vhost: replace vhost_workqueue with per-vhost kthread (c23f3445) · Commits · e / devices / android_kernel_teracube_emerald

drivers/vhost/net.c

+24 −32

Original line number	Original line	Diff line number	Diff line
	@@ -302,54 +302,58 @@ static void handle_rx(struct vhost_net *net)
	unuse_mm(net->dev.mm);		unuse_mm(net->dev.mm);
	}		}

	static void handle_tx_kick(struct work_struct *work)		static void handle_tx_kick(struct vhost_work *work)
	{		{
	struct vhost_virtqueue *vq;		struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
	struct vhost_net *net;		poll.work);
	vq = container_of(work, struct vhost_virtqueue, poll.work);		struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
	net = container_of(vq->dev, struct vhost_net, dev);
	handle_tx(net);		handle_tx(net);
	}		}

	static void handle_rx_kick(struct work_struct *work)		static void handle_rx_kick(struct vhost_work *work)
	{		{
	struct vhost_virtqueue *vq;		struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
	struct vhost_net *net;		poll.work);
	vq = container_of(work, struct vhost_virtqueue, poll.work);		struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
	net = container_of(vq->dev, struct vhost_net, dev);
	handle_rx(net);		handle_rx(net);
	}		}

	static void handle_tx_net(struct work_struct *work)		static void handle_tx_net(struct vhost_work *work)
	{		{
	struct vhost_net *net;		struct vhost_net *net = container_of(work, struct vhost_net,
	net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_TX].work);		poll[VHOST_NET_VQ_TX].work);
	handle_tx(net);		handle_tx(net);
	}		}

	static void handle_rx_net(struct work_struct *work)		static void handle_rx_net(struct vhost_work *work)
	{		{
	struct vhost_net *net;		struct vhost_net *net = container_of(work, struct vhost_net,
	net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_RX].work);		poll[VHOST_NET_VQ_RX].work);
	handle_rx(net);		handle_rx(net);
	}		}

	static int vhost_net_open(struct inode inode, struct file f)		static int vhost_net_open(struct inode inode, struct file f)
	{		{
	struct vhost_net n = kmalloc(sizeof n, GFP_KERNEL);		struct vhost_net n = kmalloc(sizeof n, GFP_KERNEL);
			struct vhost_dev *dev;
	int r;		int r;

	if (!n)		if (!n)
	return -ENOMEM;		return -ENOMEM;

			dev = &n->dev;
	n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;		n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
	n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;		n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
	r = vhost_dev_init(&n->dev, n->vqs, VHOST_NET_VQ_MAX);		r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX);
	if (r < 0) {		if (r < 0) {
	kfree(n);		kfree(n);
	return r;		return r;
	}		}

	vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT);		vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
	vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN);		vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
	n->tx_poll_state = VHOST_NET_POLL_DISABLED;		n->tx_poll_state = VHOST_NET_POLL_DISABLED;

	f->private_data = n;		f->private_data = n;
	@@ -656,25 +660,13 @@ static struct miscdevice vhost_net_misc = {

	static int vhost_net_init(void)		static int vhost_net_init(void)
	{		{
	int r = vhost_init();		return misc_register(&vhost_net_misc);
	if (r)
	goto err_init;
	r = misc_register(&vhost_net_misc);
	if (r)
	goto err_reg;
	return 0;
	err_reg:
	vhost_cleanup();
	err_init:
	return r;

	}		}
	module_init(vhost_net_init);		module_init(vhost_net_init);

	static void vhost_net_exit(void)		static void vhost_net_exit(void)
	{		{
	misc_deregister(&vhost_net_misc);		misc_deregister(&vhost_net_misc);
	vhost_cleanup();
	}		}
	module_exit(vhost_net_exit);		module_exit(vhost_net_exit);

drivers/vhost/vhost.c

+115 −28

Original line number	Original line	Diff line number	Diff line
	@@ -17,12 +17,12 @@
	#include <linux/mm.h>		#include <linux/mm.h>
	#include <linux/miscdevice.h>		#include <linux/miscdevice.h>
	#include <linux/mutex.h>		#include <linux/mutex.h>
	#include <linux/workqueue.h>
	#include <linux/rcupdate.h>		#include <linux/rcupdate.h>
	#include <linux/poll.h>		#include <linux/poll.h>
	#include <linux/file.h>		#include <linux/file.h>
	#include <linux/highmem.h>		#include <linux/highmem.h>
	#include <linux/slab.h>		#include <linux/slab.h>
			#include <linux/kthread.h>

