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Subject[PATCH 4.18 041/135] net: stmmac: Rework coalesce timer and fix multi-queue races
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jose Abreu <Jose.Abreu@synopsys.com>

[ Upstream commit 8fce3331702316d4bcfeb0771c09ac75d2192bbc ]

This follows David Miller advice and tries to fix coalesce timer in
multi-queue scenarios.

We are now using per-queue coalesce values and per-queue TX timer.

Coalesce timer default values was changed to 1ms and the coalesce frames
to 25.

Tested in B2B setup between XGMAC2 and GMAC5.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Fixes: ce736788e8a ("net: stmmac: adding multiple buffers for TX")
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/stmicro/stmmac/common.h | 4
drivers/net/ethernet/stmicro/stmmac/stmmac.h | 14 +
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 234 ++++++++++++----------
include/linux/stmmac.h | 1
4 files changed, 146 insertions(+), 107 deletions(-)

--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -256,10 +256,10 @@ struct stmmac_safety_stats {
#define MAX_DMA_RIWT 0xff
#define MIN_DMA_RIWT 0x20
/* Tx coalesce parameters */
-#define STMMAC_COAL_TX_TIMER 40000
+#define STMMAC_COAL_TX_TIMER 1000
#define STMMAC_MAX_COAL_TX_TICK 100000
#define STMMAC_TX_MAX_FRAMES 256
-#define STMMAC_TX_FRAMES 64
+#define STMMAC_TX_FRAMES 25

/* Packets types */
enum packets_types {
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -48,6 +48,8 @@ struct stmmac_tx_info {

/* Frequently used values are kept adjacent for cache effect */
struct stmmac_tx_queue {
+ u32 tx_count_frames;
+ struct timer_list txtimer;
u32 queue_index;
struct stmmac_priv *priv_data;
struct dma_extended_desc *dma_etx ____cacheline_aligned_in_smp;
@@ -73,7 +75,14 @@ struct stmmac_rx_queue {
u32 rx_zeroc_thresh;
dma_addr_t dma_rx_phy;
u32 rx_tail_addr;
+};
+
+struct stmmac_channel {
struct napi_struct napi ____cacheline_aligned_in_smp;
+ struct stmmac_priv *priv_data;
+ u32 index;
+ int has_rx;
+ int has_tx;
};

struct stmmac_tc_entry {
@@ -109,14 +118,12 @@ struct stmmac_pps_cfg {

struct stmmac_priv {
/* Frequently used values are kept adjacent for cache effect */
- u32 tx_count_frames;
u32 tx_coal_frames;
u32 tx_coal_timer;

int tx_coalesce;
int hwts_tx_en;
bool tx_path_in_lpi_mode;
- struct timer_list txtimer;
bool tso;

unsigned int dma_buf_sz;
@@ -137,6 +144,9 @@ struct stmmac_priv {
/* TX Queue */
struct stmmac_tx_queue tx_queue[MTL_MAX_TX_QUEUES];

+ /* Generic channel for NAPI */
+ struct stmmac_channel channel[STMMAC_CH_MAX];
+
bool oldlink;
int speed;
int oldduplex;
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -147,12 +147,14 @@ static void stmmac_verify_args(void)
static void stmmac_disable_all_queues(struct stmmac_priv *priv)
{
u32 rx_queues_cnt = priv->plat->rx_queues_to_use;
+ u32 tx_queues_cnt = priv->plat->tx_queues_to_use;
+ u32 maxq = max(rx_queues_cnt, tx_queues_cnt);
u32 queue;

- for (queue = 0; queue < rx_queues_cnt; queue++) {
- struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
+ for (queue = 0; queue < maxq; queue++) {
+ struct stmmac_channel *ch = &priv->channel[queue];

- napi_disable(&rx_q->napi);
+ napi_disable(&ch->napi);
}
}

@@ -163,12 +165,14 @@ static void stmmac_disable_all_queues(st
static void stmmac_enable_all_queues(struct stmmac_priv *priv)
{
u32 rx_queues_cnt = priv->plat->rx_queues_to_use;
+ u32 tx_queues_cnt = priv->plat->tx_queues_to_use;
+ u32 maxq = max(rx_queues_cnt, tx_queues_cnt);
u32 queue;

