[PATCH net-next 2/5] net: dpaa: eliminate NR_CPUS dependency in egress_fqs[] and conf_fqs[]

From: Vladimir Oltean
Date: Wed Jul 10 2024 - 19:02:27 EST


The driver uses the DPAA_TC_TXQ_NUM and DPAA_ETH_TXQ_NUM macros for TX
queue handling, and they depend on CONFIG_NR_CPUS.

In generic .config files, these can go to very large (8096 CPUs) values
for the systems that DPAA1 is integrated in (1-24 CPUs). We allocate a
lot of resources that will never be used. Those are:
- system memory
- QMan FQIDs as managed by qman_alloc_fqid_range(). This is especially
painful since currently, when booting with CONFIG_NR_CPUS=8096, a
LS1046A-RDB system will only manage to probe 3 of its 6 interfaces.
The rest will run out of FQD ("/reserved-memory/qman-fqd" in the
device tree) and fail at the qman_create_fq() stage of the probing
process.
- netdev queues as alloc_etherdev_mq() argument. The high queue indices
are simply hidden from the network stack after the call to
netif_set_real_num_tx_queues().

With just a tiny bit more effort, we can replace the NR_CPUS
compile-time constant with the num_possible_cpus() run-time constant,
and dynamically allocate the egress_fqs[] and conf_fqs[] arrays.
Even on a system with a high CONFIG_NR_CPUS, num_possible_cpus() will
remain equal to the number of available cores on the SoC.

The replacement is as follows:
- DPAA_TC_TXQ_NUM -> dpaa_num_txqs_per_tc()
- DPAA_ETH_TXQ_NUM -> dpaa_max_num_txqs()

Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
.../net/ethernet/freescale/dpaa/dpaa_eth.c | 43 +++++++++++++------
.../net/ethernet/freescale/dpaa/dpaa_eth.h | 20 ++++++---
2 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index c856b556929d..7b0317020c89 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -371,6 +371,7 @@ static int dpaa_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
void *type_data)
{
struct dpaa_priv *priv = netdev_priv(net_dev);
+ int num_txqs_per_tc = dpaa_num_txqs_per_tc();
struct tc_mqprio_qopt *mqprio = type_data;
u8 num_tc;
int i;
@@ -398,12 +399,12 @@ static int dpaa_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
netdev_set_num_tc(net_dev, num_tc);

for (i = 0; i < num_tc; i++)
- netdev_set_tc_queue(net_dev, i, DPAA_TC_TXQ_NUM,
- i * DPAA_TC_TXQ_NUM);
+ netdev_set_tc_queue(net_dev, i, num_txqs_per_tc,
+ i * num_txqs_per_tc);

out:
priv->num_tc = num_tc ? : 1;
- netif_set_real_num_tx_queues(net_dev, priv->num_tc * DPAA_TC_TXQ_NUM);
+ netif_set_real_num_tx_queues(net_dev, priv->num_tc * num_txqs_per_tc);
return 0;
}

@@ -649,7 +650,7 @@ static inline void dpaa_assign_wq(struct dpaa_fq *fq, int idx)
fq->wq = 6;
break;
case FQ_TYPE_TX:
- switch (idx / DPAA_TC_TXQ_NUM) {
+ switch (idx / dpaa_num_txqs_per_tc()) {
case 0:
/* Low priority (best effort) */
fq->wq = 6;
@@ -667,8 +668,8 @@ static inline void dpaa_assign_wq(struct dpaa_fq *fq, int idx)
fq->wq = 0;
break;
default:
- WARN(1, "Too many TX FQs: more than %d!\n",
- DPAA_ETH_TXQ_NUM);
+ WARN(1, "Too many TX FQs: more than %zu!\n",
+ dpaa_max_num_txqs());
}
break;
default:
@@ -740,7 +741,8 @@ static int dpaa_alloc_all_fqs(struct device *dev, struct list_head *list,

port_fqs->rx_pcdq = &dpaa_fq[0];

- if (!dpaa_fq_alloc(dev, 0, DPAA_ETH_TXQ_NUM, list, FQ_TYPE_TX_CONF_MQ))
+ if (!dpaa_fq_alloc(dev, 0, dpaa_max_num_txqs(), list,
+ FQ_TYPE_TX_CONF_MQ))
goto fq_alloc_failed;

dpaa_fq = dpaa_fq_alloc(dev, 0, 1, list, FQ_TYPE_TX_ERROR);
@@ -755,7 +757,7 @@ static int dpaa_alloc_all_fqs(struct device *dev, struct list_head *list,

port_fqs->tx_defq = &dpaa_fq[0];

