net/mlx5e: Implement RX mapped page cache for page recycle

Instead of reallocating and mapping pages for RX data-path,
recycle already used pages in a per ring cache.

Performance tests:
The following results were measured on a freshly booted system,
giving optimal baseline performance, as high-order pages are yet to
be fragmented and depleted.

We ran pktgen single-stream benchmarks, with iptables-raw-drop:

Single stride, 64 bytes:
* 4,739,057 - baseline
* 4,749,550 - order0 no cache
* 4,786,899 - order0 with cache
1% gain

Larger packets, no page cross, 1024 bytes:
* 3,982,361 - baseline
* 3,845,682 - order0 no cache
* 4,127,852 - order0 with cache
3.7% gain

Larger packets, every 3rd packet crosses a page, 1500 bytes:
* 3,731,189 - baseline
* 3,579,414 - order0 no cache
* 3,931,708 - order0 with cache
5.4% gain

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 136554b77c3b..8595b507e200 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -141,6 +141,10 @@ static void mlx5e_update_sw_counters(struct mlx5e_priv *priv)
 		s->rx_buff_alloc_err += rq_stats->buff_alloc_err;
 		s->rx_cqe_compress_blks += rq_stats->cqe_compress_blks;
 		s->rx_cqe_compress_pkts += rq_stats->cqe_compress_pkts;
+		s->rx_cache_reuse += rq_stats->cache_reuse;
+		s->rx_cache_full  += rq_stats->cache_full;
+		s->rx_cache_empty += rq_stats->cache_empty;
+		s->rx_cache_busy  += rq_stats->cache_busy;
 
 		for (j = 0; j < priv->params.num_tc; j++) {
 			sq_stats = &priv->channel[i]->sq[j].stats;
@@ -475,6 +479,9 @@ static int mlx5e_create_rq(struct mlx5e_channel *c,
 	INIT_WORK(&rq->am.work, mlx5e_rx_am_work);
 	rq->am.mode = priv->params.rx_cq_period_mode;
 
+	rq->page_cache.head = 0;
+	rq->page_cache.tail = 0;
+
 	return 0;
 
 err_rq_wq_destroy:
@@ -485,6 +492,8 @@ err_rq_wq_destroy:
 
 static void mlx5e_destroy_rq(struct mlx5e_rq *rq)
 {
+	int i;
+
 	switch (rq->wq_type) {
 	case MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ:
 		mlx5e_rq_free_mpwqe_info(rq);
@@ -493,6 +502,12 @@ static void mlx5e_destroy_rq(struct mlx5e_rq *rq)
 		kfree(rq->skb);
 	}
 
+	for (i = rq->page_cache.head; i != rq->page_cache.tail;
+	     i = (i + 1) & (MLX5E_CACHE_SIZE - 1)) {
+		struct mlx5e_dma_info *dma_info = &rq->page_cache.page_cache[i];
+
+		mlx5e_page_release(rq, dma_info, false);
+	}
 	mlx5_wq_destroy(&rq->wq_ctrl);
 }