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vmxnet3: add receive data ring support
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vmxnet3 driver preallocates buffers for receiving packets and posts the
buffers to the emulation. In order to deliver a received packet to the
guest, the emulation must map buffer(s) and copy the packet into it.

To avoid this memory mapping overhead, this patch introduces the receive
data ring - a set of small sized buffers that are always mapped by
the emulation. If a packet fits into the receive data ring buffer, the
emulation delivers the packet via the receive data ring (which must be
copied by the guest driver), or else the usual receive path is used.

Receive Data Ring buffer length is configurable via ethtool -G ethX rx-mini

Signed-off-by: Shrikrishna Khare <skhare@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Shrikrishna Khare authored and David S. Miller committed Jun 17, 2016
1 parent 3c8b3ef commit 50a5ce3
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Showing 4 changed files with 193 additions and 45 deletions.
14 changes: 12 additions & 2 deletions drivers/net/vmxnet3/vmxnet3_defs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -174,6 +174,8 @@ struct Vmxnet3_TxDataDesc {
u8 data[VMXNET3_HDR_COPY_SIZE];
};

typedef u8 Vmxnet3_RxDataDesc;

#define VMXNET3_TCD_GEN_SHIFT 31
#define VMXNET3_TCD_GEN_SIZE 1
#define VMXNET3_TCD_TXIDX_SHIFT 0
Expand Down Expand Up @@ -382,6 +384,10 @@ union Vmxnet3_GenericDesc {
#define VMXNET3_TXDATA_DESC_SIZE_ALIGN 64
#define VMXNET3_TXDATA_DESC_SIZE_MASK (VMXNET3_TXDATA_DESC_SIZE_ALIGN - 1)

/* Rx Data Ring buffer size must be a multiple of 64 */
#define VMXNET3_RXDATA_DESC_SIZE_ALIGN 64
#define VMXNET3_RXDATA_DESC_SIZE_MASK (VMXNET3_RXDATA_DESC_SIZE_ALIGN - 1)

/* Max ring size */
#define VMXNET3_TX_RING_MAX_SIZE 4096
#define VMXNET3_TC_RING_MAX_SIZE 4096
Expand All @@ -392,6 +398,8 @@ union Vmxnet3_GenericDesc {
#define VMXNET3_TXDATA_DESC_MIN_SIZE 128
#define VMXNET3_TXDATA_DESC_MAX_SIZE 2048

#define VMXNET3_RXDATA_DESC_MAX_SIZE 2048

/* a list of reasons for queue stop */

enum {
Expand Down Expand Up @@ -488,12 +496,14 @@ struct Vmxnet3_RxQueueConf {
__le64 rxRingBasePA[2];
__le64 compRingBasePA;
__le64 ddPA; /* driver data */
__le64 reserved;
__le64 rxDataRingBasePA;
__le32 rxRingSize[2]; /* # of rx desc */
__le32 compRingSize; /* # of rx comp desc */
__le32 ddLen; /* size of driver data */
u8 intrIdx;
u8 _pad[7];
u8 _pad1[1];
__le16 rxDataRingDescSize; /* size of rx data ring buffer */
u8 _pad2[4];
};


Expand Down
153 changes: 122 additions & 31 deletions drivers/net/vmxnet3/vmxnet3_drv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1284,9 +1284,10 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
*/
break;
}
BUG_ON(rcd->rqID != rq->qid && rcd->rqID != rq->qid2);
BUG_ON(rcd->rqID != rq->qid && rcd->rqID != rq->qid2 &&
rcd->rqID != rq->dataRingQid);
idx = rcd->rxdIdx;
ring_idx = rcd->rqID < adapter->num_rx_queues ? 0 : 1;
ring_idx = VMXNET3_GET_RING_IDX(adapter, rcd->rqID);
ring = rq->rx_ring + ring_idx;
vmxnet3_getRxDesc(rxd, &rq->rx_ring[ring_idx].base[idx].rxd,
&rxCmdDesc);
Expand All @@ -1301,8 +1302,12 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
}

if (rcd->sop) { /* first buf of the pkt */
bool rxDataRingUsed;
u16 len;

BUG_ON(rxd->btype != VMXNET3_RXD_BTYPE_HEAD ||
rcd->rqID != rq->qid);
(rcd->rqID != rq->qid &&
rcd->rqID != rq->dataRingQid));

