> From: Roopa Prabhu [mailto:ro...@cumulusnetworks.com]
> Sent: Tuesday, September 06, 2016 6:20 PM
> To: Jiri Pirko <j...@resnulli.us>
> Cc: netdev@vger.kernel.org; da...@davemloft.net; Nogah Frankel
> <nog...@mellanox.com>; Ido Schimmel <ido...@mellanox.com>; Elad Raz
> <el...@mellanox.com>; Yotam Gigi <yot...@mellanox.com>; Or Gerlitz
> <ogerl...@mellanox.com>; niko...@cumulusnetworks.com;
> linvi...@tuxdriver.com; tg...@suug.ch; go...@cumulusnetworks.com;
> sfel...@gmail.com; s...@queasysnail.net; Eran Ben Elisha
> <era...@mellanox.com>; a...@plumgrid.com; eduma...@google.com;
> han...@stressinduktion.org; f.faine...@gmail.com;
> d...@cumulusnetworks.com
> Subject: Re: [patch net-next v7 2/3] net: core: Add offload stats to
> if_stats_msg
>
> On 9/5/16, 10:18 AM, Jiri Pirko wrote:
> > From: Nogah Frankel <nog...@mellanox.com>
> >
> > Add a nested attribute of offload stats to if_stats_msg
> > named IFLA_STATS_LINK_OFFLOAD_XSTATS.
> > Under it, add SW stats, meaning stats only per packets that went via
> > slowpath to the cpu, named IFLA_OFFLOAD_XSTATS_CPU_HIT.
> >
> > Signed-off-by: Nogah Frankel <nog...@mellanox.com>
> > Signed-off-by: Jiri Pirko <j...@mellanox.com>
> > ---
> > include/uapi/linux/if_link.h | 10 +++++
> > net/core/rtnetlink.c | 88
> ++++++++++++++++++++++++++++++++++++++++++--
> > 2 files changed, 94 insertions(+), 4 deletions(-)
> >
> > diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> > index 9bf3aec..4aaa2a1 100644
> > --- a/include/uapi/linux/if_link.h
> > +++ b/include/uapi/linux/if_link.h
> > @@ -826,6 +826,7 @@ enum {
> > IFLA_STATS_LINK_64,
> > IFLA_STATS_LINK_XSTATS,
> > IFLA_STATS_LINK_XSTATS_SLAVE,
> > + IFLA_STATS_LINK_OFFLOAD_XSTATS,
> > __IFLA_STATS_MAX,
> > };
> >
> > @@ -845,6 +846,15 @@ enum {
> > };
> > #define LINK_XSTATS_TYPE_MAX (__LINK_XSTATS_TYPE_MAX - 1)
> >
> > +/* These are stats embedded into IFLA_STATS_LINK_OFFLOAD_XSTATS */
> > +enum {
> > + IFLA_OFFLOAD_XSTATS_UNSPEC,
> > + IFLA_OFFLOAD_XSTATS_CPU_HIT, /* struct rtnl_link_stats64 */
> > + __IFLA_OFFLOAD_XSTATS_MAX
> > +};
> > +#define IFLA_OFFLOAD_XSTATS_MAX (__IFLA_OFFLOAD_XSTATS_MAX - 1)
> > +#define IFLA_OFFLOAD_XSTATS_FIRST (IFLA_OFFLOAD_XSTATS_UNSPEC +
> 1)
>
> not sure why we need a first in the uapi.
I'll move it to rtnetlink.
> > +
> > /* XDP section */
> >
> > enum {
> > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> > index 1dfca1c..95eb131 100644
> > --- a/net/core/rtnetlink.c
> > +++ b/net/core/rtnetlink.c
> > @@ -3577,6 +3577,74 @@ static bool stats_attr_valid(unsigned int mask,
> int attrid, int idxattr)
> > (!idxattr || idxattr == attrid);
> > }
> >
> > +static int rtnl_get_offload_stats_attr_size(int attr_id)
> > +{
> > + switch (attr_id) {
> > + case IFLA_OFFLOAD_XSTATS_CPU_HIT:
> > + return sizeof(struct rtnl_link_stats64);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int rtnl_get_offload_stats(struct sk_buff *skb, struct net_device
> *dev)
> > +{
> > + struct nlattr *attr;
> > + int attr_id, size;
> > + void *attr_data;
> > + int err;
> > +
> > + if (!(dev->netdev_ops && dev->netdev_ops->ndo_has_offload_stats
> &&
> > + dev->netdev_ops->ndo_get_offload_stats))
> > + return 0;
> > +
> > + for (attr_id = IFLA_OFFLOAD_XSTATS_FIRST;
> > + attr_id <= IFLA_OFFLOAD_XSTATS_MAX; attr_id++) {
> > + size = rtnl_get_offload_stats_attr_size(attr_id);
> > + if (!size)
> > + continue;
> > +
> > + if (!dev->netdev_ops->ndo_has_offload_stats(attr_id))
> > + continue;
> > +
> > + attr = nla_reserve_64bit(skb, attr_id, size,
> > + IFLA_OFFLOAD_XSTATS_UNSPEC);
> > + if (!attr)
> > + return -EMSGSIZE;
>
> you need this 64bit alignment padding only for the specific nested attribute
> your driver is adding ?. The code seems to add it unconditionally for every
> attribute.
