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group_cpus_evenly() has become a generic function which can be used for other subsystems than the interrupt subsystem, so move it into lib/. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20221227022905.352674-6-ming.lei@redhat.com
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2016 Thomas Gleixner.
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* Copyright (C) 2016-2017 Christoph Hellwig.
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*/
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/cpu.h>
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#include <linux/group_cpus.h>
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static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
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{
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affd->nr_sets = 1;
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affd->set_size[0] = affvecs;
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}
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/**
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* irq_create_affinity_masks - Create affinity masks for multiqueue spreading
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* @nvecs: The total number of vectors
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* @affd: Description of the affinity requirements
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*
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* Returns the irq_affinity_desc pointer or NULL if allocation failed.
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*/
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struct irq_affinity_desc *
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irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
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{
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unsigned int affvecs, curvec, usedvecs, i;
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struct irq_affinity_desc *masks = NULL;
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/*
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* Determine the number of vectors which need interrupt affinities
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* assigned. If the pre/post request exhausts the available vectors
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* then nothing to do here except for invoking the calc_sets()
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* callback so the device driver can adjust to the situation.
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*/
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if (nvecs > affd->pre_vectors + affd->post_vectors)
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affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
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else
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affvecs = 0;
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/*
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* Simple invocations do not provide a calc_sets() callback. Install
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* the generic one.
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*/
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if (!affd->calc_sets)
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affd->calc_sets = default_calc_sets;
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/* Recalculate the sets */
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affd->calc_sets(affd, affvecs);
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if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS))
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return NULL;
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/* Nothing to assign? */
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if (!affvecs)
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return NULL;
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masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
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if (!masks)
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return NULL;
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/* Fill out vectors at the beginning that don't need affinity */
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for (curvec = 0; curvec < affd->pre_vectors; curvec++)
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cpumask_copy(&masks[curvec].mask, irq_default_affinity);
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/*
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* Spread on present CPUs starting from affd->pre_vectors. If we
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* have multiple sets, build each sets affinity mask separately.
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*/
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for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
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unsigned int this_vecs = affd->set_size[i];
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int j;
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struct cpumask *result = group_cpus_evenly(this_vecs);
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if (!result) {
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kfree(masks);
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return NULL;
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}
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for (j = 0; j < this_vecs; j++)
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cpumask_copy(&masks[curvec + j].mask, &result[j]);
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kfree(result);
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curvec += this_vecs;
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usedvecs += this_vecs;
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}
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/* Fill out vectors at the end that don't need affinity */
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if (usedvecs >= affvecs)
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curvec = affd->pre_vectors + affvecs;
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else
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curvec = affd->pre_vectors + usedvecs;
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for (; curvec < nvecs; curvec++)
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cpumask_copy(&masks[curvec].mask, irq_default_affinity);
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/* Mark the managed interrupts */
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for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)
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masks[i].is_managed = 1;
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return masks;
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}
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/**
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* irq_calc_affinity_vectors - Calculate the optimal number of vectors
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* @minvec: The minimum number of vectors available
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* @maxvec: The maximum number of vectors available
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* @affd: Description of the affinity requirements
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*/
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unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
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const struct irq_affinity *affd)
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{
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unsigned int resv = affd->pre_vectors + affd->post_vectors;
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unsigned int set_vecs;
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if (resv > minvec)
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return 0;
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if (affd->calc_sets) {
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set_vecs = maxvec - resv;
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} else {
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cpus_read_lock();
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set_vecs = cpumask_weight(cpu_possible_mask);
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cpus_read_unlock();
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}
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return resv + min(set_vecs, maxvec - resv);
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}
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