diff mbox

[2/2] net: mvneta: improve suspend/resume

Message ID 20180329181536.46e065d2@xhacker.debian (mailing list archive)
State New, archived
Headers show

Commit Message

Jisheng Zhang March 29, 2018, 10:15 a.m. UTC
Current suspend/resume implementation reuses the mvneta_open() and
mvneta_close(), but it could be optimized to take only necessary
actions during suspend/resume.

One obvious problem of current implementation is: after hundreds of
system suspend/resume cycles, the resume of mvneta could fail due to
fragmented dma coherent memory. After this patch, the non-necessary
memory alloc/free is optimized out.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 drivers/net/ethernet/marvell/mvneta.c | 76 ++++++++++++++++++++++++++++++-----
 1 file changed, 66 insertions(+), 10 deletions(-)

Comments

Thomas Petazzoni March 29, 2018, 11:54 a.m. UTC | #1
Hello Jisheng,

On Thu, 29 Mar 2018 18:15:36 +0800, Jisheng Zhang wrote:
> Current suspend/resume implementation reuses the mvneta_open() and
> mvneta_close(), but it could be optimized to take only necessary
> actions during suspend/resume.
> 
> One obvious problem of current implementation is: after hundreds of
> system suspend/resume cycles, the resume of mvneta could fail due to
> fragmented dma coherent memory. After this patch, the non-necessary
> memory alloc/free is optimized out.

Indeed, this needs to be fixed, you're totally right.

> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
>  drivers/net/ethernet/marvell/mvneta.c | 76 ++++++++++++++++++++++++++++++-----
>  1 file changed, 66 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index 4ec69bbd1eb4..1870f1dd7093 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -4575,14 +4575,46 @@ static int mvneta_remove(struct platform_device *pdev)
>  #ifdef CONFIG_PM_SLEEP
>  static int mvneta_suspend(struct device *device)
>  {
> +	int queue;
>  	struct net_device *dev = dev_get_drvdata(device);
>  	struct mvneta_port *pp = netdev_priv(dev);
>  
> -	rtnl_lock();
> -	if (netif_running(dev))
> -		mvneta_stop(dev);
> -	rtnl_unlock();
> +	if (!netif_running(dev))
> +		return 0;

This is changing the behavior I believe. The current code is:

        rtnl_lock();
        if (netif_running(dev))
                mvneta_stop(dev);
        rtnl_unlock();
        netif_device_detach(dev);
        clk_disable_unprepare(pp->clk_bus);
        clk_disable_unprepare(pp->clk);
        return 0;

So, when netif_running(dev) is false, we're indeed not calling
mvneta_stop(), but we're still doing netif_device_detach(), and
disabling the clocks. With your change, we're no longer doing these
steps.

> +
>  	netif_device_detach(dev);
> +
> +	mvneta_stop_dev(pp);
> +
> +	if (!pp->neta_armada3700) {
> +		spin_lock(&pp->lock);
> +		pp->is_stopped = true;
> +		spin_unlock(&pp->lock);

Real question: is it OK to set pp->is_stopped *after* calling
mvneta_stop_dev(), while it was set before calling mvneta_stop_dev() in
the current code ?

> +
> +		cpuhp_state_remove_instance_nocalls(online_hpstate,
> +						    &pp->node_online);
> +		cpuhp_state_remove_instance_nocalls(CPUHP_NET_MVNETA_DEAD,
> +						    &pp->node_dead);

Do we need to remove/add those CPU notifiers when suspending/resuming ?

> +	}
> +
> +	for (queue = 0; queue < rxq_number; queue++) {
> +		struct mvneta_rx_queue *rxq = &pp->rxqs[queue];
> +
> +		mvneta_rxq_drop_pkts(pp, rxq);
> +	}

Wouldn't it make sense to have
mvneta_rxq_sw_deinit/mvneta_rxq_hw_deinit(), like you did for the
initialization ?

> +
> +	for (queue = 0; queue < txq_number; queue++) {
> +		struct mvneta_tx_queue *txq = &pp->txqs[queue];
> +
> +		/* Set minimum bandwidth for disabled TXQs */
> +		mvreg_write(pp, MVETH_TXQ_TOKEN_CFG_REG(txq->id), 0);
> +		mvreg_write(pp, MVETH_TXQ_TOKEN_COUNT_REG(txq->id), 0);
> +
> +		/* Set Tx descriptors queue starting address and size */
> +		mvreg_write(pp, MVNETA_TXQ_BASE_ADDR_REG(txq->id), 0);
> +		mvreg_write(pp, MVNETA_TXQ_SIZE_REG(txq->id), 0);
> +	}

Same comment here: a mvneta_txq_sw_deinit()/mvneta_txq_hw_deinit()
would be good, and would avoid duplicating this logic.

