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Message-Id: <20180515190615.23099-13-bjorn.topel@gmail.com>
Date: Tue, 15 May 2018 21:06:15 +0200
From: Björn Töpel <bjorn.topel@...il.com>
To: bjorn.topel@...il.com, magnus.karlsson@...il.com,
magnus.karlsson@...el.com, alexander.h.duyck@...el.com,
alexander.duyck@...il.com, john.fastabend@...il.com, ast@...com,
brouer@...hat.com, willemdebruijn.kernel@...il.com,
daniel@...earbox.net, mst@...hat.com, netdev@...r.kernel.org
Cc: michael.lundkvist@...csson.com, jesse.brandeburg@...el.com,
anjali.singhai@...el.com, qi.z.zhang@...el.com,
intel-wired-lan@...ts.osuosl.org
Subject: [RFC PATCH bpf-next 12/12] i40e: implement Tx zero-copy
From: Magnus Karlsson <magnus.karlsson@...el.com>
Here, the zero-copy ndo is implemented. As a shortcut, the existing
XDP Tx rings are used for zero-copy. This means that and XDP program
cannot redirect to an AF_XDP enabled XDP Tx ring.
Signed-off-by: Magnus Karlsson <magnus.karlsson@...el.com>
---
drivers/net/ethernet/intel/i40e/i40e_main.c | 7 +-
drivers/net/ethernet/intel/i40e/i40e_txrx.c | 235 +++++++++++++++++++++++-----
drivers/net/ethernet/intel/i40e/i40e_txrx.h | 6 +
3 files changed, 212 insertions(+), 36 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index dc3d668a741e..91f8e892179a 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -3055,8 +3055,12 @@ static int i40e_configure_tx_ring(struct i40e_ring *ring)
i40e_status err = 0;
u32 qtx_ctl = 0;
- if (ring_is_xdp(ring))
+ ring->clean_tx_irq = i40e_clean_tx_irq;
+ if (ring_is_xdp(ring)) {
ring->xsk_umem = i40e_xsk_umem(ring);
+ if (ring->xsk_umem)
+ ring->clean_tx_irq = i40e_clean_tx_irq_zc;
+ }
/* some ATR related tx ring init */
if (vsi->back->flags & I40E_FLAG_FD_ATR_ENABLED) {
@@ -12309,6 +12313,7 @@ static const struct net_device_ops i40e_netdev_ops = {
.ndo_bpf = i40e_xdp,
.ndo_xdp_xmit = i40e_xdp_xmit,
.ndo_xdp_flush = i40e_xdp_flush,
+ .ndo_xsk_async_xmit = i40e_xsk_async_xmit,
};
/**
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index f89ac524652c..17c067556aba 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -649,9 +649,13 @@ void i40e_clean_tx_ring(struct i40e_ring *tx_ring)
if (!tx_ring->tx_bi)
return;
- /* Free all the Tx ring sk_buffs */
- for (i = 0; i < tx_ring->count; i++)
- i40e_unmap_and_free_tx_resource(tx_ring, &tx_ring->tx_bi[i]);
+ /* Cleanup only needed for non XSK TX ZC rings */
+ if (!tx_ring->xsk_umem) {
+ /* Free all the Tx ring sk_buffs */
+ for (i = 0; i < tx_ring->count; i++)
+ i40e_unmap_and_free_tx_resource(tx_ring,
+ &tx_ring->tx_bi[i]);
+ }
bi_size = sizeof(struct i40e_tx_buffer) * tx_ring->count;
memset(tx_ring->tx_bi, 0, bi_size);
@@ -768,8 +772,139 @@ void i40e_detect_recover_hung(struct i40e_vsi *vsi)
}
}
+static inline void i40e_xdp_ring_update_tail(struct i40e_ring *xdp_ring)
+{
+ /* Force memory writes to complete before letting h/w
+ * know there are new descriptors to fetch.
