Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-18 01:51:53 +00:00
Code Issues Packages Projects Releases Wiki Activity

net: ethernet: fec: prevent tx starvation under high rx load

Browse Source 
In the ISR, we poll the event register for the queues in need of
service and then enter polled mode. After this point, the event
register will never be read again until we exit polled mode.

In a scenario where a UDP flow is routed back out through the same
interface, i.e. "router-on-a-stick" we'll typically only see an rx
queue event initially. Once we start to process the incoming flow
we'll be locked polled mode, but we'll never clean the tx rings since
that event is never caught.

Eventually the netdev watchdog will trip, causing all buffers to be
dropped and then the process starts over again.

Rework the NAPI poll to keep trying to consome the entire budget as
long as new events are coming in, making sure to service all rx/tx
queues, in priority order, on each pass.

Fixes: 4d494cdc92 ("net: fec: change data structure to support multiqueue")
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Tested-by: Fugang Duan <fugang.duan@nxp.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tobias Waldekranz 2020-07-03 16:10:58 +02:00 committed by David S. Miller
parent 28b18e4eb5
commit 7cdaa4cc4b
2 changed files with 34 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/net/ethernet/freescale/fec.h
View File

@ -525,11 +525,6 @@ struct fec_enet_private {
unsigned int total_tx_ring_size;
unsigned int total_rx_ring_size;
unsigned long work_tx;
unsigned long work_rx;
unsigned long work_ts;
unsigned long work_mdio;
struct platform_device *pdev;
int dev_id;

100
drivers/net/ethernet/freescale/fec_main.c
View File

@ -75,8 +75,6 @@ static void fec_enet_itr_coal_init(struct net_device *ndev);
#define DRIVER_NAME "fec"
#define FEC_ENET_GET_QUQUE(_x) ((_x == 0) ? 1 : ((_x == 1) ? 2 : 0))
/* Pause frame feild and FIFO threshold */
#define FEC_ENET_FCE (1 << 5)
#define FEC_ENET_RSEM_V 0x84
@ -1248,8 +1246,6 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id)
fep = netdev_priv(ndev);
queue_id = FEC_ENET_GET_QUQUE(queue_id);
txq = fep->tx_queue[queue_id];
/* get next bdp of dirty_tx */
nq = netdev_get_tx_queue(ndev, queue_id);
@ -1340,17 +1336,14 @@ skb_done:
writel(0, txq->bd.reg_desc_active);
}
static void
fec_enet_tx(struct net_device *ndev)
static void fec_enet_tx(struct net_device *ndev)
{
struct fec_enet_private *fep = netdev_priv(ndev);
u16 queue_id;
/* First process class A queue, then Class B and Best Effort queue */
for_each_set_bit(queue_id, &fep->work_tx, FEC_ENET_MAX_TX_QS) {
clear_bit(queue_id, &fep->work_tx);
fec_enet_tx_queue(ndev, queue_id);
}
return;
int i;
/* Make sure that AVB queues are processed first. */
for (i = fep->num_tx_queues - 1; i >= 0; i--)
fec_enet_tx_queue(ndev, i);
}
static int
@ -1426,7 +1419,6 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
#ifdef CONFIG_M532x
flush_cache_all();
#endif
queue_id = FEC_ENET_GET_QUQUE(queue_id);
rxq = fep->rx_queue[queue_id];
/* First, grab all of the stats for the incoming packet.
@ -1550,6 +1542,7 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
htons(ETH_P_8021Q),
vlan_tag);
skb_record_rx_queue(skb, queue_id);
napi_gro_receive(&fep->napi, skb);
if (is_copybreak) {
@ -1595,57 +1588,21 @@ rx_processing_done:
return pkt_received;
}
static int
fec_enet_rx(struct net_device *ndev, int budget)
static int fec_enet_rx(struct net_device *ndev, int budget)
{
int pkt_received = 0;
u16 queue_id;
struct fec_enet_private *fep = netdev_priv(ndev);
int i, done = 0;
for_each_set_bit(queue_id, &fep->work_rx, FEC_ENET_MAX_RX_QS) {
int ret;
/* Make sure that AVB queues are processed first. */
for (i = fep->num_rx_queues - 1; i >= 0; i--)
done += fec_enet_rx_queue(ndev, budget - done, i);
ret = fec_enet_rx_queue(ndev,
budget - pkt_received, queue_id);
if (ret < budget - pkt_received)
clear_bit(queue_id, &fep->work_rx);
pkt_received += ret;
}
return pkt_received;
return done;
}
static bool
fec_enet_collect_events(struct fec_enet_private *fep, uint int_events)
static bool fec_enet_collect_events(struct fec_enet_private *fep)
{
if (int_events == 0)
return false;
if (int_events & FEC_ENET_RXF_0)
fep->work_rx |= (1 << 2);
if (int_events & FEC_ENET_RXF_1)
fep->work_rx |= (1 << 0);
if (int_events & FEC_ENET_RXF_2)
fep->work_rx |= (1 << 1);
if (int_events & FEC_ENET_TXF_0)
fep->work_tx |= (1 << 2);
if (int_events & FEC_ENET_TXF_1)
fep->work_tx |= (1 << 0);
if (int_events & FEC_ENET_TXF_2)
fep->work_tx |= (1 << 1);
return true;
}
static irqreturn_t
fec_enet_interrupt(int irq, void *dev_id)
{
struct net_device *ndev = dev_id;
struct fec_enet_private *fep = netdev_priv(ndev);
uint int_events;
irqreturn_t ret = IRQ_NONE;
int_events = readl(fep->hwp + FEC_IEVENT);
@ -1653,9 +1610,18 @@ fec_enet_interrupt(int irq, void *dev_id)
int_events &= ~FEC_ENET_MII;
writel(int_events, fep->hwp + FEC_IEVENT);
fec_enet_collect_events(fep, int_events);
if ((fep->work_tx || fep->work_rx) && fep->link) {
return int_events != 0;
}
static irqreturn_t
fec_enet_interrupt(int irq, void *dev_id)
{
struct net_device *ndev = dev_id;
struct fec_enet_private *fep = netdev_priv(ndev);
irqreturn_t ret = IRQ_NONE;
if (fec_enet_collect_events(fep) && fep->link) {
ret = IRQ_HANDLED;
if (napi_schedule_prep(&fep->napi)) {
@ -1672,17 +1638,19 @@ static int fec_enet_rx_napi(struct napi_struct *napi, int budget)
{
struct net_device *ndev = napi->dev;
struct fec_enet_private *fep = netdev_priv(ndev);
int pkts;
int done = 0;
pkts = fec_enet_rx(ndev, budget);
do {
done += fec_enet_rx(ndev, budget - done);
fec_enet_tx(ndev);
} while ((done < budget) && fec_enet_collect_events(fep));
fec_enet_tx(ndev);
if (pkts < budget) {
napi_complete_done(napi, pkts);
if (done < budget) {
napi_complete_done(napi, done);
writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
}
return pkts;
return done;
}
/* ------------------------------------------------------------------------- */