Re: [PATCH v3 05/11] vduse: Support automatic irq callback affinity
From: Jason Wang
Date: Thu Mar 16 2023 - 05:04:39 EST
在 2023/2/28 17:41, Xie Yongji 写道:
This brings current interrupt affinity spreading mechanism
to vduse device. We will make use of group_cpus_evenly()
to create an irq callback affinity mask for each virtqueue of
vduse device. Then we will spread IRQs between CPUs in the affinity
mask, in a round-robin manner, to run the irq callback.
Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
---
drivers/vdpa/vdpa_user/vduse_dev.c | 130 +++++++++++++++++++++++++++--
1 file changed, 123 insertions(+), 7 deletions(-)
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 98359d87a06f..bde28a8692d5 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -23,6 +23,8 @@
#include <linux/nospec.h>
#include <linux/vmalloc.h>
#include <linux/sched/mm.h>
+#include <linux/interrupt.h>
+#include <linux/group_cpus.h>
#include <uapi/linux/vduse.h>
#include <uapi/linux/vdpa.h>
#include <uapi/linux/virtio_config.h>
@@ -41,6 +43,8 @@
#define VDUSE_IOVA_SIZE (128 * 1024 * 1024)
#define VDUSE_MSG_DEFAULT_TIMEOUT 30
+#define IRQ_UNBOUND -1
+
struct vduse_virtqueue {
u16 index;
u16 num_max;
@@ -57,6 +61,8 @@ struct vduse_virtqueue {
struct vdpa_callback cb;
struct work_struct inject;
struct work_struct kick;
+ int irq_effective_cpu;
+ struct cpumask irq_affinity;
};
struct vduse_dev;
@@ -128,6 +134,7 @@ static struct class *vduse_class;
static struct cdev vduse_ctrl_cdev;
static struct cdev vduse_cdev;
static struct workqueue_struct *vduse_irq_wq;
+static struct workqueue_struct *vduse_irq_bound_wq;
static u32 allowed_device_id[] = {
VIRTIO_ID_BLOCK,
@@ -708,6 +715,82 @@ static u32 vduse_vdpa_get_generation(struct vdpa_device *vdpa)
return dev->generation;
}
+static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
+{
+ affd->nr_sets = 1;
+ affd->set_size[0] = affvecs;
+}
+
+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 void vduse_vdpa_set_irq_affinity(struct vdpa_device *vdpa,
+ struct irq_affinity *desc)
+{
+ struct vduse_dev *dev = vdpa_to_vduse(vdpa);
+ struct cpumask *masks;
+ int i;
+
+ masks = create_affinity_masks(dev->vq_num, desc);
+ if (!masks)
+ return;
+
+ for (i = 0; i < dev->vq_num; i++)
+ cpumask_copy(&dev->vqs[i]->irq_affinity, &masks[i]);
+ kfree(masks);
+}
+
static int vduse_vdpa_set_map(struct vdpa_device *vdpa,
unsigned int asid,
struct vhost_iotlb *iotlb)
@@ -758,6 +841,7 @@ static const struct vdpa_config_ops vduse_vdpa_config_ops = {
.get_config = vduse_vdpa_get_config,
.set_config = vduse_vdpa_set_config,
.get_generation = vduse_vdpa_get_generation,
+ .set_irq_affinity = vduse_vdpa_set_irq_affinity,
.reset = vduse_vdpa_reset,
.set_map = vduse_vdpa_set_map,
.free = vduse_vdpa_free,
@@ -917,7 +1001,8 @@ static void vduse_vq_irq_inject(struct work_struct *work)
}
static int vduse_dev_queue_irq_work(struct vduse_dev *dev,
- struct work_struct *irq_work)
+ struct work_struct *irq_work,
+ int irq_effective_cpu)
{
int ret = -EINVAL;
@@ -926,7 +1011,11 @@ static int vduse_dev_queue_irq_work(struct vduse_dev *dev,
goto unlock;
ret = 0;
- queue_work(vduse_irq_wq, irq_work);
+ if (irq_effective_cpu == IRQ_UNBOUND)
+ queue_work(vduse_irq_wq, irq_work);
+ else
+ queue_work_on(irq_effective_cpu,
+ vduse_irq_bound_wq, irq_work);
unlock:
up_read(&dev->rwsem);
@@ -1029,6 +1118,22 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
return ret;
}
+static void vduse_vq_update_effective_cpu(struct vduse_virtqueue *vq)
+{
+ int curr_cpu = vq->irq_effective_cpu;
+
+ while (true) {
+ curr_cpu = cpumask_next(curr_cpu, &vq->irq_affinity);
+ if (cpu_online(curr_cpu))
+ break;
+
+ if (curr_cpu >= nr_cpu_ids)
+ curr_cpu = -1;
IRQ_UNBOUND?
