LinuxPPC-Dev Archive on lore.kernel.org
 help / color / Atom feed
* [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration
@ 2019-11-06  0:06 Thomas Falcon
  2019-11-06  4:13 ` Russell Currey
                   ` (2 more replies)
  0 siblings, 3 replies; 7+ messages in thread
From: Thomas Falcon @ 2019-11-06  0:06 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: nathanl, netdev, Thomas Falcon, msuchanek, tyreld

After a migration, it is necessary to send a gratuitous ARP
from all running interfaces so that the rest of the network
is aware of its new location. However, some supported network
devices are unaware that they have been migrated. To avoid network
interruptions and other unwanted behavior, force a GARP on all
valid, running interfaces as part of the post_mobility_fixup
routine.

Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index b571285f6c14..c1abc14cf2bb 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -17,6 +17,9 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/stringify.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/net_namespace.h>
 
 #include <asm/machdep.h>
 #include <asm/rtas.h>
@@ -331,6 +334,8 @@ void post_mobility_fixup(void)
 {
 	int rc;
 	int activate_fw_token;
+	struct net_device *netdev;
+	struct net *net;
 
 	activate_fw_token = rtas_token("ibm,activate-firmware");
 	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
@@ -371,6 +376,21 @@ void post_mobility_fixup(void)
 	/* Possibly switch to a new RFI flush type */
 	pseries_setup_rfi_flush();
 
+	/* need to force a gratuitous ARP on running interfaces */
+	rtnl_lock();
+	for_each_net(net) {
+		for_each_netdev(net, netdev) {
+			if (netif_device_present(netdev) &&
+			    netif_running(netdev) &&
+			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
+				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
+							 netdev);
+				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
+							 netdev);
+		}
+	}
+	rtnl_unlock();
+
 	return;
 }
 
-- 
2.12.3


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration
  2019-11-06  0:06 [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration Thomas Falcon
@ 2019-11-06  4:13 ` Russell Currey
  2019-11-06  4:47   ` Thomas Falcon
  2019-11-06 22:14 ` Nathan Lynch
  2019-11-07  1:33 ` Michael Ellerman
  2 siblings, 1 reply; 7+ messages in thread
From: Russell Currey @ 2019-11-06  4:13 UTC (permalink / raw)
  To: Thomas Falcon, linuxppc-dev; +Cc: nathanl, netdev, msuchanek, tyreld

On Tue, 2019-11-05 at 18:06 -0600, Thomas Falcon wrote:
> After a migration, it is necessary to send a gratuitous ARP
> from all running interfaces so that the rest of the network
> is aware of its new location. However, some supported network
> devices are unaware that they have been migrated. To avoid network
> interruptions and other unwanted behavior, force a GARP on all
> valid, running interfaces as part of the post_mobility_fixup
> routine.
> 
> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>

Hi Thomas,

> ---
>  arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/pseries/mobility.c
> b/arch/powerpc/platforms/pseries/mobility.c
> index b571285f6c14..c1abc14cf2bb 100644
> --- a/arch/powerpc/platforms/pseries/mobility.c
> +++ b/arch/powerpc/platforms/pseries/mobility.c
> @@ -17,6 +17,9 @@
>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <linux/stringify.h>
> +#include <linux/netdevice.h>
> +#include <linux/rtnetlink.h>
> +#include <net/net_namespace.h>
>  
>  #include <asm/machdep.h>
>  #include <asm/rtas.h>
> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>  {
>  	int rc;
>  	int activate_fw_token;
> +	struct net_device *netdev;
> +	struct net *net;
>  
>  	activate_fw_token = rtas_token("ibm,activate-firmware");
>  	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>  	/* Possibly switch to a new RFI flush type */
>  	pseries_setup_rfi_flush();
>  
> +	/* need to force a gratuitous ARP on running interfaces */
> +	rtnl_lock();
> +	for_each_net(net) {
> +		for_each_netdev(net, netdev) {
> +			if (netif_device_present(netdev) &&
> +			    netif_running(netdev) &&
> +			    !(netdev->flags & (IFF_NOARP |
> IFF_LOOPBACK)))
> +				call_netdevice_notifiers(NETDEV_NOTIFY_
> PEERS,
> +							 netdev);

Without curly braces following the "if" statment, the second line
(below) will be executed unconditionally, which I assume with this
indentation isn't what you want.

