348 lines
8.8 KiB
C
348 lines
8.8 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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static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
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unsigned int cpus_per_vec)
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{
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const struct cpumask *siblmsk;
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int cpu, sibl;
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for ( ; cpus_per_vec > 0; ) {
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cpu = cpumask_first(nmsk);
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/* Should not happen, but I'm too lazy to think about it */
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if (cpu >= nr_cpu_ids)
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return;
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cpumask_clear_cpu(cpu, nmsk);
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cpumask_set_cpu(cpu, irqmsk);
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cpus_per_vec--;
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/* If the cpu has siblings, use them first */
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siblmsk = topology_sibling_cpumask(cpu);
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for (sibl = -1; cpus_per_vec > 0; ) {
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sibl = cpumask_next(sibl, siblmsk);
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if (sibl >= nr_cpu_ids)
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break;
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if (!cpumask_test_and_clear_cpu(sibl, nmsk))
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continue;
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cpumask_set_cpu(sibl, irqmsk);
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cpus_per_vec--;
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}
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}
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}
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static cpumask_var_t *alloc_node_to_cpumask(void)
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{
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cpumask_var_t *masks;
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int node;
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masks = kcalloc(nr_node_ids, sizeof(cpumask_var_t), GFP_KERNEL);
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if (!masks)
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return NULL;
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for (node = 0; node < nr_node_ids; node++) {
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if (!zalloc_cpumask_var(&masks[node], GFP_KERNEL))
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goto out_unwind;
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}
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return masks;
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out_unwind:
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while (--node >= 0)
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free_cpumask_var(masks[node]);
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kfree(masks);
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return NULL;
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}
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static void free_node_to_cpumask(cpumask_var_t *masks)
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{
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int node;
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for (node = 0; node < nr_node_ids; node++)
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free_cpumask_var(masks[node]);
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kfree(masks);
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}
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static void build_node_to_cpumask(cpumask_var_t *masks)
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{
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int cpu;
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for_each_possible_cpu(cpu)
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cpumask_set_cpu(cpu, masks[cpu_to_node(cpu)]);
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}
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static int get_nodes_in_cpumask(cpumask_var_t *node_to_cpumask,
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const struct cpumask *mask, nodemask_t *nodemsk)
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{
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int n, nodes = 0;
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/* Calculate the number of nodes in the supplied affinity mask */
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for_each_node(n) {
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if (cpumask_intersects(mask, node_to_cpumask[n])) {
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node_set(n, *nodemsk);
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nodes++;
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}
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}
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return nodes;
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}
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static int __irq_build_affinity_masks(const struct irq_affinity *affd,
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unsigned int startvec,
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unsigned int numvecs,
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unsigned int firstvec,
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cpumask_var_t *node_to_cpumask,
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const struct cpumask *cpu_mask,
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struct cpumask *nmsk,
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struct irq_affinity_desc *masks)
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{
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unsigned int n, nodes, cpus_per_vec, extra_vecs, done = 0;
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unsigned int last_affv = firstvec + numvecs;
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unsigned int curvec = startvec;
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nodemask_t nodemsk = NODE_MASK_NONE;
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if (!cpumask_weight(cpu_mask))
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return 0;
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nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_mask, &nodemsk);
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/*
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* If the number of nodes in the mask is greater than or equal the
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* number of vectors we just spread the vectors across the nodes.
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*/
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if (numvecs <= nodes) {
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for_each_node_mask(n, nodemsk) {
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cpumask_or(&masks[curvec].mask, &masks[curvec].mask,
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node_to_cpumask[n]);
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if (++curvec == last_affv)
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curvec = firstvec;
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}
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return numvecs;
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}
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for_each_node_mask(n, nodemsk) {
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unsigned int ncpus, v, vecs_to_assign, vecs_per_node;
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/* Spread the vectors per node */
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vecs_per_node = (numvecs - (curvec - firstvec)) / nodes;
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/* Get the cpus on this node which are in the mask */
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cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
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/* Calculate the number of cpus per vector */
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ncpus = cpumask_weight(nmsk);
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vecs_to_assign = min(vecs_per_node, ncpus);
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/* Account for rounding errors */
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extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign);
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for (v = 0; curvec < last_affv && v < vecs_to_assign;
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curvec++, v++) {
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cpus_per_vec = ncpus / vecs_to_assign;
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/* Account for extra vectors to compensate rounding errors */
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if (extra_vecs) {
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cpus_per_vec++;
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--extra_vecs;
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}
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irq_spread_init_one(&masks[curvec].mask, nmsk,
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cpus_per_vec);
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}
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done += v;
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if (done >= numvecs)
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break;
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if (curvec >= last_affv)
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curvec = firstvec;
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--nodes;
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}
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return done;
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}
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/*
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* build affinity in two stages:
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* 1) spread present CPU on these vectors
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* 2) spread other possible CPUs on these vectors
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*/
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static int irq_build_affinity_masks(const struct irq_affinity *affd,
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unsigned int startvec, unsigned int numvecs,
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unsigned int firstvec,
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struct irq_affinity_desc *masks)
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{
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unsigned int curvec = startvec, nr_present, nr_others;
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cpumask_var_t *node_to_cpumask;
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cpumask_var_t nmsk, npresmsk;
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int ret = -ENOMEM;
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if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
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return ret;
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if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL))
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goto fail_nmsk;
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node_to_cpumask = alloc_node_to_cpumask();
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if (!node_to_cpumask)
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goto fail_npresmsk;
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ret = 0;
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/* Stabilize the cpumasks */
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get_online_cpus();
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build_node_to_cpumask(node_to_cpumask);
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/* Spread on present CPUs starting from affd->pre_vectors */
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nr_present = __irq_build_affinity_masks(affd, curvec, numvecs,
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firstvec, node_to_cpumask,
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cpu_present_mask, nmsk, masks);
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/*
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* Spread on non present CPUs starting from the next vector to be
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* handled. If the spreading of present CPUs already exhausted the
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* vector space, assign the non present CPUs to the already spread
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* out vectors.
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*/
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if (nr_present >= numvecs)
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curvec = firstvec;
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else
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curvec = firstvec + nr_present;
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cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask);
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nr_others = __irq_build_affinity_masks(affd, curvec, numvecs,
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firstvec, node_to_cpumask,
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npresmsk, nmsk, masks);
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put_online_cpus();
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if (nr_present < numvecs)
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WARN_ON(nr_present + nr_others < numvecs);
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free_node_to_cpumask(node_to_cpumask);
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fail_npresmsk:
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free_cpumask_var(npresmsk);
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fail_nmsk:
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free_cpumask_var(nmsk);
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return ret;
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}
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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. If there
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* is only a single vector, then managing the queue is pointless as
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* well.
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*/
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if (nvecs > 1 && 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 ret;
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ret = irq_build_affinity_masks(affd, curvec, this_vecs,
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curvec, masks);
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if (ret) {
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kfree(masks);
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return NULL;
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}
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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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get_online_cpus();
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set_vecs = cpumask_weight(cpu_possible_mask);
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put_online_cpus();
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}
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return resv + min(set_vecs, maxvec - resv);
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}
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