@@ -265,7 +265,7 @@ static inline u32 vio_dring_avail(struct vio_dring_state *dr,
unsigned int ring_size)
{
return (dr->pending -
- ((dr->prod - dr->cons) & (ring_size - 1)));
+ ((dr->prod - dr->cons) & (ring_size - 1)) - 1);
}
#define VIO_MAX_TYPE_LEN 32
@@ -33,7 +33,7 @@ MODULE_DESCRIPTION("Sun LDOM virtual disk client driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_MODULE_VERSION);
-#define VDC_TX_RING_SIZE 256
+#define VDC_TX_RING_SIZE 512
#define WAITING_FOR_LINK_UP 0x01
#define WAITING_FOR_TX_SPACE 0x02
@@ -283,7 +283,9 @@ static void vdc_end_one(struct vdc_port *port, struct vio_dring_state *dr,
__blk_end_request(req, (desc->status ? -EIO : 0), desc->size);
- if (blk_queue_stopped(port->disk->queue))
+ /* restart blk queue when ring is half emptied */
+ if (blk_queue_stopped(port->disk->queue) &&
+ vdc_tx_dring_avail(dr) * 100 / VDC_TX_RING_SIZE >= 50)
blk_start_queue(port->disk->queue);
}
@@ -435,12 +437,6 @@ static int __send_request(struct request *req)
for (i = 0; i < nsg; i++)
len += sg[i].length;
- if (unlikely(vdc_tx_dring_avail(dr) < 1)) {
- blk_stop_queue(port->disk->queue);
- err = -ENOMEM;
- goto out;
- }
-
desc = vio_dring_cur(dr);
err = ldc_map_sg(port->vio.lp, sg, nsg,
@@ -480,21 +476,32 @@ static int __send_request(struct request *req)
port->req_id++;
dr->prod = (dr->prod + 1) & (VDC_TX_RING_SIZE - 1);
}
-out:
return err;
}
-static void do_vdc_request(struct request_queue *q)
+static void do_vdc_request(struct request_queue *rq)
{
- while (1) {
- struct request *req = blk_fetch_request(q);
+ struct request *req;
- if (!req)
- break;
+ while ((req = blk_peek_request(rq)) != NULL) {
+ struct vdc_port *port;
+ struct vio_dring_state *dr;
- if (__send_request(req) < 0)
- __blk_end_request_all(req, -EIO);
+ port = req->rq_disk->private_data;
+ dr = &port->vio.drings[VIO_DRIVER_TX_RING];
+ if (unlikely(vdc_tx_dring_avail(dr) < 1))
+ goto wait;
+
+ blk_start_request(req);
+
+ if (__send_request(req) < 0) {
+ blk_requeue_request(rq, req);
+wait:
+ /* Avoid pointless unplugs. */
+ blk_stop_queue(rq);
+ break;
+ }
}
}
@@ -690,7 +690,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
spin_lock_irqsave(&port->vio.lock, flags);
dr = &port->vio.drings[VIO_DRIVER_TX_RING];
- if (unlikely(vnet_tx_dring_avail(dr) < 2)) {
+ if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
if (!netif_queue_stopped(dev)) {
netif_stop_queue(dev);
@@ -746,7 +746,7 @@ static int vnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
dev->stats.tx_bytes += skb->len;
dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1);
- if (unlikely(vnet_tx_dring_avail(dr) < 2)) {
+ if (unlikely(vnet_tx_dring_avail(dr) < 1)) {
netif_stop_queue(dev);
if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr))
netif_wake_queue(dev);
vio_dring_avail() will allow use of every dring entry, but when the last entry is allocated then dr->prod == dr->cons which is indistinguishable from the ring empty condition. This causes the next allocation to reuse an entry. When this happens in sunvdc, the server side vds driver begins nack'ing the messages and ends up resetting the ldc channel. This problem does not effect sunvnet since it checks for < 2. The fix here is to just never allocate the very last dring slot so that full and empty are not the same condition. The request start path was changed to check for the ring being full a bit earlier, and to stop the blk_queue if there is no space left. The blk_queue will be restarted once the ring is only half full again. The number of ring entries was increased to 512 which matches the sunvnet and Solaris vdc drivers, and greatly reduces the frequency of hitting the ring full condition and the associated blk_queue stop/starting. The checks in sunvent were adjusted to account for vio_dring_avail() returning 1 less. Orabug: 19441666 OraBZ: 14983 Signed-off-by: Dwight Engen <dwight.engen@oracle.com> --- arch/sparc/include/asm/vio.h | 2 +- drivers/block/sunvdc.c | 39 +++++++++++++++++++++-------------- drivers/net/ethernet/sun/sunvnet.c | 4 +- 3 files changed, 26 insertions(+), 19 deletions(-)