In the case of using indirect, indirect desc must be allocated and
released each time, which increases a lot of cpu overhead.
Here, a cache is added for indirect. If the number of indirect desc to be
applied for is less than desc_cache_thr, the desc array with
the size of desc_cache_thr is fixed and cached for reuse.
Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
drivers/virtio/virtio_ring.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 010c47baa37f..d853a281fb43 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1118,7 +1118,11 @@ static void vring_unmap_desc_packed(const struct
vring_virtqueue *vq,
}
}
-static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
+#define desc_cache_get_packed(vq, n, gfp) \
+ _desc_cache_get(vq, n, gfp, struct vring_packed_desc)
+
+static struct vring_packed_desc *alloc_indirect_packed(struct vring_virtqueue
*vq,
+ unsigned int total_sg,
gfp_t gfp)
{
struct vring_packed_desc *desc;
@@ -1130,7 +1134,7 @@ static struct vring_packed_desc
*alloc_indirect_packed(unsigned int total_sg,
*/
gfp &= ~__GFP_HIGHMEM;
- desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp);
+ desc = desc_cache_get_packed(vq, total_sg, gfp);
return desc;
}
@@ -1150,7 +1154,7 @@ static int virtqueue_add_indirect_packed(struct
vring_virtqueue *vq,
dma_addr_t addr;
head = vq->packed.next_avail_idx;
- desc = alloc_indirect_packed(total_sg, gfp);
+ desc = alloc_indirect_packed(vq, total_sg, gfp);
if (unlikely(vq->vq.num_free < 1)) {
pr_debug("Can't add buf len 1 - avail = 0\n");
@@ -1241,7 +1245,7 @@ static int virtqueue_add_indirect_packed(struct
vring_virtqueue *vq,
for (i = 0; i < err_idx; i++)
vring_unmap_desc_packed(vq, &desc[i]);
- kfree(desc);
+ desc_cache_put(vq, desc, total_sg);
END_USE(vq);
return -ENOMEM;
@@ -1466,20 +1470,22 @@ static void detach_buf_packed(struct vring_virtqueue
*vq,
}
if (vq->indirect) {
- u32 len;
+ u32 len, n;
/* Free the indirect table, if any, now that it's unmapped. */
desc = state->indir_desc;
if (!desc)
return;
+ len = vq->packed.desc_extra[id].len;
+ n = len / sizeof(struct vring_packed_desc);
+
if (vq->use_dma_api) {
- len = vq->packed.desc_extra[id].len;
- for (i = 0; i < len / sizeof(struct vring_packed_desc);
- i++)
+ for (i = 0; i < n; i++)
vring_unmap_desc_packed(vq, &desc[i]);
}
- kfree(desc);
+
+ desc_cache_put(vq, desc, n);
state->indir_desc = NULL;
} else if (ctx) {
*ctx = state->indir_desc;
@@ -1798,6 +1804,8 @@ static struct virtqueue *vring_create_virtqueue_packed(
!context;
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
+ desc_cache_create(vq, vdev, sizeof(struct vring_packed_desc), num);
+
if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
vq->weak_barriers = false;
@@ -2417,8 +2425,8 @@ void vring_del_virtqueue(struct virtqueue *_vq)
if (!vq->packed_ring) {
kfree(vq->split.desc_state);
kfree(vq->split.desc_extra);
- desc_cache_free(vq);
}
+ desc_cache_free(vq);
kfree(vq);
}
EXPORT_SYMBOL_GPL(vring_del_virtqueue);
--
2.31.0
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
