[PATCH 9/9] virtio_scsi: use virtio IRQ affinity
From: Christoph Hellwig <hch@lst.de>
Date: 2017-01-27 08:45:53
Also in:
lkml, virtualization
Subsystem:
cpu hotplug, scsi subsystem, the rest, virtio block and scsi drivers · Maintainers:
Thomas Gleixner, Peter Zijlstra, "James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds, "Michael S. Tsirkin", Jason Wang
Use automatic IRQ affinity assignment in the virtio layer if available, and build the blk-mq queues based on it. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/scsi/virtio_scsi.c | 126 +++++---------------------------------------- include/linux/cpuhotplug.h | 1 - 2 files changed, 12 insertions(+), 115 deletions(-)
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 32a1629..5582c8b 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c@@ -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;
@@ -757,6 +757,13 @@ 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",
@@ -792,6 +799,7 @@ 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, };
@@ -808,80 +816,6 @@ 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) {
@@ -891,14 +825,8 @@ 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); }
@@ -911,6 +839,7 @@ 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);
@@ -933,7 +862,7 @@ 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;
@@ -999,10 +928,6 @@ 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;
@@ -1057,9 +982,6 @@ 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); }
@@ -1067,10 +989,6 @@ 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; }
@@ -1085,11 +1003,6 @@ 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))
@@ -1144,16 +1057,6 @@ 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;
@@ -1169,17 +1072,12 @@ 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); }
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index d936a00..16d8bb9 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h@@ -28,7 +28,6 @@ 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,
--
2.1.4