(reported by snowpatch)

- Russell

> +				call_netdevice_notifiers(NETDEV_RESEND_
> IGMP,
> +							 netdev);
> +		}
> +	}
> +	rtnl_unlock();
> +
>  	return;
>  }
>  


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration
  2019-11-06  4:13 ` Russell Currey
@ 2019-11-06  4:47   ` Thomas Falcon
  0 siblings, 0 replies; 7+ messages in thread
From: Thomas Falcon @ 2019-11-06  4:47 UTC (permalink / raw)
  To: Russell Currey, linuxppc-dev; +Cc: nathanl, netdev, msuchanek, tyreld


On 11/5/19 10:13 PM, Russell Currey wrote:
> On Tue, 2019-11-05 at 18:06 -0600, Thomas Falcon wrote:
>> After a migration, it is necessary to send a gratuitous ARP
>> from all running interfaces so that the rest of the network
>> is aware of its new location. However, some supported network
>> devices are unaware that they have been migrated. To avoid network
>> interruptions and other unwanted behavior, force a GARP on all
>> valid, running interfaces as part of the post_mobility_fixup
>> routine.
>>
>> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> Hi Thomas,
>
>> ---
>>   arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
>>
>> diff --git a/arch/powerpc/platforms/pseries/mobility.c
>> b/arch/powerpc/platforms/pseries/mobility.c
>> index b571285f6c14..c1abc14cf2bb 100644
>> --- a/arch/powerpc/platforms/pseries/mobility.c
>> +++ b/arch/powerpc/platforms/pseries/mobility.c
>> @@ -17,6 +17,9 @@
>>   #include <linux/delay.h>
>>   #include <linux/slab.h>
>>   #include <linux/stringify.h>
>> +#include <linux/netdevice.h>
>> +#include <linux/rtnetlink.h>
>> +#include <net/net_namespace.h>
>>   
>>   #include <asm/machdep.h>
>>   #include <asm/rtas.h>
>> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>>   {
>>   	int rc;
>>   	int activate_fw_token;
>> +	struct net_device *netdev;
>> +	struct net *net;
>>   
>>   	activate_fw_token = rtas_token("ibm,activate-firmware");
>>   	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
>> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>>   	/* Possibly switch to a new RFI flush type */
>>   	pseries_setup_rfi_flush();
>>   
>> +	/* need to force a gratuitous ARP on running interfaces */
>> +	rtnl_lock();
>> +	for_each_net(net) {
>> +		for_each_netdev(net, netdev) {
>> +			if (netif_device_present(netdev) &&
>> +			    netif_running(netdev) &&
>> +			    !(netdev->flags & (IFF_NOARP |
>> IFF_LOOPBACK)))
>> +				call_netdevice_notifiers(NETDEV_NOTIFY_
>> PEERS,
>> +							 netdev);
> Without curly braces following the "if" statment, the second line
> (below) will be executed unconditionally, which I assume with this
> indentation isn't what you want.
>
> (reported by snowpatch)
>
> - Russell

Thanks for catching that! I'll fix that and send a v2 soon.

Tom


>> +				call_netdevice_notifiers(NETDEV_RESEND_
>> IGMP,
>> +							 netdev);
>> +		}
>> +	}
>> +	rtnl_unlock();
>> +
>>   	return;
>>   }
>>   

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration
  2019-11-06  0:06 [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration Thomas Falcon
  2019-11-06  4:13 ` Russell Currey
@ 2019-11-06 22:14 ` Nathan Lynch
  2019-11-07 21:30   ` Thomas Falcon
  2019-11-07  1:33 ` Michael Ellerman
  2 siblings, 1 reply; 7+ messages in thread
From: Nathan Lynch @ 2019-11-06 22:14 UTC (permalink / raw)
  To: Thomas Falcon; +Cc: linuxppc-dev, netdev, msuchanek, tyreld

Hi Tom,

Thomas Falcon <tlfalcon@linux.ibm.com> writes:
> After a migration, it is necessary to send a gratuitous ARP
> from all running interfaces so that the rest of the network
> is aware of its new location. However, some supported network
> devices are unaware that they have been migrated. To avoid network
> interruptions and other unwanted behavior, force a GARP on all
> valid, running interfaces as part of the post_mobility_fixup
> routine.

[...]

> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>  {
>  	int rc;
>  	int activate_fw_token;
> +	struct net_device *netdev;
> +	struct net *net;
>  
>  	activate_fw_token = rtas_token("ibm,activate-firmware");
>  	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>  	/* Possibly switch to a new RFI flush type */
>  	pseries_setup_rfi_flush();
>  
> +	/* need to force a gratuitous ARP on running interfaces */
> +	rtnl_lock();
> +	for_each_net(net) {
> +		for_each_netdev(net, netdev) {
> +			if (netif_device_present(netdev) &&
> +			    netif_running(netdev) &&
> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
> +							 netdev);
> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
> +							 netdev);
> +		}
> +	}
> +	rtnl_unlock();
> +

This isn't an outright nak, but this is not nice. It illustrates the
need to rethink the pseries partition migration code. There is no
mechanism for drivers and other interested code to prepare for a
migration or to adjust to the destination. So post_mobility_fixup() will
continue to grow into a fragile collection of calls into unrelated
subsystems until there is a better design -- either a pseries-specific
notification/callback mechanism, or something based on the pm framework.

