Free page reporting only supports buddy pages, it can't report the
free pages reserved for hugetlbfs case. On the other hand, hugetlbfs
is a good choice for a system with a huge amount of RAM, because it
can help to reduce the memory management overhead and improve system
performance. This patch add support for reporting free hugepage to
host when guest use hugetlbfs.
A new feature bit and a new vq is added for this new feature.
Cc: Alexander Duyck
Cc: Mel Gorman
Cc: Andrea Arcangeli
Cc: Dan Williams
Cc: Dave Hansen
Cc: David Hildenbrand
Cc: Michal Hocko
Cc: Andrew Morton
Cc: Alex Williamson
Cc: Michael S. Tsirkin
Cc: Jason Wang
Cc: Mike Kravetz
Cc: Liang Li
Signed-off-by: Liang Li
---
drivers/virtio/virtio_balloon.c | 61 +
include/uapi/linux/virtio_balloon.h | 1 +
2 files changed, 62 insertions(+)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index a298517079bb..61363dfd3c2d 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -52,6 +52,7 @@ enum virtio_balloon_vq {
VIRTIO_BALLOON_VQ_STATS,
VIRTIO_BALLOON_VQ_FREE_PAGE,
VIRTIO_BALLOON_VQ_REPORTING,
+ VIRTIO_BALLOON_VQ_HPG_REPORTING,
VIRTIO_BALLOON_VQ_MAX
};
@@ -126,6 +127,10 @@ struct virtio_balloon {
/* Free page reporting device */
struct virtqueue *reporting_vq;
struct page_reporting_dev_info pr_dev_info;
+
+ /* Free hugepage reporting device */
+ struct virtqueue *hpg_reporting_vq;
+ struct page_reporting_dev_info hpr_dev_info;
};
static const struct virtio_device_id id_table[] = {
@@ -192,6 +197,33 @@ static int virtballoon_free_page_report(struct
page_reporting_dev_info *pr_dev_i
return 0;
}
+static int virtballoon_free_hugepage_report(struct page_reporting_dev_info
*hpr_dev_info,
+ struct scatterlist *sg, unsigned int nents)
+{
+ struct virtio_balloon *vb =
+ container_of(hpr_dev_info, struct virtio_balloon, hpr_dev_info);
+ struct virtqueue *vq = vb->hpg_reporting_vq;
+ unsigned int unused, err;
+
+ /* We should always be able to add these buffers to an empty queue. */
+ err = virtqueue_add_inbuf(vq, sg, nents, vb, GFP_NOWAIT | __GFP_NOWARN);
+
+ /*
+* In the extremely unlikely case that something has occurred and we
+* are able to trigger an error we will simply display a warning
+* and exit without actually processing the pages.
+*/
+ if (WARN_ON_ONCE(err))
+ return err;
+
+ virtqueue_kick(vq);
+
+ /* When host has read buffer, this completes via balloon_ack */
+ wait_event(vb->acked, virtqueue_get_buf(vq, &unused));
+
+ return 0;
+}
+
static void set_page_pfns(struct virtio_balloon *vb,
__virtio32 pfns[], struct page *page)
{
@@ -515,6 +547,7 @@ static int init_vqs(struct virtio_balloon *vb)
callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL;
names[VIRTIO_BALLOON_VQ_REPORTING] = NULL;
+ names[VIRTIO_BALLOON_VQ_HPG_REPORTING] = NULL;
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
names[VIRTIO_BALLOON_VQ_STATS] = "stats";
@@ -531,6 +564,11 @@ static int init_vqs(struct virtio_balloon *vb)
callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack;
}
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HPG_REPORTING)) {
+ names[VIRTIO_BALLOON_VQ_HPG_REPORTING] = "hpg_reporting_vq";
+ callbacks[VIRTIO_BALLOON_VQ_HPG_REPORTING] = balloon_ack;
+ }
+
err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX,
vqs, callbacks, names, NULL, NULL);
if (err)
@@ -566,6 +604,8 @@ static int init_vqs(struct virtio_balloon *vb)
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING))
vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING];
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HPG_REPORTING))
+ vb->hpg_reporting_vq = vqs[VIRTIO_BALLOON_VQ_HPG_REPORTING];
return 0;
}
@@ -1001,6 +1041,24 @@ static int virtballoon_probe(struct virtio_device *vdev)
goto out_unregister_oom;
}
+ vb->hpr_dev_info.report = virtballoon_free_hugepage_report;
+ if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_HPG_REPORTING)) {
+ unsigned int capacity;
+
+ capacity = virtqueue_get_vring_size(vb->hpg_reporting_vq);
+ if (capacity < PAGE_REPORTING_CAPACITY) {
+ err = -ENOSPC;
+ goto out_unregister_oom;
+ }
+
+ vb->hpr_dev_info.mini_order = 0;
+ vb->hpr_dev_info.batch_size = 2 * 1024 * 1024; /* 2M */
+ vb->h
