One addendum below, Aaron.
>
>>Hi Mark,
>>
>>Thanks for the patch! I've not done a very thorough review of this, but
>>my first-blush comments are inline.
>
>Thanks for the review Aaron!
>
>Any additional comments are welcome - my initial responses are inline, below.
>
>Thanks,
>Mark
>
>>
>>Mark Kavanagh <mark.b.kavan...@intel.com> writes:
>>> Add support for Jumbo Frames to DPDK-enabled port types,
>>> using single-segment-mbufs.
>>>
>>> Using this approach, the amount of memory allocated for each mbuf
>>> to store frame data is increased to a value greater than 1518B
>>> (typical Ethernet maximum frame length). The increased space
>>> available in the mbuf means that an entire Jumbo Frame can be carried
>>> in a single mbuf, as opposed to partitioning it across multiple mbuf
>>> segments.
>>>
>>> The amount of space allocated to each mbuf to hold frame data is
>>> defined dynamically by the user when adding a DPDK port to a bridge.
>>> If an MTU value is not supplied, or the user-supplied value is invalid,
>>> the MTU for the port defaults to standard Ethernet MTU (i.e. 1500B).
>>>
>>> Signed-off-by: Mark Kavanagh <mark.b.kavan...@intel.com>
>>> ---
>>
>>This is a new feature which has user-visible impact, so should be
>>announced in NEWS (plus, it's great news).
>
>No problem - I'll add an entry.
>
>>
>>> INSTALL.DPDK.md | 59 ++++++++-
>>> lib/netdev-dpdk.c | 356
>>> +++++++++++++++++++++++++++++++++++++++++-------------
>>> 2 files changed, 328 insertions(+), 87 deletions(-)
>>>
>>> diff --git a/INSTALL.DPDK.md b/INSTALL.DPDK.md
>>> index 96b686c..2f23e27 100644
>>> --- a/INSTALL.DPDK.md
>>> +++ b/INSTALL.DPDK.md
>>> @@ -859,10 +859,61 @@ by adding the following string:
>>> to <interface> sections of all network devices used by DPDK. Parameter 'N'
>>> determines how many queues can be used by the guest.
>>>
>>> +
>>> +Jumbo Frames
>>> +------------
>>> +
>>> +Support for Jumbo Frames may be enabled at run-time for DPDK-type ports.
>>> +
>>> +To avail of Jumbo Frame support, add the '--dpdk-mtu' option to the
>>> ovs-vsctl
>>> +'add-port' command-line, along with the required MTU for the port.
>>> +e.g.
>>
>>This text and the example do not match. I think '--dpdk-mtu' is not valid.
>
>Good catch, thanks.
>
>>
>>> +
>>> + ```
>>> + ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk
>>> options:dpdk-mtu=9000
>>> + ```
>>> +
>>> +When Jumbo Frames are enabled, the size of a DPDK port's mbuf segments are
>>> +increased, such that a full Jumbo Frame may be accommodated inside a single
>>> +mbuf segment. Once set, the MTU for a DPDK port is immutable.
>>
>>Why no support? DPDK supports changing the mtu.
>
>I guess my rationale here is that an MTU change can't be triggered via OVS
>command-line, nor
>can it be triggered programmatically via DPDK (apart from an explicit call to
>rte_eth_dev_set_mtu).
>So, while technically it's possibly, from a user's point of view, there's no
>way to configure
>it, outside of modifying the code directly. If I've missed something here,
>please let me
>know.
>
>>
>>> +Jumbo frame support has been validated against 13312B frames, using the
>>> +DPDK `igb_uio` driver, but larger frames and other DPDK NIC drivers may
>>> +theoretically be supported. Supported port types excludes vHost-Cuse
>>> ports, as
>>> +this feature is pending deprecation.
>>> +
>>> +
>>> +vHost Ports and Jumbo Frames
>>> +----------------------------
>>> +Jumbo frame support is available for DPDK vHost-User ports only. Some
>>> additional
>>> +configuration is needed to take advantage of this feature:
>>> +
>>> + 1. `mergeable buffers` must be enabled for vHost ports, as demonstrated
>>> in
>>> + the QEMU command line snippet below:
>>> +
>>> + ```
>>> + '-netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \'
>>> + '-device
>>> virtio-net-pci,mac=00:00:00:00:00:01,netdev=mynet1,mrg_rxbuf=on'
>>> + ```
>>> +
>>> + 2. Where virtio devices are bound to the Linux kernel driver in a guest
>>> + environment (i.e. interfaces are not bound to an in-guest DPDK
>>> driver), the
>>> + MTU of those logical network interfaces must also be increased. This
>>> + avoids segmentation of Jumbo Frames in the guest. Note that 'MTU'
>>> refers
>>> + to the length of the IP packet only, and not that of the entire frame.