My understanding is that this is needed specifically for ibmveth and,
unlike ibmvnic, the platform does not provide any notification to that
driver that a migration has occurred, right?

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration
  2019-11-06  0:06 [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration Thomas Falcon
  2019-11-06  4:13 ` Russell Currey
  2019-11-06 22:14 ` Nathan Lynch
@ 2019-11-07  1:33 ` Michael Ellerman
  2019-11-07 21:16   ` Thomas Falcon
  2 siblings, 1 reply; 7+ messages in thread
From: Michael Ellerman @ 2019-11-07  1:33 UTC (permalink / raw)
  To: Thomas Falcon, linuxppc-dev
  Cc: nathanl, netdev, Thomas Falcon, msuchanek, tyreld

Hi Thomas,

Thomas Falcon <tlfalcon@linux.ibm.com> writes:
> After a migration, it is necessary to send a gratuitous ARP
> from all running interfaces so that the rest of the network
> is aware of its new location. However, some supported network
> devices are unaware that they have been migrated. To avoid network
> interruptions and other unwanted behavior, force a GARP on all
> valid, running interfaces as part of the post_mobility_fixup
> routine.
>
> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> ---
>  arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)

This patch is in powerpc code, but it's doing networking stuff that I
don't really understand.

So I'd like an Ack from Dave or someone else in netdev land before I
merge it.

cheers


> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
> index b571285f6c14..c1abc14cf2bb 100644
> --- a/arch/powerpc/platforms/pseries/mobility.c
> +++ b/arch/powerpc/platforms/pseries/mobility.c
> @@ -17,6 +17,9 @@
>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <linux/stringify.h>
> +#include <linux/netdevice.h>
> +#include <linux/rtnetlink.h>
> +#include <net/net_namespace.h>
>  
>  #include <asm/machdep.h>
>  #include <asm/rtas.h>
> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>  {
>  	int rc;
>  	int activate_fw_token;
> +	struct net_device *netdev;
> +	struct net *net;
>  
>  	activate_fw_token = rtas_token("ibm,activate-firmware");
>  	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>  	/* Possibly switch to a new RFI flush type */
>  	pseries_setup_rfi_flush();
>  
> +	/* need to force a gratuitous ARP on running interfaces */
> +	rtnl_lock();
> +	for_each_net(net) {
> +		for_each_netdev(net, netdev) {
> +			if (netif_device_present(netdev) &&
> +			    netif_running(netdev) &&
> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
> +							 netdev);
> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
> +							 netdev);
> +		}
> +	}
> +	rtnl_unlock();
> +
>  	return;
>  }
>  
> -- 
> 2.12.3

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration
  2019-11-07  1:33 ` Michael Ellerman
@ 2019-11-07 21:16   ` Thomas Falcon
  0 siblings, 0 replies; 7+ messages in thread
From: Thomas Falcon @ 2019-11-07 21:16 UTC (permalink / raw)
  To: Michael Ellerman, linuxppc-dev; +Cc: nathanl, netdev, msuchanek, tyreld


On 11/6/19 7:33 PM, Michael Ellerman wrote:
> Hi Thomas,
>
> Thomas Falcon <tlfalcon@linux.ibm.com> writes:
>> After a migration, it is necessary to send a gratuitous ARP
>> from all running interfaces so that the rest of the network
>> is aware of its new location. However, some supported network
>> devices are unaware that they have been migrated. To avoid network
>> interruptions and other unwanted behavior, force a GARP on all
>> valid, running interfaces as part of the post_mobility_fixup
>> routine.
>>
>> Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
>> ---
>>   arch/powerpc/platforms/pseries/mobility.c | 20 ++++++++++++++++++++
>>   1 file changed, 20 insertions(+)
> This patch is in powerpc code, but it's doing networking stuff that I
> don't really understand.
>
> So I'd like an Ack from Dave or someone else in netdev land before I
> merge it.

Thanks, I've already included netdev in the CC list. I'll wait and keep 
an eye out for any comments from that side.

