[dpdk-dev] [PATCH v2 2/6] ethdev: add port ownership

Matan Azrad matan at mellanox.com
Wed Jan 10 17:58:48 CET 2018


Hi Konstantin

From: Ananyev, Konstantin, Wednesday, January 10, 2018 3:36 PM
> Hi Matan,
> 
> Few comments from me below.
> BTW, do you plan to add ownership mandatory check in control path
> functions that change port configuration?

No.


> Konstantin
> 
> > -----Original Message-----
> > From: Matan Azrad [mailto:matan at mellanox.com]
> > Sent: Sunday, January 7, 2018 9:46 AM
> > To: Thomas Monjalon <thomas at monjalon.net>; Gaetan Rivet
> > <gaetan.rivet at 6wind.com>; Wu, Jingjing <jingjing.wu at intel.com>
> > Cc: dev at dpdk.org; Neil Horman <nhorman at tuxdriver.com>; Richardson,
> > Bruce <bruce.richardson at intel.com>; Ananyev, Konstantin
> > <konstantin.ananyev at intel.com>
> > Subject: [PATCH v2 2/6] ethdev: add port ownership
> >
> > The ownership of a port is implicit in DPDK.
> > Making it explicit is better from the next reasons:
> > 1. It will define well who is in charge of the port usage synchronization.
> > 2. A library could work on top of a port.
> > 3. A port can work on top of another port.
> >
> > Also in the fail-safe case, an issue has been met in testpmd.
> > We need to check that the application is not trying to use a port
> > which is already managed by fail-safe.
> >
> > A port owner is built from owner id(number) and owner name(string)
> > while the owner id must be unique to distinguish between two identical
> > entity instances and the owner name can be any name.
> > The name helps to logically recognize the owner by different DPDK
> > entities and allows easy debug.
> > Each DPDK entity can allocate an owner unique identifier and can use
> > it and its preferred name to owns valid ethdev ports.
> > Each DPDK entity can get any port owner status to decide if it can
> > manage the port or not.
> >
> > The mechanism is synchronized for both the primary process threads and
> > the secondary processes threads to allow secondary process entity to
> > be a port owner.
> >
> > Add a sinchronized ownership mechanism to DPDK Ethernet devices to
> > avoid multiple management of a device by different DPDK entities.
> >
> > The current ethdev internal port management is not affected by this
> > feature.
> >
> > Signed-off-by: Matan Azrad <matan at mellanox.com>
> > ---
> >  doc/guides/prog_guide/poll_mode_drv.rst |  14 ++-
> >  lib/librte_ether/rte_ethdev.c           | 206
> ++++++++++++++++++++++++++++++--
> >  lib/librte_ether/rte_ethdev.h           |  89 ++++++++++++++
> >  lib/librte_ether/rte_ethdev_version.map |  12 ++
> >  4 files changed, 311 insertions(+), 10 deletions(-)
> 
> 
> >
> >
> > diff --git a/lib/librte_ether/rte_ethdev.c
> > b/lib/librte_ether/rte_ethdev.c index 684e3e8..0e12452 100644
> > --- a/lib/librte_ether/rte_ethdev.c
> > +++ b/lib/librte_ether/rte_ethdev.c
> > @@ -70,7 +70,10 @@
> >
> >  static const char *MZ_RTE_ETH_DEV_DATA = "rte_eth_dev_data";  struct
> > rte_eth_dev rte_eth_devices[RTE_MAX_ETHPORTS];
> > +/* ports data array stored in shared memory */
> >  static struct rte_eth_dev_data *rte_eth_dev_data;
> > +/* next owner identifier stored in shared memory */ static uint16_t
> > +*rte_eth_next_owner_id;
> >  static uint8_t eth_dev_last_created_port;
> >
> >  /* spinlock for eth device callbacks */ @@ -82,6 +85,9 @@
> >  /* spinlock for add/remove tx callbacks */  static rte_spinlock_t
> > rte_eth_tx_cb_lock = RTE_SPINLOCK_INITIALIZER;
> >
> > +/* spinlock for eth device ownership management stored in shared
> > +memory */ static rte_spinlock_t *rte_eth_dev_ownership_lock;
> > +
> >  /* store statistics names and its offset in stats structure  */
> > struct rte_eth_xstats_name_off {
> >  	char name[RTE_ETH_XSTATS_NAME_SIZE]; @@ -153,14 +159,18 @@
> enum {  }
> >
> >  static void
> > -rte_eth_dev_data_alloc(void)
> > +rte_eth_dev_share_data_alloc(void)
> >  {
> >  	const unsigned flags = 0;
> >  	const struct rte_memzone *mz;
> > +	const unsigned int data_size = RTE_MAX_ETHPORTS *
> > +						sizeof(*rte_eth_dev_data);
> >
> >  	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
> > +		/* Allocate shared memory for port data and ownership */
> >  		mz = rte_memzone_reserve(MZ_RTE_ETH_DEV_DATA,
> > -				RTE_MAX_ETHPORTS *
> sizeof(*rte_eth_dev_data),
> > +				data_size + sizeof(*rte_eth_next_owner_id)
> +
> > +				sizeof(*rte_eth_dev_ownership_lock),
> >  				rte_socket_id(), flags);
> >  	} else
> >  		mz = rte_memzone_lookup(MZ_RTE_ETH_DEV_DATA);
> > @@ -168,9 +178,17 @@ enum {
> >  		rte_panic("Cannot allocate memzone for ethernet port
> data\n");
> >
> >  	rte_eth_dev_data = mz->addr;
> > -	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
> > -		memset(rte_eth_dev_data, 0,
> > -				RTE_MAX_ETHPORTS *
> sizeof(*rte_eth_dev_data));
> > +	rte_eth_next_owner_id = (uint16_t *)((uintptr_t)mz->addr +
> > +					     data_size);
> > +	rte_eth_dev_ownership_lock = (rte_spinlock_t *)
> > +		((uintptr_t)rte_eth_next_owner_id +
> > +		 sizeof(*rte_eth_next_owner_id));
> 
> 
> I think that might make  rte_eth_dev_ownership_lock location not 4B
> aligned...