>>> +
>>> + e.g. To calculate the exact MTU of a standard IPv4 frame, subtract
>>> the L2
>>> + header and CRC lengths (i.e. 18B) from the max supported frame size.
>>> + So, to set the MTU for a 13312B Jumbo Frame:
>>> +
>>> + ```
>>> + ifconfig eth1 mtu 13294
>>> + ```
>>> +
>>> +
>>> Restrictions:
>>> -------------
>>>
>>> - - Work with 1500 MTU, needs few changes in DPDK lib to fix this issue.
>>> - Currently DPDK port does not make use any offload functionality.
>>> - DPDK-vHost support works with 1G huge pages.
>>>
>>> @@ -903,6 +954,12 @@ Restrictions:
>>> the next release of DPDK (which includes the above patch) is available
>>> and
>>> integrated into OVS.
>>>
>>> + Jumbo Frames:
>>> + - `virtio-pmd`: DPDK apps in the guest do not exit gracefully. The
>>> source of
>>> + this issue is currently being investigated.
>>> + - vHost-Cuse: Jumbo Frame support is not available for vHost Cuse ports.
>>> +
>>> +
>>> Bug Reporting:
>>> --------------
>>>
>>> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
>>> index de7e488..5f23e28 100644
>>> --- a/lib/netdev-dpdk.c
>>> +++ b/lib/netdev-dpdk.c
>>> @@ -62,20 +62,25 @@ static struct vlog_rate_limit rl =
>>> VLOG_RATE_LIMIT_INIT(5, 20);
>>> #define OVS_CACHE_LINE_SIZE CACHE_LINE_SIZE
>>> #define OVS_VPORT_DPDK "ovs_dpdk"
>>>
>>> +#define NETDEV_DPDK_JUMBO_FRAME_ENABLED 1
>>> +#define NETDEV_DPDK_DEFAULT_RX_BUFSIZE 1024
>>> +
>>> /*
>>> * need to reserve tons of extra space in the mbufs so we can align the
>>> * DMA addresses to 4KB.
>>> * The minimum mbuf size is limited to avoid scatter behaviour and drop in
>>> * performance for standard Ethernet MTU.
>>> */
>>> -#define MTU_TO_MAX_LEN(mtu) ((mtu) + ETHER_HDR_LEN + ETHER_CRC_LEN)
>>> -#define MBUF_SIZE_MTU(mtu) (MTU_TO_MAX_LEN(mtu) \
>>> - + sizeof(struct dp_packet) \
>>> - + RTE_PKTMBUF_HEADROOM)
>>> -#define MBUF_SIZE_DRIVER (2048 \
>>> - + sizeof (struct rte_mbuf) \
>>> - + RTE_PKTMBUF_HEADROOM)
>>> -#define MBUF_SIZE(mtu) MAX(MBUF_SIZE_MTU(mtu), MBUF_SIZE_DRIVER)
>>> +#define MTU_TO_FRAME_LEN(mtu) ((mtu) + ETHER_HDR_LEN + ETHER_CRC_LEN)
>>> +#define FRAME_LEN_TO_MTU(frame_len) ((frame_len)- ETHER_HDR_LEN -
>>> ETHER_CRC_LEN)
>>> +#define MBUF_SEGMENT_SIZE(mtu) ( MTU_TO_FRAME_LEN(mtu) \
>>> + + sizeof(struct dp_packet) \
>>> + + RTE_PKTMBUF_HEADROOM)
>>> +
>>> +/* This value should be specified as a multiple of the DPDK NIC driver's
>>> + * 'min_rx_bufsize' attribute (currently 1024B for 'igb_uio').
>>> + */
>>> +#define NETDEV_DPDK_MAX_FRAME_LEN 13312
>>>
>>> /* Max and min number of packets in the mempool. OVS tries to allocate a
>>> * mempool with MAX_NB_MBUF: if this fails (because the system doesn't have
>>> @@ -86,6 +91,8 @@ static struct vlog_rate_limit rl =
>>> VLOG_RATE_LIMIT_INIT(5, 20);
>>> #define MIN_NB_MBUF (4096 * 4)
>>> #define MP_CACHE_SZ RTE_MEMPOOL_CACHE_MAX_SIZE
>>>
>>> +#define DPDK_VLAN_TAG_LEN 4
>>> +
>>> /* MAX_NB_MBUF can be divided by 2 many times, until MIN_NB_MBUF */
>>> BUILD_ASSERT_DECL(MAX_NB_MBUF % ROUND_DOWN_POW2(MAX_NB_MBUF/MIN_NB_MBUF)
>>> == 0);
>>>
>>> @@ -114,7 +121,6 @@ static const struct rte_eth_conf port_conf = {
>>> .header_split = 0, /* Header Split disabled */
>>> .hw_ip_checksum = 0, /* IP checksum offload disabled */
>>> .hw_vlan_filter = 0, /* VLAN filtering disabled */
>>> - .jumbo_frame = 0, /* Jumbo Frame Support disabled */
>>> .hw_strip_crc = 0,
>>> },
>>> .rx_adv_conf = {
>>> @@ -254,6 +260,39 @@ is_dpdk_class(const struct netdev_class *class)
>>> return class->construct == netdev_dpdk_construct;
>>> }
>>>
>>> +/* DPDK NIC drivers allocate RX buffers at a particular granularity
>>> + * (specified by rte_eth_dev_info.min_rx_bufsize - currently 1K for
>>> igb_uio).