	#include <linux/net.h>		#include <linux/net.h>
	#include <linux/if_packet.h>		#include <linux/if_packet.h>
	@@ -37,8 +37,6 @@ enum {
	VHOST_MEMORY_F_LOG = 0x1,		VHOST_MEMORY_F_LOG = 0x1,
	};		};

	static struct workqueue_struct *vhost_workqueue;

	static void vhost_poll_func(struct file file, wait_queue_head_t wqh,		static void vhost_poll_func(struct file file, wait_queue_head_t wqh,
	poll_table *pt)		poll_table *pt)
	{		{
	@@ -52,23 +50,31 @@ static void vhost_poll_func(struct file file, wait_queue_head_t wqh,
	static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,		static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
	void *key)		void *key)
	{		{
	struct vhost_poll *poll;		struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
	poll = container_of(wait, struct vhost_poll, wait);
	if (!((unsigned long)key & poll->mask))		if (!((unsigned long)key & poll->mask))
	return 0;		return 0;

	queue_work(vhost_workqueue, &poll->work);		vhost_poll_queue(poll);
	return 0;		return 0;
	}		}

	/* Init poll structure */		/* Init poll structure */
	void vhost_poll_init(struct vhost_poll *poll, work_func_t func,		void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
	unsigned long mask)		unsigned long mask, struct vhost_dev *dev)
	{		{
	INIT_WORK(&poll->work, func);		struct vhost_work *work = &poll->work;

	init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);		init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
	init_poll_funcptr(&poll->table, vhost_poll_func);		init_poll_funcptr(&poll->table, vhost_poll_func);
	poll->mask = mask;		poll->mask = mask;
			poll->dev = dev;

			INIT_LIST_HEAD(&work->node);
			work->fn = fn;
			init_waitqueue_head(&work->done);
			work->flushing = 0;
			work->queue_seq = work->done_seq = 0;
	}		}

	/* Start polling a file. We add ourselves to file's wait queue. The caller must		/* Start polling a file. We add ourselves to file's wait queue. The caller must
	@@ -92,12 +98,40 @@ void vhost_poll_stop(struct vhost_poll *poll)
	* locks that are also used by the callback. */		* locks that are also used by the callback. */
	void vhost_poll_flush(struct vhost_poll *poll)		void vhost_poll_flush(struct vhost_poll *poll)
	{		{
	flush_work(&poll->work);		struct vhost_work *work = &poll->work;
			unsigned seq;
			int left;
			int flushing;

			spin_lock_irq(&poll->dev->work_lock);
			seq = work->queue_seq;
			work->flushing++;
			spin_unlock_irq(&poll->dev->work_lock);
			wait_event(work->done, ({
			spin_lock_irq(&poll->dev->work_lock);
			left = seq - work->done_seq <= 0;
			spin_unlock_irq(&poll->dev->work_lock);
			left;
			}));
			spin_lock_irq(&poll->dev->work_lock);
			flushing = --work->flushing;
			spin_unlock_irq(&poll->dev->work_lock);
			BUG_ON(flushing < 0);
	}		}

	void vhost_poll_queue(struct vhost_poll *poll)		void vhost_poll_queue(struct vhost_poll *poll)
	{		{
	queue_work(vhost_workqueue, &poll->work);		struct vhost_dev *dev = poll->dev;
			struct vhost_work *work = &poll->work;
			unsigned long flags;

			spin_lock_irqsave(&dev->work_lock, flags);
			if (list_empty(&work->node)) {
			list_add_tail(&work->node, &dev->work_list);
			work->queue_seq++;
			wake_up_process(dev->worker);
			}
			spin_unlock_irqrestore(&dev->work_lock, flags);
	}		}

	static void vhost_vq_reset(struct vhost_dev *dev,		static void vhost_vq_reset(struct vhost_dev *dev,
	@@ -125,10 +159,51 @@ static void vhost_vq_reset(struct vhost_dev *dev,
	vq->log_ctx = NULL;		vq->log_ctx = NULL;
	}		}

			static int vhost_worker(void *data)
			{
			struct vhost_dev *dev = data;
			struct vhost_work *work = NULL;
			unsigned uninitialized_var(seq);

			for (;;) {
			/* mb paired w/ kthread_stop */
			set_current_state(TASK_INTERRUPTIBLE);

			spin_lock_irq(&dev->work_lock);
			if (work) {
			work->done_seq = seq;
			if (work->flushing)
			wake_up_all(&work->done);
			}

			if (kthread_should_stop()) {
			spin_unlock_irq(&dev->work_lock);
			__set_current_state(TASK_RUNNING);
			return 0;
			}
			if (!list_empty(&dev->work_list)) {
			work = list_first_entry(&dev->work_list,
			struct vhost_work, node);
			list_del_init(&work->node);
			seq = work->queue_seq;
			} else
			work = NULL;
			spin_unlock_irq(&dev->work_lock);

			if (work) {
			__set_current_state(TASK_RUNNING);
			work->fn(work);
			} else
			schedule();

