1 // SPDX-License-Identifier: GPL-2.0
4  * Copyright (C) 2016-2017 Christoph Hellwig.
6 #include <linux/interrupt.h>
27 		cpus_per_vec--;  in irq_spread_init_one()
31 		for (sibl = -1; cpus_per_vec > 0; ) {  in irq_spread_init_one()
38 			cpus_per_vec--;  in irq_spread_init_one()
60 	while (--node >= 0)  in alloc_node_to_cpumask()
88 	/* Calculate the number of nodes in the supplied affinity mask */  in get_nodes_in_cpumask()
112 	return ln->ncpus - rn->ncpus;  in ncpus_cmp_func()
161 	 * node's nr_cpus to remaining un-assigned ncpus. 'numvecs' is  in alloc_nodes_vectors()
166 	 * least one vector, and the theory is simple: over-allocation  in alloc_nodes_vectors()
184 	 * 	vecs(B) = V - vecs(A)  in alloc_nodes_vectors()
187 	 * 	V = N - delta, and 0 <= delta <= N - 2  in alloc_nodes_vectors()
200 	 * 	over-allocated, so vecs(B) <= ncpu(B),  in alloc_nodes_vectors()
206 	 * 		round_down((N - delta) * ncpu(A) / N) =  in alloc_nodes_vectors()
207 	 * 		round_down((N * ncpu(A) - delta * ncpu(A)) / N)	 >=  in alloc_nodes_vectors()
208 	 * 		round_down((N * ncpu(A) - delta * N) / N)	 =  in alloc_nodes_vectors()
209 	 * 		cpu(A) - delta  in alloc_nodes_vectors()
213 	 * 	vecs(A) - V >= ncpu(A) - delta - V  in alloc_nodes_vectors()
215 	 * 	V - vecs(A) <= V + delta - ncpu(A)  in alloc_nodes_vectors()
217 	 * 	vecs(B) <= N - ncpu(A)  in alloc_nodes_vectors()
223 	 * and we always re-calculate 'remaining_ncpus' & 'numvecs', and  in alloc_nodes_vectors()
242 		remaining_ncpus -= ncpus;  in alloc_nodes_vectors()
243 		numvecs -= nvectors;  in alloc_nodes_vectors()
284 		return -ENOMEM;  in __irq_build_affinity_masks()
294 		if (nv->nvectors == UINT_MAX)  in __irq_build_affinity_masks()
298 		cpumask_and(nmsk, cpu_mask, node_to_cpumask[nv->id]);  in __irq_build_affinity_masks()
303 		WARN_ON_ONCE(nv->nvectors > ncpus);  in __irq_build_affinity_masks()
306 		extra_vecs = ncpus - nv->nvectors * (ncpus / nv->nvectors);  in __irq_build_affinity_masks()
309 		for (v = 0; v < nv->nvectors; v++, curvec++) {  in __irq_build_affinity_masks()
310 			cpus_per_vec = ncpus / nv->nvectors;  in __irq_build_affinity_masks()
315 				--extra_vecs;  in __irq_build_affinity_masks()
327 		done += nv->nvectors;  in __irq_build_affinity_masks()
334  * build affinity in two stages:
345 	int ret = -ENOMEM;  in irq_build_affinity_masks()
361 	/* Spread on present CPUs starting from affd->pre_vectors */  in irq_build_affinity_masks()
404 	affd->nr_sets = 1;  in default_calc_sets()
405 	affd->set_size[0] = affvecs;  in default_calc_sets()
409  * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
411  * @affd:	Description of the affinity requirements
422 	 * Determine the number of vectors which need interrupt affinities  in irq_create_affinity_masks()
427 	if (nvecs > affd->pre_vectors + affd->post_vectors)  in irq_create_affinity_masks()
428 		affvecs = nvecs - affd->pre_vectors - affd->post_vectors;  in irq_create_affinity_masks()
436 	if (!affd->calc_sets)  in irq_create_affinity_masks()
437 		affd->calc_sets = default_calc_sets;  in irq_create_affinity_masks()
440 	affd->calc_sets(affd, affvecs);  in irq_create_affinity_masks()
442 	if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS))  in irq_create_affinity_masks()
453 	/* Fill out vectors at the beginning that don't need affinity */  in irq_create_affinity_masks()
454 	for (curvec = 0; curvec < affd->pre_vectors; curvec++)  in irq_create_affinity_masks()
458 	 * Spread on present CPUs starting from affd->pre_vectors. If we  in irq_create_affinity_masks()
459 	 * have multiple sets, build each sets affinity mask separately.  in irq_create_affinity_masks()
461 	for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {  in irq_create_affinity_masks()
462 		unsigned int this_vecs = affd->set_size[i];  in irq_create_affinity_masks()
475 	/* Fill out vectors at the end that don't need affinity */  in irq_create_affinity_masks()
477 		curvec = affd->pre_vectors + affvecs;  in irq_create_affinity_masks()
479 		curvec = affd->pre_vectors + usedvecs;  in irq_create_affinity_masks()
484 	for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)  in irq_create_affinity_masks()
491  * irq_calc_affinity_vectors - Calculate the optimal number of vectors
494  * @affd:	Description of the affinity requirements
499 	unsigned int resv = affd->pre_vectors + affd->post_vectors;  in irq_calc_affinity_vectors()
505 	if (affd->calc_sets) {  in irq_calc_affinity_vectors()
506 		set_vecs = maxvec - resv;  in irq_calc_affinity_vectors()
513 	return resv + min(set_vecs, maxvec - resv);  in irq_calc_affinity_vectors()