing it in the numa_pwq_tbl or while
-	 * work items are executing on it, so the retrying is guaranteed to
-	 * make forward-progress.
+	 * pwq is determined and locked. For unbound pools, we could have raced
+	 * with pwq release and it could already be dead. If its refcnt is zero,
+	 * repeat pwq selection. Note that unbound pwqs never die without
+	 * another pwq replacing it in cpu_pwq or while work items are executing
+	 * on it, so the retrying is guaranteed to make forward-progress.
 	 */
 	if (unlikely(!pwq->refcnt)) {
 		if (wq->flags & WQ_UNBOUND) {
@@ -3818,12 +3785,8 @@ static void rcu_free_wq(struct rcu_head *rcu)
 		container_of(rcu, struct workqueue_struct, rcu);
 
 	wq_free_lockdep(wq);
-
-	if (!(wq->flags & WQ_UNBOUND))
-		free_percpu(wq->cpu_pwq);
-	else
-		free_workqueue_attrs(wq->unbound_attrs);
-
+	free_percpu(wq->cpu_pwq);
+	free_workqueue_attrs(wq->unbound_attrs);
 	kfree(wq);
 }
 
@@ -4174,11 +4137,8 @@ static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
  *
  * The caller is responsible for ensuring that the cpumask of @node stays
  * stable.
- *
- * Return: %true if the resulting @cpumask is different from @attrs->cpumask,
- * %false if equal.
  */
-static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node,
+static void wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node,
 				 int cpu_going_down, cpumask_t *cpumask)
 {
 	if (!wq_numa_enabled || attrs->no_numa)
@@ -4195,23 +4155,18 @@ static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node,
 	/* yeap, return possible CPUs in @node that @attrs wants */
 	cpumask_and(cpumask, attrs->cpumask, wq_numa_possible_cpumask[node]);
 
-	if (cpumask_empty(cpumask)) {
+	if (cpumask_empty(cpumask))
 		pr_warn_once("WARNING: workqueue cpumask: online intersect > "
 				"possible intersect\n");
-		return false;
-	}
-
-	return !cpumask_equal(cpumask, attrs->cpumask);
+	return;
 
 use_dfl:
 	cpumask_copy(cpumask, attrs->cpumask);
-	return false;
 }
 
-/* install @pwq into @wq's numa_pwq_tbl[] for @node and return the old pwq */
-static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq,
-						   int node,
-						   struct pool_workqueue *pwq)
+/* install @pwq into @wq's cpu_pwq and return the old pwq */
+static struct pool_workqueue *install_unbound_pwq(struct workqueue_struct *wq,
+					int cpu, struct pool_workqueue *pwq)
 {
 	struct pool_workqueue *old_pwq;
 
@@ -4221,8 +4176,8 @@ static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq,
 	/* link_pwq() can handle duplicate calls */
 	link_pwq(pwq);
 
-	old_pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
-	rcu_assign_pointer(wq->numa_pwq_tbl[node], pwq);
+	old_pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
+	rcu_assign_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu), pwq);
 	return old_pwq;
 }
 
@@ -4239,10 +4194,10 @@ struct apply_wqattrs_ctx {
 static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx)
 {
 	if (ctx) {
-		int node;
+		int cpu;
 
-		for_each_node(node)
-			put_pwq_unlocked(ctx->pwq_tbl[node]);
+		for_each_possible_cpu(cpu)
+			put_pwq_unlocked(ctx->pwq_tbl[cpu]);
 		put_pwq_unlocked(ctx->dfl_pwq);
 
 		free_workqueue_attrs(ctx->attrs);
@@ -4259,11 +4214,11 @@ apply_wqattrs_prepare(struct workqueue_struct *wq,
 {
 	struct apply_wqattrs_ctx *ctx;
 	struct workqueue_attrs *new_attrs, *tmp_attrs;
-	int node;
+	int cpu;
 
 	lockdep_assert_held(&wq_pool_mutex);
 
-	ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_node_ids), GFP_KERNEL);
+	ctx = kzalloc(struct_size(ctx, pwq_tbl, nr_cpu_ids), GFP_KERNEL);
 
 	new_attrs = alloc_workqueue_attrs();
 	tmp_attrs = alloc_workqueue_attrs();
@@ -4297,14 +4252,16 @@ apply_wqattrs_prepare(struct workqueue_struct *wq,
 	if (!ctx->dfl_pwq)
 		goto out_free;
 
-	for_each_node(node) {
-		if (wq_calc_node_cpumask(new_attrs, node, -1, tmp_attrs->cpumask)) {
-			ctx->pwq_tbl[node] = alloc_unbound_pwq(wq, tmp_attrs);
-			if (!ctx->pwq_tbl[node])
-				goto out_free;
-		} else {
+	for_each_possible_cpu(cpu) {
+		if (new_attrs->no_numa) {
 			ctx->dfl_pwq->refcnt++;
-			ctx->pwq_tbl[node] = ctx->dfl_pwq;
+			ctx->pwq_tbl[cpu] = ctx->dfl_pwq;
+		} else {
+			wq_calc_node_cpumask(new_attrs, cpu_to_node(cpu), -1,
+					     tmp_attrs->cpumask);
+			ctx->pwq_tbl[cpu] = alloc_unbound_pwq(wq, tmp_attrs);
+			if (!ctx->pwq_tbl[cpu])
+				goto out_free;
 		}
 	}
 
