[ovs-dev] [PATCH v3 1/5] netdev-dpdk: fix mempool management with vhu client.
Loftus, Ciara
ciara.loftus at intel.com
Fri Oct 6 10:39:54 UTC 2017
>
> In a PVP test where vhostuser ports are configured as
> clients, OvS crashes when QEMU is launched.
> This patch avoids to call dpdk_mp_put() - and erroneously
> release the mempool - when it already exists.
Thanks for investigating this issue and for the patch.
I think the commit message could be made more generic since the freeing of the pre-existing mempool could potentially happen for other port types and topologies, not just vhostuserclient & PVP.
>
> CC: Kevin Traynor <ktraynor at redhat.com>
> CC: Aaron Conole <aconole at redhat.com>
> Reported-by: Ciara Loftus <ciara.loftus at intel.com>
> Fixes: d555d9bded5f ("netdev-dpdk: Create separate memory pool for each
> port.")
> Signed-off-by: Antonio Fischetti <antonio.fischetti at intel.com>
> ---
> I've tested this patch by
> - changing at run-time the number of Rx queues:
> ovs-vsctl set Interface dpdk0 type=dpdk options:n_rxq=4
>
> - reducing the MTU of the dpdk ports of 1 byte to force
> the configuration of an existing mempool:
> ovs-vsctl set Interface dpdk0 mtu_request=1499
>
> To replicate the bug scenario:
>
> PVP test setup
> --------------
> CLIENT_SOCK_DIR=/tmp
> SOCK0=dpdkvhostuser0
> SOCK1=dpdkvhostuser1
>
> 1 PMD
> Add 2 dpdk ports, n_rxq=1
> Add 2 vhu ports both of type dpdkvhostuserclient and specify vhost-server-
> path
> ovs-vsctl set Interface dpdkvhostuser0 options:vhost-server-
> path="$CLIENT_SOCK_DIR/$SOCK0"
> ovs-vsctl set Interface dpdkvhostuser1 options:vhost-server-
> path="$CLIENT_SOCK_DIR/$SOCK1"
>
> Set port-based rules: dpdk0 <--> vhu0 and dpdk1 <--> vhu1
> add-flow br0 in_port=1,action=output:3
> add-flow br0 in_port=3,action=output:1
> add-flow br0 in_port=4,action=output:2
> add-flow br0 in_port=2,action=output:4
Nit - the steps to reproduce the bug are over-complicated. One only needs 1 vhostuserclient port (no dpdk ports, no flows), and just boot the VM = crash.
>
> Launch QEMU
> -----------
> As OvS vhu ports are acting as clients, we must specify 'server' in the next
> command.
> VM_IMAGE=<path/to/your/vm/image>
>
> sudo -E taskset 0x3F00 $QEMU_DIR/x86_64-softmmu/qemu-system-x86_64
> -name us-vhost-vm1 -cpu host -enable-kvm -m 4096M -object memory-
> backend-file,id=mem,size=4096M,mem-path=/dev/hugepages,share=on -
> numa node,memdev=mem -mem-prealloc -smp 4 -drive file=$VM_IMAGE -
> chardev socket,id=char0,path=$CLIENT_SOCK_DIR/$SOCK0,server -netdev
> type=vhost-user,id=mynet1,chardev=char0,vhostforce -device virtio-net-
> pci,mac=00:00:00:00:00:01,netdev=mynet1,mrg_rxbuf=off -chardev
> socket,id=char1,path=$CLIENT_SOCK_DIR/$SOCK1,server -netdev
> type=vhost-user,id=mynet2,chardev=char1,vhostforce -device virtio-net-
> pci,mac=00:00:00:00:00:02,netdev=mynet2,mrg_rxbuf=off --nographic
>
> Expected behavior
> -----------------
> With this fix OvS shouldn't crash.
