2018-03-29 10:13:52

by Jisheng Zhang

[permalink] [raw]
Subject: [PATCH 0/2] net: mvneta: improve suspend/resume

This series tries to optimize the mvneta's suspend/resume
implementation by only taking necessary actions.

Jisheng Zhang (2):
net: mvneta: split rxq/txq init into SW and HW parts
net: mvneta: improve suspend/resume

drivers/net/ethernet/marvell/mvneta.c | 146 +++++++++++++++++++++++++++-------
1 file changed, 119 insertions(+), 27 deletions(-)

--
2.16.3



2018-03-29 10:15:19

by Jisheng Zhang

[permalink] [raw]
Subject: [PATCH 1/2] net: mvneta: split rxq/txq init into SW and HW parts

This is to prepare the suspend/resume improvement in next patch. The
SW parts can be optimized out during resume.

Signed-off-by: Jisheng Zhang <[email protected]>
---
drivers/net/ethernet/marvell/mvneta.c | 70 ++++++++++++++++++++++++++---------
1 file changed, 53 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 30aab9bf77cc..4ec69bbd1eb4 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2796,10 +2796,8 @@ static void mvneta_rx_reset(struct mvneta_port *pp)

/* Rx/Tx queue initialization/cleanup methods */

-/* Create a specified RX queue */
-static int mvneta_rxq_init(struct mvneta_port *pp,
- struct mvneta_rx_queue *rxq)
-
+static int mvneta_rxq_sw_init(struct mvneta_port *pp,
+ struct mvneta_rx_queue *rxq)
{
rxq->size = pp->rx_ring_size;

@@ -2812,6 +2810,12 @@ static int mvneta_rxq_init(struct mvneta_port *pp,

rxq->last_desc = rxq->size - 1;

+ return 0;
+}
+
+static void mvneta_rxq_hw_init(struct mvneta_port *pp,
+ struct mvneta_rx_queue *rxq)
+{
/* Set Rx descriptors queue starting address */
mvreg_write(pp, MVNETA_RXQ_BASE_ADDR_REG(rxq->id), rxq->descs_phys);
mvreg_write(pp, MVNETA_RXQ_SIZE_REG(rxq->id), rxq->size);
@@ -2835,6 +2839,20 @@ static int mvneta_rxq_init(struct mvneta_port *pp,
mvneta_rxq_short_pool_set(pp, rxq);
mvneta_rxq_non_occup_desc_add(pp, rxq, rxq->size);
}
+}
+
+/* Create a specified RX queue */
+static int mvneta_rxq_init(struct mvneta_port *pp,
+ struct mvneta_rx_queue *rxq)
+
+{
+ int ret;
+
+ ret = mvneta_rxq_sw_init(pp, rxq);
+ if (ret)
+ return ret;
+
+ mvneta_rxq_hw_init(pp, rxq);

return 0;
}
@@ -2857,9 +2875,8 @@ static void mvneta_rxq_deinit(struct mvneta_port *pp,
rxq->descs_phys = 0;
}

-/* Create and initialize a tx queue */
-static int mvneta_txq_init(struct mvneta_port *pp,
- struct mvneta_tx_queue *txq)
+static int mvneta_txq_sw_init(struct mvneta_port *pp,
+ struct mvneta_tx_queue *txq)
{
int cpu;

@@ -2872,7 +2889,6 @@ static int mvneta_txq_init(struct mvneta_port *pp,
txq->tx_stop_threshold = txq->size - MVNETA_MAX_SKB_DESCS;
txq->tx_wake_threshold = txq->tx_stop_threshold / 2;

-
/* Allocate memory for TX descriptors */
txq->descs = dma_alloc_coherent(pp->dev->dev.parent,
txq->size * MVNETA_DESC_ALIGNED_SIZE,
@@ -2882,14 +2898,6 @@ static int mvneta_txq_init(struct mvneta_port *pp,

txq->last_desc = txq->size - 1;

- /* Set maximum bandwidth for enabled TXQs */
- mvreg_write(pp, MVETH_TXQ_TOKEN_CFG_REG(txq->id), 0x03ffffff);
- mvreg_write(pp, MVETH_TXQ_TOKEN_COUNT_REG(txq->id), 0x3fffffff);
-
- /* Set Tx descriptors queue starting address */
- mvreg_write(pp, MVNETA_TXQ_BASE_ADDR_REG(txq->id), txq->descs_phys);
- mvreg_write(pp, MVNETA_TXQ_SIZE_REG(txq->id), txq->size);
-
txq->tx_skb = kmalloc_array(txq->size, sizeof(*txq->tx_skb),
GFP_KERNEL);
if (!txq->tx_skb) {
@@ -2910,7 +2918,6 @@ static int mvneta_txq_init(struct mvneta_port *pp,
txq->descs, txq->descs_phys);
return -ENOMEM;
}
- mvneta_tx_done_pkts_coal_set(pp, txq, txq->done_pkts_coal);

/* Setup XPS mapping */
if (txq_number > 1)
@@ -2923,6 +2930,35 @@ static int mvneta_txq_init(struct mvneta_port *pp,
return 0;
}