+ */
+ wmb();
+ writel_relaxed(xdp_ring->next_to_use, xdp_ring->tail);
+}
+
#define WB_STRIDE 4
+static void i40e_update_stats_and_arm_wb(struct i40e_ring *tx_ring,
+ struct i40e_vsi *vsi,
+ unsigned int total_packets,
+ unsigned int total_bytes,
+ int budget)
+{
+ u64_stats_update_begin(&tx_ring->syncp);
+ tx_ring->stats.bytes += total_bytes;
+ tx_ring->stats.packets += total_packets;
+ u64_stats_update_end(&tx_ring->syncp);
+ tx_ring->q_vector->tx.total_bytes += total_bytes;
+ tx_ring->q_vector->tx.total_packets += total_packets;
+
+ if (tx_ring->flags & I40E_TXR_FLAGS_WB_ON_ITR) {
+ /* check to see if there are < 4 descriptors
+ * waiting to be written back, then kick the hardware to force
+ * them to be written back in case we stay in NAPI.
+ * In this mode on X722 we do not enable Interrupt.
+ */
+ unsigned int j = i40e_get_tx_pending(tx_ring, false);
+
+ if (budget &&
+ ((j / WB_STRIDE) == 0) && (j > 0) &&
+ !test_bit(__I40E_VSI_DOWN, vsi->state) &&
+ (I40E_DESC_UNUSED(tx_ring) != tx_ring->count))
+ tx_ring->arm_wb = true;
+ }
+}
+
+/* Returns true if the work is finished */
+static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget)
+{
+ bool work_done = true, xdp_xmit = false;
+ struct i40e_tx_buffer *tx_bi;
+ struct i40e_tx_desc *tx_desc;
+ dma_addr_t dma;
+ u16 offset;
+ u32 len;
+
+ while (budget-- > 0) {
+ if (!unlikely(I40E_DESC_UNUSED(xdp_ring))) {
+ xdp_ring->tx_stats.tx_busy++;
+ work_done = false;
+ break;
+ }
+
+ if (!xsk_umem_consume_tx(xdp_ring->xsk_umem, &dma, &len,
+ &offset))
+ break;
+
+ xdp_xmit = true;
+ dma_sync_single_for_device(xdp_ring->dev, dma, len,
+ DMA_BIDIRECTIONAL);
+
+ tx_bi = &xdp_ring->tx_bi[xdp_ring->next_to_use];
+ tx_bi->bytecount = len;
+ tx_bi->gso_segs = 1;
+
+ tx_desc = I40E_TX_DESC(xdp_ring, xdp_ring->next_to_use);
+ tx_desc->buffer_addr = cpu_to_le64(dma);
+ tx_desc->cmd_type_offset_bsz = build_ctob(I40E_TX_DESC_CMD_ICRC
+ | I40E_TX_DESC_CMD_EOP,
+ 0, len, 0);
+
+ xdp_ring->next_to_use++;
+ if (xdp_ring->next_to_use == xdp_ring->count)
+ xdp_ring->next_to_use = 0;
+ }
+
+ /* Request an interrupt for the last frame and bump tail ptr. */
+ if (xdp_xmit) {
+ tx_desc->cmd_type_offset_bsz |= (I40E_TX_DESC_CMD_RS <<
+ I40E_TXD_QW1_CMD_SHIFT);
+ i40e_xdp_ring_update_tail(xdp_ring);
+ }
+
+ return !!budget && work_done;
+}
+
+bool i40e_clean_tx_irq_zc(struct i40e_vsi *vsi,
+ struct i40e_ring *tx_ring, int napi_budget)
+{
+ unsigned int total_bytes = 0, total_packets = 0;
+ struct xdp_umem *umem = tx_ring->xsk_umem;
+ u32 head_idx = i40e_get_head(tx_ring);
+ unsigned int budget = vsi->work_limit;
+ bool work_done = true, xmit_done;
+ u32 completed_frames;
+ u32 frames_ready;
+
+ if (head_idx < tx_ring->next_to_clean)
+ head_idx += tx_ring->count;
+ frames_ready = head_idx - tx_ring->next_to_clean;
+
+ if (frames_ready == 0) {
