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-rw-r--r--kernel/irq/affinity.c128
1 files changed, 128 insertions, 0 deletions
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
new file mode 100644
index 000000000..44a4eba80
--- /dev/null
+++ b/kernel/irq/affinity.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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>
+#include <linux/group_cpus.h>
+
+static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
+{
+ affd->nr_sets = 1;
+ affd->set_size[0] = affvecs;
+}
+
+/**
+ * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
+ * @nvecs: The total number of vectors
+ * @affd: Description of the affinity requirements
+ *
+ * Returns the irq_affinity_desc pointer or NULL if allocation failed.
+ */
+struct irq_affinity_desc *
+irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
+{
+ unsigned int affvecs, curvec, usedvecs, i;
+ struct irq_affinity_desc *masks = NULL;
+
+ /*
+ * Determine the number of vectors which need interrupt affinities
+ * assigned. If the pre/post request exhausts the available vectors
+ * then nothing to do here except for invoking the calc_sets()
+ * callback so the device driver can adjust to the situation.
+ */
+ if (nvecs > affd->pre_vectors + affd->post_vectors)
+ affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
+ else
+ affvecs = 0;
+
+ /*
+ * Simple invocations do not provide a calc_sets() callback. Install
+ * the generic one.
+ */
+ if (!affd->calc_sets)
+ affd->calc_sets = default_calc_sets;
+
+ /* Recalculate the sets */
+ affd->calc_sets(affd, affvecs);
+
+ if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS))
+ return NULL;
+
+ /* Nothing to assign? */
+ if (!affvecs)
+ return NULL;
+
+ masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
+ if (!masks)
+ return NULL;
+
+ /* Fill out vectors at the beginning that don't need affinity */
+ for (curvec = 0; curvec < affd->pre_vectors; curvec++)
+ cpumask_copy(&masks[curvec].mask, irq_default_affinity);
+
+ /*
+ * Spread on present CPUs starting from affd->pre_vectors. If we
+ * have multiple sets, build each sets affinity mask separately.
+ */
+ for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
+ unsigned int this_vecs = affd->set_size[i];
+ int j;
+ struct cpumask *result = group_cpus_evenly(this_vecs);
+
+ if (!result) {
+ kfree(masks);
+ return NULL;
+ }
+
+ for (j = 0; j < this_vecs; j++)
+ cpumask_copy(&masks[curvec + j].mask, &result[j]);
+ kfree(result);
+
+ curvec += this_vecs;
+ usedvecs += this_vecs;
+ }
+
+ /* Fill out vectors at the end that don't need affinity */
+ if (usedvecs >= affvecs)
+ curvec = affd->pre_vectors + affvecs;
+ else
+ curvec = affd->pre_vectors + usedvecs;
+ for (; curvec < nvecs; curvec++)
+ cpumask_copy(&masks[curvec].mask, irq_default_affinity);
+
+ /* Mark the managed interrupts */
+ for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)
+ masks[i].is_managed = 1;
+
+ 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
+ */
+unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
+ const struct irq_affinity *affd)
+{
+ unsigned int resv = affd->pre_vectors + affd->post_vectors;
+ unsigned int set_vecs;
+
+ if (resv > minvec)
+ return 0;
+
+ if (affd->calc_sets) {
+ set_vecs = maxvec - resv;
+ } else {
+ cpus_read_lock();
+ set_vecs = cpumask_weight(cpu_possible_mask);
+ cpus_read_unlock();
+ }
+
+ return resv + min(set_vecs, maxvec - resv);
+}