[PATCH v2 37/37] net/mvpp2: Replace tasklet with softirq hrtimer

Anna-Maria Gleixner
2017-10-22T21:43:42Z

[-- Attachment #1: netmvpp2_Replace_tasklet_with_softirq_hrtimer.patch --]
[-- Type: text/plain, Size: 3918 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

The tx_done_tasklet tasklet is used in invoke the hrtimer
(mvpp2_hr_timer_cb) in softirq context. This can be also achieved without
the tasklet but with HRTIMER_MODE_SOFT as hrtimer mode.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: netdev@vger.kernel.org
---
drivers/net/ethernet/marvell/mvpp2.c | 62 ++++++++++++++---------------------
1 file changed, 25 insertions(+), 37 deletions(-)

--- a/drivers/net/ethernet/marvell/mvpp2.c
+++ b/drivers/net/ethernet/marvell/mvpp2.c
@@ -830,9 +830,8 @@ struct mvpp2_pcpu_stats {
/* Per-CPU port control */
struct mvpp2_port_pcpu {
struct hrtimer tx_done_timer;
+ struct net_device *dev;
bool timer_scheduled;
- /* Tasklet for egress finalization */
- struct tasklet_struct tx_done_tasklet;
};

struct mvpp2_queue_vector {
@@ -5973,46 +5972,34 @@ static void mvpp2_link_event(struct net_
}
}

-static void mvpp2_timer_set(struct mvpp2_port_pcpu *port_pcpu)
-{
- ktime_t interval;
-
- if (!port_pcpu->timer_scheduled) {
- port_pcpu->timer_scheduled = true;
- interval = MVPP2_TXDONE_HRTIMER_PERIOD_NS;
- hrtimer_start(&port_pcpu->tx_done_timer, interval,
- HRTIMER_MODE_REL_PINNED);
- }
-}
-
-static void mvpp2_tx_proc_cb(unsigned long data)
+static enum hrtimer_restart mvpp2_hr_timer_cb(struct hrtimer *timer)
{
- struct net_device *dev = (struct net_device *)data;
- struct mvpp2_port *port = netdev_priv(dev);
- struct mvpp2_port_pcpu *port_pcpu = this_cpu_ptr(port->pcpu);
+ struct net_device *dev;
+ struct mvpp2_port *port;
+ struct mvpp2_port_pcpu *port_pcpu;
unsigned int tx_todo, cause;

+ port_pcpu = container_of(timer, struct mvpp2_port_pcpu, tx_done_timer);
+ dev = port_pcpu->dev;
+
if (!netif_running(dev))
- return;
+ return HRTIMER_NORESTART;
+
port_pcpu->timer_scheduled = false;
+ port = netdev_priv(dev);

/* Process all the Tx queues */
cause = (1 << port->ntxqs) - 1;
tx_todo = mvpp2_tx_done(port, cause, smp_processor_id());

/* Set the timer in case not all the packets were processed */
- if (tx_todo)
- mvpp2_timer_set(port_pcpu);
-}
-
-static enum hrtimer_restart mvpp2_hr_timer_cb(struct hrtimer *timer)
-{
- struct mvpp2_port_pcpu *port_pcpu = container_of(timer,
- struct mvpp2_port_pcpu,
- tx_done_timer);
-
- tasklet_schedule(&port_pcpu->tx_done_tasklet);
+ if (tx_todo && !port_pcpu->timer_scheduled) {
+ port_pcpu->timer_scheduled = true;
+ hrtimer_forward_now(&port_pcpu->tx_done_timer,
+ MVPP2_TXDONE_HRTIMER_PERIOD_NS);

+ return HRTIMER_RESTART;
+ }
return HRTIMER_NORESTART;
}

@@ -6498,7 +6485,12 @@ static int mvpp2_tx(struct sk_buff *skb,
txq_pcpu->count > 0) {
struct mvpp2_port_pcpu *port_pcpu = this_cpu_ptr(port->pcpu);

- mvpp2_timer_set(port_pcpu);
+ if (!port_pcpu->timer_scheduled) {
+ port_pcpu->timer_scheduled = true;
+ hrtimer_start(&port_pcpu->tx_done_timer,
+ MVPP2_TXDONE_HRTIMER_PERIOD_NS,
+ HRTIMER_MODE_REL_PINNED_SOFT);
+ }
}

return NETDEV_TX_OK;
@@ -6883,7 +6875,6 @@ static int mvpp2_stop(struct net_device

hrtimer_cancel(&port_pcpu->tx_done_timer);
port_pcpu->timer_scheduled = false;
- tasklet_kill(&port_pcpu->tx_done_tasklet);
}
}
mvpp2_cleanup_rxqs(port);
@@ -7651,13 +7642,10 @@ static int mvpp2_port_probe(struct platf
port_pcpu = per_cpu_ptr(port->pcpu, cpu);

hrtimer_init(&port_pcpu->tx_done_timer, CLOCK_MONOTONIC,
- HRTIMER_MODE_REL_PINNED);
+ HRTIMER_MODE_REL_PINNED_SOFT);
port_pcpu->tx_done_timer.function = mvpp2_hr_timer_cb;
port_pcpu->timer_scheduled = false;
-
- tasklet_init(&port_pcpu->tx_done_tasklet,
- mvpp2_tx_proc_cb,
- (unsigned long)dev);
+ port_pcpu->dev = dev;
}
}