>>> + * If 'frame_len' is not a multiple of this value, insufficient buffers are
>>> + * allocated to accomodate the packet in its entirety. Furthermore, the
>>> igb_uio
>>> + * driver needs to ensure that there is also sufficient space in the Rx
>>> buffer
>>> + * to accommodate two VLAN tags (for QinQ frames). If the RX buffer is too
>>> + * small, then the driver enables scatter RX behaviour, which reduces
>>> + * performance. To prevent this, use a buffer size that is closest to
>>> + * 'frame_len', but which satisfies the aforementioned criteria.
>>> + */
>>> +static uint32_t
>>> +dpdk_buf_size(struct netdev_dpdk *netdev, int frame_len)
>>> +{
>>> + struct rte_eth_dev_info info;
>>> + uint32_t buf_size;
>>> + uint32_t len = frame_len + (2 * DPDK_VLAN_TAG_LEN);
>>> +
>>> + if(netdev->type == DPDK_DEV_ETH) {
>>> + rte_eth_dev_info_get(netdev->port_id, &info);
>>> + buf_size = (info.min_rx_bufsize == 0) ?
>>> + NETDEV_DPDK_DEFAULT_RX_BUFSIZE :
>>> + info.min_rx_bufsize;
>>
>>Why not use the rte_eth_dev_get_mtu call to get the port configured mtu?
>
>I'm not sure if I follow - the MTU isn't the issue here, but rather the
>buffer size used
>when creating the rte_mempool, which must be a multiple of the driver's
>min_rx_bufsize.
>
>>
>>> + } else {
>>> + buf_size = NETDEV_DPDK_DEFAULT_RX_BUFSIZE;
>>> + }
>>> +
>>> + if(len % buf_size) {
>>> + len = buf_size * ((len/buf_size) + 1);
>>> + }
>>> +
>>> + return len;
>>> +}
>>> +
>>> /* XXX: use dpdk malloc for entire OVS. in fact huge page should be used
>>> * for all other segments data, bss and text. */
>>>
>>> @@ -280,31 +319,70 @@ free_dpdk_buf(struct dp_packet *p)
>>> }
>>>
>>> static void
>>> -__rte_pktmbuf_init(struct rte_mempool *mp,
>>> - void *opaque_arg OVS_UNUSED,
>>> - void *_m,
>>> - unsigned i OVS_UNUSED)
>>> +ovs_rte_pktmbuf_pool_init(struct rte_mempool *mp, void *opaque_arg)
>>> {
>>> - struct rte_mbuf *m = _m;
>>> - uint32_t buf_len = mp->elt_size - sizeof(struct dp_packet);
>>> + struct rte_pktmbuf_pool_private *user_mbp_priv, *mbp_priv;
>>> + struct rte_pktmbuf_pool_private default_mbp_priv;
>>> + uint16_t roomsz;
>>>
>>> RTE_MBUF_ASSERT(mp->elt_size >= sizeof(struct dp_packet));
>>>
>>> - memset(m, 0, mp->elt_size);
>>> + /* if no structure is provided, assume no mbuf private area */
>>> +
>>> + user_mbp_priv = opaque_arg;
>>> + if (user_mbp_priv == NULL) {
>>> + default_mbp_priv.mbuf_priv_size = 0;
>>> + if (mp->elt_size > sizeof(struct dp_packet)) {
>>> + roomsz = mp->elt_size - sizeof(struct dp_packet);
>>> + } else {
>>> + roomsz = 0;
>>> + }
>>> + default_mbp_priv.mbuf_data_room_size = roomsz;
>>> + user_mbp_priv = &default_mbp_priv;
>>> + }
>>> +
>>> + RTE_MBUF_ASSERT(mp->elt_size >= sizeof(struct dp_packet) +
>>> + user_mbp_priv->mbuf_data_room_size +
>>> + user_mbp_priv->mbuf_priv_size);
>>> +
>>> + mbp_priv = rte_mempool_get_priv(mp);
>>> + memcpy(mbp_priv, user_mbp_priv, sizeof(*mbp_priv));
>>> +}
>>> +