+ goto out_xmit;
+ } else if (frames_ready > budget) {
+ completed_frames = budget;
+ work_done = false;
+ } else {
+ completed_frames = frames_ready;
+ }
+
+ /* XXX Need to be calculated. */
+ /*total_bytes += tx_buf->bytecount;*/
+ total_packets += completed_frames;
+
+ tx_ring->next_to_clean += completed_frames;
+ if (unlikely(tx_ring->next_to_clean >= tx_ring->count))
+ tx_ring->next_to_clean -= tx_ring->count;
+
+ xsk_umem_complete_tx(umem, completed_frames);
+
+ i40e_update_stats_and_arm_wb(tx_ring, vsi, total_packets,
+ total_bytes, budget);
+
+out_xmit:
+ xmit_done = i40e_xmit_zc(tx_ring, budget);
+
+ return work_done && xmit_done;
+}
+
/**
* i40e_clean_tx_irq - Reclaim resources after transmit completes
* @vsi: the VSI we care about
@@ -778,8 +913,8 @@ void i40e_detect_recover_hung(struct i40e_vsi *vsi)
*
* Returns true if there's any budget left (e.g. the clean is finished)
**/
-static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
- struct i40e_ring *tx_ring, int napi_budget)
+bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
+ struct i40e_ring *tx_ring, int napi_budget)
{
u16 i = tx_ring->next_to_clean;
struct i40e_tx_buffer *tx_buf;
@@ -874,27 +1009,9 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
i += tx_ring->count;
tx_ring->next_to_clean = i;
- u64_stats_update_begin(&tx_ring->syncp);
- tx_ring->stats.bytes += total_bytes;
- tx_ring->stats.packets += total_packets;
- u64_stats_update_end(&tx_ring->syncp);
- tx_ring->q_vector->tx.total_bytes += total_bytes;
- tx_ring->q_vector->tx.total_packets += total_packets;
- if (tx_ring->flags & I40E_TXR_FLAGS_WB_ON_ITR) {
- /* check to see if there are < 4 descriptors
- * waiting to be written back, then kick the hardware to force
- * them to be written back in case we stay in NAPI.
- * In this mode on X722 we do not enable Interrupt.
- */
- unsigned int j = i40e_get_tx_pending(tx_ring, false);
-
- if (budget &&
- ((j / WB_STRIDE) == 0) && (j > 0) &&
- !test_bit(__I40E_VSI_DOWN, vsi->state) &&
- (I40E_DESC_UNUSED(tx_ring) != tx_ring->count))
- tx_ring->arm_wb = true;
- }
+ i40e_update_stats_and_arm_wb(tx_ring, vsi, total_packets,
+ total_bytes, budget);
if (ring_is_xdp(tx_ring))
return !!budget;
@@ -2266,15 +2383,6 @@ static void i40e_rx_buffer_flip(struct i40e_ring *rx_ring,
#endif
}
-static inline void i40e_xdp_ring_update_tail(struct i40e_ring *xdp_ring)
-{
- /* Force memory writes to complete before letting h/w
- * know there are new descriptors to fetch.
- */
- wmb();
- writel_relaxed(xdp_ring->next_to_use, xdp_ring->tail);
-}
-
/**
* i40e_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
* @rx_ring: rx descriptor ring to transact packets on
@@ -2904,10 +3012,11 @@ int i40e_napi_poll(struct napi_struct *napi, int budget)
* budget and be more aggressive about cleaning up the Tx descriptors.