- for (queue = 0; queue < rx_queues_cnt; queue++) {
- struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
+ for (queue = 0; queue < maxq; queue++) {
+ struct stmmac_channel *ch = &priv->channel[queue];

- napi_enable(&rx_q->napi);
+ napi_enable(&ch->napi);
}
}

@@ -1822,18 +1826,18 @@ static void stmmac_dma_operation_mode(st
* @queue: TX queue index
* Description: it reclaims the transmit resources after transmission completes.
*/
-static void stmmac_tx_clean(struct stmmac_priv *priv, u32 queue)
+static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue)
{
struct stmmac_tx_queue *tx_q = &priv->tx_queue[queue];
unsigned int bytes_compl = 0, pkts_compl = 0;
- unsigned int entry;
+ unsigned int entry, count = 0;

- netif_tx_lock(priv->dev);
+ __netif_tx_lock_bh(netdev_get_tx_queue(priv->dev, queue));

priv->xstats.tx_clean++;

entry = tx_q->dirty_tx;
- while (entry != tx_q->cur_tx) {
+ while ((entry != tx_q->cur_tx) && (count < budget)) {
struct sk_buff *skb = tx_q->tx_skbuff[entry];
struct dma_desc *p;
int status;
@@ -1849,6 +1853,8 @@ static void stmmac_tx_clean(struct stmma
if (unlikely(status & tx_dma_own))
break;

+ count++;
+
/* Make sure descriptor fields are read after reading
* the own bit.
*/
@@ -1916,7 +1922,10 @@ static void stmmac_tx_clean(struct stmma
stmmac_enable_eee_mode(priv);
mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(eee_timer));
}
- netif_tx_unlock(priv->dev);
+
+ __netif_tx_unlock_bh(netdev_get_tx_queue(priv->dev, queue));
+
+ return count;
}

/**
@@ -1999,6 +2008,33 @@ static bool stmmac_safety_feat_interrupt
return false;
}

+static int stmmac_napi_check(struct stmmac_priv *priv, u32 chan)
+{
+ int status = stmmac_dma_interrupt_status(priv, priv->ioaddr,
+ &priv->xstats, chan);
+ struct stmmac_channel *ch = &priv->channel[chan];
+ bool needs_work = false;
+
+ if ((status & handle_rx) && ch->has_rx) {
+ needs_work = true;
+ } else {
+ status &= ~handle_rx;
+ }
+
+ if ((status & handle_tx) && ch->has_tx) {
+ needs_work = true;
+ } else {
+ status &= ~handle_tx;
+ }
+
+ if (needs_work && napi_schedule_prep(&ch->napi)) {
+ stmmac_disable_dma_irq(priv, priv->ioaddr, chan);
+ __napi_schedule(&ch->napi);
+ }
+
+ return status;
+}
+
/**
* stmmac_dma_interrupt - DMA ISR
* @priv: driver private structure
@@ -2013,57 +2049,14 @@ static void stmmac_dma_interrupt(struct
u32 channels_to_check = tx_channel_count > rx_channel_count ?
tx_channel_count : rx_channel_count;
u32 chan;
- bool poll_scheduled = false;
int status[max_t(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)];

/* Make sure we never check beyond our status buffer. */
if (WARN_ON_ONCE(channels_to_check > ARRAY_SIZE(status)))
channels_to_check = ARRAY_SIZE(status);