> ---
> lib/netdev-dpdk.c | 27 ++++++++++++++-------------
> 1 file changed, 14 insertions(+), 13 deletions(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index c60f46f..80a6ff3 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -508,7 +508,7 @@ dpdk_mp_name(struct dpdk_mp *dmp)
> }
>
> static struct dpdk_mp *
> -dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
> +dpdk_mp_create(struct netdev_dpdk *dev, int mtu, bool *mp_exists)
> {
> struct dpdk_mp *dmp = dpdk_rte_mzalloc(sizeof *dmp);
> if (!dmp) {
> @@ -530,8 +530,6 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
> + MIN(RTE_MAX_LCORE, dev->requested_n_rxq) *
> NETDEV_MAX_BURST
> + MIN_NB_MBUF;
>
> - bool mp_exists = false;
> -
> do {
> char *mp_name = dpdk_mp_name(dmp);
Slightly unrelated to this patch but another issue with the d555d9bded5f "netdev-dpdk: Create separate memory pool for each port." commit I came across when reviewing this fix:
dpdk_mp_name doesn't reflect what socket the mempool is allocated on. So that commit also breaks the vHost User NUMA feature. Could you include a fix for that bug too in this patch / part of this patchset?
>
> @@ -559,7 +557,7 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
> /* As the mempool create returned EEXIST we can expect the
> * lookup has returned a valid pointer. If for some reason
> * that's not the case we keep track of it. */
> - mp_exists = true;
> + *mp_exists = true;
> } else {
> VLOG_ERR("Failed mempool \"%s\" create request of %u mbufs",
> mp_name, dmp->mp_size);
> @@ -573,7 +571,7 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
> rte_mempool_obj_iter(dmp->mp, ovs_rte_pktmbuf_init, NULL);
> return dmp;
> }
> - } while (!mp_exists &&
> + } while (!(*mp_exists) &&
> (rte_errno == ENOMEM && (dmp->mp_size /= 2) >=
> MIN_NB_MBUF));
>
> rte_free(dmp);
> @@ -581,12 +579,12 @@ dpdk_mp_create(struct netdev_dpdk *dev, int
> mtu)
> }
>
> static struct dpdk_mp *
> -dpdk_mp_get(struct netdev_dpdk *dev, int mtu)
> +dpdk_mp_get(struct netdev_dpdk *dev, int mtu, bool *mp_exists)
> {
> struct dpdk_mp *dmp;
>
> ovs_mutex_lock(&dpdk_mp_mutex);
> - dmp = dpdk_mp_create(dev, mtu);
> + dmp = dpdk_mp_create(dev, mtu, mp_exists);
> ovs_mutex_unlock(&dpdk_mp_mutex);
>
> return dmp;
> @@ -620,14 +618,17 @@ netdev_dpdk_mempool_configure(struct
> netdev_dpdk *dev)
> {
> uint32_t buf_size = dpdk_buf_size(dev->requested_mtu);
> struct dpdk_mp *mp;
> + bool mp_exists = false;
>
> - mp = dpdk_mp_get(dev, FRAME_LEN_TO_MTU(buf_size));
> + mp = dpdk_mp_get(dev, FRAME_LEN_TO_MTU(buf_size), &mp_exists);
> if (!mp) {
> VLOG_ERR("Failed to create memory pool for netdev "
> "%s, with MTU %d on socket %d: %s\n",
> dev->up.name, dev->requested_mtu, dev->requested_socket_id,
> rte_strerror(rte_errno));
> return rte_errno;
> + } else if (mp_exists) {
> + return EEXIST;
> } else {
> dpdk_mp_put(dev->dpdk_mp);
> dev->dpdk_mp = mp;
> @@ -3207,7 +3208,7 @@ netdev_dpdk_reconfigure(struct netdev *netdev)
> rte_eth_dev_stop(dev->port_id);
>
> err = netdev_dpdk_mempool_configure(dev);
> - if (err) {
> + if (err && err != EEXIST) {
> goto out;
> }
>
> @@ -3247,12 +3248,12 @@ dpdk_vhost_reconfigure_helper(struct
> netdev_dpdk *dev)
> netdev_dpdk_remap_txqs(dev);
>
> err = netdev_dpdk_mempool_configure(dev);
> - if (err) {
> - return err;
> - } else {
> + if (!err) {
> + /* A new mempool was created. */
> netdev_change_seq_changed(&dev->up);
> + } else if (err != EEXIST){
> + return err;
> }
> -
> if (netdev_dpdk_get_vid(dev) >= 0) {
> if (dev->vhost_reconfigured == false) {
> dev->vhost_reconfigured = true;
I've verified this patch fixes the issue with reconfigure of vHost User client ports & I no longer see a crash on VM boot.
Tested-by: Ciara Loftus <ciara.loftus at intel.com>
Thanks,
Ciara
> --
> 2.4.11
>
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