			}
			}

	long vhost_dev_init(struct vhost_dev *dev,		long vhost_dev_init(struct vhost_dev *dev,
	struct vhost_virtqueue *vqs, int nvqs)		struct vhost_virtqueue *vqs, int nvqs)
	{		{
	int i;		int i;

	dev->vqs = vqs;		dev->vqs = vqs;
	dev->nvqs = nvqs;		dev->nvqs = nvqs;
	mutex_init(&dev->mutex);		mutex_init(&dev->mutex);
	@@ -136,6 +211,9 @@ long vhost_dev_init(struct vhost_dev *dev,
	dev->log_file = NULL;		dev->log_file = NULL;
	dev->memory = NULL;		dev->memory = NULL;
	dev->mm = NULL;		dev->mm = NULL;
			spin_lock_init(&dev->work_lock);
			INIT_LIST_HEAD(&dev->work_list);
			dev->worker = NULL;

	for (i = 0; i < dev->nvqs; ++i) {		for (i = 0; i < dev->nvqs; ++i) {
	dev->vqs[i].dev = dev;		dev->vqs[i].dev = dev;
	@@ -143,9 +221,9 @@ long vhost_dev_init(struct vhost_dev *dev,
	vhost_vq_reset(dev, dev->vqs + i);		vhost_vq_reset(dev, dev->vqs + i);
	if (dev->vqs[i].handle_kick)		if (dev->vqs[i].handle_kick)
	vhost_poll_init(&dev->vqs[i].poll,		vhost_poll_init(&dev->vqs[i].poll,
	dev->vqs[i].handle_kick,		dev->vqs[i].handle_kick, POLLIN, dev);
	POLLIN);
	}		}

	return 0;		return 0;
	}		}

	@@ -159,12 +237,31 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
	/* Caller should have device mutex */		/* Caller should have device mutex */
	static long vhost_dev_set_owner(struct vhost_dev *dev)		static long vhost_dev_set_owner(struct vhost_dev *dev)
	{		{
			struct task_struct *worker;
			int err;
	/* Is there an owner already? */		/* Is there an owner already? */
	if (dev->mm)		if (dev->mm) {
	return -EBUSY;		err = -EBUSY;
			goto err_mm;
			}
	/* No owner, become one */		/* No owner, become one */
	dev->mm = get_task_mm(current);		dev->mm = get_task_mm(current);
			worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
			if (IS_ERR(worker)) {
			err = PTR_ERR(worker);
			goto err_worker;
			}

			dev->worker = worker;
			wake_up_process(worker); /* avoid contributing to loadavg */

	return 0;		return 0;
			err_worker:
			if (dev->mm)
			mmput(dev->mm);
			dev->mm = NULL;
			err_mm:
			return err;
	}		}

	/* Caller should have device mutex */		/* Caller should have device mutex */
	@@ -217,6 +314,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
	if (dev->mm)		if (dev->mm)
	mmput(dev->mm);		mmput(dev->mm);
	dev->mm = NULL;		dev->mm = NULL;

			WARN_ON(!list_empty(&dev->work_list));
			kthread_stop(dev->worker);
	}		}

	static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)		static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
	@@ -1115,16 +1215,3 @@ void vhost_disable_notify(struct vhost_virtqueue *vq)
	vq_err(vq, "Failed to enable notification at %p: %d\n",		vq_err(vq, "Failed to enable notification at %p: %d\n",
	&vq->used->flags, r);		&vq->used->flags, r);
	}		}

	int vhost_init(void)
	{
	vhost_workqueue = create_singlethread_workqueue("vhost");
	if (!vhost_workqueue)
	return -ENOMEM;
	return 0;
	}

	void vhost_cleanup(void)
	{
	destroy_workqueue(vhost_workqueue);
	}

drivers/vhost/vhost.h

+25 −13

Original line number	Original line	Diff line number	Diff line
	@@ -5,13 +5,13 @@
	#include <linux/vhost.h>		#include <linux/vhost.h>
	#include <linux/mm.h>		#include <linux/mm.h>
	#include <linux/mutex.h>		#include <linux/mutex.h>
	#include <linux/workqueue.h>
	#include <linux/poll.h>		#include <linux/poll.h>
	#include <linux/file.h>		#include <linux/file.h>
	#include <linux/skbuff.h>		#include <linux/skbuff.h>
	#include <linux/uio.h>		#include <linux/uio.h>
	#include <linux/virtio_config.h>		#include <linux/virtio_config.h>
	#include <linux/virtio_ring.h>		#include <linux/virtio_ring.h>
			#include <asm/atomic.h>

	struct vhost_device;		struct vhost_device;

