From c23f3445e68e1db0e74099f264bc5ff5d55ebdeb Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 2 Jun 2010 20:40:00 +0200 Subject: vhost: replace vhost_workqueue with per-vhost kthread Replace vhost_workqueue with per-vhost kthread. Other than callback argument change from struct work_struct * to struct vhost_work *, there's no visible change to vhost_poll_*() interface. This conversion is to make each vhost use a dedicated kthread so that resource control via cgroup can be applied. Partially based on Sridhar Samudrala's patch. * Updated to use sub structure vhost_work instead of directly using vhost_poll at Michael's suggestion. * Added flusher wake_up() optimization at Michael's suggestion. Changes by MST: * Converted atomics/barrier use to a spinlock. * Create thread on SET_OWNER * Fix flushing Signed-off-by: Tejun Heo Signed-off-by: Michael S. Tsirkin Cc: Sridhar Samudrala --- drivers/vhost/vhost.h | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) (limited to 'drivers/vhost/vhost.h') diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 11ee13dba0f7..3693327549b3 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -5,13 +5,13 @@ #include #include #include -#include #include #include #include #include #include #include +#include struct vhost_device; @@ -20,19 +20,31 @@ enum { 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) */ /* Note: there's nothing vhost specific about this structure. */ struct vhost_poll { poll_table table; wait_queue_head_t *wqh; wait_queue_t wait; - /* struct which will handle all actual work. */ - struct work_struct work; + struct vhost_work work; unsigned long mask; + struct vhost_dev *dev; }; -void vhost_poll_init(struct vhost_poll *poll, work_func_t func, - unsigned long mask); +void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, + unsigned long mask, struct vhost_dev *dev); void vhost_poll_start(struct vhost_poll *poll, struct file *file); void vhost_poll_stop(struct vhost_poll *poll); void vhost_poll_flush(struct vhost_poll *poll); @@ -63,7 +75,7 @@ struct vhost_virtqueue { struct vhost_poll poll; /* 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. */ u16 last_avail_idx; @@ -86,11 +98,11 @@ struct vhost_virtqueue { struct iovec hdr[VHOST_NET_MAX_SG]; size_t hdr_size; /* We use a kind of RCU to access private pointer. - * All readers access it from workqueue, which makes it possible to - * flush the workqueue instead of synchronize_rcu. Therefore readers do + * All readers access it from worker, which makes it possible to + * flush the vhost_work instead of synchronize_rcu. Therefore readers do * 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 - * work item execution acts instead of rcu_read_lock(). + * vhost_work execution acts instead of rcu_read_lock() and the end of + * vhost_work execution acts instead of rcu_read_lock(). * Writers use virtqueue mutex. */ void *private_data; /* Log write descriptors */ @@ -110,6 +122,9 @@ struct vhost_dev { int nvqs; struct file *log_file; 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); @@ -136,9 +151,6 @@ bool vhost_enable_notify(struct vhost_virtqueue *); int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, unsigned int log_num, u64 len); -int vhost_init(void); -void vhost_cleanup(void); - #define vq_err(vq, fmt, ...) do { \ pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ if ((vq)->error_ctx) \ -- cgit v1.2.1