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authorBenoît Ganne <bganne@cisco.com>2021-05-19 16:41:03 +0200
committerDamjan Marion <dmarion@me.com>2021-05-21 21:07:02 +0000
commit1a06e53341224bb08cff2fb6d218415c50f947d3 (patch)
tree9402b008b0ec37c8bfcd4b27a080211e1e4d3153
parent73b71225b1f6bdd65923ac8ac786ed226d57228e (diff)
af_xdp: use desc offset on rx
Instead of pre-programming the data offset on rx, use offset passed in the descriptor. This is more robust and future-proof. Type: fix Change-Id: I2bd910d92b8b03d17be5be85a24108be711dc7b9 Signed-off-by: Benoît Ganne <bganne@cisco.com>
-rw-r--r--src/plugins/af_xdp/device.c13
-rw-r--r--src/plugins/af_xdp/input.c54
2 files changed, 26 insertions, 41 deletions
diff --git a/src/plugins/af_xdp/device.c b/src/plugins/af_xdp/device.c
index 03a3053e449..7a10bce4290 100644
--- a/src/plugins/af_xdp/device.c
+++ b/src/plugins/af_xdp/device.c
@@ -215,18 +215,7 @@ af_xdp_create_queue (vlib_main_t *vm, af_xdp_create_if_args_t *args,
umem_config.comp_size = args->txq_size;
umem_config.frame_size =
sizeof (vlib_buffer_t) + vlib_buffer_get_default_data_size (vm);
- /*
- * Note about headroom: for some reasons, there seem to be a discrepency
- * between 0-copy and copy mode:
- * - 0-copy: XDP_PACKET_HEADROOM will be added to the user headroom
- * - copy: nothing is added to the user headroom
- * We privileged 0-copy and set headroom so that frame_headroom +
- * XDP_PACKET_HEADROOM == sizeof(vlib_buffer_t), ie data will correctly
- * point to vlib_buffer_t->data for 0-copy. In copy mode, we have to add
- * XDP_PACKET_HEADROOM to desc offset during refill.
- */
- STATIC_ASSERT (sizeof (vlib_buffer_t) >= XDP_PACKET_HEADROOM, "wrong size");
- umem_config.frame_headroom = sizeof (vlib_buffer_t) - XDP_PACKET_HEADROOM;
+ umem_config.frame_headroom = sizeof (vlib_buffer_t);
umem_config.flags = XDP_UMEM_UNALIGNED_CHUNK_FLAG;
if (xsk_umem__create
(umem, uword_to_pointer (vm->buffer_main->buffer_mem_start, void *),
diff --git a/src/plugins/af_xdp/input.c b/src/plugins/af_xdp/input.c
index 98d841b77a0..4f3ac5725a4 100644
--- a/src/plugins/af_xdp/input.c
+++ b/src/plugins/af_xdp/input.c
@@ -106,8 +106,7 @@ af_xdp_device_input_refill_db (vlib_main_t * vm,
static_always_inline void
af_xdp_device_input_refill_inline (vlib_main_t *vm,
const vlib_node_runtime_t *node,
- af_xdp_device_t *ad, af_xdp_rxq_t *rxq,
- const int copy)
+ af_xdp_device_t *ad, af_xdp_rxq_t *rxq)
{
__u64 *fill;
const u32 size = rxq->fq.size;
@@ -133,13 +132,7 @@ af_xdp_device_input_refill_inline (vlib_main_t *vm,
n = clib_min (n_alloc, size - (idx & mask));
n_wrap = n_alloc - n;
- /*
- * Note about headroom: for some reasons, there seem to be a discrepency
- * between 0-copy and copy mode. See
- * src/plugins/af_xdp/device.c:af_xdp_create_queue()
- */
-#define bi2addr(bi) \
- (((bi) << CLIB_LOG2_CACHE_LINE_BYTES) + (copy ? XDP_PACKET_HEADROOM : 0))
+#define bi2addr(bi) ((bi) << CLIB_LOG2_CACHE_LINE_BYTES)
wrap_around:
@@ -208,27 +201,30 @@ af_xdp_device_input_ethernet (vlib_main_t * vm, vlib_node_runtime_t * node,
}
static_always_inline u32
-af_xdp_device_input_bufs (vlib_main_t * vm, const af_xdp_device_t * ad,
- af_xdp_rxq_t * rxq, u32 * bis, const u32 n_rx,
- vlib_buffer_t * bt, u32 idx, const int copy)
+af_xdp_device_input_bufs (vlib_main_t *vm, const af_xdp_device_t *ad,
+ af_xdp_rxq_t *rxq, u32 *bis, const u32 n_rx,
+ vlib_buffer_t *bt, u32 idx)
{
vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
+ u16 offs[VLIB_FRAME_SIZE], *off = offs;
u16 lens[VLIB_FRAME_SIZE], *len = lens;
const u32 mask = rxq->rx.mask;
u32 n = n_rx, *bi = bis, bytes = 0;
-#define addr2bi(addr) \
- (((addr) - (copy ? XDP_PACKET_HEADROOM : 0)) >> CLIB_LOG2_CACHE_LINE_BYTES)