BUG_ON(rbi->buf_type != VMXNET3_RX_BUF_SKB);
BUG_ON(ctx->skb != NULL || rbi->skb == NULL);
Expand All @@ -1318,8 +1323,12 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,

skip_page_frags = false;
ctx->skb = rbi->skb;

rxDataRingUsed =
VMXNET3_RX_DATA_RING(adapter, rcd->rqID);
len = rxDataRingUsed ? rcd->len : rbi->len;
new_skb = netdev_alloc_skb_ip_align(adapter->netdev,
rbi->len);
len);
if (new_skb == NULL) {
/* Skb allocation failed, do not handover this
* skb to stack. Reuse it. Drop the existing pkt
Expand All @@ -1330,25 +1339,48 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
skip_page_frags = true;
goto rcd_done;
}
new_dma_addr = dma_map_single(&adapter->pdev->dev,
new_skb->data, rbi->len,
PCI_DMA_FROMDEVICE);
if (dma_mapping_error(&adapter->pdev->dev,
new_dma_addr)) {
dev_kfree_skb(new_skb);
/* Skb allocation failed, do not handover this
* skb to stack. Reuse it. Drop the existing pkt
*/
rq->stats.rx_buf_alloc_failure++;
ctx->skb = NULL;
rq->stats.drop_total++;
skip_page_frags = true;
goto rcd_done;
}

dma_unmap_single(&adapter->pdev->dev, rbi->dma_addr,
rbi->len,
PCI_DMA_FROMDEVICE);
if (rxDataRingUsed) {
size_t sz;

BUG_ON(rcd->len > rq->data_ring.desc_size);

ctx->skb = new_skb;
sz = rcd->rxdIdx * rq->data_ring.desc_size;
memcpy(new_skb->data,
&rq->data_ring.base[sz], rcd->len);
} else {
ctx->skb = rbi->skb;

new_dma_addr =
dma_map_single(&adapter->pdev->dev,
new_skb->data, rbi->len,
PCI_DMA_FROMDEVICE);
if (dma_mapping_error(&adapter->pdev->dev,
new_dma_addr)) {
dev_kfree_skb(new_skb);
/* Skb allocation failed, do not
* handover this skb to stack. Reuse
* it. Drop the existing pkt.
*/
rq->stats.rx_buf_alloc_failure++;
ctx->skb = NULL;
rq->stats.drop_total++;
skip_page_frags = true;
goto rcd_done;
}

dma_unmap_single(&adapter->pdev->dev,
rbi->dma_addr,
rbi->len,
PCI_DMA_FROMDEVICE);

/* Immediate refill */
rbi->skb = new_skb;
rbi->dma_addr = new_dma_addr;
rxd->addr = cpu_to_le64(rbi->dma_addr);
rxd->len = rbi->len;
}

#ifdef VMXNET3_RSS
if (rcd->rssType != VMXNET3_RCD_RSS_TYPE_NONE &&
Expand All @@ -1359,11 +1391,6 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
#endif
skb_put(ctx->skb, rcd->len);

/* Immediate refill */
rbi->skb = new_skb;
rbi->dma_addr = new_dma_addr;
rxd->addr = cpu_to_le64(rbi->dma_addr);
rxd->len = rbi->len;
if (VMXNET3_VERSION_GE_2(adapter) &&
rcd->type == VMXNET3_CDTYPE_RXCOMP_LRO) {
struct Vmxnet3_RxCompDescExt *rcdlro;
Expand Down Expand Up @@ -1590,6 +1617,13 @@ static void vmxnet3_rq_destroy(struct vmxnet3_rx_queue *rq,
rq->buf_info[i] = NULL;
}

if (rq->data_ring.base) {
dma_free_coherent(&adapter->pdev->dev,
rq->rx_ring[0].size * rq->data_ring.desc_size,
rq->data_ring.base, rq->data_ring.basePA);
rq->data_ring.base = NULL;
}

if (rq->comp_ring.base) {
dma_free_coherent(&adapter->pdev->dev, rq->comp_ring.size
* sizeof(struct Vmxnet3_RxCompDesc),
Expand All @@ -1605,6 +1639,25 @@ static void vmxnet3_rq_destroy(struct vmxnet3_rx_queue *rq,
}
}

void
vmxnet3_rq_destroy_all_rxdataring(struct vmxnet3_adapter *adapter)
{
int i;

for (i = 0; i < adapter->num_rx_queues; i++) {
struct vmxnet3_rx_queue *rq = &adapter->rx_queue[i];

if (rq->data_ring.base) {
dma_free_coherent(&adapter->pdev->dev,
(rq->rx_ring[0].size *
rq->data_ring.desc_size),
rq->data_ring.base,
rq->data_ring.basePA);
rq->data_ring.base = NULL;
rq->data_ring.desc_size = 0;
}
}
}

static int
vmxnet3_rq_init(struct vmxnet3_rx_queue *rq,
Expand Down Expand Up @@ -1698,6 +1751,22 @@ vmxnet3_rq_create(struct vmxnet3_rx_queue *rq, struct vmxnet3_adapter *adapter)
}
}

if ((adapter->rxdataring_enabled) && (rq->data_ring.desc_size != 0)) {
sz = rq->rx_ring[0].size * rq->data_ring.desc_size;
rq->data_ring.base =
dma_alloc_coherent(&adapter->pdev->dev, sz,
&rq->data_ring.basePA,
GFP_KERNEL);
if (!rq->data_ring.base) {
netdev_err(adapter->netdev,
"rx data ring will be disabled\n");
adapter->rxdataring_enabled = false;
}
} else {
rq->data_ring.base = NULL;
rq->data_ring.desc_size = 0;
}