Where can I find the documentation about it?

> Why just not to put all data that you are trying to allocate as one chunck into
> the same struct:
> static struct {
>         uint16_t next_owner_id;
>         /* spinlock for eth device ownership management stored in shared
> memory */
>         rte_spinlock_t dev_ownership_lock;
>         rte_eth_dev_data *data;
> } rte_eth_dev_data;
> and allocate/use it everywhere?
> That would simplify allocation/management stuff.
>
I don't understand what exactly do you mean. ?
If you mean to group all in one struct like:

static struct {
        uint16_t next_owner_id;
        rte_spinlock_t dev_ownership_lock;
        rte_eth_dev_data  data[];
} rte_eth_dev_share_data;

Just to simplify the addresses calculation above,
It will change more code in ethdev relative to the old rte_eth_dev_data global array and will be more intrusive.
Stay it as is, focuses the change only here.

I can just move the spinlock memory allocation to be at the beginning of the memzone(to be sure about the alignment).
 
> It is good to see that now scanning/updating rte_eth_dev_data[] is lock
> protected, but it might be not very plausible to protect both data[] and
> next_owner_id using the same lock.

I guess you mean to the owner structure in rte_eth_dev_data[port_id].
The next_owner_id is read by ownership APIs(for owner validation), so it makes sense to use the same lock.
Actually, why not?

> In fact, for next_owner_id, you don't need a lock - just rte_atomic_t should
> be enough.

I don't think so, it is problematic in next_owner_id wraparound and may complicate the code in other places which read it.
Why not just to keep it simple and using the same lock?

> Another alternative would be to use 2 locks - one for next_owner_id second
> for actual data[] protection.
> 
> Another thing - you'll probably need to grab/release a lock inside
> rte_eth_dev_allocated() too.
> It is a public function used by drivers, so need to be protected too.
> 

Yes, I thought about it, but decided not to use lock in next:
rte_eth_dev_allocated
rte_eth_dev_count
rte_eth_dev_get_name_by_port
rte_eth_dev_get_port_by_name
maybe more...

