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Commit 0d9f0a52 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Michael S. Tsirkin
Browse files

virtio_scsi: use virtio IRQ affinity 



Use automatic IRQ affinity assignment in the virtio layer if available,
and build the blk-mq queues based on it.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent ad71473d

drivers/scsi/virtio_scsi.c

+12 −114
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/module.h>

#include <linux/slab.h>

#include <linux/mempool.h>

#include <linux/interrupt.h>

#include <linux/virtio.h>

#include <linux/virtio_ids.h>

#include <linux/virtio_config.h>
@@ -29,6 +30,7 @@ 
#include <scsi/scsi_cmnd.h>

#include <scsi/scsi_tcq.h>

#include <linux/seqlock.h>

#include <linux/blk-mq-virtio.h>



#define VIRTIO_SCSI_MEMPOOL_SZ 64

#define VIRTIO_SCSI_EVENT_LEN 8
@@ -108,7 +110,6 @@ struct virtio_scsi { 
	bool affinity_hint_set;



	struct hlist_node node;

	struct hlist_node node_dead;



	/* Protected by event_vq lock */

	bool stop_events;
@@ -118,7 +119,6 @@ struct virtio_scsi { 
	struct virtio_scsi_vq req_vqs[];

};



static enum cpuhp_state virtioscsi_online;

static struct kmem_cache *virtscsi_cmd_cache;

static mempool_t *virtscsi_cmd_pool;
@@ -766,6 +766,13 @@ static void virtscsi_target_destroy(struct scsi_target *starget) 
	kfree(tgt);

}



static int virtscsi_map_queues(struct Scsi_Host *shost)

{

	struct virtio_scsi *vscsi = shost_priv(shost);



	return blk_mq_virtio_map_queues(&shost->tag_set, vscsi->vdev, 2);

}



static struct scsi_host_template virtscsi_host_template_single = {

	.module = THIS_MODULE,

	.name = "Virtio SCSI HBA",
@@ -801,6 +808,7 @@ static struct scsi_host_template virtscsi_host_template_multi = { 
	.use_clustering = ENABLE_CLUSTERING,

	.target_alloc = virtscsi_target_alloc,

	.target_destroy = virtscsi_target_destroy,

	.map_queues = virtscsi_map_queues,

	.track_queue_depth = 1,

};
@@ -817,80 +825,6 @@ static struct scsi_host_template virtscsi_host_template_multi = { 
		virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \

	} while(0)



static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)

{

	int i;

	int cpu;



	/* In multiqueue mode, when the number of cpu is equal

	 * to the number of request queues, we let the qeueues

	 * to be private to one cpu by setting the affinity hint

	 * to eliminate the contention.

	 */

	if ((vscsi->num_queues == 1 ||

	     vscsi->num_queues != num_online_cpus()) && affinity) {

		if (vscsi->affinity_hint_set)

			affinity = false;

		else

			return;

	}



	if (affinity) {

		i = 0;

		for_each_online_cpu(cpu) {

			virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);

			i++;

		}



		vscsi->affinity_hint_set = true;

	} else {

		for (i = 0; i < vscsi->num_queues; i++) {

			if (!vscsi->req_vqs[i].vq)

				continue;



			virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);

		}



		vscsi->affinity_hint_set = false;

	}

}



static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)

{

	get_online_cpus();

	__virtscsi_set_affinity(vscsi, affinity);

	put_online_cpus();

}



static int virtscsi_cpu_online(unsigned int cpu, struct hlist_node *node)

{

	struct virtio_scsi *vscsi = hlist_entry_safe(node, struct virtio_scsi,

						     node);

	__virtscsi_set_affinity(vscsi, true);

	return 0;

}



static int virtscsi_cpu_notif_add(struct virtio_scsi *vi)

{

	int ret;



	ret = cpuhp_state_add_instance(virtioscsi_online, &vi->node);

	if (ret)

		return ret;



	ret = cpuhp_state_add_instance(CPUHP_VIRT_SCSI_DEAD, &vi->node_dead);

	if (ret)

		cpuhp_state_remove_instance(virtioscsi_online, &vi->node);

	return ret;

}



static void virtscsi_cpu_notif_remove(struct virtio_scsi *vi)

{

	cpuhp_state_remove_instance_nocalls(virtioscsi_online, &vi->node);

	cpuhp_state_remove_instance_nocalls(CPUHP_VIRT_SCSI_DEAD,

					    &vi->node_dead);