Tom



>
> cheers
>
>
>> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
>> index b571285f6c14..c1abc14cf2bb 100644
>> --- a/arch/powerpc/platforms/pseries/mobility.c
>> +++ b/arch/powerpc/platforms/pseries/mobility.c
>> @@ -17,6 +17,9 @@
>>   #include <linux/delay.h>
>>   #include <linux/slab.h>
>>   #include <linux/stringify.h>
>> +#include <linux/netdevice.h>
>> +#include <linux/rtnetlink.h>
>> +#include <net/net_namespace.h>
>>   
>>   #include <asm/machdep.h>
>>   #include <asm/rtas.h>
>> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>>   {
>>   	int rc;
>>   	int activate_fw_token;
>> +	struct net_device *netdev;
>> +	struct net *net;
>>   
>>   	activate_fw_token = rtas_token("ibm,activate-firmware");
>>   	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
>> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>>   	/* Possibly switch to a new RFI flush type */
>>   	pseries_setup_rfi_flush();
>>   
>> +	/* need to force a gratuitous ARP on running interfaces */
>> +	rtnl_lock();
>> +	for_each_net(net) {
>> +		for_each_netdev(net, netdev) {
>> +			if (netif_device_present(netdev) &&
>> +			    netif_running(netdev) &&
>> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
>> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
>> +							 netdev);
>> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
>> +							 netdev);
>> +		}
>> +	}
>> +	rtnl_unlock();
>> +
>>   	return;
>>   }
>>   
>> -- 
>> 2.12.3

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration
  2019-11-06 22:14 ` Nathan Lynch
@ 2019-11-07 21:30   ` Thomas Falcon
  0 siblings, 0 replies; 7+ messages in thread
From: Thomas Falcon @ 2019-11-07 21:30 UTC (permalink / raw)
  To: Nathan Lynch; +Cc: linuxppc-dev, netdev, msuchanek, tyreld


On 11/6/19 4:14 PM, Nathan Lynch wrote:
> Hi Tom,
>
> Thomas Falcon <tlfalcon@linux.ibm.com> writes:
>> After a migration, it is necessary to send a gratuitous ARP
>> from all running interfaces so that the rest of the network
>> is aware of its new location. However, some supported network
>> devices are unaware that they have been migrated. To avoid network
>> interruptions and other unwanted behavior, force a GARP on all
>> valid, running interfaces as part of the post_mobility_fixup
>> routine.
> [...]
>
>> @@ -331,6 +334,8 @@ void post_mobility_fixup(void)
>>   {
>>   	int rc;
>>   	int activate_fw_token;
>> +	struct net_device *netdev;
>> +	struct net *net;
>>   
>>   	activate_fw_token = rtas_token("ibm,activate-firmware");
>>   	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
>> @@ -371,6 +376,21 @@ void post_mobility_fixup(void)
>>   	/* Possibly switch to a new RFI flush type */
>>   	pseries_setup_rfi_flush();
>>   
>> +	/* need to force a gratuitous ARP on running interfaces */
>> +	rtnl_lock();
>> +	for_each_net(net) {
>> +		for_each_netdev(net, netdev) {
>> +			if (netif_device_present(netdev) &&
>> +			    netif_running(netdev) &&
>> +			    !(netdev->flags & (IFF_NOARP | IFF_LOOPBACK)))
>> +				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
>> +							 netdev);
>> +				call_netdevice_notifiers(NETDEV_RESEND_IGMP,
>> +							 netdev);
>> +		}
>> +	}
>> +	rtnl_unlock();
>> +
> This isn't an outright nak, but this is not nice. It illustrates the
> need to rethink the pseries partition migration code. There is no
> mechanism for drivers and other interested code to prepare for a
> migration or to adjust to the destination. So post_mobility_fixup() will
> continue to grow into a fragile collection of calls into unrelated
> subsystems until there is a better design -- either a pseries-specific
> notification/callback mechanism, or something based on the pm framework.
>
> My understanding is that this is needed specifically for ibmveth and,
> unlike ibmvnic, the platform does not provide any notification to that
> driver that a migration has occurred, right?

Correct, the ibmveth device, unlike ibmvnic, receives no signal or 
notification at all in the event of a partition migration, so it can not 
handle it or send a gratuitous ARP because from the driver's perspective 
nothing has changed.  As you've described, there is no existing notifier 
in the kernel to inform interested parties that the system has migrated 
or is about to migrate. Without adding the needed infrastructure to do 
that, I'm not sure how else to fix this.

Tom


^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, back to index

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-11-06  0:06 [RFC PATCH] powerpc/pseries/mobility: notify network peers after migration Thomas Falcon
2019-11-06  4:13 ` Russell Currey
2019-11-06  4:47   ` Thomas Falcon
2019-11-06 22:14 ` Nathan Lynch
2019-11-07 21:30   ` Thomas Falcon
2019-11-07  1:33 ` Michael Ellerman
2019-11-07 21:16   ` Thomas Falcon

LinuxPPC-Dev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linuxppc-dev/0 linuxppc-dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linuxppc-dev linuxppc-dev/ https://lore.kernel.org/linuxppc-dev \
		linuxppc-dev@lists.ozlabs.org linuxppc-dev@ozlabs.org
	public-inbox-index linuxppc-dev

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.ozlabs.lists.linuxppc-dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git