Don't you think it is just timing depended?(ask in the next moment and you may get another answer) I don't see optional crash.

> > +
> > +	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
> > +		memset(rte_eth_dev_data, 0, data_size);
> > +		*rte_eth_next_owner_id = RTE_ETH_DEV_NO_OWNER + 1;
> > +		rte_spinlock_init(rte_eth_dev_ownership_lock);
> > +	}
> >  }
> >
> >  struct rte_eth_dev *
> > @@ -225,7 +243,7 @@ struct rte_eth_dev *
> >  	}
> >
> >  	if (rte_eth_dev_data == NULL)
> > -		rte_eth_dev_data_alloc();
> > +		rte_eth_dev_share_data_alloc();
> >
> >  	if (rte_eth_dev_allocated(name) != NULL) {
> >  		RTE_PMD_DEBUG_TRACE("Ethernet Device with name %s
> already
> > allocated!\n", @@ -253,7 +271,7 @@ struct rte_eth_dev *
> >  	struct rte_eth_dev *eth_dev;
> >
> >  	if (rte_eth_dev_data == NULL)
> > -		rte_eth_dev_data_alloc();
> > +		rte_eth_dev_share_data_alloc();
> >
> >  	for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
> >  		if (strcmp(rte_eth_dev_data[i].name, name) == 0) @@ -
> 278,8 +296,12
> > @@ struct rte_eth_dev *
> >  	if (eth_dev == NULL)
> >  		return -EINVAL;
> >
> > -	memset(eth_dev->data, 0, sizeof(struct rte_eth_dev_data));
> > +	rte_spinlock_lock(rte_eth_dev_ownership_lock);
> > +
> >  	eth_dev->state = RTE_ETH_DEV_UNUSED;
> > +	memset(eth_dev->data, 0, sizeof(struct rte_eth_dev_data));
> > +
> > +	rte_spinlock_unlock(rte_eth_dev_ownership_lock);
> >  	return 0;
> >  }
> >
> > @@ -294,6 +316,174 @@ struct rte_eth_dev *
> >  		return 1;
> >  }
> >
> > +static int
> > +rte_eth_is_valid_owner_id(uint16_t owner_id) {
> > +	if (owner_id == RTE_ETH_DEV_NO_OWNER ||
> > +	    (*rte_eth_next_owner_id > RTE_ETH_DEV_NO_OWNER &&
> > +	     *rte_eth_next_owner_id <= owner_id)) {
> > +		RTE_LOG(ERR, EAL, "Invalid owner_id=%d.\n", owner_id);
> > +		return 0;
> > +	}
> > +	return 1;
> > +}
> > +
> > +uint16_t
> > +rte_eth_find_next_owned_by(uint16_t port_id, const uint16_t
> owner_id)
> > +{
> > +	while (port_id < RTE_MAX_ETHPORTS &&
> > +	       (rte_eth_devices[port_id].state != RTE_ETH_DEV_ATTACHED ||
> > +	       rte_eth_devices[port_id].data->owner.id != owner_id))
> > +		port_id++;
> > +
> > +	if (port_id >= RTE_MAX_ETHPORTS)
> > +		return RTE_MAX_ETHPORTS;
> > +
> > +	return port_id;
> > +}
> > +
> > +int
> > +rte_eth_dev_owner_new(uint16_t *owner_id) {
> > +	int ret = 0;
> > +
> > +	rte_spinlock_lock(rte_eth_dev_ownership_lock);
> > +
> > +	if (*rte_eth_next_owner_id == RTE_ETH_DEV_NO_OWNER) {
> > +		/* Counter wrap around. */
> > +		RTE_PMD_DEBUG_TRACE("Reached maximum number of
> Ethernet port owners.\n");
> > +		ret = -EUSERS;
> > +	} else {
> > +		*owner_id = (*rte_eth_next_owner_id)++;
> > +	}
> > +
> > +	rte_spinlock_unlock(rte_eth_dev_ownership_lock);
> > +	return ret;
> > +}
> > +
> > +int
> > +rte_eth_dev_owner_set(const uint16_t port_id,
> > +		      const struct rte_eth_dev_owner *owner)
> 
> As a nit - if you'll have rte_eth_dev_owner_set(port_id, old_owner,
> new_owner)
> - that might be more plausible for user, and would greatly simplify unset()
> part:
> just set(port_id, cur_owner, zero_owner);
> 

How the user should know the old owner?