>>> +/* Initialise some fields in the mbuf structure that are not modified by
>>> the
>>> + * user once created (origin pool, buffer start address, etc.*/
>>> +static void
>>> +__ovs_rte_pktmbuf_init(struct rte_mempool *mp,
>>> + void *opaque_arg OVS_UNUSED,
>>> + void *_m,
>>> + unsigned i OVS_UNUSED)
>>> +{
>>> + struct rte_mbuf *m = _m;
>>> + uint32_t buf_size, buf_len, priv_size;
>>> +
>>> + priv_size = rte_pktmbuf_priv_size(mp);
>>> + buf_size = sizeof(struct dp_packet) + priv_size;
>>> + buf_len = rte_pktmbuf_data_room_size(mp);
>>>
>>> - /* start of buffer is just after mbuf structure */
>>> - m->buf_addr = (char *)m + sizeof(struct dp_packet);
>>> - m->buf_physaddr = rte_mempool_virt2phy(mp, m) +
>>> - sizeof(struct dp_packet);
>>> - m->buf_len = (uint16_t)buf_len;
>>> + RTE_MBUF_ASSERT(RTE_ALIGN(priv_size, RTE_MBUF_PRIV_ALIGN) == priv_size);
>>> + RTE_MBUF_ASSERT(mp->elt_size >= buf_size);
>>> + RTE_MBUF_ASSERT(buf_len <= UINT16_MAX);
>>>
>>> - /* keep some headroom between start of buffer and data */
>>> - m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, m->buf_len);
>>> + memset(m, 0, mp->elt_size);
>>>
>>> - /* init some constant fields */
>>> - m->pool = mp;
>>> - m->nb_segs = 1;
>>> - m->port = 0xff;
>>> + /* start of buffer is after dp_packet structure and priv data */
>>> + m->priv_size = priv_size;
>>> + m->buf_addr = (char *)m + buf_size;
>>> + m->buf_physaddr = rte_mempool_virt2phy(mp, m) + buf_size;
>>> + m->buf_len = (uint16_t)buf_len;
>>> +
>>> + /* keep some headroom between start of buffer and data */
>>> + m->data_off = RTE_MIN(RTE_PKTMBUF_HEADROOM, (uint16_t)m->buf_len);
>>> +
>>> + /* init some constant fields */
>>> + m->pool = mp;
>>> + m->nb_segs = 1;
>>> + m->port = 0xff;
>>
>>Please don't mix tabs and spaces in the file.
>
>Apologies - this was a copy/paste from a DPDK file, which uses tabs.
>
>>
>>> }
>>>
>>> static void
>>> @@ -315,7 +393,7 @@ ovs_rte_pktmbuf_init(struct rte_mempool *mp,
>>> {
>>> struct rte_mbuf *m = _m;
>>>
>>> - __rte_pktmbuf_init(mp, opaque_arg, _m, i);
>>> + __ovs_rte_pktmbuf_init(mp, opaque_arg, m, i);
>>>
>>> dp_packet_init_dpdk((struct dp_packet *) m, m->buf_len);
>>> }
>>> @@ -326,6 +404,7 @@ dpdk_mp_get(int socket_id, int mtu)
>>> OVS_REQUIRES(dpdk_mutex)
>>> struct dpdk_mp *dmp = NULL;
>>> char mp_name[RTE_MEMPOOL_NAMESIZE];
>>> unsigned mp_size;
>>> + struct rte_pktmbuf_pool_private mbp_priv;
>>>
>>> LIST_FOR_EACH (dmp, list_node, &dpdk_mp_list) {
>>> if (dmp->socket_id == socket_id && dmp->mtu == mtu) {
>>> @@ -338,6 +417,8 @@ dpdk_mp_get(int socket_id, int mtu)
>>> OVS_REQUIRES(dpdk_mutex)
>>> dmp->socket_id = socket_id;
>>> dmp->mtu = mtu;
>>> dmp->refcount = 1;
>>> + mbp_priv.mbuf_data_room_size = MTU_TO_FRAME_LEN(mtu) +
>>> RTE_PKTMBUF_HEADROOM;
>>> + mbp_priv.mbuf_priv_size = 0;
>>>
>>> mp_size = MAX_NB_MBUF;
>>> do {
>>> @@ -346,10 +427,10 @@ dpdk_mp_get(int socket_id, int mtu)
>>> OVS_REQUIRES(dpdk_mutex)
>>> return NULL;
