[dpdk-dev] [PATCH v4 07/10] net/mlx5: probe all port representors
Adrien Mazarguil
adrien.mazarguil at 6wind.com
Tue Jul 10 12:58:41 CEST 2018
On Tue, Jul 10, 2018 at 10:13:25AM +0000, Shahaf Shuler wrote:
> Tuesday, July 10, 2018 12:37 PM, Adrien Mazarguil:
> > Subject: Re: [PATCH v4 07/10] net/mlx5: probe all port representors
> >
> > On Mon, Jul 09, 2018 at 11:57:29AM +0000, Shahaf Shuler wrote:
> > > Hi Adrien,
> > >
> > >
> > > Thursday, July 5, 2018 11:46 AM, Adrien Mazarguil:
> > > > Subject: [PATCH v4 07/10] net/mlx5: probe all port representors
> > > >
> > > > Probe existing port representors in addition to their master device
> > > > and associate them automatically.
> > > >
> > > > To avoid collision between Ethernet devices, they are named as follows:
> > > >
> > > > - "{DBDF}" for master/switch devices.
> > > > - "{DBDF}_representor_{rep}" with "rep" starting from 0 for port
> > > > representors.
> > > >
> > > > (Patch based on prior work from Yuanhan Liu)
> > > >
> > > > Signed-off-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
> > > > Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro at 6wind.com>
> > > > Reviewed-by: Xueming Li <xuemingl at mellanox.com>
> > > > Cc: Xueming Li <xuemingl at mellanox.com>
> > > > Cc: Shahaf Shuler <shahafs at mellanox.com>
> > > > --
> > > > v4 changes:
> > > >
> > > > - Fixed domain ID release once the last port using it is closed. Closed
> > > > devices are not necessarily detached, their presence is not a good
> > > > indicator. Code was modified to check if they still use their domain IDs
> > > > before deciding to release it.
> > <snip>
> > > > @@ -883,6 +915,41 @@ mlx5_dev_spawn(struct rte_device *dpdk_dev,
> > > > priv->nl_socket_rdma = mlx5_nl_init(0, NETLINK_RDMA);
> > > > priv->nl_socket_route = mlx5_nl_init(RTMGRP_LINK,
> > > > NETLINK_ROUTE);
> > > > priv->nl_sn = 0;
> > > > + priv->representor = !!switch_info->representor;
> > > > + priv->domain_id = RTE_ETH_DEV_SWITCH_DOMAIN_ID_INVALID;
> > > > + priv->representor_id =
> > > > + switch_info->representor ? switch_info->port_name : -1;
> > > > + /*
> > > > + * Look for sibling devices in order to reuse their switch domain
> > > > + * if any, otherwise allocate one.
> > > > + */
> > > > + i = mlx5_dev_to_port_id(dpdk_dev, NULL, 0);
> > > > + if (i > 0) {
> > > > + uint16_t port_id[i];
> > > > +
> > > > + i = RTE_MIN(mlx5_dev_to_port_id(dpdk_dev, port_id, i), i);
> > > > + while (i--) {
> > > > + const struct priv *opriv =
> > > > + rte_eth_devices[port_id[i]].data-
> > > > >dev_private;
> > > > +
> > > > + if (!opriv ||
> > > > + opriv->domain_id ==
> > > > + RTE_ETH_DEV_SWITCH_DOMAIN_ID_INVALID)
> > > > + continue;
> > > > + priv->domain_id = opriv->domain_id;
> > >
> > > It looks like for the second port it will use the domain_id of the first port. Is
> > that what you intent?
> >
> > Yes, it's on purpose. Master and representors of a given device must share
> > the same domain ID to let applications know they can create flow rules to
> > forward traffic between them all.
>
> But this is not the case in Mellanox devices. On Mellanox devices each PF along w/ its representors has a separate eswitch, and traffic cannot be routed between the switches using flow rules.
> For example if we have PF0 along w/ its representor REP0_0 and PF1 along w/ its representor REP1_0 . PF0 and REP0_0 will belong to switch X and PF1 and REP1_0 will belong to switch domain Y. it is also being reflected on the phys_switch_id.
>
> We should have switch domain per PF.
Looks like I didn't understand your previous comment. I confirm there is no
such issue, one domain ID is allocated per PF/representors group, which are
identified by a common PCI bus address. It's fine because on mlx5, each
physical port exposes its own address, I assumed there was no need to
additionally compare phys_switch_id. Can this happen?