*/
i40e_for_each_ring(ring, q_vector->tx) {
- if (!i40e_clean_tx_irq(vsi, ring, budget)) {
+ if (!ring->clean_tx_irq(vsi, ring, budget)) {
clean_complete = false;
continue;
}
+
arm_wb |= ring->arm_wb;
ring->arm_wb = false;
}
@@ -3810,6 +3919,30 @@ static inline int i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb,
return -1;
}
+/**
+ * i40e_napi_is_scheduled - If napi is running, set the NAPIF_STATE_MISSED
+ * @n: napi context
+ *
+ * Returns true if NAPI is scheduled.
+ **/
+static bool i40e_napi_is_scheduled(struct napi_struct *n)
+{
+ unsigned long val, new;
+
+ do {
+ val = READ_ONCE(n->state);
+ if (val & NAPIF_STATE_DISABLE)
+ return true;
+
+ if (!(val & NAPIF_STATE_SCHED))
+ return false;
+
+ new = val | NAPIF_STATE_MISSED;
+ } while (cmpxchg(&n->state, val, new) != val);
+
+ return true;
+}
+
/**
* i40e_xmit_xdp_ring - transmits an XDP buffer to an XDP Tx ring
* @xdp: data to transmit
@@ -4025,6 +4158,9 @@ int i40e_xdp_xmit(struct net_device *dev, struct xdp_frame *xdpf)
if (!i40e_enabled_xdp_vsi(vsi) || queue_index >= vsi->num_queue_pairs)
return -ENXIO;
+ if (vsi->xdp_rings[queue_index]->xsk_umem)
+ return -ENXIO;
+
err = i40e_xmit_xdp_ring(xdpf, vsi->xdp_rings[queue_index]);
if (err != I40E_XDP_TX)
return -ENOSPC;
@@ -4048,5 +4184,34 @@ void i40e_xdp_flush(struct net_device *dev)
if (!i40e_enabled_xdp_vsi(vsi) || queue_index >= vsi->num_queue_pairs)
return;
+ if (vsi->xdp_rings[queue_index]->xsk_umem)
+ return;
+
i40e_xdp_ring_update_tail(vsi->xdp_rings[queue_index]);
}
+
+int i40e_xsk_async_xmit(struct net_device *dev, u32 queue_id)
+{
+ struct i40e_netdev_priv *np = netdev_priv(dev);
+ struct i40e_vsi *vsi = np->vsi;
+ struct i40e_ring *ring;
+
+ if (test_bit(__I40E_VSI_DOWN, vsi->state))
+ return -ENETDOWN;
+
+ if (!i40e_enabled_xdp_vsi(vsi))
+ return -ENXIO;
+
+ if (queue_id >= vsi->num_queue_pairs)
+ return -ENXIO;
+
+ if (!vsi->xdp_rings[queue_id]->xsk_umem)
+ return -ENXIO;
+
+ ring = vsi->xdp_rings[queue_id];
+
+ if (!i40e_napi_is_scheduled(&ring->q_vector->napi))
+ i40e_force_wb(vsi, ring->q_vector);
+
+ return 0;
+}
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
index 9d5d9862e9f1..ea1cac00cad4 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
@@ -428,6 +428,7 @@ struct i40e_ring {
int (*clean_rx_irq)(struct i40e_ring *, int);
bool (*alloc_rx_buffers)(struct i40e_ring *, u16);
+ bool (*clean_tx_irq)(struct i40e_vsi *, struct i40e_ring *, int);
struct xdp_umem *xsk_umem;
struct zero_copy_allocator zca; /* ZC allocator anchor */
@@ -510,6 +511,11 @@ void i40e_xdp_flush(struct net_device *dev);
int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget);
int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget);
void i40e_zca_free(struct zero_copy_allocator *alloc, unsigned long handle);
+bool i40e_clean_tx_irq_zc(struct i40e_vsi *vsi,
+ struct i40e_ring *tx_ring, int napi_budget);
+bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
+ struct i40e_ring *tx_ring, int napi_budget);
+int i40e_xsk_async_xmit(struct net_device *dev, u32 queue_id);
/**
* i40e_get_head - Retrieve head from head writeback
--
2.14.1
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