+#define addr2bi(addr) ((addr) >> CLIB_LOG2_CACHE_LINE_BYTES)
while (n >= 1)
{
const struct xdp_desc *desc = xsk_ring_cons__rx_desc (&rxq->rx, idx);
- bi[0] = addr2bi (xsk_umem__extract_addr (desc->addr));
+ const u64 addr = desc->addr;
+ bi[0] = addr2bi (xsk_umem__extract_addr (addr));
ASSERT (vlib_buffer_is_known (vm, bi[0]) ==
VLIB_BUFFER_KNOWN_ALLOCATED);
+ off[0] = xsk_umem__extract_offset (addr) - sizeof (vlib_buffer_t);
len[0] = desc->len;
idx = (idx + 1) & mask;
bi += 1;
+ off += 1;
len += 1;
n -= 1;
}
@@ -236,27 +232,33 @@ af_xdp_device_input_bufs (vlib_main_t * vm, const af_xdp_device_t * ad,
vlib_get_buffers (vm, bis, bufs, n_rx);
n = n_rx;
+ off = offs;
len = lens;
while (n >= 8)
{
vlib_prefetch_buffer_header (b[4], LOAD);
vlib_buffer_copy_template (b[0], bt);
+ b[0]->current_data = off[0];
bytes += b[0]->current_length = len[0];
vlib_prefetch_buffer_header (b[5], LOAD);
vlib_buffer_copy_template (b[1], bt);
+ b[1]->current_data = off[1];
bytes += b[1]->current_length = len[1];
vlib_prefetch_buffer_header (b[6], LOAD);
vlib_buffer_copy_template (b[2], bt);
+ b[2]->current_data = off[2];
bytes += b[2]->current_length = len[2];
vlib_prefetch_buffer_header (b[7], LOAD);
vlib_buffer_copy_template (b[3], bt);
+ b[3]->current_data = off[3];
bytes += b[3]->current_length = len[3];
b += 4;
+ off += 4;
len += 4;
n -= 4;
}
@@ -264,8 +266,10 @@ af_xdp_device_input_bufs (vlib_main_t * vm, const af_xdp_device_t * ad,
while (n >= 1)
{
vlib_buffer_copy_template (b[0], bt);
+ b[0]->current_data = off[0];
bytes += b[0]->current_length = len[0];
b += 1;
+ off += 1;
len += 1;
n -= 1;
}
@@ -275,9 +279,8 @@ af_xdp_device_input_bufs (vlib_main_t * vm, const af_xdp_device_t * ad,
}
static_always_inline uword
-af_xdp_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
- vlib_frame_t * frame, af_xdp_device_t * ad,
- u16 qid, const int copy)
+af_xdp_device_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
+ vlib_frame_t *frame, af_xdp_device_t *ad, u16 qid)
{
vnet_main_t *vnm = vnet_get_main ();
af_xdp_rxq_t *rxq = vec_elt_at_index (ad->rxqs, qid);
@@ -299,8 +302,7 @@ af_xdp_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
vlib_get_new_next_frame (vm, node, next_index, to_next, n_left_to_next);
n_rx_bytes =
- af_xdp_device_input_bufs (vm, ad, rxq, to_next, n_rx_packets, &bt, idx,
- copy);
+ af_xdp_device_input_bufs (vm, ad, rxq, to_next, n_rx_packets, &bt, idx);
af_xdp_device_input_ethernet (vm, node, next_index, ad->sw_if_index,
ad->hw_if_index);
@@ -315,7 +317,7 @@ af_xdp_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
ad->hw_if_index, n_rx_packets, n_rx_bytes);
refill:
- af_xdp_device_input_refill_inline (vm, node, ad, rxq, copy);
+ af_xdp_device_input_refill_inline (vm, node, ad, rxq);
return n_rx_packets;
}
@@ -334,12 +336,7 @@ VLIB_NODE_FN (af_xdp_input_node) (vlib_main_t * vm,
af_xdp_device_t *ad = vec_elt_at_index (am->devices, p->dev_instance);
if ((ad->flags & AF_XDP_DEVICE_F_ADMIN_UP) == 0)
continue;
- if (PREDICT_TRUE (ad->flags & AF_XDP_DEVICE_F_ZEROCOPY))
- n_rx += af_xdp_device_input_inline (vm, node, frame, ad, p->queue_id,
- /* copy */ 0);
- else
- n_rx += af_xdp_device_input_inline (vm, node, frame, ad, p->queue_id,
- /* copy */ 1);
+ n_rx += af_xdp_device_input_inline (vm, node, frame, ad, p->queue_id);
}
return n_rx;
@@ -352,8 +349,7 @@ af_xdp_device_input_refill (af_xdp_device_t *ad)
vlib_main_t *vm = vlib_get_main ();
af_xdp_rxq_t *rxq;
vec_foreach (rxq, ad->rxqs)
- af_xdp_device_input_refill_inline (
- vm, 0, ad, rxq, 0 == (ad->flags & AF_XDP_DEVICE_F_ZEROCOPY));
+ af_xdp_device_input_refill_inline (vm, 0, ad, rxq);
}
#endif /* CLIB_MARCH_VARIANT */