Commit 3dad5682 authored by Xie Yongji's avatar Xie Yongji Committed by Michael S. Tsirkin
Browse files

virtio-vdpa: Support interrupt affinity spreading mechanism 



To support interrupt affinity spreading mechanism,
this makes use of group_cpus_evenly() to create
an irq callback affinity mask for each virtqueue
of vdpa device. Then we will unify set_vq_affinity
callback to pass the affinity to the vdpa device driver.

Signed-off-by: default avatarXie Yongji <xieyongji@bytedance.com>
Message-Id: <20230323053043.35-4-xieyongji@bytedance.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
parent 1d246927

drivers/virtio/virtio_vdpa.c

+68 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/uuid.h>

#include <linux/group_cpus.h>

#include <linux/virtio.h>

#include <linux/vdpa.h>

#include <linux/virtio_config.h>
@@ -272,6 +273,66 @@ static void virtio_vdpa_del_vqs(struct virtio_device *vdev) 
		virtio_vdpa_del_vq(vq);

}



static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)

{

	affd->nr_sets = 1;

	affd->set_size[0] = affvecs;

}



static struct cpumask *

create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)

{

	unsigned int affvecs = 0, curvec, usedvecs, i;

	struct cpumask *masks = NULL;



	if (nvecs > affd->pre_vectors + affd->post_vectors)

		affvecs = nvecs - affd->pre_vectors - affd->post_vectors;



	if (!affd->calc_sets)

		affd->calc_sets = default_calc_sets;



	affd->calc_sets(affd, affvecs);



	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_setall(&masks[curvec]);



	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], &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_setall(&masks[curvec]);



	return masks;

}



static int virtio_vdpa_find_vqs(struct virtio_device *vdev, unsigned int nvqs,

				struct virtqueue *vqs[],

				vq_callback_t *callbacks[],
@@ -282,9 +343,15 @@ static int virtio_vdpa_find_vqs(struct virtio_device *vdev, unsigned int nvqs, 
	struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev);

	struct vdpa_device *vdpa = vd_get_vdpa(vdev);

	const struct vdpa_config_ops *ops = vdpa->config;

	struct irq_affinity default_affd = { 0 };

	struct cpumask *masks;

	struct vdpa_callback cb;

	int i, err, queue_idx = 0;



	masks = create_affinity_masks(nvqs, desc ? desc : &default_affd);

	if (!masks)

		return -ENOMEM;



	for (i = 0; i < nvqs; ++i) {

		if (!names[i]) {

			vqs[i] = NULL;
@@ -298,6 +365,7 @@ static int virtio_vdpa_find_vqs(struct virtio_device *vdev, unsigned int nvqs, 
			err = PTR_ERR(vqs[i]);

			goto err_setup_vq;

		}

		ops->set_vq_affinity(vdpa, i, &masks[i]);

	}



	cb.callback = virtio_vdpa_config_cb;