sz = rq->comp_ring.size * sizeof(struct Vmxnet3_RxCompDesc);
rq->comp_ring.base = dma_alloc_coherent(&adapter->pdev->dev, sz,
&rq->comp_ring.basePA,
Expand Down Expand Up @@ -1730,6 +1799,8 @@ vmxnet3_rq_create_all(struct vmxnet3_adapter *adapter)
{
int i, err = 0;

adapter->rxdataring_enabled = VMXNET3_VERSION_GE_3(adapter);

for (i = 0; i < adapter->num_rx_queues; i++) {
err = vmxnet3_rq_create(&adapter->rx_queue[i], adapter);
if (unlikely(err)) {
Expand All @@ -1739,6 +1810,10 @@ vmxnet3_rq_create_all(struct vmxnet3_adapter *adapter)
goto err_out;
}
}

if (!adapter->rxdataring_enabled)
vmxnet3_rq_destroy_all_rxdataring(adapter);

return err;
err_out:
vmxnet3_rq_destroy_all(adapter);
Expand Down Expand Up @@ -2046,10 +2121,9 @@ vmxnet3_request_irqs(struct vmxnet3_adapter *adapter)
struct vmxnet3_rx_queue *rq = &adapter->rx_queue[i];
rq->qid = i;
rq->qid2 = i + adapter->num_rx_queues;
rq->dataRingQid = i + 2 * adapter->num_rx_queues;
}



/* init our intr settings */
for (i = 0; i < intr->num_intrs; i++)
intr->mod_levels[i] = UPT1_IML_ADAPTIVE;
Expand Down Expand Up @@ -2362,6 +2436,12 @@ vmxnet3_setup_driver_shared(struct vmxnet3_adapter *adapter)
(rqc->rxRingSize[0] +
rqc->rxRingSize[1]));
rqc->intrIdx = rq->comp_ring.intr_idx;
if (VMXNET3_VERSION_GE_3(adapter)) {
rqc->rxDataRingBasePA =
cpu_to_le64(rq->data_ring.basePA);
rqc->rxDataRingDescSize =
cpu_to_le16(rq->data_ring.desc_size);
}
}

#ifdef VMXNET3_RSS
Expand Down Expand Up @@ -2692,7 +2772,7 @@ vmxnet3_adjust_rx_ring_size(struct vmxnet3_adapter *adapter)
int
vmxnet3_create_queues(struct vmxnet3_adapter *adapter, u32 tx_ring_size,
u32 rx_ring_size, u32 rx_ring2_size,
u16 txdata_desc_size)
u16 txdata_desc_size, u16 rxdata_desc_size)
{
int err = 0, i;

Expand All @@ -2718,12 +2798,15 @@ vmxnet3_create_queues(struct vmxnet3_adapter *adapter, u32 tx_ring_size,
adapter->rx_queue[0].rx_ring[0].size = rx_ring_size;
adapter->rx_queue[0].rx_ring[1].size = rx_ring2_size;
vmxnet3_adjust_rx_ring_size(adapter);

adapter->rxdataring_enabled = VMXNET3_VERSION_GE_3(adapter);
for (i = 0; i < adapter->num_rx_queues; i++) {
struct vmxnet3_rx_queue *rq = &adapter->rx_queue[i];
/* qid and qid2 for rx queues will be assigned later when num
* of rx queues is finalized after allocating intrs */
rq->shared = &adapter->rqd_start[i].ctrl;
rq->adapter = adapter;
rq->data_ring.desc_size = rxdata_desc_size;
err = vmxnet3_rq_create(rq, adapter);
if (err) {
if (i == 0) {
Expand All @@ -2741,6 +2824,10 @@ vmxnet3_create_queues(struct vmxnet3_adapter *adapter, u32 tx_ring_size,
}
}
}

if (!adapter->rxdataring_enabled)
vmxnet3_rq_destroy_all_rxdataring(adapter);

return err;
queue_err:
vmxnet3_tq_destroy_all(adapter);
Expand Down Expand Up @@ -2785,7 +2872,8 @@ vmxnet3_open(struct net_device *netdev)
adapter->tx_ring_size,
adapter->rx_ring_size,
adapter->rx_ring2_size,
adapter->txdata_desc_size);
adapter->txdata_desc_size,
adapter->rxdata_desc_size);
if (err)
goto queue_err;

Expand Down Expand Up @@ -3260,6 +3348,9 @@ vmxnet3_probe_device(struct pci_dev *pdev,
SET_NETDEV_DEV(netdev, &pdev->dev);
vmxnet3_declare_features(adapter, dma64);

adapter->rxdata_desc_size = VMXNET3_VERSION_GE_3(adapter) ?
VMXNET3_DEF_RXDATA_DESC_SIZE : 0;

if (adapter->num_tx_queues == adapter->num_rx_queues)
adapter->share_intr = VMXNET3_INTR_BUDDYSHARE;
else
Expand Down
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