- /* Each DMA channel can be used for rx and tx simultaneously, yet
- * napi_struct is embedded in struct stmmac_rx_queue rather than in a
- * stmmac_channel struct.
- * Because of this, stmmac_poll currently checks (and possibly wakes)
- * all tx queues rather than just a single tx queue.
- */
for (chan = 0; chan < channels_to_check; chan++)
- status[chan] = stmmac_dma_interrupt_status(priv, priv->ioaddr,
- &priv->xstats, chan);
-
- for (chan = 0; chan < rx_channel_count; chan++) {
- if (likely(status[chan] & handle_rx)) {
- struct stmmac_rx_queue *rx_q = &priv->rx_queue[chan];
-
- if (likely(napi_schedule_prep(&rx_q->napi))) {
- stmmac_disable_dma_irq(priv, priv->ioaddr, chan);
- __napi_schedule(&rx_q->napi);
- poll_scheduled = true;
- }
- }
- }
-
- /* If we scheduled poll, we already know that tx queues will be checked.
- * If we didn't schedule poll, see if any DMA channel (used by tx) has a
- * completed transmission, if so, call stmmac_poll (once).
- */
- if (!poll_scheduled) {
- for (chan = 0; chan < tx_channel_count; chan++) {
- if (status[chan] & handle_tx) {
- /* It doesn't matter what rx queue we choose
- * here. We use 0 since it always exists.
- */
- struct stmmac_rx_queue *rx_q =
- &priv->rx_queue[0];
-
- if (likely(napi_schedule_prep(&rx_q->napi))) {
- stmmac_disable_dma_irq(priv,
- priv->ioaddr, chan);
- __napi_schedule(&rx_q->napi);
- }
- break;
- }
- }
- }
+ status[chan] = stmmac_napi_check(priv, chan);

for (chan = 0; chan < tx_channel_count; chan++) {
if (unlikely(status[chan] & tx_hard_error_bump_tc)) {
@@ -2211,6 +2204,13 @@ static int stmmac_init_dma_engine(struct
return ret;
}

+static void stmmac_tx_timer_arm(struct stmmac_priv *priv, u32 queue)
+{
+ struct stmmac_tx_queue *tx_q = &priv->tx_queue[queue];
+
+ mod_timer(&tx_q->txtimer, STMMAC_COAL_TIMER(priv->tx_coal_timer));
+}
+
/**
* stmmac_tx_timer - mitigation sw timer for tx.
* @data: data pointer
@@ -2219,13 +2219,14 @@ static int stmmac_init_dma_engine(struct
*/
static void stmmac_tx_timer(struct timer_list *t)
{
- struct stmmac_priv *priv = from_timer(priv, t, txtimer);
- u32 tx_queues_count = priv->plat->tx_queues_to_use;
- u32 queue;
+ struct stmmac_tx_queue *tx_q = from_timer(tx_q, t, txtimer);
+ struct stmmac_priv *priv = tx_q->priv_data;
+ struct stmmac_channel *ch;

- /* let's scan all the tx queues */
- for (queue = 0; queue < tx_queues_count; queue++)
- stmmac_tx_clean(priv, queue);
+ ch = &priv->channel[tx_q->queue_index];
+
+ if (likely(napi_schedule_prep(&ch->napi)))
+ __napi_schedule(&ch->napi);
}

/**
@@ -2238,11 +2239,17 @@ static void stmmac_tx_timer(struct timer
*/
static void stmmac_init_tx_coalesce(struct stmmac_priv *priv)
{
+ u32 tx_channel_count = priv->plat->tx_queues_to_use;
+ u32 chan;
+
priv->tx_coal_frames = STMMAC_TX_FRAMES;
priv->tx_coal_timer = STMMAC_COAL_TX_TIMER;
- timer_setup(&priv->txtimer, stmmac_tx_timer, 0);
- priv->txtimer.expires = STMMAC_COAL_TIMER(priv->tx_coal_timer);
- add_timer(&priv->txtimer);
+
+ for (chan = 0; chan < tx_channel_count; chan++) {
+ struct stmmac_tx_queue *tx_q = &priv->tx_queue[chan];
+
+ timer_setup(&tx_q->txtimer, stmmac_tx_timer, 0);
+ }
}

static void stmmac_set_rings_length(struct stmmac_priv *priv)
@@ -2570,6 +2577,7 @@ static void stmmac_hw_teardown(struct ne
static int stmmac_open(struct net_device *dev)
{
struct stmmac_priv *priv = netdev_priv(dev);
+ u32 chan;
int ret;

stmmac_check_ether_addr(priv);
@@ -2666,7 +2674,9 @@ irq_error:
if (dev->phydev)
phy_stop(dev->phydev);