> But, I am guessing future attribute authors will need to adjust this somehow.
>
I think it's best to wait till we have more attributes to see how to implement
it.
> > +
> > + attr_data = nla_data(attr);
> > + memset(attr_data, 0, size);
> > + err = dev->netdev_ops->ndo_get_offload_stats(attr_id, dev,
> > + attr_data);
> > + if (err)
> > + return err;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int rtnl_get_offload_stats_size(const struct net_device *dev)
> > +{
> > + int size = 0;
> > + int attr_id;
> > +
> > + if (!(dev->netdev_ops && dev->netdev_ops->ndo_has_offload_stats
> &&
> > + dev->netdev_ops->ndo_get_offload_stats))
> > + return nla_total_size(0);
> > +
> > + for (attr_id = IFLA_OFFLOAD_XSTATS_FIRST;
> > + attr_id <= IFLA_OFFLOAD_XSTATS_MAX; attr_id++) {
> > + if (!dev->netdev_ops->ndo_has_offload_stats(attr_id))
> > + continue;
> > +
> > + size += rtnl_get_offload_stats_attr_size(attr_id);
> > + }
> > +
> > + size += nla_total_size(0);
> > +
> > + return size;
> > +}
> > +
> > static int rtnl_fill_statsinfo(struct sk_buff *skb, struct net_device *dev,
> > int type, u32 pid, u32 seq, u32 change,
> > unsigned int flags, unsigned int filter_mask,
> > @@ -3586,6 +3654,7 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb,
> struct net_device *dev,
> > struct nlmsghdr *nlh;
> > struct nlattr *attr;
> > int s_prividx = *prividx;
> > + int err;
> >
> > ASSERT_RTNL();
> >
> > @@ -3614,8 +3683,6 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb,
> struct net_device *dev,
> > const struct rtnl_link_ops *ops = dev->rtnl_link_ops;
> >
> > if (ops && ops->fill_linkxstats) {
> > - int err;
> > -
> > *idxattr = IFLA_STATS_LINK_XSTATS;
> > attr = nla_nest_start(skb,
> > IFLA_STATS_LINK_XSTATS);
> > @@ -3639,8 +3706,6 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb,
> struct net_device *dev,
> > if (master)
> > ops = master->rtnl_link_ops;
> > if (ops && ops->fill_linkxstats) {
> > - int err;
> > -
> > *idxattr = IFLA_STATS_LINK_XSTATS_SLAVE;
> > attr = nla_nest_start(skb,
> > IFLA_STATS_LINK_XSTATS_SLAVE);
> > @@ -3655,6 +3720,18 @@ static int rtnl_fill_statsinfo(struct sk_buff *skb,
> struct net_device *dev,
> > }
> > }
> >
> > + if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_OFFLOAD_XSTATS,
> > + *idxattr)) {
> > + attr = nla_nest_start(skb,
> IFLA_STATS_LINK_OFFLOAD_XSTATS);
> > + if (!attr)
> > + goto nla_put_failure;
> > +
> > + err = rtnl_get_offload_stats(skb, dev);
> > + nla_nest_end(skb, attr);
>
> seems like this can result in an empty nested attribute. better thing would
> be to
> cancel the nest if size from rtnl_get_offload_stats is zero ?
>
I'll fix it.
> > + if (err)
> > + goto nla_put_failure;
> > + }
> > +
> > nlmsg_end(skb, nlh);
> >
> > return 0;
> > @@ -3712,6 +3789,9 @@ static size_t if_nlmsg_stats_size(const struct
> net_device *dev,
> > }
> > }
> >
> > + if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_OFFLOAD_XSTATS,
> 0))
> > + size += rtnl_get_offload_stats_size(dev);
> > +
> > return size;
> > }
> >
