This patch shows how it is possible to have both the driver local page
cache, which uses elevated refcnt for "catching"/avoiding SKB
put_page. And at the same time, have pages getting returned to the
page_pool from ndp_xdp_xmit DMA completion.
Performance is surprisingly good. Tested DMA-TX completion on ixgbe,
that calls "xdp_return_frame", which call page_pool_put_page().
Stats show DMA-TX-completion runs on CPU#9 and mlx5 RX runs on CPU#5.
(Internally page_pool uses ptr_ring, which is what gives the good
cross CPU performance).
Show adapter(s) (ixgbe2 mlx5p2) statistics (ONLY that changed!)
Ethtool(ixgbe2 ) stat: 732863573 ( 732,863,573) <= tx_bytes /sec
Ethtool(ixgbe2 ) stat: 781724427 ( 781,724,427) <= tx_bytes_nic /sec
Ethtool(ixgbe2 ) stat: 12214393 ( 12,214,393) <= tx_packets /sec
Ethtool(ixgbe2 ) stat: 12214435 ( 12,214,435) <= tx_pkts_nic /sec
Ethtool(mlx5p2 ) stat: 12211786 ( 12,211,786) <= rx3_cache_empty /sec
Ethtool(mlx5p2 ) stat: 36506736 ( 36,506,736) <= rx_64_bytes_phy /sec
Ethtool(mlx5p2 ) stat: 2336430575 ( 2,336,430,575) <= rx_bytes_phy /sec
Ethtool(mlx5p2 ) stat: 12211786 ( 12,211,786) <= rx_cache_empty /sec
Ethtool(mlx5p2 ) stat: 22823073 ( 22,823,073) <= rx_discards_phy /sec
Ethtool(mlx5p2 ) stat: 1471860 ( 1,471,860) <= rx_out_of_buffer /sec
Ethtool(mlx5p2 ) stat: 36506715 ( 36,506,715) <= rx_packets_phy /sec
Ethtool(mlx5p2 ) stat: 2336542282 ( 2,336,542,282) <= rx_prio0_bytes /sec
Ethtool(mlx5p2 ) stat: 13683921 ( 13,683,921) <= rx_prio0_packets /sec
Ethtool(mlx5p2 ) stat: 821015537 ( 821,015,537) <=
rx_vport_unicast_bytes /sec
Ethtool(mlx5p2 ) stat: 13683608 ( 13,683,608) <=
rx_vport_unicast_packets /sec
Before this patch: single flow performance was 6Mpps, and if I started
two flows the collective performance drop to 4Mpps, because we hit the
page allocator lock (further negative scaling occurs).
Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en.h | 3 ++
drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 39 ++++++++++++++++++---
drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 10 ++++-
3 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h
b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 28cc26debeda..ab91166f7c5a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -53,6 +53,8 @@
#include "mlx5_core.h"
#include "en_stats.h"
+struct page_pool;
+
#define MLX5_SET_CFG(p, f, v) MLX5_SET(create_flow_group_in, p, f, v)
#define MLX5E_ETH_HARD_MTU (ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN)
@@ -535,6 +537,7 @@ struct mlx5e_rq {
/* XDP */
struct bpf_prog *xdp_prog;
struct mlx5e_xdpsq xdpsq;
+ struct page_pool *page_pool;
/* control */
struct mlx5_wq_ctrl wq_ctrl;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 49732c8c27c1..fbe27110ff02 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -44,6 +44,8 @@
#include "accel/ipsec.h"
#include "vxlan.h"
+#include <net/page_pool.h>
+
struct mlx5e_rq_param {
u32 rqc[MLX5_ST_SZ_DW(rqc)];
struct mlx5_wq_param wq;
@@ -396,6 +398,8 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
int err;
int i;
+ struct page_pool_params pp_params = { 0 };
+
rqp->wq.db_numa_node = cpu_to_node(c->cpu);
err = mlx5_wq_ll_create(mdev, &rqp->wq, rqc_wq, &rq->wq,
@@ -506,12 +510,33 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
rq->mkey_be = c->mkey_be;
}
- /* This must only be activate for order-0 pages */
- if (rq->xdp_prog)
- err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
- MEM_TYPE_PAGE_ORDER0, NULL);
- if (err)
+ /* Create a page_pool and register it with rxq */
+ pp_params.size = PAGE_POOL_PARAMS_SIZE;
+ pp_params.order = rq->buff.page_order;
+ pp_params.dev = c->pdev;
+ pp_params.nid = cpu_to_node(c->cpu);
+ pp_params.dma_dir = rq->buff.map_dir;
+ pp_params.pool_size = 1 << params->log_rq_size;
+ pp_params.flags = 0; /* No-internal DMA mapping in page_pool */
+
+ /* page_pool can be used even when there is no rq->xdp_prog,
+ * given page_pool does not handle DMA mapping there is no
+ * required state to clear. And page_pool gracefully handle
+ * elevated refcnt.
+ */
+ rq->page_pool = page_pool_create(&pp_params);
+ if (IS_ERR_OR_NULL(rq->page_pool)) {
+ kfree(rq->wqe.frag_info);
+ rq->page_pool = NULL;
+ err = -ENOMEM;
goto err_rq_wq_destroy;
+ }
+ err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
+ MEM_TYPE_PAGE_POOL, rq->page_pool);
+ if (err) {
+ err = -ENOMEM;
+ goto err_rq_wq_destroy;
+ }
for (i = 0; i < wq_sz; i++) {
struct mlx5e_rx_wqe *wqe = mlx5_wq_ll_get_wqe(&rq->wq, i);
@@ -549,6 +574,8 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
if (rq->xdp_prog)
bpf_prog_put(rq->xdp_prog);
xdp_rxq_info_unreg(&rq->xdp_rxq);
+ if (rq->page_pool)
+ page_pool_destroy_rcu(rq->page_pool);
mlx5_wq_destroy(&rq->wq_ctrl);
return err;
@@ -562,6 +589,8 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq)
bpf_prog_put(rq->xdp_prog);
xdp_rxq_info_unreg(&rq->xdp_rxq);
+ if (rq->page_pool)
+ page_pool_destroy_rcu(rq->page_pool);
switch (rq->wq_type) {
case MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ:
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 6dcc3e8fbd3e..4898239467d9 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -45,6 +45,8 @@
#include "en_accel/ipsec_rxtx.h"
#include "lib/clock.h"
+#include <net/page_pool.h>
+
static inline bool mlx5e_rx_hw_stamp(struct hwtstamp_config *config)
{
return config->rx_filter == HWTSTAMP_FILTER_ALL;
@@ -221,7 +223,7 @@ static inline int mlx5e_page_alloc_mapped(struct mlx5e_rq
*rq,
if (mlx5e_rx_cache_get(rq, dma_info))
return 0;
- dma_info->page = dev_alloc_pages(rq->buff.page_order);
+ dma_info->page = page_pool_dev_alloc_pages(rq->page_pool);
if (unlikely(!dma_info->page))
return -ENOMEM;
@@ -250,7 +252,11 @@ void mlx5e_page_release(struct mlx5e_rq *rq, struct
mlx5e_dma_info *dma_info,
return;
mlx5e_page_dma_unmap(rq, dma_info);
- put_page(dma_info->page);
+
+ if (likely(recycle))
+ page_pool_recycle_direct(rq->page_pool, dma_info->page);
+ else
+ put_page(dma_info->page);
}
static inline bool mlx5e_page_reuse(struct mlx5e_rq *rq,