@@ -4327,7 +4284,7 @@ out_free:
 /* set attrs and install prepared pwqs, @ctx points to old pwqs on return */
 static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
 {
-	int node;
+	int cpu;
 
 	/* all pwqs have been created successfully, let's install'em */
 	mutex_lock(&ctx->wq->mutex);
@@ -4335,9 +4292,9 @@ static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
 	copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs);
 
 	/* save the previous pwq and install the new one */
-	for_each_node(node)
-		ctx->pwq_tbl[node] = numa_pwq_tbl_install(ctx->wq, node,
-							  ctx->pwq_tbl[node]);
+	for_each_possible_cpu(cpu)
+		ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu,
+							ctx->pwq_tbl[cpu]);
 
 	/* @dfl_pwq might not have been used, ensure it's linked */
 	link_pwq(ctx->dfl_pwq);
@@ -4466,20 +4423,13 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
 	cpumask = target_attrs->cpumask;
 
 	copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
-	pwq = unbound_pwq_by_node(wq, node);
 
-	/*
-	 * Let's determine what needs to be done.  If the target cpumask is
-	 * different from the default pwq's, we need to compare it to @pwq's
-	 * and create a new one if they don't match.  If the target cpumask
-	 * equals the default pwq's, the default pwq should be used.
-	 */
-	if (wq_calc_node_cpumask(wq->dfl_pwq->pool->attrs, node, off_cpu, cpumask)) {
-		if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask))
-			return;
-	} else {
-		goto use_dfl_pwq;
-	}
+	/* nothing to do if the target cpumask matches the current pwq */
+	wq_calc_node_cpumask(wq->dfl_pwq->pool->attrs, node, off_cpu, cpumask);
+	pwq = rcu_dereference_protected(*per_cpu_ptr(wq->cpu_pwq, cpu),
+					lockdep_is_held(&wq_pool_mutex));
+	if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask))
+		return;
 
 	/* create a new pwq */
 	pwq = alloc_unbound_pwq(wq, target_attrs);
@@ -4491,7 +4441,7 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
 
 	/* Install the new pwq. */
 	mutex_lock(&wq->mutex);
-	old_pwq = numa_pwq_tbl_install(wq, node, pwq);
+	old_pwq = install_unbound_pwq(wq, cpu, pwq);
 	goto out_unlock;
 
 use_dfl_pwq:
@@ -4499,7 +4449,7 @@ use_dfl_pwq:
 	raw_spin_lock_irq(&wq->dfl_pwq->pool->lock);
 	get_pwq(wq->dfl_pwq);
 	raw_spin_unlock_irq(&wq->dfl_pwq->pool->lock);
-	old_pwq = numa_pwq_tbl_install(wq, node, wq->dfl_pwq);
+	old_pwq = install_unbound_pwq(wq, cpu, wq->dfl_pwq);
 out_unlock:
 	mutex_unlock(&wq->mutex);
 	put_pwq_unlocked(old_pwq);
@@ -4510,11 +4460,11 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq)
 	bool highpri = wq->flags & WQ_HIGHPRI;
 	int cpu, ret;
 
-	if (!(wq->flags & WQ_UNBOUND)) {
-		wq->cpu_pwq = alloc_percpu(struct pool_workqueue *);
-		if (!wq->cpu_pwq)
-			goto enomem;
+	wq->cpu_pwq = alloc_percpu(struct pool_workqueue *);
+	if (!wq->cpu_pwq)
+		goto enomem;
 
+	if (!(wq->flags & WQ_UNBOUND)) {
 		for_each_possible_cpu(cpu) {
 			struct pool_workqueue **pwq_p =
 				per_cpu_ptr(wq->cpu_pwq, cpu);
@@ -4562,13 +4512,11 @@ enomem:
 static int wq_clamp_max_active(int max_active, unsigned int flags,
 			       const char *name)
 {
-	int lim = flags & WQ_UNBOUND ? WQ_UNBOUND_MAX_ACTIVE : WQ_MAX_ACTIVE;
-
-	if (max_active < 1 || max_active > lim)
+	if (max_active < 1 || max_active > WQ_MAX_ACTIVE)
 		pr_warn("workqueue: max_active %d requested for %s is out of range, clamping between %d and %d\n",
-			max_active, name, 1, lim);
+			max_active, name, 1, WQ_MAX_ACTIVE);
 
-	return clamp_val(max_active, 1, lim);
+	return clamp_val(max_active, 1, WQ_MAX_ACTIVE);
 }
 