> +
>  	clk_disable_unprepare(pp->clk_bus);
>  	clk_disable_unprepare(pp->clk);
>  	return 0;
> @@ -4593,7 +4625,7 @@ static int mvneta_resume(struct device *device)
>  	struct platform_device *pdev = to_platform_device(device);
>  	struct net_device *dev = dev_get_drvdata(device);
>  	struct mvneta_port *pp = netdev_priv(dev);
> -	int err;
> +	int err, queue;
>  
>  	clk_prepare_enable(pp->clk);
>  	if (!IS_ERR(pp->clk_bus))
> @@ -4614,13 +4646,37 @@ static int mvneta_resume(struct device *device)
>  		return err;
>  	}
>  
> +	if (!netif_running(dev))
> +		return 0;
> +
>  	netif_device_attach(dev);
> -	rtnl_lock();
> -	if (netif_running(dev)) {
> -		mvneta_open(dev);
> -		mvneta_set_rx_mode(dev);
> +
> +	for (queue = 0; queue < rxq_number; queue++) {
> +		struct mvneta_rx_queue *rxq = &pp->rxqs[queue];
> +
> +		rxq->next_desc_to_proc = 0;
> +		mvneta_rxq_hw_init(pp, rxq);
>  	}
> -	rtnl_unlock();
> +
> +	for (queue = 0; queue < txq_number; queue++) {
> +		struct mvneta_tx_queue *txq = &pp->txqs[queue];
> +
> +		txq->next_desc_to_proc = 0;
> +		mvneta_txq_hw_init(pp, txq);
> +	}
> +
> +	if (!pp->neta_armada3700) {
> +		spin_lock(&pp->lock);
> +		pp->is_stopped = false;
> +		spin_unlock(&pp->lock);
> +		cpuhp_state_add_instance_nocalls(online_hpstate,
> +						 &pp->node_online);
> +		cpuhp_state_add_instance_nocalls(CPUHP_NET_MVNETA_DEAD,
> +						 &pp->node_dead);
> +	}
> +
> +	mvneta_set_rx_mode(dev);
> +	mvneta_start_dev(pp);

Thanks!

Thomas
Jisheng Zhang March 30, 2018, 9:15 a.m. UTC | #2
On Thu, 29 Mar 2018 13:54:32 +0200 Thomas Petazzoni wrote:

> Hello Jisheng,

Hi Thomas,

> 
> On Thu, 29 Mar 2018 18:15:36 +0800, Jisheng Zhang wrote:
> > Current suspend/resume implementation reuses the mvneta_open() and
> > mvneta_close(), but it could be optimized to take only necessary
> > actions during suspend/resume.
> > 
> > One obvious problem of current implementation is: after hundreds of
> > system suspend/resume cycles, the resume of mvneta could fail due to
> > fragmented dma coherent memory. After this patch, the non-necessary
> > memory alloc/free is optimized out.  
> 
> Indeed, this needs to be fixed, you're totally right.
> 
> > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> > ---
> >  drivers/net/ethernet/marvell/mvneta.c | 76 ++++++++++++++++++++++++++++++-----
> >  1 file changed, 66 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> > index 4ec69bbd1eb4..1870f1dd7093 100644
> > --- a/drivers/net/ethernet/marvell/mvneta.c
> > +++ b/drivers/net/ethernet/marvell/mvneta.c
> > @@ -4575,14 +4575,46 @@ static int mvneta_remove(struct platform_device *pdev)
> >  #ifdef CONFIG_PM_SLEEP
> >  static int mvneta_suspend(struct device *device)
> >  {
> > +	int queue;
> >  	struct net_device *dev = dev_get_drvdata(device);
> >  	struct mvneta_port *pp = netdev_priv(dev);
> >  
> > -	rtnl_lock();
> > -	if (netif_running(dev))
> > -		mvneta_stop(dev);
> > -	rtnl_unlock();
> > +	if (!netif_running(dev))
> > +		return 0;  
> 
> This is changing the behavior I believe. The current code is:
> 
>         rtnl_lock();
>         if (netif_running(dev))
>                 mvneta_stop(dev);
>         rtnl_unlock();
>         netif_device_detach(dev);
>         clk_disable_unprepare(pp->clk_bus);
>         clk_disable_unprepare(pp->clk);
>         return 0;
> 
> So, when netif_running(dev) is false, we're indeed not calling
> mvneta_stop(), but we're still doing netif_device_detach(), and
> disabling the clocks. With your change, we're no longer doing these
> steps.