> > +{
> > +	struct rte_eth_dev_owner *port_owner;
> > +	int ret = 0;
> > +	int sret;
> > +
> > +	rte_spinlock_lock(rte_eth_dev_ownership_lock);
> > +
> > +	if (!rte_eth_dev_is_valid_port(port_id)) {
> > +		RTE_PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
> > +		ret = -ENODEV;
> > +		goto unlock;
> > +	}
> > +
> > +	if (!rte_eth_is_valid_owner_id(owner->id)) {
> > +		ret = -EINVAL;
> > +		goto unlock;
> > +	}
> > +
> > +	port_owner = &rte_eth_devices[port_id].data->owner;
> > +	if (port_owner->id != RTE_ETH_DEV_NO_OWNER &&
> > +	    port_owner->id != owner->id) {
> > +		RTE_LOG(ERR, EAL,
> > +			"Cannot set owner to port %d already owned by
> %s_%05d.\n",
> > +			port_id, port_owner->name, port_owner->id);
> > +		ret = -EPERM;
> > +		goto unlock;
> > +	}
> > +
> > +	sret = snprintf(port_owner->name,
> RTE_ETH_MAX_OWNER_NAME_LEN, "%s",
> > +			owner->name);
> > +	if (sret < 0 || sret >= RTE_ETH_MAX_OWNER_NAME_LEN) {
> 
> Personally, I don't see any reason to fail if description was truncated...
> Another alternative - just use rte_malloc() here to allocate big enough buffer
> to hold the description.
> 

But it is static allocation like in the device name, why to allocate it differently?
 
> > +		memset(port_owner->name, 0,
> RTE_ETH_MAX_OWNER_NAME_LEN);
> > +		RTE_LOG(ERR, EAL, "Invalid owner name.\n");
> > +		ret = -EINVAL;
> > +		goto unlock;
> > +	}
> > +
> > +	port_owner->id = owner->id;
> > +	RTE_PMD_DEBUG_TRACE("Port %d owner is %s_%05d.\n", port_id,
> > +			    owner->name, owner->id);
> > +
> 
> As another nit - you can avoid all these gotos by restructuring code a bit:
> 
> rte_eth_dev_owner_set(const uint16_t port_id, const struct
> rte_eth_dev_owner *owner) {
>     rte_spinlock_lock(...);
>     ret = _eth_dev_owner_set_unlocked(port_id, owner);
>     rte_spinlock_unlock(...);
>     return ret;
> }
> 
Don't you like gotos? :)
I personally use it only in error\performance scenarios.
Do you think it worth the effort?