}



static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,

			     struct virtqueue *vq)

{
@@ -900,14 +834,8 @@ static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq, 


static void virtscsi_remove_vqs(struct virtio_device *vdev)

{

	struct Scsi_Host *sh = virtio_scsi_host(vdev);

	struct virtio_scsi *vscsi = shost_priv(sh);



	virtscsi_set_affinity(vscsi, false);



	/* Stop all the virtqueues. */

	vdev->config->reset(vdev);



	vdev->config->del_vqs(vdev);

}
@@ -920,6 +848,7 @@ static int virtscsi_init(struct virtio_device *vdev, 
	vq_callback_t **callbacks;

	const char **names;

	struct virtqueue **vqs;

	struct irq_affinity desc = { .pre_vectors = 2 };



	num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;

	vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
@@ -942,7 +871,7 @@ static int virtscsi_init(struct virtio_device *vdev, 


	/* Discover virtqueues and write information to configuration.  */

	err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names,

			NULL);

			&desc);

	if (err)

		goto out;
@@ -1008,10 +937,6 @@ static int virtscsi_probe(struct virtio_device *vdev) 
	if (err)

		goto virtscsi_init_failed;



	err = virtscsi_cpu_notif_add(vscsi);

	if (err)

		goto scsi_add_host_failed;



	cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;

	shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);

	shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
@@ -1066,9 +991,6 @@ static void virtscsi_remove(struct virtio_device *vdev) 
		virtscsi_cancel_event_work(vscsi);



	scsi_remove_host(shost);



	virtscsi_cpu_notif_remove(vscsi);



	virtscsi_remove_vqs(vdev);

	scsi_host_put(shost);

}
@@ -1076,10 +998,6 @@ static void virtscsi_remove(struct virtio_device *vdev) 
#ifdef CONFIG_PM_SLEEP

static int virtscsi_freeze(struct virtio_device *vdev)

{

	struct Scsi_Host *sh = virtio_scsi_host(vdev);

	struct virtio_scsi *vscsi = shost_priv(sh);



	virtscsi_cpu_notif_remove(vscsi);

	virtscsi_remove_vqs(vdev);

	return 0;

}
@@ -1094,11 +1012,6 @@ static int virtscsi_restore(struct virtio_device *vdev) 
	if (err)

		return err;



	err = virtscsi_cpu_notif_add(vscsi);

	if (err) {

		vdev->config->del_vqs(vdev);

		return err;

	}

	virtio_device_ready(vdev);



	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
@@ -1153,16 +1066,6 @@ static int __init init(void) 
		pr_err("mempool_create() for virtscsi_cmd_pool failed\n");

		goto error;

	}

	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,

				      "scsi/virtio:online",

				      virtscsi_cpu_online, NULL);

	if (ret < 0)

		goto error;

	virtioscsi_online = ret;

	ret = cpuhp_setup_state_multi(CPUHP_VIRT_SCSI_DEAD, "scsi/virtio:dead",

				      NULL, virtscsi_cpu_online);

	if (ret)

		goto error;

	ret = register_virtio_driver(&virtio_scsi_driver);

	if (ret < 0)

		goto error;
@@ -1178,17 +1081,12 @@ static int __init init(void) 
		kmem_cache_destroy(virtscsi_cmd_cache);

		virtscsi_cmd_cache = NULL;

	}

	if (virtioscsi_online)

		cpuhp_remove_multi_state(virtioscsi_online);

	cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);

	return ret;

}



static void __exit fini(void)

{

	unregister_virtio_driver(&virtio_scsi_driver);

	cpuhp_remove_multi_state(virtioscsi_online);

	cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);

	mempool_destroy(virtscsi_cmd_pool);

	kmem_cache_destroy(virtscsi_cmd_cache);

}

include/linux/cpuhotplug.h

+0 −1
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ enum cpuhp_state { 
	CPUHP_ARM_OMAP_WAKE_DEAD,

	CPUHP_IRQ_POLL_DEAD,

	CPUHP_BLOCK_SOFTIRQ_DEAD,

	CPUHP_VIRT_SCSI_DEAD,

	CPUHP_ACPI_CPUDRV_DEAD,

	CPUHP_S390_PFAULT_DEAD,

	CPUHP_BLK_MQ_DEAD,