Add a new vq to report hints of guest free pages to the host. Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx> Signed-off-by: Liang Li <liang.z.li@xxxxxxxxx> --- drivers/virtio/virtio_balloon.c | 167 +++++++++++++++++++++++++++++++----- include/uapi/linux/virtio_balloon.h | 1 + 2 files changed, 147 insertions(+), 21 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 72041b4..e6755bc 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -54,11 +54,12 @@ static struct vfsmount *balloon_mnt; struct virtio_balloon { struct virtio_device *vdev; - struct virtqueue *inflate_vq, *deflate_vq, *stats_vq; + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; /* The balloon servicing is delegated to a freezable workqueue. */ struct work_struct update_balloon_stats_work; struct work_struct update_balloon_size_work; + struct work_struct report_free_page_work; /* Prevent updating balloon when it is being canceled. */ spinlock_t stop_update_lock; @@ -90,6 +91,13 @@ struct virtio_balloon { /* Memory statistics */ struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; + /* + * Used by the device and driver to signal each other. + * device->driver: start the free page report. + * driver->device: end the free page report. + */ + __virtio32 report_free_page_signal; + /* To register callback in oom notifier call chain */ struct notifier_block nb; }; @@ -174,6 +182,17 @@ static void send_balloon_page_sg(struct virtio_balloon *vb, } while (unlikely(ret == -ENOSPC)); } +static void send_free_page_sg(struct virtqueue *vq, void *addr, uint32_t size) +{ + unsigned int len; + + add_one_sg(vq, addr, size); + virtqueue_kick(vq); + /* Release entries if there are */ + while (virtqueue_get_buf(vq, &len)) + ; +} + /* * Send balloon pages in sgs to host. The balloon pages are recorded in the * page xbitmap. Each bit in the bitmap corresponds to a page of PAGE_SIZE. @@ -511,42 +530,143 @@ static void update_balloon_size_func(struct work_struct *work) queue_work(system_freezable_wq, work); } +static void virtio_balloon_send_free_pages(void *opaque, unsigned long pfn, + unsigned long nr_pages) +{ + struct virtio_balloon *vb = (struct virtio_balloon *)opaque; + void *addr = (void *)pfn_to_kaddr(pfn); + uint32_t len = nr_pages << PAGE_SHIFT; + + send_free_page_sg(vb->free_page_vq, addr, len); +} + +static void report_free_page_completion(struct virtio_balloon *vb) +{ + struct virtqueue *vq = vb->free_page_vq; + struct scatterlist sg; + unsigned int len; + int ret; + + sg_init_one(&sg, &vb->report_free_page_signal, sizeof(__virtio32)); +retry: + ret = virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL); + virtqueue_kick(vq); + if (unlikely(ret == -ENOSPC)) { + wait_event(vb->acked, virtqueue_get_buf(vq, &len)); + goto retry; + } +} + +static void report_free_page(struct work_struct *work) +{ + struct virtio_balloon *vb; + + vb = container_of(work, struct virtio_balloon, report_free_page_work); + walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages); + report_free_page_completion(vb); +} + +static void free_page_request(struct virtqueue *vq) +{ + struct virtio_balloon *vb = vq->vdev->priv; + + queue_work(system_freezable_wq, &vb->report_free_page_work); +} + static int init_vqs(struct virtio_balloon *vb) { - struct virtqueue *vqs[3]; - vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request }; - static const char * const names[] = { "inflate", "deflate", "stats" }; - int err, nvqs; + struct virtqueue **vqs; + vq_callback_t **callbacks; + const char **names; + struct scatterlist sg; + int i, nvqs, err = -ENOMEM; + + /* Inflateq and deflateq are used unconditionally */ + nvqs = 2; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) + nvqs++; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_VQ)) + nvqs++; + + /* Allocate space for find_vqs parameters */ + vqs = kcalloc(nvqs, sizeof(*vqs), GFP_KERNEL); + if (!vqs) + goto err_vq; + callbacks = kmalloc_array(nvqs, sizeof(*callbacks), GFP_KERNEL); + if (!callbacks) + goto err_callback; + names = kmalloc_array(nvqs, sizeof(*names), GFP_KERNEL); + if (!names) + goto err_names; + + callbacks[0] = balloon_ack; + names[0] = "inflate"; + callbacks[1] = balloon_ack; + names[1] = "deflate"; + + i = 2; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { + callbacks[i] = stats_request; + names[i] = "stats"; + i++; + } - /* - * We expect two virtqueues: inflate and deflate, and - * optionally stat. - */ - nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; - err = virtio_find_vqs(vb->vdev, nvqs, vqs, callbacks, names, NULL); + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_VQ)) { + callbacks[i] = free_page_request; + names[i] = "free_page_vq"; + } + + err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names, + NULL, NULL); if (err) - return err; + goto err_find; vb->inflate_vq = vqs[0]; vb->deflate_vq = vqs[1]; + i = 2; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { - struct scatterlist sg; - unsigned int num_stats; - vb->stats_vq = vqs[2]; - + vb->stats_vq = vqs[i++]; /* * Prime this virtqueue with one buffer so the hypervisor can * use it to signal us later (it can't be broken yet!). */ - num_stats = update_balloon_stats(vb); - - sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats); + sg_init_one(&sg, vb->stats, sizeof(vb->stats)); if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL) - < 0) - BUG(); + < 0) { + dev_warn(&vb->vdev->dev, "%s: add stat_vq failed\n", + __func__); + goto err_find; + } virtqueue_kick(vb->stats_vq); } + + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_VQ)) { + vb->free_page_vq = vqs[i]; + vb->report_free_page_signal = 0; + sg_init_one(&sg, &vb->report_free_page_signal, + sizeof(__virtio32)); + if (virtqueue_add_outbuf(vb->free_page_vq, &sg, 1, vb, + GFP_KERNEL) < 0) { + dev_warn(&vb->vdev->dev, "%s: add signal buf failed\n", + __func__); + goto err_find; + } + virtqueue_kick(vb->free_page_vq); + } + + kfree(names); + kfree(callbacks); + kfree(vqs); return 0; + +err_find: + kfree(names); +err_names: + kfree(callbacks); +err_callback: + kfree(vqs); +err_vq: + return err; } #ifdef CONFIG_BALLOON_COMPACTION @@ -675,6 +795,9 @@ static int virtballoon_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_SG)) xb_init(&vb->page_xb); + if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_VQ)) + INIT_WORK(&vb->report_free_page_work, report_free_page); + vb->nb.notifier_call = virtballoon_oom_notify; vb->nb.priority = VIRTBALLOON_OOM_NOTIFY_PRIORITY; err = register_oom_notifier(&vb->nb); @@ -739,6 +862,7 @@ static void virtballoon_remove(struct virtio_device *vdev) spin_unlock_irq(&vb->stop_update_lock); cancel_work_sync(&vb->update_balloon_size_work); cancel_work_sync(&vb->update_balloon_stats_work); + cancel_work_sync(&vb->report_free_page_work); remove_common(vb); #ifdef CONFIG_BALLOON_COMPACTION @@ -792,6 +916,7 @@ static unsigned int features[] = { VIRTIO_BALLOON_F_STATS_VQ, VIRTIO_BALLOON_F_DEFLATE_ON_OOM, VIRTIO_BALLOON_F_SG, + VIRTIO_BALLOON_F_FREE_PAGE_VQ, }; static struct virtio_driver virtio_balloon_driver = { diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h index 37780a7..8214f84 100644 --- a/include/uapi/linux/virtio_balloon.h +++ b/include/uapi/linux/virtio_balloon.h @@ -35,6 +35,7 @@ #define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */ #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ #define VIRTIO_BALLOON_F_SG 3 /* Use sg instead of PFN lists */ +#define VIRTIO_BALLOON_F_FREE_PAGE_VQ 4 /* Virtqueue to report free pages */ /* Size of a PFN in the balloon interface. */ #define VIRTIO_BALLOON_PFN_SHIFT 12 -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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