Indeed, will try to keep the behavior in v2

> 
> > +
> >  	netif_device_detach(dev);
> > +
> > +	mvneta_stop_dev(pp);
> > +
> > +	if (!pp->neta_armada3700) {
> > +		spin_lock(&pp->lock);
> > +		pp->is_stopped = true;
> > +		spin_unlock(&pp->lock);  
> 
> Real question: is it OK to set pp->is_stopped *after* calling
> mvneta_stop_dev(), while it was set before calling mvneta_stop_dev() in
> the current code ?

oops, you are right. Fixed in v2

> 
> > +
> > +		cpuhp_state_remove_instance_nocalls(online_hpstate,
> > +						    &pp->node_online);
> > +		cpuhp_state_remove_instance_nocalls(CPUHP_NET_MVNETA_DEAD,
> > +						    &pp->node_dead);  
> 
> Do we need to remove/add those CPU notifiers when suspending/resuming ?

Take mvneta_cpu_online() as an example, if we don't remove it during
suspend, when system is resume back, it will touch mac when secondary
cpu is ON, but at this point the mvneta isn't resumed, this is not safe.

> 
> > +	}
> > +
> > +	for (queue = 0; queue < rxq_number; queue++) {
> > +		struct mvneta_rx_queue *rxq = &pp->rxqs[queue];
> > +
> > +		mvneta_rxq_drop_pkts(pp, rxq);
> > +	}  
> 
> Wouldn't it make sense to have
> mvneta_rxq_sw_deinit/mvneta_rxq_hw_deinit(), like you did for the
> initialization ?

For rxq deinit, we'd like to drop rx pkts, this is both HW and SW operation.
So we reuse mvneta_rxq_drop_pkts() here.

> 
> > +
> > +	for (queue = 0; queue < txq_number; queue++) {
> > +		struct mvneta_tx_queue *txq = &pp->txqs[queue];
> > +
> > +		/* Set minimum bandwidth for disabled TXQs */
> > +		mvreg_write(pp, MVETH_TXQ_TOKEN_CFG_REG(txq->id), 0);
> > +		mvreg_write(pp, MVETH_TXQ_TOKEN_COUNT_REG(txq->id), 0);
> > +
> > +		/* Set Tx descriptors queue starting address and size */
> > +		mvreg_write(pp, MVNETA_TXQ_BASE_ADDR_REG(txq->id), 0);
> > +		mvreg_write(pp, MVNETA_TXQ_SIZE_REG(txq->id), 0);
> > +	}  
> 
> Same comment here: a mvneta_txq_sw_deinit()/mvneta_txq_hw_deinit()
> would be good, and would avoid duplicating this logic.

yep, will do in v2.

Thanks a lot for the kind review.
Thomas Petazzoni March 30, 2018, 9:49 a.m. UTC | #3
Hello,

On Fri, 30 Mar 2018 17:15:47 +0800, Jisheng Zhang wrote:

> > > +		cpuhp_state_remove_instance_nocalls(online_hpstate,
> > > +						    &pp->node_online);
> > > +		cpuhp_state_remove_instance_nocalls(CPUHP_NET_MVNETA_DEAD,
> > > +						    &pp->node_dead);    
> > 
> > Do we need to remove/add those CPU notifiers when suspending/resuming ?  
> 
> Take mvneta_cpu_online() as an example, if we don't remove it during
> suspend, when system is resume back, it will touch mac when secondary
> cpu is ON, but at this point the mvneta isn't resumed, this is not safe.

Hm. I'm still a bit confused by this new CPU hotplug API. I understand
the issue you have and indeed unregistering the CPU hotplug callbacks
is a way to solve the problem, but I find it weird that we have to do
this.

Anyway, it's OK to do it, because it's anyway what was done so far. It
is just annoying that there is a duplication of the logic between
mvneta_suspend() and mvneta_stop() on one side, and duplication between
mvneta_resume() and mvnete_start() on the other side.

> > > +	for (queue = 0; queue < rxq_number; queue++) {
> > > +		struct mvneta_rx_queue *rxq = &pp->rxqs[queue];
> > > +
> > > +		mvneta_rxq_drop_pkts(pp, rxq);
> > > +	}    
> > 
> > Wouldn't it make sense to have
> > mvneta_rxq_sw_deinit/mvneta_rxq_hw_deinit(), like you did for the
> > initialization ?  
> 
> For rxq deinit, we'd like to drop rx pkts, this is both HW and SW operation.
> So we reuse mvneta_rxq_drop_pkts() here.