> 
> > +unlock:
> > +	rte_spinlock_unlock(rte_eth_dev_ownership_lock);
> > +	return ret;
> > +}
> > +
> > +int
> > +rte_eth_dev_owner_unset(const uint16_t port_id, const uint16_t
> > +owner_id) {
> > +	struct rte_eth_dev_owner *port_owner;
> > +	int ret = 0;
> > +
> > +	rte_spinlock_lock(rte_eth_dev_ownership_lock);
> > +
> > +	if (!rte_eth_dev_is_valid_port(port_id)) {
> > +		RTE_PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
> > +		ret = -ENODEV;
> > +		goto unlock;
> > +	}
> > +
> > +	if (!rte_eth_is_valid_owner_id(owner_id)) {
> > +		ret = -EINVAL;
> > +		goto unlock;
> > +	}
> > +
> > +	port_owner = &rte_eth_devices[port_id].data->owner;
> > +	if (port_owner->id != owner_id) {
> > +		RTE_LOG(ERR, EAL, "Cannot unset port %d owner (%s_%05d)
> by"
> > +			" a different owner with id %5d.\n", port_id,
> > +			port_owner->name, port_owner->id, owner_id);
> > +		ret = -EPERM;
> > +		goto unlock;
> > +	}
> > +	RTE_PMD_DEBUG_TRACE("Port %d owner %s_%05d has
> removed.\n", port_id,
> > +			    port_owner->name, port_owner->id);
> > +
> > +	memset(port_owner, 0, sizeof(struct rte_eth_dev_owner));
> > +
> > +unlock:
> > +	rte_spinlock_unlock(rte_eth_dev_ownership_lock);
> > +	return ret;
> > +}
> > +
> > +void
> > +rte_eth_dev_owner_delete(const uint16_t owner_id) {
> > +	uint16_t port_id;
> > +
> > +	rte_spinlock_lock(rte_eth_dev_ownership_lock);
> > +
> > +	if (rte_eth_is_valid_owner_id(owner_id)) {
> > +		RTE_ETH_FOREACH_DEV_OWNED_BY(port_id, owner_id)
> > +			memset(&rte_eth_devices[port_id].data->owner, 0,
> > +			       sizeof(struct rte_eth_dev_owner));
> > +		RTE_PMD_DEBUG_TRACE("All port owners owned by %05d
> identifier"
> > +				    " have removed.\n", owner_id);
> > +	}
> > +
> > +	rte_spinlock_unlock(rte_eth_dev_ownership_lock);
> > +}
> > +
> > +int
> > +rte_eth_dev_owner_get(const uint16_t port_id, struct
> > +rte_eth_dev_owner *owner) {
> > +	int ret = 0;
> > +
> > +	rte_spinlock_lock(rte_eth_dev_ownership_lock);
> > +
> > +	if (!rte_eth_dev_is_valid_port(port_id)) {
> > +		RTE_PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id);
> > +		ret = -ENODEV;
> > +	} else {
> > +		rte_memcpy(owner, &rte_eth_devices[port_id].data-
> >owner,
> > +			   sizeof(*owner));
> > +	}
> > +
> > +	rte_spinlock_unlock(rte_eth_dev_ownership_lock);
> > +	return ret;
> > +}
> > +
> >  int
> >  rte_eth_dev_socket_id(uint16_t port_id)  { diff --git
> > a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h index
> > 57b61ed..88ad765 100644
> > --- a/lib/librte_ether/rte_ethdev.h
> > +++ b/lib/librte_ether/rte_ethdev.h
> > @@ -1760,6 +1760,15 @@ struct rte_eth_dev_sriov {
> >
> >  #define RTE_ETH_NAME_MAX_LEN RTE_DEV_NAME_MAX_LEN
> >
> > +#define RTE_ETH_DEV_NO_OWNER 0
> > +
> > +#define RTE_ETH_MAX_OWNER_NAME_LEN 64
> > +
> > +struct rte_eth_dev_owner {
> > +	uint16_t id; /**< The owner unique identifier. */
> 
> Why limit yourself to 16bit here?
> Why not uint32_t/uint64_t - or even uuid_t and make system library to
> generate it for you?
> Wouldn't need to worry about overflows then.
> 

Interesting.
Will change it and will remove the overflow code from next_id!
(just didn't think about realistic usage of a lot of owners and take same type as port ID).

