[26/28] net/mlx5: zero the LRO mbuf headroom
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Commit Message
LRO packet may consume all the stride memory, hence the PMD cannot
guaranty head-room for the LRO mbuf.
The issue is lack in HW support to write the packet in offset from the
stride start.
A new striding RQ feature may be added in CX6 DX to allow head-room and
tail-room for the LRO strides.
Signed-off-by: Matan Azrad <matan@mellanox.com>
---
drivers/net/mlx5/mlx5_rxq.c | 16 +++++++++++-----
drivers/net/mlx5/mlx5_rxtx.c | 6 ++++--
drivers/net/mlx5/mlx5_rxtx.h | 3 ++-
3 files changed, 17 insertions(+), 8 deletions(-)
Comments
> -----Original Message-----
> From: Matan Azrad <matan@mellanox.com>
> Sent: Monday, July 22, 2019 12:13
> To: Shahaf Shuler <shahafs@mellanox.com>; Yongseok Koh
> <yskoh@mellanox.com>; Slava Ovsiienko <viacheslavo@mellanox.com>
> Cc: dev@dpdk.org; Dekel Peled <dekelp@mellanox.com>
> Subject: [PATCH 26/28] net/mlx5: zero the LRO mbuf headroom
>
> LRO packet may consume all the stride memory, hence the PMD cannot
> guaranty head-room for the LRO mbuf.
>
> The issue is lack in HW support to write the packet in offset from the stride
> start.
>
> A new striding RQ feature may be added in CX6 DX to allow head-room and
> tail-room for the LRO strides.
>
> Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
@@ -1569,6 +1569,12 @@ struct mlx5_rxq_ctrl *
unsigned int mprq_stride_size;
struct mlx5_dev_config *config = &priv->config;
/*
+ * LRO packet may consume all the stride memory, hence we cannot
+ * guaranty head-room. A new striding RQ feature may be added in CX6 DX
+ * to allow head-room and tail-room for the LRO packets.
+ */
+ unsigned int strd_headroom_en = mlx5_lro_on(dev) ? 0 : 1;
+ /*
* Always allocate extra slots, even if eventually
* the vector Rx will not be used.
*/
@@ -1603,9 +1609,9 @@ struct mlx5_rxq_ctrl *
* stride.
* Otherwise, enable Rx scatter if necessary.
*/
- assert(mb_len >= RTE_PKTMBUF_HEADROOM);
+ assert(mb_len >= RTE_PKTMBUF_HEADROOM * strd_headroom_en);
mprq_stride_size = dev->data->dev_conf.rxmode.max_rx_pkt_len +
- RTE_PKTMBUF_HEADROOM;
+ RTE_PKTMBUF_HEADROOM * strd_headroom_en;
if (mprq_en &&
desc > (1U << config->mprq.stride_num_n) &&
mprq_stride_size <= (1U << config->mprq.max_stride_size_n)) {
@@ -1617,9 +1623,9 @@ struct mlx5_rxq_ctrl *
tmpl->rxq.strd_sz_n = RTE_MAX(log2above(mprq_stride_size),
config->mprq.min_stride_size_n);
tmpl->rxq.strd_shift_en = MLX5_MPRQ_TWO_BYTE_SHIFT;
- tmpl->rxq.mprq_max_memcpy_len =
- RTE_MIN(mb_len - RTE_PKTMBUF_HEADROOM,
- config->mprq.max_memcpy_len);
+ tmpl->rxq.strd_headroom_en = strd_headroom_en;
+ tmpl->rxq.mprq_max_memcpy_len = RTE_MIN(mb_len -
+ RTE_PKTMBUF_HEADROOM, config->mprq.max_memcpy_len);
DRV_LOG(DEBUG,
"port %u Rx queue %u: Multi-Packet RQ is enabled"
" strd_num_n = %u, strd_sz_n = %u",
@@ -1540,6 +1540,7 @@ enum mlx5_txcmp_code {
unsigned int i = 0;
uint32_t rq_ci = rxq->rq_ci;
uint16_t consumed_strd = rxq->consumed_strd;
+ uint16_t headroom_sz = rxq->strd_headroom_en * RTE_PKTMBUF_HEADROOM;
struct mlx5_mprq_buf *buf = (*rxq->mprq_bufs)[rq_ci & wq_mask];
while (i < pkts_n) {
@@ -1650,7 +1651,7 @@ enum mlx5_txcmp_code {
rte_atomic16_add_return(&buf->refcnt, 1);
assert((uint16_t)rte_atomic16_read(&buf->refcnt) <=
strd_n + 1);
- buf_addr = RTE_PTR_SUB(addr, RTE_PKTMBUF_HEADROOM);
+ buf_addr = RTE_PTR_SUB(addr, headroom_sz);
/*
* MLX5 device doesn't use iova but it is necessary in a
* case where the Rx packet is transmitted via a
@@ -1668,7 +1669,8 @@ enum mlx5_txcmp_code {
*/
rte_pktmbuf_attach_extbuf(pkt, buf_addr, buf_iova,
buf_len, shinfo);
- rte_pktmbuf_reset_headroom(pkt);
+ /* Set mbuf head-room. */
+ pkt->data_off = headroom_sz;
assert(pkt->ol_flags == EXT_ATTACHED_MBUF);
/*
* Prevent potential overflow due to MTU change through
@@ -114,7 +114,8 @@ struct mlx5_rxq_data {
unsigned int strd_sz_n:4; /* Log 2 of stride size. */
unsigned int strd_shift_en:1; /* Enable 2bytes shift on a stride. */
unsigned int err_state:2; /* enum mlx5_rxq_err_state. */
- unsigned int :4; /* Remaining bits. */
+ unsigned int strd_headroom_en:1; /* Enable mbuf headroom in MPRQ. */
+ unsigned int :3; /* Remaining bits. */
volatile uint32_t *rq_db;
volatile uint32_t *cq_db;
uint16_t port_id;