>>> }
>>>
>>> - dmp->mp = rte_mempool_create(mp_name, mp_size, MBUF_SIZE(mtu),
>>> + dmp->mp = rte_mempool_create(mp_name, mp_size,
>>> MBUF_SEGMENT_SIZE(mtu),
>>> MP_CACHE_SZ,
>>> sizeof(struct
>>> rte_pktmbuf_pool_private),
>>> - rte_pktmbuf_pool_init, NULL,
>>> + ovs_rte_pktmbuf_pool_init, &mbp_priv,
>>> ovs_rte_pktmbuf_init, NULL,
>>> socket_id, 0);
>>> } while (!dmp->mp && rte_errno == ENOMEM && (mp_size /= 2) >=
>>> MIN_NB_MBUF);
>>> @@ -433,6 +514,7 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int
>>> n_rxq, int
>n_txq)
>>> {
>>> int diag = 0;
>>> int i;
>>> + struct rte_eth_conf conf = port_conf;
>>>
>>> /* A device may report more queues than it makes available (this has
>>> * been observed for Intel xl710, which reserves some of them for
>>> @@ -444,7 +526,12 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int
>>> n_rxq, int
>>n_txq)
>>> VLOG_INFO("Retrying setup with (rxq:%d txq:%d)", n_rxq, n_txq);
>>> }
>>>
>>> - diag = rte_eth_dev_configure(dev->port_id, n_rxq, n_txq,
>>> &port_conf);
>>> + if(OVS_UNLIKELY(dev->mtu > ETHER_MTU)) {
>>> + conf.rxmode.jumbo_frame = NETDEV_DPDK_JUMBO_FRAME_ENABLED;
>>> + conf.rxmode.max_rx_pkt_len = MTU_TO_FRAME_LEN(dev->mtu);
>>> + }
>>> +
>>> + diag = rte_eth_dev_configure(dev->port_id, n_rxq, n_txq, &conf);
>>> if (diag) {
>>> break;
>>> }
>>> @@ -586,6 +673,7 @@ netdev_dpdk_init(struct netdev *netdev_, unsigned int
>>> port_no,
>>> struct netdev_dpdk *netdev = netdev_dpdk_cast(netdev_);
>>> int sid;
>>> int err = 0;
>>> + uint32_t buf_size;
>>>
>>> ovs_mutex_init(&netdev->mutex);
>>> ovs_mutex_lock(&netdev->mutex);
>>> @@ -605,10 +693,16 @@ netdev_dpdk_init(struct netdev *netdev_, unsigned int
>>> port_no,
>>> netdev->port_id = port_no;
>>> netdev->type = type;
>>> netdev->flags = 0;
>>> +
>>> + /* Initialize port's MTU and frame len to the default Ethernet values.
>>> + * Larger, user-specified (jumbo) frame buffers are accommodated in
>>> + * netdev_dpdk_set_config.
>>> + */
>>> + netdev->max_packet_len = ETHER_MAX_LEN;
>>> netdev->mtu = ETHER_MTU;
>>> - netdev->max_packet_len = MTU_TO_MAX_LEN(netdev->mtu);
>>>
>>> - netdev->dpdk_mp = dpdk_mp_get(netdev->socket_id, netdev->mtu);
>>> + buf_size = dpdk_buf_size(netdev, ETHER_MAX_LEN);
>>> + netdev->dpdk_mp = dpdk_mp_get(netdev->socket_id,
>>> FRAME_LEN_TO_MTU(buf_size));
>>> if (!netdev->dpdk_mp) {
>>> err = ENOMEM;
>>> goto unlock;
>>> @@ -651,6 +745,24 @@ dpdk_dev_parse_name(const char dev_name[], const char
>>> prefix[],
>>> return 0;
>>> }
>>>
>>> +static void
>>> +dpdk_dev_parse_mtu(const struct smap *args, int *mtu)
>>> +{
>>> + const char *mtu_str = smap_get(args, "dpdk-mtu");
>>> + int local_mtu;
>>> +
>>> + if(mtu_str) {
>>> + local_mtu = atoi(mtu_str);
>>
>>Please use strtol or strtoul here, and detect errors in the string by
>>checking endptr. That way, we can be sure that random garbage on the
>>stack won't accidentally become the mtu.
>
>Will do, thanks.
