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#include <poll.h>
#include <string.h>
#include <vlib/vlib.h>
#include <vlib/unix/unix.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/devices/devices.h>
#include <af_xdp/af_xdp.h>
#define AF_XDP_TX_RETRIES 5
static_always_inline void
af_xdp_device_output_free (vlib_main_t * vm, const vlib_node_runtime_t * node,
af_xdp_txq_t * txq)
{
const __u64 *compl;
const u32 size = txq->cq.size;
const u32 mask = size - 1;
u32 bis[VLIB_FRAME_SIZE], *bi = bis;
u32 n_wrap, idx;
u32 n = xsk_ring_cons__peek (&txq->cq, ARRAY_LEN (bis), &idx);
const u32 n_free = n;
/* we rely on on casting addr (u64) -> bi (u32) to discard XSK offset below */
STATIC_ASSERT (BITS (bi[0]) + CLIB_LOG2_CACHE_LINE_BYTES <=
XSK_UNALIGNED_BUF_OFFSET_SHIFT, "wrong size");
ASSERT (mask == txq->cq.mask);
if (!n_free)
return;
compl = xsk_ring_cons__comp_addr (&txq->cq, idx);
n = clib_min (n_free, size - (idx & mask));
n_wrap = n_free - n;
wrap_around:
while (n >= 8)
{
#ifdef CLIB_HAVE_VEC256
u64x4 b0 = (*(u64x4u *) (compl + 0)) >> CLIB_LOG2_CACHE_LINE_BYTES;
u64x4 b1 = (*(u64x4u *) (compl + 4)) >> CLIB_LOG2_CACHE_LINE_BYTES;
/* permute 256-bit register so lower u32s of each buffer index are
* placed into lower 128-bits */
const u32x8 mask = { 0, 2, 4, 6, 1, 3, 5, 7 };
u32x8 b2 = u32x8_permute ((u32x8) b0, mask);
u32x8 b3 = u32x8_permute ((u32x8) b1, mask);
/* extract lower 128-bits and save them to the array of buffer indices */
*(u32x4u *) (bi + 0) = u32x8_extract_lo (b2);
*(u32x4u *) (bi + 4) = u32x8_extract_lo (b3);
#else
bi[0] = compl[0] >> CLIB_LOG2_CACHE_LINE_BYTES;
bi[1] = compl[1] >> CLIB_LOG2_CACHE_LINE_BYTES;
bi[2] = compl[2] >> CLIB_LOG2_CACHE_LINE_BYTES;
bi[3] = compl[3] >> CLIB_LOG2_CACHE_LINE_BYTES;
bi[4] = compl[4] >> CLIB_LOG2_CACHE_LINE_BYTES;
bi[5] = compl[5] >> CLIB_LOG2_CACHE_LINE_BYTES;
bi[6] = compl[6] >> CLIB_LOG2_CACHE_LINE_BYTES;
bi[7] = compl[7] >> CLIB_LOG2_CACHE_LINE_BYTES;
#endif
compl += 8;
bi += 8;
n -= 8;
}
while (n >= 1)
{
bi[0] = compl[0] >> CLIB_LOG2_CACHE_LINE_BYTES;
ASSERT (vlib_buffer_is_known (vm, bi[0]) ==
VLIB_BUFFER_KNOWN_ALLOCATED);
compl += 1;
bi += 1;
n -= 1;
}
if (n_wrap)
{
compl = xsk_ring_cons__comp_addr (&txq->cq, 0);
n = n_wrap;
n_wrap = 0;
goto wrap_around;
}
xsk_ring_cons__release (&txq->cq, n_free);
vlib_buffer_free (vm, bis, n_free);
}
static_always_inline void
af_xdp_device_output_tx_db (vlib_main_t * vm,
const vlib_node_runtime_t * node,
af_xdp_device_t * ad,
af_xdp_txq_t * txq, const u32 n_tx)
{
xsk_ring_prod__submit (&txq->tx, n_tx);
if (!xsk_ring_prod__needs_wakeup (&txq->tx))
return;
vlib_error_count (vm, node->node_index, AF_XDP_TX_ERROR_SYSCALL_REQUIRED, 1);
clib_spinlock_lock_if_init (&txq->syscall_lock);
if (xsk_ring_prod__needs_wakeup (&txq->tx))
{
struct pollfd fd = { .fd = txq->xsk_fd, .events = POLLIN | POLLOUT };
int ret = poll (&fd, 1, 0);
if (PREDICT_FALSE (ret < 0))
{
/* something bad is happening */
vlib_error_count (vm, node->node_index,
AF_XDP_TX_ERROR_SYSCALL_FAILURES, 1);
af_xdp_device_error (ad, "tx poll() failed");
}
}
clib_spinlock_unlock_if_init (&txq->syscall_lock);
}
static_always_inline u32
af_xdp_device_output_tx_try (vlib_main_t * vm,