 /*
@@ -4612,7 +4560,6 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
 					 unsigned int flags,
 					 int max_active, ...)
 {
-	size_t tbl_size = 0;
 	va_list args;
 	struct workqueue_struct *wq;
 	struct pool_workqueue *pwq;
@@ -4632,10 +4579,7 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
 		flags |= WQ_UNBOUND;
 
 	/* allocate wq and format name */
-	if (flags & WQ_UNBOUND)
-		tbl_size = nr_node_ids * sizeof(wq->numa_pwq_tbl[0]);
-
-	wq = kzalloc(sizeof(*wq) + tbl_size, GFP_KERNEL);
+	wq = kzalloc(sizeof(*wq), GFP_KERNEL);
 	if (!wq)
 		return NULL;
 
@@ -4730,7 +4674,7 @@ static bool pwq_busy(struct pool_workqueue *pwq)
 void destroy_workqueue(struct workqueue_struct *wq)
 {
 	struct pool_workqueue *pwq;
-	int cpu, node;
+	int cpu;
 
 	/*
 	 * Remove it from sysfs first so that sanity check failure doesn't
@@ -4789,29 +4733,23 @@ void destroy_workqueue(struct workqueue_struct *wq)
 	list_del_rcu(&wq->list);
 	mutex_unlock(&wq_pool_mutex);
 
-	if (!(wq->flags & WQ_UNBOUND)) {
-		for_each_possible_cpu(cpu)
-			put_pwq_unlocked(*per_cpu_ptr(wq->cpu_pwq, cpu));
-	} else {
-		/*
-		 * We're the sole accessor of @wq at this point.  Directly
-		 * access numa_pwq_tbl[] and dfl_pwq to put the base refs.
-		 * @wq will be freed when the last pwq is released.
-		 */
-		for_each_node(node) {
-			pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
-			RCU_INIT_POINTER(wq->numa_pwq_tbl[node], NULL);
-			put_pwq_unlocked(pwq);
-		}
+	/*
+	 * We're the sole accessor of @wq. Directly access cpu_pwq and dfl_pwq
+	 * to put the base refs. @wq will be auto-destroyed from the last
+	 * pwq_put. RCU read lock prevents @wq from going away from under us.
+	 */
+	rcu_read_lock();
 
-		/*
-		 * Put dfl_pwq.  @wq may be freed any time after dfl_pwq is
-		 * put.  Don't access it afterwards.
-		 */
-		pwq = wq->dfl_pwq;
-		wq->dfl_pwq = NULL;
+	for_each_possible_cpu(cpu) {
+		pwq = rcu_access_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu));
+		RCU_INIT_POINTER(*per_cpu_ptr(wq->cpu_pwq, cpu), NULL);
 		put_pwq_unlocked(pwq);
 	}
+
+	put_pwq_unlocked(wq->dfl_pwq);
+	wq->dfl_pwq = NULL;
+
+	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(destroy_workqueue);
 
@@ -4888,10 +4826,11 @@ bool current_is_workqueue_rescuer(void)
  * unreliable and only useful as advisory hints or for debugging.
  *
  * If @cpu is WORK_CPU_UNBOUND, the test is performed on the local CPU.
- * Note that both per-cpu and unbound workqueues may be associated with
- * multiple pool_workqueues which have separate congested states.  A
- * workqueue being congested on one CPU doesn't mean the workqueue is also
- * contested on other CPUs / NUMA nodes.
+ *
+ * With the exception of ordered workqueues, all workqueues have per-cpu
+ * pool_workqueues, each with its own congested state. A workqueue being
+ * congested on one CPU doesn't mean that the workqueue is contested on any
+ * other CPUs.
  *
  * Return:
  * %true if congested, %false otherwise.
@@ -4907,12 +4846,9 @@ bool workqueue_congested(int cpu, struct workqueue_struct *wq)
 	if (cpu == WORK_CPU_UNBOUND)
 		cpu = smp_processor_id();
 
-	if (!(wq->flags & WQ_UNBOUND))
-		pwq = *per_cpu_ptr(wq->cpu_pwq, cpu);
-	else
-		pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
-
+	pwq = *per_cpu_ptr(wq->cpu_pwq, cpu);
 	ret = !list_empty(&pwq->inactive_works);
+
 	preempt_enable();
 	rcu_read_unlock();
 
@@ -6434,7 +6370,7 @@ void __init workqueue_init_early(void)
 	system_highpri_wq = alloc_workqueue("events_highpri", WQ_HIGHPRI, 0);
 	system_long_wq = alloc_workqueue("events_long", 0, 0);
 	system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND,
-					    WQ_UNBOUND_MAX_ACTIVE);
+					    WQ_MAX_ACTIVE);
 	system_freezable_wq = alloc_workqueue("events_freezable",
 					      WQ_FREEZABLE, 0);
 	system_power_efficient_wq = alloc_workqueue("events_power_efficient",