	@@ -20,19 +20,31 @@ enum {
	VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2,		VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2,
	};		};

			struct vhost_work;
			typedef void (vhost_work_fn_t)(struct vhost_work work);

			struct vhost_work {
			struct list_head node;
			vhost_work_fn_t fn;
			wait_queue_head_t done;
			int flushing;
			unsigned queue_seq;
			unsigned done_seq;
			};

	/* Poll a file (eventfd or socket) */		/* Poll a file (eventfd or socket) */
	/* Note: there's nothing vhost specific about this structure. */		/* Note: there's nothing vhost specific about this structure. */
	struct vhost_poll {		struct vhost_poll {
	poll_table table;		poll_table table;
	wait_queue_head_t *wqh;		wait_queue_head_t *wqh;
	wait_queue_t wait;		wait_queue_t wait;
	/* struct which will handle all actual work. */		struct vhost_work work;
	struct work_struct work;
	unsigned long mask;		unsigned long mask;
			struct vhost_dev *dev;
	};		};

	void vhost_poll_init(struct vhost_poll *poll, work_func_t func,		void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
	unsigned long mask);		unsigned long mask, struct vhost_dev *dev);
	void vhost_poll_start(struct vhost_poll poll, struct file file);		void vhost_poll_start(struct vhost_poll poll, struct file file);
	void vhost_poll_stop(struct vhost_poll *poll);		void vhost_poll_stop(struct vhost_poll *poll);
	void vhost_poll_flush(struct vhost_poll *poll);		void vhost_poll_flush(struct vhost_poll *poll);
	@@ -63,7 +75,7 @@ struct vhost_virtqueue {
	struct vhost_poll poll;		struct vhost_poll poll;

	/* The routine to call when the Guest pings us, or timeout. */		/* The routine to call when the Guest pings us, or timeout. */
	work_func_t handle_kick;		vhost_work_fn_t handle_kick;

	/* Last available index we saw. */		/* Last available index we saw. */
	u16 last_avail_idx;		u16 last_avail_idx;
	@@ -86,11 +98,11 @@ struct vhost_virtqueue {
	struct iovec hdr[VHOST_NET_MAX_SG];		struct iovec hdr[VHOST_NET_MAX_SG];
	size_t hdr_size;		size_t hdr_size;
	/* We use a kind of RCU to access private pointer.		/* We use a kind of RCU to access private pointer.
	* All readers access it from workqueue, which makes it possible to		* All readers access it from worker, which makes it possible to
	* flush the workqueue instead of synchronize_rcu. Therefore readers do		* flush the vhost_work instead of synchronize_rcu. Therefore readers do
	* not need to call rcu_read_lock/rcu_read_unlock: the beginning of		* not need to call rcu_read_lock/rcu_read_unlock: the beginning of
	* work item execution acts instead of rcu_read_lock() and the end of		* vhost_work execution acts instead of rcu_read_lock() and the end of
	* work item execution acts instead of rcu_read_lock().		* vhost_work execution acts instead of rcu_read_lock().
	* Writers use virtqueue mutex. */		* Writers use virtqueue mutex. */
	void *private_data;		void *private_data;
	/* Log write descriptors */		/* Log write descriptors */
	@@ -110,6 +122,9 @@ struct vhost_dev {
	int nvqs;		int nvqs;
	struct file *log_file;		struct file *log_file;
	struct eventfd_ctx *log_ctx;		struct eventfd_ctx *log_ctx;
			spinlock_t work_lock;
			struct list_head work_list;
			struct task_struct *worker;
	};		};

	long vhost_dev_init(struct vhost_dev , struct vhost_virtqueue vqs, int nvqs);		long vhost_dev_init(struct vhost_dev , struct vhost_virtqueue vqs, int nvqs);
	@@ -136,9 +151,6 @@ bool vhost_enable_notify(struct vhost_virtqueue *);
	int vhost_log_write(struct vhost_virtqueue vq, struct vhost_log log,		int vhost_log_write(struct vhost_virtqueue vq, struct vhost_log log,
	unsigned int log_num, u64 len);		unsigned int log_num, u64 len);

	int vhost_init(void);
	void vhost_cleanup(void);

	#define vq_err(vq, fmt, ...) do { \		#define vq_err(vq, fmt, ...) do { \
	pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \		pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
	if ((vq)->error_ctx) \		if ((vq)->error_ctx) \