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Sender: Tejun Heo <htejun@gmail.com>
From:   Tejun Heo <tj@kernel.org>
To:     jiangshanlai@gmail.com
Cc:     torvalds@linux-foundation.org, peterz@infradead.org,
        linux-kernel@vger.kernel.org, kernel-team@meta.com,
        joshdon@google.com, brho@google.com, briannorris@chromium.org,
        nhuck@google.com, agk@redhat.com, snitzer@kernel.org,
        void@manifault.com, Tejun Heo <tj@kernel.org>
Subject: [PATCH 06/24] workqueue: Remove module param disable_numa and sysfs knobs pool_ids and numa
Date:   Thu, 18 May 2023 14:16:51 -1000
Message-Id: <20230519001709.2563-7-tj@kernel.org>
In-Reply-To: <20230519001709.2563-1-tj@kernel.org>
References: <20230519001709.2563-1-tj@kernel.org>
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Unbound workqueue CPU affinity is going to receive an overhaul and the NUMA
specific knobs won't make sense anymore. Remove them. Also, the pool_ids
knob was used for debugging and not really meaningful given that there is no
visibility into the pools associated with those IDs. Remove it too. A future
patch will improve overall visibility.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 .../admin-guide/kernel-parameters.txt         |  9 ---
 kernel/workqueue.c                            | 73 -------------------
 2 files changed, 82 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 3ed7dda4c994..042275425c32 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6943,15 +6943,6 @@
 			threshold repeatedly. They are likely good
 			candidates for using WQ_UNBOUND workqueues instead.
 
-	workqueue.disable_numa
-			By default, all work items queued to unbound
-			workqueues are affine to the NUMA nodes they're
-			issued on, which results in better behavior in
-			general.  If NUMA affinity needs to be disabled for
-			whatever reason, this option can be used.  Note
-			that this also can be controlled per-workqueue for
-			workqueues visible under /sys/bus/workqueue/.
-
 	workqueue.power_efficient
 			Per-cpu workqueues are generally preferred because
 			they show better performance thanks to cache
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 6ec22eb87283..f39d04e7e5f9 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -337,9 +337,6 @@ static cpumask_var_t *wq_numa_possible_cpumask;
 static unsigned long wq_cpu_intensive_thresh_us = 10000;
 module_param_named(cpu_intensive_thresh_us, wq_cpu_intensive_thresh_us, ulong, 0644);
 
-static bool wq_disable_numa;
-module_param_named(disable_numa, wq_disable_numa, bool, 0444);
-
 /* see the comment above the definition of WQ_POWER_EFFICIENT */
 static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT);
 module_param_named(power_efficient, wq_power_efficient, bool, 0444);
@@ -5777,10 +5774,8 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
  *
  * Unbound workqueues have the following extra attributes.
  *
- *  pool_ids	RO int	: the associated pool IDs for each node
  *  nice	RW int	: nice value of the workers
  *  cpumask	RW mask	: bitmask of allowed CPUs for the workers
- *  numa	RW bool	: whether enable NUMA affinity
  */
 struct wq_device {
 	struct workqueue_struct		*wq;
@@ -5833,28 +5828,6 @@ static struct attribute *wq_sysfs_attrs[] = {
 };
 ATTRIBUTE_GROUPS(wq_sysfs);
 
-static ssize_t wq_pool_ids_show(struct device *dev,
-				struct device_attribute *attr, char *buf)
-{
-	struct workqueue_struct *wq = dev_to_wq(dev);
-	const char *delim = "";
-	int node, written = 0;
-
-	cpus_read_lock();
-	rcu_read_lock();
-	for_each_node(node) {
-		written += scnprintf(buf + written, PAGE_SIZE - written,
-				     "%s%d:%d", delim, node,
-				     unbound_pwq_by_node(wq, node)->pool->id);
-		delim = " ";
-	}
-	written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
-	rcu_read_unlock();
-	cpus_read_unlock();
-
-	return written;
-}
-
 static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr,
 			    char *buf)
 {
@@ -5945,50 +5918,9 @@ static ssize_t wq_cpumask_store(struct device *dev,
 	return ret ?: count;
 }
 
-static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr,
-			    char *buf)
-{
-	struct workqueue_struct *wq = dev_to_wq(dev);
-	int written;
-
-	mutex_lock(&wq->mutex);
-	written = scnprintf(buf, PAGE_SIZE, "%d\n",
-			    !wq->unbound_attrs->no_numa);
-	mutex_unlock(&wq->mutex);
-
-	return written;
-}
-
-static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr,
-			     const char *buf, size_t count)
-{
-	struct workqueue_struct *wq = dev_to_wq(dev);
-	struct workqueue_attrs *attrs;
-	int v, ret = -ENOMEM;
-
-	apply_wqattrs_lock();
-
-	attrs = wq_sysfs_prep_attrs(wq);
-	if (!attrs)
-		goto out_unlock;
-
-	ret = -EINVAL;
-	if (sscanf(buf, "%d", &v) == 1) {
-		attrs->no_numa = !v;
-		ret = apply_workqueue_attrs_locked(wq, attrs);
-	}
-
-out_unlock:
-	apply_wqattrs_unlock();
-	free_workqueue_attrs(attrs);
-	return ret ?: count;
-}
-
 static struct device_attribute wq_sysfs_unbound_attrs[] = {
-	__ATTR(pool_ids, 0444, wq_pool_ids_show, NULL),
 	__ATTR(nice, 0644, wq_nice_show, wq_nice_store),
 	__ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
-	__ATTR(numa, 0644, wq_numa_show, wq_numa_store),
 	__ATTR_NULL,
 };
 
@@ -6362,11 +6294,6 @@ static void __init wq_numa_init(void)
 	if (num_possible_nodes() <= 1)
 		return;
 
-	if (wq_disable_numa) {
-		pr_info("workqueue: NUMA affinity support disabled\n");
-		return;
-	}
-
 	for_each_possible_cpu(cpu) {
 		if (WARN_ON(cpu_to_node(cpu) == NUMA_NO_NODE)) {
 			pr_warn("workqueue: NUMA node mapping not available for cpu%d, disabling NUMA support\n", cpu);
-- 
2.40.1