>
>>
>>> + }
>>> + if(!mtu_str || local_mtu < ETHER_MTU ||
>>> + local_mtu >
>>> FRAME_LEN_TO_MTU(NETDEV_DPDK_MAX_FRAME_LEN)) {
>>> + local_mtu = ETHER_MTU;
>>> + VLOG_WARN("Invalid or missing dpdk-mtu parameter - defaulting to
>>> %d.\n",
>>> + local_mtu);
>>> + }
>>> + *mtu = local_mtu;
>>> +}
>>> +
>>> static int
>>> vhost_construct_helper(struct netdev *netdev_) OVS_REQUIRES(dpdk_mutex)
>>> {
>>> @@ -777,11 +889,77 @@ netdev_dpdk_get_config(const struct netdev *netdev_,
>>> struct smap
>>*args)
>>> smap_add_format(args, "configured_rx_queues", "%d", netdev_->n_rxq);
>>> smap_add_format(args, "requested_tx_queues", "%d", netdev_->n_txq);
>>> smap_add_format(args, "configured_tx_queues", "%d", dev->real_n_txq);
>>> + smap_add_format(args, "mtu", "%d", dev->mtu);
>>> ovs_mutex_unlock(&dev->mutex);
>>>
>>> return 0;
>>> }
>>>
>>> +/* Set the mtu of DPDK_DEV_ETH ports */
>>> +static int
>>> +netdev_dpdk_set_mtu(const struct netdev *netdev, int mtu)
>>> +{
>>> + struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>>> + int old_mtu, err;
>>> + uint32_t buf_size;
>>> + int dpdk_mtu;
>>> + struct dpdk_mp *old_mp;
>>> + struct dpdk_mp *mp;
>>> +
>>> + ovs_mutex_lock(&dpdk_mutex);
>>> + ovs_mutex_lock(&dev->mutex);
>>> + if (dev->mtu == mtu) {
>>> + err = 0;
>>> + goto out;
>>> + }
>>> +
>>> + buf_size = dpdk_buf_size(dev, MTU_TO_FRAME_LEN(mtu));
>>> + dpdk_mtu = FRAME_LEN_TO_MTU(buf_size);
>>> +
>>> + mp = dpdk_mp_get(dev->socket_id, dpdk_mtu);
>>> + if (!mp) {
>>> + err = ENOMEM;
>>> + goto out;
>>> + }
>>> +
>>> + rte_eth_dev_stop(dev->port_id);
>>> +
>>> + old_mtu = dev->mtu;
>>> + old_mp = dev->dpdk_mp;
>>> + dev->dpdk_mp = mp;
>>> + dev->mtu = mtu;
>>> + dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
>>> +
>>> + err = dpdk_eth_dev_init(dev);
>>
>>Why call the dpdk_eth_dev_init here? Since you are directly calling
>>rte_eth_dev_X functions here - wouldn't it make sense to use the
>>rte_eth_dev_start() instead?
>
>This is legacy code, but I can refactor if needs be.
>
>>
>>> + if (err) {
>>> + VLOG_WARN("Unable to set MTU '%d' for '%s'; reverting to last
>>> known "
>>> + "good value '%d'\n", mtu, dev->up.name, old_mtu);
>>> + dpdk_mp_put(mp);
>>> + dev->mtu = old_mtu;
>>> + dev->dpdk_mp = old_mp;
>>> + dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
>>> + err = dpdk_eth_dev_init(dev);
>>
>>What happens if this returns a failure? By using dpdk_eth_dev_init, you
>>will cause a queue reconfiguration action, which is not needed, and can
>>error.
>>
>
>As above.
>
>>If you are intending to set MTU, I would have expected calls to
>>rte_eth_dev_set_mtu. However, I don't see any. Is there a reason? I
>>recognize that much of this is legacy, but since you are touching it :)
>
>I actually had a number of issues with rte_eth_dev_set_mtu early on in the
>patch; I can take
>a second look now that the code is more stable though.
I remembered why I didn't use this.
If you look at the IXGBE driver's mtu_set function, it refuses frame lengths
which are larger than the eth_dev's min_rx_buf_size (- RTE_PKTMBUF_HEADROOM).
This might be avoided by configuring the device for scatter RX behavior, but
this incurs a performance impact.
<snippet>
ixgbe_dev_mtu_set(...) {
...
/* refuse mtu that requires the support of scattered packets when this
* feature has not been enabled before. */
if (!dev->data->scattered_rx &&
(frame_size + 2 * IXGBE_VLAN_TAG_SIZE >
dev->data->min_rx_buf_size - RTE_PKTMBUF_HEADROOM))
return -EINVAL;
...
