[linux-2.6-block.git] / kernel / irq / affinity.c

// 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);
}
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Copyright (C) 2016 Thomas Gleixner.
	4	* Copyright (C) 2016-2017 Christoph Hellwig.
	5	*/
	6	#include <linux/interrupt.h>
	7	#include <linux/kernel.h>
	8	#include <linux/slab.h>
	9	#include <linux/cpu.h>
	10	#include <linux/group_cpus.h>
	11
	12	static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
	13	{
	14	affd->nr_sets = 1;
	15	affd->set_size[0] = affvecs;
	16	}
	17
	18	/**
	19	* irq_create_affinity_masks - Create affinity masks for multiqueue spreading
	20	* @nvecs: The total number of vectors
	21	* @affd: Description of the affinity requirements
	22	*
	23	* Returns the irq_affinity_desc pointer or NULL if allocation failed.
	24	*/
	25	struct irq_affinity_desc *
	26	irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
	27	{
	28	unsigned int affvecs, curvec, usedvecs, i;
	29	struct irq_affinity_desc *masks = NULL;
	30
	31	/*
	32	* Determine the number of vectors which need interrupt affinities
	33	* assigned. If the pre/post request exhausts the available vectors
	34	* then nothing to do here except for invoking the calc_sets()
	35	* callback so the device driver can adjust to the situation.
	36	*/
	37	if (nvecs > affd->pre_vectors + affd->post_vectors)
	38	affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
	39	else
	40	affvecs = 0;
	41
	42	/*
	43	* Simple invocations do not provide a calc_sets() callback. Install
	44	* the generic one.
	45	*/
	46	if (!affd->calc_sets)
	47	affd->calc_sets = default_calc_sets;
	48
	49	/* Recalculate the sets */
	50	affd->calc_sets(affd, affvecs);
	51
	52	if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS))
	53	return NULL;
	54
	55	/* Nothing to assign? */
	56	if (!affvecs)
	57	return NULL;
	58
	59	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
	60	if (!masks)
	61	return NULL;
	62
	63	/* Fill out vectors at the beginning that don't need affinity */
	64	for (curvec = 0; curvec < affd->pre_vectors; curvec++)
	65	cpumask_copy(&masks[curvec].mask, irq_default_affinity);
	66
	67	/*
	68	* Spread on present CPUs starting from affd->pre_vectors. If we
	69	* have multiple sets, build each sets affinity mask separately.
	70	*/
	71	for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
	72	unsigned int this_vecs = affd->set_size[i];
	73	int j;
	74	struct cpumask *result = group_cpus_evenly(this_vecs);
	75
	76	if (!result) {
	77	kfree(masks);
	78	return NULL;
	79	}
	80
	81	for (j = 0; j < this_vecs; j++)
	82	cpumask_copy(&masks[curvec + j].mask, &result[j]);
	83	kfree(result);
	84
	85	curvec += this_vecs;
	86	usedvecs += this_vecs;
	87	}
	88
	89	/* Fill out vectors at the end that don't need affinity */
	90	if (usedvecs >= affvecs)
	91	curvec = affd->pre_vectors + affvecs;
	92	else
	93	curvec = affd->pre_vectors + usedvecs;
	94	for (; curvec < nvecs; curvec++)
	95	cpumask_copy(&masks[curvec].mask, irq_default_affinity);
	96
	97	/* Mark the managed interrupts */
	98	for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)
	99	masks[i].is_managed = 1;
	100
	101	return masks;
	102	}
	103
	104	/**
	105	* irq_calc_affinity_vectors - Calculate the optimal number of vectors
	106	* @minvec: The minimum number of vectors available
	107	* @maxvec: The maximum number of vectors available
	108	* @affd: Description of the affinity requirements
	109	*/
	110	unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
	111	const struct irq_affinity *affd)
	112	{
	113	unsigned int resv = affd->pre_vectors + affd->post_vectors;
	114	unsigned int set_vecs;
	115
	116	if (resv > minvec)
	117	return 0;
	118
	119	if (affd->calc_sets) {
	120	set_vecs = maxvec - resv;
	121	} else {
	122	cpus_read_lock();
	123	set_vecs = cpumask_weight(cpu_possible_mask);
	124	cpus_read_unlock();
	125	}
	126
	127	return resv + min(set_vecs, maxvec - resv);
	128	}