+ }
+
+ vq->irq_effective_cpu = curr_cpu;
+}
+
static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
@@ -1111,7 +1216,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
break;
}
case VDUSE_DEV_INJECT_CONFIG_IRQ:
- ret = vduse_dev_queue_irq_work(dev, &dev->inject);
+ ret = vduse_dev_queue_irq_work(dev, &dev->inject, IRQ_UNBOUND);
break;
case VDUSE_VQ_SETUP: {
struct vduse_vq_config config;
@@ -1198,7 +1303,10 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
break;
index = array_index_nospec(index, dev->vq_num);
- ret = vduse_dev_queue_irq_work(dev, &dev->vqs[index]->inject);
+
+ vduse_vq_update_effective_cpu(dev->vqs[index]);
+ ret = vduse_dev_queue_irq_work(dev, &dev->vqs[index]->inject,
+ dev->vqs[index]->irq_effective_cpu);
break;
}
case VDUSE_IOTLB_REG_UMEM: {
@@ -1367,10 +1475,12 @@ static int vduse_dev_init_vqs(struct vduse_dev *dev, u32 vq_align, u32 vq_num)
goto err;
dev->vqs[i]->index = i;
+ dev->vqs[i]->irq_effective_cpu = -1;
IRQ_UNBOUND?
Other looks good.
Thanks
INIT_WORK(&dev->vqs[i]->inject, vduse_vq_irq_inject);
INIT_WORK(&dev->vqs[i]->kick, vduse_vq_kick_work);
spin_lock_init(&dev->vqs[i]->kick_lock);
spin_lock_init(&dev->vqs[i]->irq_lock);
+ cpumask_setall(&dev->vqs[i]->irq_affinity);
}
return 0;
@@ -1858,12 +1968,15 @@ static int vduse_init(void)
if (ret)
goto err_cdev;
+ ret = -ENOMEM;
vduse_irq_wq = alloc_workqueue("vduse-irq",
WQ_HIGHPRI | WQ_SYSFS | WQ_UNBOUND, 0);
- if (!vduse_irq_wq) {
- ret = -ENOMEM;
+ if (!vduse_irq_wq)
goto err_wq;
- }
+
+ vduse_irq_bound_wq = alloc_workqueue("vduse-irq-bound", WQ_HIGHPRI, 0);
+ if (!vduse_irq_bound_wq)
+ goto err_bound_wq;
ret = vduse_domain_init();
if (ret)
@@ -1877,6 +1990,8 @@ static int vduse_init(void)
err_mgmtdev:
vduse_domain_exit();
err_domain:
+ destroy_workqueue(vduse_irq_bound_wq);
+err_bound_wq:
destroy_workqueue(vduse_irq_wq);
err_wq:
cdev_del(&vduse_cdev);
@@ -1896,6 +2011,7 @@ static void vduse_exit(void)
{
vduse_mgmtdev_exit();
vduse_domain_exit();
+ destroy_workqueue(vduse_irq_bound_wq);
destroy_workqueue(vduse_irq_wq);
cdev_del(&vduse_cdev);
device_destroy(vduse_class, vduse_major);