+static void mvneta_txq_hw_init(struct mvneta_port *pp,
+ struct mvneta_tx_queue *txq)
+{
+ /* Set maximum bandwidth for enabled TXQs */
+ mvreg_write(pp, MVETH_TXQ_TOKEN_CFG_REG(txq->id), 0x03ffffff);
+ mvreg_write(pp, MVETH_TXQ_TOKEN_COUNT_REG(txq->id), 0x3fffffff);
+
+ /* Set Tx descriptors queue starting address */
+ mvreg_write(pp, MVNETA_TXQ_BASE_ADDR_REG(txq->id), txq->descs_phys);
+ mvreg_write(pp, MVNETA_TXQ_SIZE_REG(txq->id), txq->size);
+
+ mvneta_tx_done_pkts_coal_set(pp, txq, txq->done_pkts_coal);
+}
+
+/* Create and initialize a tx queue */
+static int mvneta_txq_init(struct mvneta_port *pp,
+ struct mvneta_tx_queue *txq)
+{
+ int ret;
+
+ ret = mvneta_txq_sw_init(pp, txq);
+ if (ret < 0)
+ return ret;
+
+ mvneta_txq_hw_init(pp, txq);
+
+ return 0;
+}
+
/* Free allocated resources when mvneta_txq_init() fails to allocate memory*/
static void mvneta_txq_deinit(struct mvneta_port *pp,
struct mvneta_tx_queue *txq)
--
2.16.3


2018-03-29 10:17:12

by Jisheng Zhang

[permalink] [raw]
Subject: [PATCH 2/2] net: mvneta: improve suspend/resume

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 <[email protected]>
---
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;
+
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;
}
--
2.16.3


2018-03-29 11:45:32

by Thomas Petazzoni

[permalink] [raw]
Subject: Re: [PATCH 1/2] net: mvneta: split rxq/txq init into SW and HW parts

Hello,

On Thu, 29 Mar 2018 18:13:56 +0800, Jisheng Zhang wrote:
> This is to prepare the suspend/resume improvement in next patch. The
> SW parts can be optimized out during resume.
>
> Signed-off-by: Jisheng Zhang <[email protected]>

Thanks, I have two very minor nits below, but otherwise:

Acked-by: Thomas Petazzoni <[email protected]>

> +/* Create a specified RX queue */
> +static int mvneta_rxq_init(struct mvneta_port *pp,
> + struct mvneta_rx_queue *rxq)
> +
> +{
> + int ret;
> +
> + ret = mvneta_rxq_sw_init(pp, rxq);
> + if (ret)

Here you're testing if (ret), while in mvneta_txq_init(), in the same
situation, you're doing if (ret < 0). I don't have a preference for one
or the other, but having them consistent between the two lpaces would
be nice.

> -/* Create and initialize a tx queue */
> -static int mvneta_txq_init(struct mvneta_port *pp,
> - struct mvneta_tx_queue *txq)
> +static int mvneta_txq_sw_init(struct mvneta_port *pp,
> + struct mvneta_tx_queue *txq)
> {
> int cpu;
>
> @@ -2872,7 +2889,6 @@ static int mvneta_txq_init(struct mvneta_port *pp,
> txq->tx_stop_threshold = txq->size - MVNETA_MAX_SKB_DESCS;
> txq->tx_wake_threshold = txq->tx_stop_threshold / 2;
>
> -

Spurious change.

Thanks!

Thomas Petazzoni
--
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

2018-03-29 11:55:48

by Thomas Petazzoni

[permalink] [raw]
Subject: Re: [PATCH 2/2] net: mvneta: improve suspend/resume

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 <[email protected]>
> ---
> 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
--
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

2018-03-30 09:06:00

by Jisheng Zhang

[permalink] [raw]
Subject: Re: [PATCH 1/2] net: mvneta: split rxq/txq init into SW and HW parts

Hi,

On Thu, 29 Mar 2018 13:42:59 +0200 Thomas Petazzoni wrote:

> Hello,
>
> On Thu, 29 Mar 2018 18:13:56 +0800, Jisheng Zhang wrote:
> > This is to prepare the suspend/resume improvement in next patch. The
> > SW parts can be optimized out during resume.
> >
> > Signed-off-by: Jisheng Zhang <[email protected]>
>
> Thanks, I have two very minor nits below, but otherwise:
>
> Acked-by: Thomas Petazzoni <[email protected]>

Thanks for reviewing.

>
> > +/* Create a specified RX queue */
> > +static int mvneta_rxq_init(struct mvneta_port *pp,
> > + struct mvneta_rx_queue *rxq)
> > +
> > +{
> > + int ret;
> > +
> > + ret = mvneta_rxq_sw_init(pp, rxq);
> > + if (ret)
>
> Here you're testing if (ret), while in mvneta_txq_init(), in the same
> situation, you're doing if (ret < 0). I don't have a preference for one
> or the other, but having them consistent between the two lpaces would
> be nice.

updated in v2.

>
> > -/* Create and initialize a tx queue */
> > -static int mvneta_txq_init(struct mvneta_port *pp,
> > - struct mvneta_tx_queue *txq)
> > +static int mvneta_txq_sw_init(struct mvneta_port *pp,
> > + struct mvneta_tx_queue *txq)
> > {
> > int cpu;
> >
> > @@ -2872,7 +2889,6 @@ static int mvneta_txq_init(struct mvneta_port *pp,
> > txq->tx_stop_threshold = txq->size - MVNETA_MAX_SKB_DESCS;
> > txq->tx_wake_threshold = txq->tx_stop_threshold / 2;
> >
> > -
>
> Spurious change.

There's an extra blank line here, so I removed it ;)

Thanks

2018-03-30 09:17:30

by Jisheng Zhang

[permalink] [raw]
Subject: Re: [PATCH 2/2] net: mvneta: improve suspend/resume

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 <[email protected]>
> > ---
> > 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.

2018-03-30 09:50:57

by Thomas Petazzoni

[permalink] [raw]
Subject: Re: [PATCH 2/2] net: mvneta: improve suspend/resume

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
--
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com