}
</snippet>
>
>>
>>> + goto out;
>>> + }
>>> +
>>> + dpdk_mp_put(old_mp);
>>> + netdev_change_seq_changed(netdev);
>>> +out:
>>> + ovs_mutex_unlock(&dev->mutex);
>>> + ovs_mutex_unlock(&dpdk_mutex);
>>> + return err;
>>> +}
>>> +
>>> +static int
>>> +netdev_dpdk_set_config(struct netdev *netdev_, const struct smap *args)
>>> +{
>>> + int mtu;
>>> +
>>> + dpdk_dev_parse_mtu(args, &mtu);
>>> +
>>> + return netdev_dpdk_set_mtu(netdev_, mtu);
>>> +}
>>> +
>>> static int
>>> netdev_dpdk_get_numa_id(const struct netdev *netdev_)
>>> {
>>> @@ -1358,54 +1536,6 @@ netdev_dpdk_get_mtu(const struct netdev *netdev, int
>>> *mtup)
>>>
>>> return 0;
>>> }
>>> -
>>> -static int
>>> -netdev_dpdk_set_mtu(const struct netdev *netdev, int mtu)
>>> -{
>>> - struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>>> - int old_mtu, err;
>>> - struct dpdk_mp *old_mp;
>>> - struct dpdk_mp *mp;
>>> -
>>> - ovs_mutex_lock(&dpdk_mutex);
>>> - ovs_mutex_lock(&dev->mutex);
>>> - if (dev->mtu == mtu) {
>>> - err = 0;
>>> - goto out;
>>> - }
>>> -
>>> - mp = dpdk_mp_get(dev->socket_id, dev->mtu);
>>> - if (!mp) {
>>> - err = ENOMEM;
>>> - goto out;
>>> - }
>>> -
>>> - rte_eth_dev_stop(dev->port_id);
>>> -
>>> - old_mtu = dev->mtu;
>>> - old_mp = dev->dpdk_mp;
>>> - dev->dpdk_mp = mp;
>>> - dev->mtu = mtu;
>>> - dev->max_packet_len = MTU_TO_MAX_LEN(dev->mtu);
>>> -
>>> - err = dpdk_eth_dev_init(dev);
>>> - if (err) {
>>> - dpdk_mp_put(mp);
>>> - dev->mtu = old_mtu;
>>> - dev->dpdk_mp = old_mp;
>>> - dev->max_packet_len = MTU_TO_MAX_LEN(dev->mtu);
>>> - dpdk_eth_dev_init(dev);
>>> - goto out;
>>> - }
>>> -
>>> - dpdk_mp_put(old_mp);
>>> - netdev_change_seq_changed(netdev);
>>> -out:
>>> - ovs_mutex_unlock(&dev->mutex);
>>> - ovs_mutex_unlock(&dpdk_mutex);
>>> - return err;
>>> -}
>>> -
>>> static int
>>> netdev_dpdk_get_carrier(const struct netdev *netdev_, bool *carrier);
>>>
>>> @@ -1682,7 +1812,7 @@ netdev_dpdk_get_status(const struct netdev *netdev_,
>>> struct smap
>>*args)
>>> smap_add_format(args, "numa_id", "%d",
>>> rte_eth_dev_socket_id(dev->port_id));
>>> smap_add_format(args, "driver_name", "%s", dev_info.driver_name);
>>> smap_add_format(args, "min_rx_bufsize", "%u", dev_info.min_rx_bufsize);
>>> - smap_add_format(args, "max_rx_pktlen", "%u", dev_info.max_rx_pktlen);
>>> + smap_add_format(args, "max_rx_pktlen", "%u", dev->max_packet_len);
>>> smap_add_format(args, "max_rx_queues", "%u", dev_info.max_rx_queues);
>>> smap_add_format(args, "max_tx_queues", "%u", dev_info.max_tx_queues);
>>> smap_add_format(args, "max_mac_addrs", "%u", dev_info.max_mac_addrs);
>>> @@ -1904,6 +2034,51 @@ dpdk_vhost_user_class_init(void)
>>> return 0;
>>> }
>>>
>>> +/* Set the mtu of DPDK_DEV_VHOST ports */
>>> +static int
>>> +netdev_dpdk_vhost_set_mtu(const struct netdev *netdev, int mtu)
>>> +{
>>> + struct netdev_dpdk *dev = netdev_dpdk_cast(netdev);
>>> + int err = 0;
>>> + struct dpdk_mp *old_mp;
>>> + struct dpdk_mp *mp;
>>> +
>>> + ovs_mutex_lock(&dpdk_mutex);
>>> + ovs_mutex_lock(&dev->mutex);
>>> + if (dev->mtu == mtu) {
>>> + err = 0;
>>> + goto out;
>>> + }
>>> +
>>> + mp = dpdk_mp_get(dev->socket_id, mtu);
>>> + if (!mp) {