> > > Note - I couldn't test it due to compilation errors:
> > >
> > >
> > /.autodirect/swgwork/shahafs/workspace/dpdk.org/drivers/net/mlx5/mlx5
> > _nl.c: In function 'mlx5_nl_switch_info_cb':
> > >
> > /.autodirect/swgwork/shahafs/workspace/dpdk.org/drivers/net/mlx5/mlx5
> > _
> > > nl.c:843:8: error: 'IFLA_PHYS_PORT_NAME' undecl ared (first use in this
> > function)
> > > case IFLA_PHYS_PORT_NAME:
> > > ^
> > >
> > /.autodirect/swgwork/shahafs/workspace/dpdk.org/drivers/net/mlx5/mlx5
> > _
> > > nl.c:843:8: note: each undeclared identifier is reported only once
> > > for each function it appears in
> > >
> > /.autodirect/swgwork/shahafs/workspace/dpdk.org/drivers/net/mlx5/mlx5
> > _
> > > nl.c:851:8: error: 'IFLA_PHYS_SWITCH_ID' undecl ared (first use in this
> > function)
> > > case IFLA_PHYS_SWITCH_ID:
> > > ^
> > >
> > > My system info:
> > > NAME="Red Hat Enterprise Linux Server"
> > > VERSION="7.3 (Maipo)"
> > > ID="rhel"
> > > ID_LIKE="fedora"
> > > VERSION_ID="7.3"
> > > PRETTY_NAME="Red Hat Enterprise Linux Server 7.3 (Maipo)"
> > > ANSI_COLOR="0;31"
> > > CPE_NAME="cpe:/o:redhat:enterprise_linux:7.3:GA:server"
> > >
> > HOME_URL="https://emea01.safelinks.protection.outlook.com/?url=https%
> > 3A%2F%2Fwww.redhat.com%2F&data=02%7C01%7Cshahafs%40mellan
> > ox.com%7C661e7b51087b460817c008d5e648bf1e%7Ca652971c7d2e4d9ba6a4
> > d149256f461b%7C0%7C0%7C636668122474445351&sdata=Lg8arhiYLvH5L
> > 2hef8DVhS8A3fVJ%2B5IZkLIHmqCd%2FmY%3D&reserved=0"
> > >
> > BUG_REPORT_URL="https://emea01.safelinks.protection.outlook.com/?url=
> > https%3A%2F%2Fbugzilla.redhat.com%2F&data=02%7C01%7Cshahafs%
> > 40mellanox.com%7C661e7b51087b460817c008d5e648bf1e%7Ca652971c7d2e
> > 4d9ba6a4d149256f461b%7C0%7C0%7C636668122474445351&sdata=3Do
> > RKjxovM8tOgKLssC1mq2wwfhjpVUZSExXV4ywBEQ%3D&reserved=0"
> > >
> > > REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 7"
> > > REDHAT_BUGZILLA_PRODUCT_VERSION=7.3
> > > REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
> > > REDHAT_SUPPORT_PRODUCT_VERSION="7.3"
> > > Red Hat Enterprise Linux Server release 7.3 (Maipo) Red Hat Enterprise
> > > Linux Server release 7.3 (Maipo)
> >
> > OK, I'll redefine in v5 in case they are missing on the host system.
> >
> > <snip>
> > > > diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h index
> > > > 704046270..cc01310e0 100644
> > > > --- a/drivers/net/mlx5/mlx5.h
> > > > +++ b/drivers/net/mlx5/mlx5.h
> > > > @@ -159,6 +159,7 @@ struct priv {
> > > > struct ibv_context *ctx; /* Verbs context. */
> > > > struct ibv_device_attr_ex device_attr; /* Device properties. */
> > > > struct ibv_pd *pd; /* Protection Domain. */
> > > > + char ibdev_name[IBV_SYSFS_NAME_MAX]; /* IB device name. */
> > >
> > >
> > > Why we need a dedicated entry for the ibdev_name? it is already part of
> > priv->ctx->device->name.
> >
> > Heh, same reason as the next line below, don't forget those damn
> > secondaries which can't dereference local pointers from the primary process
> > :)
>
> Right 😊.
>
> >
> > > > char ibdev_path[IBV_SYSFS_PATH_MAX]; /* IB device path for
> > > > secondary */
> > <snip>
> > > > struct rte_eth_dev_info *info)
> > > > info->speed_capa = priv->link_speed_capa;
> > > > info->flow_type_rss_offloads = ~MLX5_RSS_HF_MASK;
> > > > mlx5_set_default_params(dev, info);
> > > > + info->switch_info.name = dev->data->name;
> > > > + info->switch_info.domain_id = priv->domain_id;
> > > > + info->switch_info.port_id = priv->representor_id;
> > > > + if (priv->representor) {
> > > > + unsigned int i = mlx5_dev_to_port_id(dev->device, NULL, 0);
> > > > + uint16_t port_id[i];
> > > > +
> > > > + i = RTE_MIN(mlx5_dev_to_port_id(dev->device, port_id, i),
> > > > i);
> > > > + while (i--) {
> > > > + struct priv *opriv =
> > > > + rte_eth_devices[port_id[i]].data-
> > > > >dev_private;
> > > > +
> > > > + if (!opriv ||
> > > > + opriv->representor ||
> > > > + opriv->domain_id != priv->domain_id)
> > > > + continue;
> > > > + /*
> > > > + * Override switch name with that of the master
> > > > + * device.
> > > > + */
> > > > + info->switch_info.name = opriv->dev_data->name;
> > > > + break;
> > >
> > > According to this logic it means once the master device is closed, all the
> > representors are no longer belong to the same switch (switch name of each
> > is different) which is not correct.
> >
> > They still share the same domain ID, which is what actually matters. The
> > switch name is only provided to let applications identify the master
> > (control) device in case it's needed.
> >
> > > According to your notes it is possible to close master w/o closing the
> > representor.
> >
> > This allows devices to be probed in any order on a needed basis, not all at
> > once. It's done on purpose to pave the way for hotplug support.
> >
> > > Why not just storing the master switch name when probing the
> > representor and to use it as is on the dev_info?
> >
> > The switch name *must* be that of the master device. If the master is not
> > probed, there can't be a switch name. However there's no real provision for
> > this in the API, so I chose the most acceptable unique name, which is the
> > name of the local device. Would you prefer an empty name instead?
>
> The current approach is OK.
> I was just suggesting to skip the loop iteration by saving the switch name on the private structure.
This is unsafe, if the master device is never probed or somehow replaced by
a different device with no relationship, this information could be wrong.
Keep in mind these ethdev names are just identifiers. The only requirement
is that they must be unique, however anything can be written in there. If
some name is not taken, another device can use it.
> > Thing is, on mlx5 flow rules can be created directly between representors
> > without involving the master device. An empty switch name may be
> > misleading in this respect.
> >
> > What do you suggest?
--
Adrien Mazarguil
6WIND
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