workqueue: Simplify wq_calc_pod_cpumask() with wq_online_cpumask

Avoid relying on cpu_online_mask for wqattrs changes so that cpus_read_lock() can be removed from apply_wqattrs_lock(). And with wq_online_cpumask, attrs->__pod_cpumask doesn't need to be reused as a temporary storage to calculate if the pod have any online CPUs @attrs wants since @cpu_going_down is not in the wq_online_cpumask.

Lai Jiangshan committed 2 years ago

Commit fbb3d4c1 parent 8d84baf1 file · +3 −9Browse files

Showing the changes to kernel/workqueue.c (1 of 1 file). Show all

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kernel/workqueue.c+3−9

 	const struct wq_pod_type *pt = wqattrs_pod_type(attrs);
 	int pod = pt->cpu_pod[cpu];
-	/* does @pod have any online CPUs @attrs wants? */
+	/* calculate possible CPUs in @pod that @attrs wants */
 	cpumask_and(attrs->__pod_cpumask, pt->pod_cpus[pod], attrs->cpumask);
-	cpumask_and(attrs->__pod_cpumask, attrs->__pod_cpumask, cpu_online_mask);
+	/* does @pod have any online CPUs @attrs wants? */
-	if (cpu_going_down >= 0)
+	if (!cpumask_intersects(attrs->__pod_cpumask, wq_online_cpumask)) {
-		cpumask_clear_cpu(cpu_going_down, attrs->__pod_cpumask);
-	if (cpumask_empty(attrs->__pod_cpumask)) {
 		cpumask_copy(attrs->__pod_cpumask, attrs->cpumask);
 		return;
 	}
-	/* yeap, return possible CPUs in @pod that @attrs wants */
-	cpumask_and(attrs->__pod_cpumask, attrs->cpumask, pt->pod_cpus[pod]);
 	if (cpumask_empty(attrs->__pod_cpumask))
 		pr_warn_once("WARNING: workqueue cpumask: online intersect > "
 				"possible intersect\n");