>>> + err = ENOMEM;
>>> + goto out;
>>> + }
>>> +
>>> + old_mp = dev->dpdk_mp;
>>> + dev->dpdk_mp = mp;
>>> + dev->mtu = mtu;
>>> + dev->max_packet_len = MTU_TO_FRAME_LEN(dev->mtu);
>>> +
>>> + dpdk_mp_put(old_mp);
>>> + netdev_change_seq_changed(netdev);
>>> +out:
>>> + ovs_mutex_unlock(&dev->mutex);
>>> + ovs_mutex_unlock(&dpdk_mutex);
>>> + return err;
>>> +}
>>> +
>>> +static int
>>> +netdev_dpdk_vhost_set_config(struct netdev *netdev_, const struct smap
>>> *args)
>>> +{
>>> + int mtu;
>>> +
>>> + dpdk_dev_parse_mtu(args, &mtu);
>>> +
>>> + return netdev_dpdk_vhost_set_mtu(netdev_, mtu);
>>> +}
>>> +
>>> static void
>>> dpdk_common_init(void)
>>> {
>>> @@ -2040,8 +2215,9 @@ unlock_dpdk:
>>> return err;
>>> }
>>>
>>> -#define NETDEV_DPDK_CLASS(NAME, INIT, CONSTRUCT, DESTRUCT, MULTIQ, SEND, \
>>> - GET_CARRIER, GET_STATS, GET_FEATURES, GET_STATUS, RXQ_RECV) \
>>> +#define NETDEV_DPDK_CLASS(NAME, INIT, CONSTRUCT, DESTRUCT, SET_CONFIG, \
>>> + MULTIQ, SEND, SET_MTU, GET_CARRIER, GET_STATS, GET_FEATURES, \
>>> + GET_STATUS, RXQ_RECV) \
>>> { \
>>> NAME, \
>>> INIT, /* init */ \
>>> @@ -2053,7 +2229,7 @@ unlock_dpdk:
>>> DESTRUCT, \
>>> netdev_dpdk_dealloc, \
>>> netdev_dpdk_get_config, \
>>> - NULL, /* netdev_dpdk_set_config */ \
>>> + SET_CONFIG, \
>>> NULL, /* get_tunnel_config */ \
>>> NULL, /* build header */ \
>>> NULL, /* push header */ \
>>> @@ -2067,7 +2243,7 @@ unlock_dpdk:
>>> netdev_dpdk_set_etheraddr, \
>>> netdev_dpdk_get_etheraddr, \
>>> netdev_dpdk_get_mtu, \
>>> - netdev_dpdk_set_mtu, \
>>> + SET_MTU, \
>>> netdev_dpdk_get_ifindex, \
>>> GET_CARRIER, \
>>> netdev_dpdk_get_carrier_resets, \
>>> @@ -2213,8 +2389,10 @@ static const struct netdev_class dpdk_class =
>>> NULL,
>>> netdev_dpdk_construct,
>>> netdev_dpdk_destruct,
>>> + netdev_dpdk_set_config,
>>> netdev_dpdk_set_multiq,
>>> netdev_dpdk_eth_send,
>>> + netdev_dpdk_set_mtu,
>>> netdev_dpdk_get_carrier,
>>> netdev_dpdk_get_stats,
>>> netdev_dpdk_get_features,
>>> @@ -2227,8 +2405,10 @@ static const struct netdev_class dpdk_ring_class =
>>> NULL,
>>> netdev_dpdk_ring_construct,
>>> netdev_dpdk_destruct,
>>> + netdev_dpdk_set_config,
>>> netdev_dpdk_set_multiq,
>>> netdev_dpdk_ring_send,
>>> + netdev_dpdk_set_mtu,
>>> netdev_dpdk_get_carrier,
>>> netdev_dpdk_get_stats,
>>> netdev_dpdk_get_features,
>>> @@ -2241,8 +2421,10 @@ static const struct netdev_class OVS_UNUSED
>>> dpdk_vhost_cuse_class =
>>> dpdk_vhost_cuse_class_init,
>>> netdev_dpdk_vhost_cuse_construct,
>>> netdev_dpdk_vhost_destruct,
>>> + NULL,
>>> netdev_dpdk_vhost_set_multiq,
>>> netdev_dpdk_vhost_send,
>>> + NULL,
>>> netdev_dpdk_vhost_get_carrier,
>>> netdev_dpdk_vhost_get_stats,
>>> NULL,
>>> @@ -2255,8 +2437,10 @@ static const struct netdev_class OVS_UNUSED
>>> dpdk_vhost_user_class =
>>> dpdk_vhost_user_class_init,
>>> netdev_dpdk_vhost_user_construct,
>>> netdev_dpdk_vhost_destruct,
>>> + netdev_dpdk_vhost_set_config,
>>> netdev_dpdk_vhost_set_multiq,
>>> netdev_dpdk_vhost_send,
>>> + netdev_dpdk_vhost_set_mtu,
>>> netdev_dpdk_vhost_get_carrier,
>>> netdev_dpdk_vhost_get_stats,
>>> NULL,
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