Hum, OK, indeed. It would have been nicer to have something symmetric,
with the hw/sw parts split in a similar way for the init and deinit of
both txqs and rxqs, but I agree that dropping the RX packets before
going into suspend involves both HW and SW operations.

Thanks!

Thomas Petazzoni
diff mbox

Patch

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 4ec69bbd1eb4..1870f1dd7093 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -4575,14 +4575,46 @@  static int mvneta_remove(struct platform_device *pdev)
 #ifdef CONFIG_PM_SLEEP
 static int mvneta_suspend(struct device *device)
 {
+	int queue;
 	struct net_device *dev = dev_get_drvdata(device);
 	struct mvneta_port *pp = netdev_priv(dev);
 
-	rtnl_lock();
-	if (netif_running(dev))
-		mvneta_stop(dev);
-	rtnl_unlock();
+	if (!netif_running(dev))
+		return 0;
+
 	netif_device_detach(dev);
+
+	mvneta_stop_dev(pp);
+
+	if (!pp->neta_armada3700) {
+		spin_lock(&pp->lock);
+		pp->is_stopped = true;
+		spin_unlock(&pp->lock);
+
+		cpuhp_state_remove_instance_nocalls(online_hpstate,
+						    &pp->node_online);
+		cpuhp_state_remove_instance_nocalls(CPUHP_NET_MVNETA_DEAD,
+						    &pp->node_dead);
+	}
+
+	for (queue = 0; queue < rxq_number; queue++) {
+		struct mvneta_rx_queue *rxq = &pp->rxqs[queue];
+
+		mvneta_rxq_drop_pkts(pp, rxq);
+	}
+
+	for (queue = 0; queue < txq_number; queue++) {
+		struct mvneta_tx_queue *txq = &pp->txqs[queue];
+
+		/* Set minimum bandwidth for disabled TXQs */
+		mvreg_write(pp, MVETH_TXQ_TOKEN_CFG_REG(txq->id), 0);
+		mvreg_write(pp, MVETH_TXQ_TOKEN_COUNT_REG(txq->id), 0);
+
+		/* Set Tx descriptors queue starting address and size */
+		mvreg_write(pp, MVNETA_TXQ_BASE_ADDR_REG(txq->id), 0);
+		mvreg_write(pp, MVNETA_TXQ_SIZE_REG(txq->id), 0);
+	}
+
 	clk_disable_unprepare(pp->clk_bus);
 	clk_disable_unprepare(pp->clk);
 	return 0;
@@ -4593,7 +4625,7 @@  static int mvneta_resume(struct device *device)
 	struct platform_device *pdev = to_platform_device(device);
 	struct net_device *dev = dev_get_drvdata(device);
 	struct mvneta_port *pp = netdev_priv(dev);
-	int err;
+	int err, queue;
 
 	clk_prepare_enable(pp->clk);
 	if (!IS_ERR(pp->clk_bus))
@@ -4614,13 +4646,37 @@  static int mvneta_resume(struct device *device)
 		return err;
 	}
 
+	if (!netif_running(dev))
+		return 0;
+
 	netif_device_attach(dev);
-	rtnl_lock();
-	if (netif_running(dev)) {
-		mvneta_open(dev);
-		mvneta_set_rx_mode(dev);
+
+	for (queue = 0; queue < rxq_number; queue++) {
+		struct mvneta_rx_queue *rxq = &pp->rxqs[queue];
+
+		rxq->next_desc_to_proc = 0;
+		mvneta_rxq_hw_init(pp, rxq);
 	}
-	rtnl_unlock();
+
+	for (queue = 0; queue < txq_number; queue++) {
+		struct mvneta_tx_queue *txq = &pp->txqs[queue];
+
+		txq->next_desc_to_proc = 0;
+		mvneta_txq_hw_init(pp, txq);
+	}
+
+	if (!pp->neta_armada3700) {
+		spin_lock(&pp->lock);
+		pp->is_stopped = false;
+		spin_unlock(&pp->lock);
+		cpuhp_state_add_instance_nocalls(online_hpstate,
+						 &pp->node_online);
+		cpuhp_state_add_instance_nocalls(CPUHP_NET_MVNETA_DEAD,
+						 &pp->node_dead);
+	}
+
+	mvneta_set_rx_mode(dev);
+	mvneta_start_dev(pp);
 
 	return 0;
 }