> > +	char name[RTE_ETH_MAX_OWNER_NAME_LEN]; /**< The owner
> name. */ };
> > +
> >  /**
> >   * @internal
> >   * The data part, with no function pointers, associated with each ethernet
> device.
> > @@ -1810,6 +1819,7 @@ struct rte_eth_dev_data {
> >  	int numa_node;  /**< NUMA node connection */
> >  	struct rte_vlan_filter_conf vlan_filter_conf;
> >  	/**< VLAN filter configuration. */
> > +	struct rte_eth_dev_owner owner; /**< The port owner. */
> >  };
> >
> >  /** Device supports link state interrupt */ @@ -1846,6 +1856,85 @@
> > struct rte_eth_dev_data {
> >
> >
> >  /**
> > + * Iterates over valid ethdev ports owned by a specific owner.
> > + *
> > + * @param port_id
> > + *   The id of the next possible valid owned port.
> > + * @param	owner_id
> > + *  The owner identifier.
> > + *  RTE_ETH_DEV_NO_OWNER means iterate over all valid ownerless
> ports.
> > + * @return
> > + *   Next valid port id owned by owner_id, RTE_MAX_ETHPORTS if there is
> none.
> > + */
> > +uint16_t rte_eth_find_next_owned_by(uint16_t port_id, const uint16_t
> > +owner_id);
> > +
> > +/**
> > + * Macro to iterate over all enabled ethdev ports owned by a specific
> owner.
> > + */
> > +#define RTE_ETH_FOREACH_DEV_OWNED_BY(p, o) \
> > +	for (p = rte_eth_find_next_owned_by(0, o); \
> > +	     (unsigned int)p < (unsigned int)RTE_MAX_ETHPORTS; \
> > +	     p = rte_eth_find_next_owned_by(p + 1, o))
> > +
> > +/**
> > + * Get a new unique owner identifier.
> > + * An owner identifier is used to owns Ethernet devices by only one
> > +DPDK entity
> > + * to avoid multiple management of device by different entities.
> > + *
> > + * @param	owner_id
> > + *   Owner identifier pointer.
> > + * @return
> > + *   Negative errno value on error, 0 on success.
> > + */
> > +int rte_eth_dev_owner_new(uint16_t *owner_id);
> > +
> > +/**
> > + * Set an Ethernet device owner.
> > + *
> > + * @param	port_id
> > + *  The identifier of the port to own.
> > + * @param	owner
> > + *  The owner pointer.
> > + * @return
> > + *  Negative errno value on error, 0 on success.
> > + */
> > +int rte_eth_dev_owner_set(const uint16_t port_id,
> > +			  const struct rte_eth_dev_owner *owner);
> > +
> > +/**
> > + * Unset Ethernet device owner to make the device ownerless.
> > + *
> > + * @param	port_id
> > + *  The identifier of port to make ownerless.
> > + * @param	owner
> > + *  The owner identifier.
> > + * @return
> > + *  0 on success, negative errno value on error.
> > + */
> > +int rte_eth_dev_owner_unset(const uint16_t port_id, const uint16_t
> > +owner_id);
> > +
> > +/**
> > + * Remove owner from all Ethernet devices owned by a specific owner.
> > + *
> > + * @param	owner
> > + *  The owner identifier.
> > + */
> > +void rte_eth_dev_owner_delete(const uint16_t owner_id);
> > +
> > +/**
> > + * Get the owner of an Ethernet device.
> > + *
> > + * @param	port_id
> > + *  The port identifier.
> > + * @param	owner
> > + *  The owner structure pointer to fill.
> > + * @return
> > + *  0 on success, negative errno value on error..
> > + */
> > +int rte_eth_dev_owner_get(const uint16_t port_id,
> > +			  struct rte_eth_dev_owner *owner);
> > +
> > +/**
> >   * Get the total number of Ethernet devices that have been successfully
> >   * initialized by the matching Ethernet driver during the PCI probing phase
> >   * and that are available for applications to use. These devices must
> > be diff --git a/lib/librte_ether/rte_ethdev_version.map
> > b/lib/librte_ether/rte_ethdev_version.map
> > index e9681ac..5d20b5f 100644
> > --- a/lib/librte_ether/rte_ethdev_version.map
> > +++ b/lib/librte_ether/rte_ethdev_version.map
> > @@ -198,6 +198,18 @@ DPDK_17.11 {
> >
> >  } DPDK_17.08;
> >
> > +DPDK_18.02 {
> > +	global:
> > +
> > +	rte_eth_dev_owner_delete;
> > +	rte_eth_dev_owner_get;
> > +	rte_eth_dev_owner_new;
> > +	rte_eth_dev_owner_set;
> > +	rte_eth_dev_owner_unset;
> > +	rte_eth_find_next_owned_by;
> > +
> > +} DPDK_17.11;
> > +
> >  EXPERIMENTAL {
> >  	global:
> >
> > --
> > 1.8.3.1



More information about the dev mailing list