[Devel] [PATCH rh7 1/3] net: Add ipv6 statistics cpu notifier

[Konstantin Khorenko]

Andrey, please review the patchset.

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 08/25/2016 04:37 PM, Kirill Tkhai wrote:
> Patch adds a notifier, which moves some ipv6 percpu statistics
> from died cpu to online cpu.
>
> This allows to do not iterate over all possible cpus during
> calculation statistics for a user.
>
> This will be used in next patch.
>
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>  net/ipv6/af_inet6.c |   52 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
>
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> index 082fdaf..6f4c929 100644
> --- a/net/ipv6/af_inet6.c
> +++ b/net/ipv6/af_inet6.c
> @@ -44,6 +44,7 @@
>  #include <linux/netdevice.h>
>  #include <linux/icmpv6.h>
>  #include <linux/netfilter_ipv6.h>
> +#include <linux/cpu.h>
>
>  #include <net/ip.h>
>  #include <net/ipv6.h>
> @@ -700,6 +701,54 @@ bool ipv6_opt_accepted(const struct sock *sk, const struct sk_buff *skb)
>  }
>  EXPORT_SYMBOL_GPL(ipv6_opt_accepted);
>
> +static void move_ipv6_percpu_stats(int cpu, void **mib, int items)
> +{
> +	int this_cpu, i;
> +
> +	local_irq_disable();
> +	this_cpu = smp_processor_id();
> +
> +	for (i = 1; i < items; i++) {
> +		*(((u64 *) per_cpu_ptr(mib[0], this_cpu)) + i) +=
> +		*(((u64 *) per_cpu_ptr(mib[0], cpu)) + i);
> +
> +		*(((u64 *) per_cpu_ptr(mib[0], cpu)) + i) = 0;
> +	}
> +	local_irq_enable();
> +}
> +
> +
> +static int ipv6_cpu_notify(struct notifier_block *self,
> +			   unsigned long action, void *hcpu)
> +{
> +	int cpu = (unsigned long)hcpu;
> +	struct net_device *dev;
> +	struct inet6_dev *idev;
> +	struct net *net;
> +
> +	switch (action) {
> +		case CPU_DEAD:
> +		case CPU_DEAD_FROZEN:
> +		rtnl_lock();
> +		for_each_net(net) {
> +			for_each_netdev(net, dev) {
> +				idev = __in6_dev_get(dev);
> +				if (!idev)
> +					continue;
> +				move_ipv6_percpu_stats(cpu,
> +						(void **)idev->stats.ipv6,
> +						IPSTATS_MIB_MAX);
> +			}
> +		}
> +		rtnl_unlock();
> +	}
> +	return NOTIFY_OK;
> +}
> +
> +static struct notifier_block ipv6_cpu_notifier = {
> +	.notifier_call  = ipv6_cpu_notify,
> +};
> +
>  static struct packet_type ipv6_packet_type __read_mostly = {
>  	.type = cpu_to_be16(ETH_P_IPV6),
>  	.func = ipv6_rcv,
> @@ -951,6 +1000,7 @@ static int __init inet6_init(void)
>  	if (err)
>  		goto sysctl_fail;
>  #endif
> +	register_cpu_notifier(&ipv6_cpu_notifier);
>  out:
>  	return err;
>
> @@ -1020,6 +1070,8 @@ static void __exit inet6_exit(void)
>  	if (disable_ipv6_mod)
>  		return;
>
> +	unregister_cpu_notifier(&ipv6_cpu_notifier);
> +
>  	/* First of all disallow new sockets creation. */
>  	sock_unregister(PF_INET6);
>  	/* Disallow any further netlink messages */
>
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