const vlib_node_runtime_t * node,
af_xdp_device_t * ad, af_xdp_txq_t * txq,
u32 n_tx, u32 * bi)
{
vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
const uword start = vm->buffer_main->buffer_mem_start;
const u32 size = txq->tx.size;
const u32 mask = size - 1;
struct xdp_desc *desc;
u64 offset, addr;
u32 idx, n, n_wrap;
ASSERT (mask == txq->cq.mask);
n_tx = xsk_ring_prod__reserve (&txq->tx, n_tx, &idx);
/* if ring is full, do nothing */
if (PREDICT_FALSE (0 == n_tx))
return 0;
vlib_get_buffers (vm, bi, bufs, n_tx);
desc = xsk_ring_prod__tx_desc (&txq->tx, idx);
n = clib_min (n_tx, size - (idx & mask));
n_wrap = n_tx - n;
wrap_around:
while (n >= 8)
{
vlib_prefetch_buffer_header (b[4], LOAD);
offset =
(sizeof (vlib_buffer_t) +
b[0]->current_data) << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
addr = pointer_to_uword (b[0]) - start;
desc[0].addr = offset | addr;
desc[0].len = b[0]->current_length;
vlib_prefetch_buffer_header (b[5], LOAD);
offset =
(sizeof (vlib_buffer_t) +
b[1]->current_data) << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
addr = pointer_to_uword (b[1]) - start;
desc[1].addr = offset | addr;
desc[1].len = b[1]->current_length;
vlib_prefetch_buffer_header (b[6], LOAD);
offset =
(sizeof (vlib_buffer_t) +
b[2]->current_data) << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
addr = pointer_to_uword (b[2]) - start;
desc[2].addr = offset | addr;
desc[2].len = b[2]->current_length;
vlib_prefetch_buffer_header (b[7], LOAD);
offset =
(sizeof (vlib_buffer_t) +
b[3]->current_data) << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
addr = pointer_to_uword (b[3]) - start;
desc[3].addr = offset | addr;
desc[3].len = b[3]->current_length;
desc += 4;
b += 4;
n -= 4;
}
while (n >= 1)
{
offset =
(sizeof (vlib_buffer_t) +
b[0]->current_data) << XSK_UNALIGNED_BUF_OFFSET_SHIFT;
addr = pointer_to_uword (b[0]) - start;
desc[0].addr = offset | addr;
desc[0].len = b[0]->current_length;
desc += 1;
b += 1;
n -= 1;
}
if (n_wrap)
{
desc = xsk_ring_prod__tx_desc (&txq->tx, 0);
n = n_wrap;
n_wrap = 0;
goto wrap_around;
}
return n_tx;
}
VNET_DEVICE_CLASS_TX_FN (af_xdp_device_class) (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_frame_t * frame)
{
af_xdp_main_t *rm = &af_xdp_main;
vnet_interface_output_runtime_t *ord = (void *) node->runtime_data;
af_xdp_device_t *ad = pool_elt_at_index (rm->devices, ord->dev_instance);
u32 thread_index = vm->thread_index;
af_xdp_txq_t *txq = vec_elt_at_index (
ad->txqs, (thread_index - 1 + ad->txq_num) % ad->txq_num);
u32 *from;
u32 n, n_tx;
int i;
from = vlib_frame_vector_args (frame);
n_tx = frame->n_vectors;
clib_spinlock_lock_if_init (&txq->lock);
for (i = 0, n = 0; i < AF_XDP_TX_RETRIES && n < n_tx; i++)
{
u32 n_enq;
af_xdp_device_output_free (vm, node, txq);
n_enq =
af_xdp_device_output_tx_try (vm, node, ad, txq, n_tx - n, from + n);
n += n_enq;
}
af_xdp_device_output_tx_db (vm, node, ad, txq, n);
clib_spinlock_unlock_if_init (&txq->lock);
if (PREDICT_FALSE (n != n_tx))
{
vlib_buffer_free (vm, from + n, n_tx - n);
vlib_error_count (vm, node->node_index,
AF_XDP_TX_ERROR_NO_FREE_SLOTS, n_tx - n);
}
return n;
}
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
|