- del_timer_sync(&priv->txtimer);
+ for (chan = 0; chan < priv->plat->tx_queues_to_use; chan++)
+ del_timer_sync(&priv->tx_queue[chan].txtimer);
+
stmmac_hw_teardown(dev);
init_error:
free_dma_desc_resources(priv);
@@ -2686,6 +2696,7 @@ dma_desc_error:
static int stmmac_release(struct net_device *dev)
{
struct stmmac_priv *priv = netdev_priv(dev);
+ u32 chan;

if (priv->eee_enabled)
del_timer_sync(&priv->eee_ctrl_timer);
@@ -2700,7 +2711,8 @@ static int stmmac_release(struct net_dev

stmmac_disable_all_queues(priv);

- del_timer_sync(&priv->txtimer);
+ for (chan = 0; chan < priv->plat->tx_queues_to_use; chan++)
+ del_timer_sync(&priv->tx_queue[chan].txtimer);

/* Free the IRQ lines */
free_irq(dev->irq, dev);
@@ -2914,14 +2926,13 @@ static netdev_tx_t stmmac_tso_xmit(struc
priv->xstats.tx_tso_nfrags += nfrags;

/* Manage tx mitigation */
- priv->tx_count_frames += nfrags + 1;
- if (likely(priv->tx_coal_frames > priv->tx_count_frames)) {
- mod_timer(&priv->txtimer,
- STMMAC_COAL_TIMER(priv->tx_coal_timer));
- } else {
- priv->tx_count_frames = 0;
+ tx_q->tx_count_frames += nfrags + 1;
+ if (priv->tx_coal_frames <= tx_q->tx_count_frames) {
stmmac_set_tx_ic(priv, desc);
priv->xstats.tx_set_ic_bit++;
+ tx_q->tx_count_frames = 0;
+ } else {
+ stmmac_tx_timer_arm(priv, queue);
}

skb_tx_timestamp(skb);
@@ -3125,14 +3136,13 @@ static netdev_tx_t stmmac_xmit(struct sk
* This approach takes care about the fragments: desc is the first
* element in case of no SG.
*/
- priv->tx_count_frames += nfrags + 1;
- if (likely(priv->tx_coal_frames > priv->tx_count_frames)) {
- mod_timer(&priv->txtimer,
- STMMAC_COAL_TIMER(priv->tx_coal_timer));
- } else {
- priv->tx_count_frames = 0;
+ tx_q->tx_count_frames += nfrags + 1;
+ if (priv->tx_coal_frames <= tx_q->tx_count_frames) {
stmmac_set_tx_ic(priv, desc);
priv->xstats.tx_set_ic_bit++;
+ tx_q->tx_count_frames = 0;
+ } else {
+ stmmac_tx_timer_arm(priv, queue);
}

skb_tx_timestamp(skb);
@@ -3300,6 +3310,7 @@ static inline void stmmac_rx_refill(stru
static int stmmac_rx(struct stmmac_priv *priv, int limit, u32 queue)
{
struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
+ struct stmmac_channel *ch = &priv->channel[queue];
unsigned int entry = rx_q->cur_rx;
int coe = priv->hw->rx_csum;
unsigned int next_entry;
@@ -3469,7 +3480,7 @@ static int stmmac_rx(struct stmmac_priv
else
skb->ip_summed = CHECKSUM_UNNECESSARY;

