#include <linux/virtio.h>
#include <linux/virtio_balloon.h>
#include <linux/swap.h>
-#include <linux/kthread.h>
-#include <linux/freezer.h>
+#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
struct virtio_device *vdev;
struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;
- /* Where the ballooning thread waits for config to change. */
- wait_queue_head_t config_change;
+ /* The balloon servicing is delegated to a freezable workqueue. */
+ struct work_struct work;
- /* The thread servicing the balloon. */
- struct task_struct *thread;
+ /* Prevent updating balloon when it is being canceled. */
+ spinlock_t stop_update_lock;
+ bool stop_update;
/* Waiting for host to ack the pages we released. */
wait_queue_head_t acked;
pfns[i] = page_to_balloon_pfn(page) + i;
}
-static void fill_balloon(struct virtio_balloon *vb, size_t num)
+static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
{
struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;
+ unsigned num_allocated_pages;
/* We can only do one array worth at a time. */
num = min(num, ARRAY_SIZE(vb->pfns));
adjust_managed_page_count(page, -1);
}
+ num_allocated_pages = vb->num_pfns;
/* Did we get any? */
if (vb->num_pfns != 0)
tell_host(vb, vb->inflate_vq);
mutex_unlock(&vb->balloon_lock);
+
+ return num_allocated_pages;
}
static void release_pages_balloon(struct virtio_balloon *vb)
* with a single buffer. From that point forward, all conversations consist of
* a hypervisor request (a call to this function) which directs us to refill
* the virtqueue with a fresh stats buffer. Since stats collection can sleep,
- * we notify our kthread which does the actual work via stats_handle_request().
+ * we delegate the job to a freezable workqueue that will do the actual work via
+ * stats_handle_request().
*/
static void stats_request(struct virtqueue *vq)
{
struct virtio_balloon *vb = vq->vdev->priv;
vb->need_stats_update = 1;
- wake_up(&vb->config_change);
+
+ spin_lock(&vb->stop_update_lock);
+ if (!vb->stop_update)
+ queue_work(system_freezable_wq, &vb->work);
+ spin_unlock(&vb->stop_update_lock);
}
static void stats_handle_request(struct virtio_balloon *vb)
static void virtballoon_changed(struct virtio_device *vdev)
{
struct virtio_balloon *vb = vdev->priv;
+ unsigned long flags;
- wake_up(&vb->config_change);
+ spin_lock_irqsave(&vb->stop_update_lock, flags);
+ if (!vb->stop_update)
+ queue_work(system_freezable_wq, &vb->work);
+ spin_unlock_irqrestore(&vb->stop_update_lock, flags);
}
static inline s64 towards_target(struct virtio_balloon *vb)
return NOTIFY_OK;
}
-static int balloon(void *_vballoon)
+static void balloon(struct work_struct *work)
{
- struct virtio_balloon *vb = _vballoon;
- DEFINE_WAIT_FUNC(wait, woken_wake_function);
-
- set_freezable();
- while (!kthread_should_stop()) {
- s64 diff;
-
- try_to_freeze();
-
- add_wait_queue(&vb->config_change, &wait);
- for (;;) {
- if ((diff = towards_target(vb)) != 0 ||
- vb->need_stats_update ||
- kthread_should_stop() ||
- freezing(current))
- break;
- wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
- }
- remove_wait_queue(&vb->config_change, &wait);
+ struct virtio_balloon *vb;
+ s64 diff;
- if (vb->need_stats_update)
- stats_handle_request(vb);
- if (diff > 0)
- fill_balloon(vb, diff);
- else if (diff < 0)
- leak_balloon(vb, -diff);
- update_balloon_size(vb);
+ vb = container_of(work, struct virtio_balloon, work);
+ diff = towards_target(vb);
- /*
- * For large balloon changes, we could spend a lot of time
- * and always have work to do. Be nice if preempt disabled.
- */
- cond_resched();
- }
- return 0;
+ if (vb->need_stats_update)
+ stats_handle_request(vb);
+
+ if (diff > 0)
+ diff -= fill_balloon(vb, diff);
+ else if (diff < 0)
+ diff += leak_balloon(vb, -diff);
+ update_balloon_size(vb);
+
+ if (diff)
+ queue_work(system_freezable_wq, work);
}
static int init_vqs(struct virtio_balloon *vb)
goto out;
}
+ INIT_WORK(&vb->work, balloon);
+ spin_lock_init(&vb->stop_update_lock);
+ vb->stop_update = false;
vb->num_pages = 0;
mutex_init(&vb->balloon_lock);
- init_waitqueue_head(&vb->config_change);
init_waitqueue_head(&vb->acked);
vb->vdev = vdev;
vb->need_stats_update = 0;
virtio_device_ready(vdev);
- vb->thread = kthread_run(balloon, vb, "vballoon");
- if (IS_ERR(vb->thread)) {
- err = PTR_ERR(vb->thread);
- goto out_del_vqs;
- }
-
return 0;
-out_del_vqs:
- unregister_oom_notifier(&vb->nb);
out_oom_notify:
vdev->config->del_vqs(vdev);
out_free_vb:
struct virtio_balloon *vb = vdev->priv;
unregister_oom_notifier(&vb->nb);
- kthread_stop(vb->thread);
+
+ spin_lock_irq(&vb->stop_update_lock);
+ vb->stop_update = true;
+ spin_unlock_irq(&vb->stop_update_lock);
+ cancel_work_sync(&vb->work);
+
remove_common(vb);
kfree(vb);
}
struct virtio_balloon *vb = vdev->priv;
/*
- * The kthread is already frozen by the PM core before this
+ * The workqueue is already frozen by the PM core before this
* function is called.
*/
-
remove_common(vb);
return 0;
}
virtio_device_ready(vdev);
- fill_balloon(vb, towards_target(vb));
+ if (towards_target(vb))
+ virtballoon_changed(vdev);
update_balloon_size(vb);
return 0;
}
projects / cascardo / linux.git / blobdiff