/* * Copyright (C) 2016 Thomas Gleixner. * Copyright (C) 2016-2017 Christoph Hellwig. */#include <linux/interrupt.h>#include <linux/kernel.h>#include <linux/slab.h>#include <linux/cpu.h> static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,				int cpus_per_vec){	const struct cpumask *siblmsk;	int cpu, sibl; 	for ( ; cpus_per_vec > 0; ) {		cpu = cpumask_first(nmsk); 		/* Should not happen, but I'm too lazy to think about it */		if (cpu >= nr_cpu_ids)			return; 		cpumask_clear_cpu(cpu, nmsk);		cpumask_set_cpu(cpu, irqmsk);		cpus_per_vec--; 		/* If the cpu has siblings, use them first */		siblmsk = topology_sibling_cpumask(cpu);		for (sibl = -1; cpus_per_vec > 0; ) {			sibl = cpumask_next(sibl, siblmsk);			if (sibl >= nr_cpu_ids)				break;			if (!cpumask_test_and_clear_cpu(sibl, nmsk))				continue;			cpumask_set_cpu(sibl, irqmsk);			cpus_per_vec--;		}	}} static cpumask_var_t *alloc_node_to_present_cpumask(void){	cpumask_var_t *masks;	int node; 	masks = kcalloc(nr_node_ids, sizeof(cpumask_var_t), GFP_KERNEL);	if (!masks)		return NULL; 	for (node = 0; node < nr_node_ids; node++) {		if (!zalloc_cpumask_var(&masks[node], GFP_KERNEL))			goto out_unwind;	} 	return masks; out_unwind:	while (--node >= 0)		free_cpumask_var(masks[node]);	kfree(masks);	return NULL;} static void free_node_to_present_cpumask(cpumask_var_t *masks){	int node; 	for (node = 0; node < nr_node_ids; node++)		free_cpumask_var(masks[node]);	kfree(masks);} static void build_node_to_present_cpumask(cpumask_var_t *masks){	int cpu; 	for_each_present_cpu(cpu)		cpumask_set_cpu(cpu, masks[cpu_to_node(cpu)]);} static int get_nodes_in_cpumask(cpumask_var_t *node_to_present_cpumask,				const struct cpumask *mask, nodemask_t *nodemsk){	int n, nodes = 0; 	/* Calculate the number of nodes in the supplied affinity mask */	for_each_node(n) {		if (cpumask_intersects(mask, node_to_present_cpumask[n])) {			node_set(n, *nodemsk);			nodes++;		}	}	return nodes;} /** * irq_create_affinity_masks - Create affinity masks for multiqueue spreading * @nvecs:	The total number of vectors * @affd:	Description of the affinity requirements * * Returns the masks pointer or NULL if allocation failed. */struct cpumask *irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd){	int n, nodes, cpus_per_vec, extra_vecs, curvec;	int affv = nvecs - affd->pre_vectors - affd->post_vectors;	int last_affv = affv + affd->pre_vectors;	nodemask_t nodemsk = NODE_MASK_NONE;	struct cpumask *masks;	cpumask_var_t nmsk, *node_to_present_cpumask; 	/*	 * If there aren't any vectors left after applying the pre/post	 * vectors don't bother with assigning affinity.	 */	if (!affv)		return NULL; 	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))		return NULL; 	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);	if (!masks)		goto out; 	node_to_present_cpumask = alloc_node_to_present_cpumask();	if (!node_to_present_cpumask)		goto out; 	/* Fill out vectors at the beginning that don't need affinity */	for (curvec = 0; curvec < affd->pre_vectors; curvec++)		cpumask_copy(masks + curvec, irq_default_affinity); 	/* Stabilize the cpumasks */	get_online_cpus();	build_node_to_present_cpumask(node_to_present_cpumask);	nodes = get_nodes_in_cpumask(node_to_present_cpumask, cpu_present_mask,				     &nodemsk); 	/*	 * If the number of nodes in the mask is greater than or equal the	 * number of vectors we just spread the vectors across the nodes.	 */	if (affv <= nodes) {		for_each_node_mask(n, nodemsk) {			cpumask_copy(masks + curvec,				     node_to_present_cpumask[n]);			if (++curvec == last_affv)				break;		}		goto done;	} 	for_each_node_mask(n, nodemsk) {		int ncpus, v, vecs_to_assign, vecs_per_node; 		/* Spread the vectors per node */		vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes; 		/* Get the cpus on this node which are in the mask */		cpumask_and(nmsk, cpu_present_mask, node_to_present_cpumask[n]); 		/* Calculate the number of cpus per vector */		ncpus = cpumask_weight(nmsk);		vecs_to_assign = min(vecs_per_node, ncpus); 		/* Account for rounding errors */		extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign); 		for (v = 0; curvec < last_affv && v < vecs_to_assign;		     curvec++, v++) {			cpus_per_vec = ncpus / vecs_to_assign; 			/* Account for extra vectors to compensate rounding errors */			if (extra_vecs) {				cpus_per_vec++;				--extra_vecs;			}			irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);		} 		if (curvec >= last_affv)			break;		--nodes;	} done:	put_online_cpus(); 	/* Fill out vectors at the end that don't need affinity */	for (; curvec < nvecs; curvec++)		cpumask_copy(masks + curvec, irq_default_affinity);	free_node_to_present_cpumask(node_to_present_cpumask);out:	free_cpumask_var(nmsk);	return masks;} /** * irq_calc_affinity_vectors - Calculate the optimal number of vectors * @minvec:	The minimum number of vectors available * @maxvec:	The maximum number of vectors available * @affd:	Description of the affinity requirements */int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd){	int resv = affd->pre_vectors + affd->post_vectors;	int vecs = maxvec - resv;	int ret; 	if (resv > minvec)		return 0; 	get_online_cpus();	ret = min_t(int, cpumask_weight(cpu_present_mask), vecs) + resv;	put_online_cpus();	return ret;}