- napi_gro_receive(&rx_q->napi, skb);
+ napi_gro_receive(&ch->napi, skb);

priv->dev->stats.rx_packets++;
priv->dev->stats.rx_bytes += frame_len;
@@ -3492,27 +3503,33 @@ static int stmmac_rx(struct stmmac_priv
* Description :
* To look at the incoming frames and clear the tx resources.
*/
-static int stmmac_poll(struct napi_struct *napi, int budget)
+static int stmmac_napi_poll(struct napi_struct *napi, int budget)
{
- struct stmmac_rx_queue *rx_q =
- container_of(napi, struct stmmac_rx_queue, napi);
- struct stmmac_priv *priv = rx_q->priv_data;
- u32 tx_count = priv->plat->tx_queues_to_use;
- u32 chan = rx_q->queue_index;
- int work_done = 0;
- u32 queue;
+ struct stmmac_channel *ch =
+ container_of(napi, struct stmmac_channel, napi);
+ struct stmmac_priv *priv = ch->priv_data;
+ int work_done = 0, work_rem = budget;
+ u32 chan = ch->index;

priv->xstats.napi_poll++;

- /* check all the queues */
- for (queue = 0; queue < tx_count; queue++)
- stmmac_tx_clean(priv, queue);
-
- work_done = stmmac_rx(priv, budget, rx_q->queue_index);
- if (work_done < budget) {
- napi_complete_done(napi, work_done);
- stmmac_enable_dma_irq(priv, priv->ioaddr, chan);
+ if (ch->has_tx) {
+ int done = stmmac_tx_clean(priv, work_rem, chan);
+
+ work_done += done;
+ work_rem -= done;
+ }
+
+ if (ch->has_rx) {
+ int done = stmmac_rx(priv, work_rem, chan);
+
+ work_done += done;
+ work_rem -= done;
}
+
+ if (work_done < budget && napi_complete_done(napi, work_done))
+ stmmac_enable_dma_irq(priv, priv->ioaddr, chan);
+
return work_done;
}

@@ -4172,8 +4189,8 @@ int stmmac_dvr_probe(struct device *devi
{
struct net_device *ndev = NULL;
struct stmmac_priv *priv;
+ u32 queue, maxq;
int ret = 0;
- u32 queue;

ndev = alloc_etherdev_mqs(sizeof(struct stmmac_priv),
MTL_MAX_TX_QUEUES,
@@ -4293,11 +4310,22 @@ int stmmac_dvr_probe(struct device *devi
"Enable RX Mitigation via HW Watchdog Timer\n");
}

- for (queue = 0; queue < priv->plat->rx_queues_to_use; queue++) {
- struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
+ /* Setup channels NAPI */
+ maxq = max(priv->plat->rx_queues_to_use, priv->plat->tx_queues_to_use);

- netif_napi_add(ndev, &rx_q->napi, stmmac_poll,
- (8 * priv->plat->rx_queues_to_use));
+ for (queue = 0; queue < maxq; queue++) {
+ struct stmmac_channel *ch = &priv->channel[queue];
+
+ ch->priv_data = priv;
+ ch->index = queue;
+
+ if (queue < priv->plat->rx_queues_to_use)
+ ch->has_rx = true;
+ if (queue < priv->plat->tx_queues_to_use)
+ ch->has_tx = true;
+
+ netif_napi_add(ndev, &ch->napi, stmmac_napi_poll,
+ NAPI_POLL_WEIGHT);
}

mutex_init(&priv->lock);
@@ -4343,10 +4371,10 @@ error_netdev_register:
priv->hw->pcs != STMMAC_PCS_RTBI)
stmmac_mdio_unregister(ndev);
error_mdio_register:
- for (queue = 0; queue < priv->plat->rx_queues_to_use; queue++) {
- struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
+ for (queue = 0; queue < maxq; queue++) {
+ struct stmmac_channel *ch = &priv->channel[queue];

- netif_napi_del(&rx_q->napi);
+ netif_napi_del(&ch->napi);
}
error_hw_init:
destroy_workqueue(priv->wq);
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -30,6 +30,7 @@

#define MTL_MAX_RX_QUEUES 8
#define MTL_MAX_TX_QUEUES 8
+#define STMMAC_CH_MAX 8

#define STMMAC_RX_COE_NONE 0
#define STMMAC_RX_COE_TYPE1 1

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