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vhost: dynamically allocate vhost_worker

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This patchset allows us to allocate multiple workers, so this has us
move from the vhost_worker that's embedded in the vhost_dev to
dynamically allocating it.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20230626232307.97930-3-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Mike Christie 2023-06-26 18:22:52 -05:00 committed by Michael S. Tsirkin
parent 3e11c6eb6a
commit c011bb669d
2 changed files with 47 additions and 27 deletions
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70
drivers/vhost/vhost.c
View File

@ -235,36 +235,40 @@ void vhost_dev_flush(struct vhost_dev *dev)
{
struct vhost_flush_struct flush;
if (dev->worker.vtsk) {
init_completion(&flush.wait_event);
vhost_work_init(&flush.work, vhost_flush_work);
init_completion(&flush.wait_event);
vhost_work_init(&flush.work, vhost_flush_work);
vhost_work_queue(dev, &flush.work);
if (vhost_work_queue(dev, &flush.work))
wait_for_completion(&flush.wait_event);
}
}
EXPORT_SYMBOL_GPL(vhost_dev_flush);
void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
bool vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
{
if (!dev->worker.vtsk)
return;
if (!dev->worker)
return false;
/*
* vsock can queue while we do a VHOST_SET_OWNER, so we have a smp_wmb
* when setting up the worker. We don't have a smp_rmb here because
* test_and_set_bit gives us a mb already.
*/
if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
/* We can only add the work to the list after we're
* sure it was not in the list.
* test_and_set_bit() implies a memory barrier.
*/
llist_add(&work->node, &dev->worker.work_list);
vhost_task_wake(dev->worker.vtsk);
llist_add(&work->node, &dev->worker->work_list);
vhost_task_wake(dev->worker->vtsk);
}
return true;
}
EXPORT_SYMBOL_GPL(vhost_work_queue);
/* A lockless hint for busy polling code to exit the loop */
bool vhost_has_work(struct vhost_dev *dev)
{
return !llist_empty(&dev->worker.work_list);
return !llist_empty(&dev->worker->work_list);
}
EXPORT_SYMBOL_GPL(vhost_has_work);
@ -458,8 +462,7 @@ void vhost_dev_init(struct vhost_dev *dev,
dev->umem = NULL;
dev->iotlb = NULL;
dev->mm = NULL;
memset(&dev->worker, 0, sizeof(dev->worker));
init_llist_head(&dev->worker.work_list);
dev->worker = NULL;
dev->iov_limit = iov_limit;
dev->weight = weight;
dev->byte_weight = byte_weight;
@ -533,30 +536,47 @@ static void vhost_detach_mm(struct vhost_dev *dev)
static void vhost_worker_free(struct vhost_dev *dev)
{
if (!dev->worker.vtsk)
if (!dev->worker)
return;
WARN_ON(!llist_empty(&dev->worker.work_list));
vhost_task_stop(dev->worker.vtsk);
dev->worker.kcov_handle = 0;
dev->worker.vtsk = NULL;
WARN_ON(!llist_empty(&dev->worker->work_list));
vhost_task_stop(dev->worker->vtsk);
kfree(dev->worker);
dev->worker = NULL;
}
static int vhost_worker_create(struct vhost_dev *dev)
{
struct vhost_worker *worker;
struct vhost_task *vtsk;
char name[TASK_COMM_LEN];
snprintf(name, sizeof(name), "vhost-%d", current->pid);
vtsk = vhost_task_create(vhost_worker, &dev->worker, name);
if (!vtsk)
worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
if (!worker)
return -ENOMEM;
dev->worker.kcov_handle = kcov_common_handle();
dev->worker.vtsk = vtsk;
snprintf(name, sizeof(name), "vhost-%d", current->pid);
vtsk = vhost_task_create(vhost_worker, worker, name);
if (!vtsk)
goto free_worker;
init_llist_head(&worker->work_list);
worker->kcov_handle = kcov_common_handle();
worker->vtsk = vtsk;
/*
* vsock can already try to queue so make sure llist and vtsk are both
* set before vhost_work_queue sees dev->worker is set.
*/
smp_wmb();
dev->worker = worker;
vhost_task_start(vtsk);
return 0;
free_worker:
kfree(worker);
return -ENOMEM;
}
/* Caller should have device mutex */

4
drivers/vhost/vhost.h
View File

@ -44,7 +44,7 @@ struct vhost_poll {
};
void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
bool vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
bool vhost_has_work(struct vhost_dev *dev);
void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
@ -158,7 +158,7 @@ struct vhost_dev {
struct vhost_virtqueue **vqs;
int nvqs;
struct eventfd_ctx *log_ctx;
struct vhost_worker worker;
struct vhost_worker *worker;
struct vhost_iotlb *umem;
struct vhost_iotlb *iotlb;
spinlock_t iotlb_lock;