- if (!dpaa_fq_alloc(dev, 0, DPAA_ETH_TXQ_NUM, list, FQ_TYPE_TX))
+ if (!dpaa_fq_alloc(dev, 0, dpaa_max_num_txqs(), list, FQ_TYPE_TX))
goto fq_alloc_failed;

return 0;
@@ -972,7 +974,7 @@ static int dpaa_fq_setup(struct dpaa_priv *priv,
/* If we have more Tx queues than the number of cores,
* just ignore the extra ones.
*/
- if (egress_cnt < DPAA_ETH_TXQ_NUM)
+ if (egress_cnt < dpaa_max_num_txqs())
priv->egress_fqs[egress_cnt++] = &fq->fq_base;
break;
case FQ_TYPE_TX_CONF_MQ:
@@ -992,12 +994,12 @@ static int dpaa_fq_setup(struct dpaa_priv *priv,
}

/* Make sure all CPUs receive a corresponding Tx queue. */
- while (egress_cnt < DPAA_ETH_TXQ_NUM) {
+ while (egress_cnt < dpaa_max_num_txqs()) {
list_for_each_entry(fq, &priv->dpaa_fq_list, list) {
if (fq->fq_type != FQ_TYPE_TX)
continue;
priv->egress_fqs[egress_cnt++] = &fq->fq_base;
- if (egress_cnt == DPAA_ETH_TXQ_NUM)
+ if (egress_cnt == dpaa_max_num_txqs())
break;
}
}
@@ -1012,7 +1014,7 @@ static inline int dpaa_tx_fq_to_id(const struct dpaa_priv *priv,
{
int i;

- for (i = 0; i < DPAA_ETH_TXQ_NUM; i++)
+ for (i = 0; i < dpaa_max_num_txqs(); i++)
if (priv->egress_fqs[i] == tx_fq)
return i;

@@ -3332,7 +3334,7 @@ static int dpaa_eth_probe(struct platform_device *pdev)
/* Allocate this early, so we can store relevant information in
* the private area
*/
- net_dev = alloc_etherdev_mq(sizeof(*priv), DPAA_ETH_TXQ_NUM);
+ net_dev = alloc_etherdev_mq(sizeof(*priv), dpaa_max_num_txqs());
if (!net_dev) {
dev_err(dev, "alloc_etherdev_mq() failed\n");
return -ENOMEM;
@@ -3347,6 +3349,18 @@ static int dpaa_eth_probe(struct platform_device *pdev)

priv->msg_enable = netif_msg_init(debug, DPAA_MSG_DEFAULT);

+ priv->egress_fqs = devm_kcalloc(dev, dpaa_max_num_txqs(),
+ sizeof(*priv->egress_fqs),
+ GFP_KERNEL);
+ if (!priv->egress_fqs)
+ goto free_netdev;
+
+ priv->conf_fqs = devm_kcalloc(dev, dpaa_max_num_txqs(),
+ sizeof(*priv->conf_fqs),
+ GFP_KERNEL);
+ if (!priv->conf_fqs)
+ goto free_netdev;
+
mac_dev = dpaa_mac_dev_get(pdev);
if (IS_ERR(mac_dev)) {
netdev_err(net_dev, "dpaa_mac_dev_get() failed\n");
@@ -3472,7 +3486,8 @@ static int dpaa_eth_probe(struct platform_device *pdev)
}

priv->num_tc = 1;
- netif_set_real_num_tx_queues(net_dev, priv->num_tc * DPAA_TC_TXQ_NUM);
+ netif_set_real_num_tx_queues(net_dev,
+ priv->num_tc * dpaa_num_txqs_per_tc());

/* Initialize NAPI */
err = dpaa_napi_add(net_dev);
diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h
index ac3c8ed57bbe..7ed659eb08de 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h
@@ -18,10 +18,6 @@

/* Number of prioritised traffic classes */
#define DPAA_TC_NUM 4
-/* Number of Tx queues per traffic class */
-#define DPAA_TC_TXQ_NUM NR_CPUS
-/* Total number of Tx queues */
-#define DPAA_ETH_TXQ_NUM (DPAA_TC_NUM * DPAA_TC_TXQ_NUM)

/* More detailed FQ types - used for fine-grained WQ assignments */
enum dpaa_fq_type {
@@ -142,8 +138,8 @@ struct dpaa_priv {
struct mac_device *mac_dev;
struct device *rx_dma_dev;
struct device *tx_dma_dev;
- struct qman_fq *egress_fqs[DPAA_ETH_TXQ_NUM];
- struct qman_fq *conf_fqs[DPAA_ETH_TXQ_NUM];
+ struct qman_fq **egress_fqs;
+ struct qman_fq **conf_fqs;

u16 channel;
struct list_head dpaa_fq_list;
@@ -185,4 +181,16 @@ extern const struct ethtool_ops dpaa_ethtool_ops;
/* from dpaa_eth_sysfs.c */
void dpaa_eth_sysfs_remove(struct device *dev);
void dpaa_eth_sysfs_init(struct device *dev);
+
+static inline size_t dpaa_num_txqs_per_tc(void)
+{
+ return num_possible_cpus();
+}
+
+/* Total number of Tx queues */
+static inline size_t dpaa_max_num_txqs(void)
+{
+ return DPAA_TC_NUM * dpaa_num_txqs_per_tc();
+}
+
#endif /* __DPAA_H */
--
2.34.1