[PATCH net-next v3] lan966x: Don't use xdp_frame when action is XDP_TX
From: Horatiu Vultur
Date: Sat Apr 22 2023 - 10:27:28 EST
When the action of an xdp program was XDP_TX, lan966x was creating
a xdp_frame and use this one to send the frame back. But it is also
possible to send back the frame without needing a xdp_frame, because
it is possible to send it back using the page.
And then once the frame is transmitted is possible to use directly
page_pool_recycle_direct as lan966x is using page pools.
This would save some CPU usage on this path, which results in higher
number of transmitted frames. Bellow are the statistics:
Frame size: Improvement:
64 ~8%
256 ~11%
512 ~8%
1000 ~0%
1500 ~0%
Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
v2->v3:
- fix length issue when the XDP action is XDP_REDIRECT, this issue was
introduced in v2 of this patch series.
- reduce the number of changes by moving back all the assignments to
next_dcb_buf
v1->v2:
- reduce number of arguments for the function lan966x_fdma_xmit_xdpf,
as some of them are mutual exclusive, and other can be replaced with
deduced from the other ones
- update commit message and add statistics for the improvement
---
.../ethernet/microchip/lan966x/lan966x_fdma.c | 35 ++++++++++++-------
.../ethernet/microchip/lan966x/lan966x_main.h | 6 ++--
.../ethernet/microchip/lan966x/lan966x_xdp.c | 10 ++----
3 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index 2ed76bb61a731..bd72fbc2220f3 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -390,6 +390,7 @@ static void lan966x_fdma_stop_netdev(struct lan966x *lan966x)
static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)
{
struct lan966x_tx *tx = &lan966x->tx;
+ struct lan966x_rx *rx = &lan966x->rx;
struct lan966x_tx_dcb_buf *dcb_buf;
struct xdp_frame_bulk bq;
struct lan966x_db *db;
@@ -432,7 +433,8 @@ static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)
if (dcb_buf->xdp_ndo)
xdp_return_frame_bulk(dcb_buf->data.xdpf, &bq);
else
- xdp_return_frame_rx_napi(dcb_buf->data.xdpf);
+ page_pool_recycle_direct(rx->page_pool,
+ dcb_buf->data.page);
}
clear = true;
@@ -699,15 +701,14 @@ static void lan966x_fdma_tx_start(struct lan966x_tx *tx, int next_to_use)
tx->last_in_use = next_to_use;
}
-int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
- struct xdp_frame *xdpf,
- struct page *page,
- bool dma_map)
+int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len)
{
struct lan966x *lan966x = port->lan966x;
struct lan966x_tx_dcb_buf *next_dcb_buf;
struct lan966x_tx *tx = &lan966x->tx;
+ struct xdp_frame *xdpf;
dma_addr_t dma_addr;
+ struct page *page;
int next_to_use;
__be32 *ifh;
int ret = 0;
@@ -722,8 +723,13 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
goto out;
}
+ /* Get the next buffer */
+ next_dcb_buf = &tx->dcbs_buf[next_to_use];
+
/* Generate new IFH */
- if (dma_map) {
+ if (!len) {
+ xdpf = ptr;
+
if (xdpf->headroom < IFH_LEN_BYTES) {
ret = NETDEV_TX_OK;
goto out;
@@ -743,11 +749,16 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
goto out;
}
+ next_dcb_buf->data.xdpf = xdpf;
+ next_dcb_buf->len = xdpf->len + IFH_LEN_BYTES;
+
/* Setup next dcb */
lan966x_fdma_tx_setup_dcb(tx, next_to_use,
xdpf->len + IFH_LEN_BYTES,
dma_addr);
} else {
+ page = ptr;
+
ifh = page_address(page) + XDP_PACKET_HEADROOM;
memset(ifh, 0x0, sizeof(__be32) * IFH_LEN);
lan966x_ifh_set_bypass(ifh, 1);
@@ -756,21 +767,21 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
dma_addr = page_pool_get_dma_addr(page);
dma_sync_single_for_device(lan966x->dev,
dma_addr + XDP_PACKET_HEADROOM,
- xdpf->len + IFH_LEN_BYTES,
+ len + IFH_LEN_BYTES,
DMA_TO_DEVICE);
+ next_dcb_buf->data.page = page;
+ next_dcb_buf->len = len + IFH_LEN_BYTES;
+
/* Setup next dcb */
lan966x_fdma_tx_setup_dcb(tx, next_to_use,
- xdpf->len + IFH_LEN_BYTES,
+ len + IFH_LEN_BYTES,
dma_addr + XDP_PACKET_HEADROOM);
}
/* Fill up the buffer */
- next_dcb_buf = &tx->dcbs_buf[next_to_use];
next_dcb_buf->use_skb = false;
- next_dcb_buf->data.xdpf = xdpf;
- next_dcb_buf->xdp_ndo = dma_map;
- next_dcb_buf->len = xdpf->len + IFH_LEN_BYTES;
+ next_dcb_buf->xdp_ndo = !len;
next_dcb_buf->dma_addr = dma_addr;
next_dcb_buf->used = true;
next_dcb_buf->ptp = false;
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
index 757378516f1fd..27f272831ea5c 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.h
@@ -262,6 +262,7 @@ struct lan966x_tx_dcb_buf {
union {
struct sk_buff *skb;
struct xdp_frame *xdpf;
+ struct page *page;
} data;
u32 len;
u32 used : 1;
@@ -593,10 +594,7 @@ int lan966x_ptp_setup_traps(struct lan966x_port *port, struct ifreq *ifr);
int lan966x_ptp_del_traps(struct lan966x_port *port);
int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev);
-int lan966x_fdma_xmit_xdpf(struct lan966x_port *port,
- struct xdp_frame *frame,
- struct page *page,
- bool dma_map);
+int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len);
int lan966x_fdma_change_mtu(struct lan966x *lan966x);
void lan966x_fdma_netdev_init(struct lan966x *lan966x, struct net_device *dev);
void lan966x_fdma_netdev_deinit(struct lan966x *lan966x, struct net_device *dev);
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
index 2e6f486ec67d7..9ee61db8690b4 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_xdp.c
@@ -62,7 +62,7 @@ int lan966x_xdp_xmit(struct net_device *dev,
struct xdp_frame *xdpf = frames[i];
int err;
- err = lan966x_fdma_xmit_xdpf(port, xdpf, NULL, true);
+ err = lan966x_fdma_xmit_xdpf(port, xdpf, 0);
if (err)
break;
@@ -76,7 +76,6 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
{
struct bpf_prog *xdp_prog = port->xdp_prog;
struct lan966x *lan966x = port->lan966x;
- struct xdp_frame *xdpf;
struct xdp_buff xdp;
u32 act;
@@ -90,11 +89,8 @@ int lan966x_xdp_run(struct lan966x_port *port, struct page *page, u32 data_len)
case XDP_PASS:
return FDMA_PASS;
case XDP_TX:
- xdpf = xdp_convert_buff_to_frame(&xdp);
- if (!xdpf)
- return FDMA_DROP;
-
- return lan966x_fdma_xmit_xdpf(port, xdpf, page, false) ?
+ return lan966x_fdma_xmit_xdpf(port, page,
+ data_len - IFH_LEN_BYTES) ?
FDMA_DROP : FDMA_TX;
case XDP_REDIRECT:
if (xdp_do_redirect(port->dev, &xdp, xdp_prog))
--
2.38.0