On 2/5/24 13:02, Adrian Moreno wrote:
> netdev_linux_get_speed needs to lock netdev_linux->mutex, and so do the
> internal tc operations. Therefore, the former cannot be called from the
> latter.
>
> Create a lock-free version of netdev_linux_get_speed() and call it from
> tc operations.
>
> Also expand the unit test to cover queues where ceil is determined by
> the maximum link speed.
>
> Fixes: b8f8fad86435 ("netdev-linux: Use speed as max rate in tc classes.")
> Reported-by: Daryl Wang <[email protected]>
> Suggested-by: Ilya Maximets <[email protected]>
> Signed-off-by: Adrian Moreno <[email protected]>
> ---
> lib/netdev-linux.c | 32 +++++++++++++++----------
> tests/system-traffic.at | 53 ++++++++++++++++++++++++++++-------------
> 2 files changed, 56 insertions(+), 29 deletions(-)
>
> diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
> index 1b2e5b6c2..00df7f634 100644
> --- a/lib/netdev-linux.c
> +++ b/lib/netdev-linux.c
> @@ -2721,16 +2721,11 @@ exit:
> }
>
> static int
> -netdev_linux_get_speed(const struct netdev *netdev_, uint32_t *current,
> - uint32_t *max)
> +netdev_linux_get_speed_locked(struct netdev_linux *netdev,
> + uint32_t *current, uint32_t *max)
> {
> - struct netdev_linux *netdev = netdev_linux_cast(netdev_);
> - int error;
> -
> - ovs_mutex_lock(&netdev->mutex);
> if (netdev_linux_netnsid_is_remote(netdev)) {
> - error = EOPNOTSUPP;
> - goto exit;
> + return EOPNOTSUPP;
> }
>
> netdev_linux_read_features(netdev);
> @@ -2740,9 +2735,18 @@ netdev_linux_get_speed(const struct netdev *netdev_,
> uint32_t *current,
> *max = MIN(UINT32_MAX,
> netdev_features_to_bps(netdev->supported, 0) /
> 1000000ULL);
> }
> - error = netdev->get_features_error;
> + return netdev->get_features_error;
> +}
>
> -exit:
> +static int
> +netdev_linux_get_speed(const struct netdev *netdev_, uint32_t *current,
> + uint32_t *max)
> +{
> + struct netdev_linux *netdev = netdev_linux_cast(netdev_);
> + int error;
> +
> + ovs_mutex_lock(&netdev->mutex);
> + error = netdev_linux_get_speed_locked(netdev, current, max);
> ovs_mutex_unlock(&netdev->mutex);
> return error;
> }
> @@ -4954,8 +4958,10 @@ htb_parse_qdisc_details__(struct netdev *netdev, const
> struct smap *details,
> hc->max_rate = smap_get_ullong(details, "max-rate", 0) / 8;
> if (!hc->max_rate) {
> uint32_t current_speed;
> + uint32_t max_speed OVS_UNUSED;
>
> - netdev_get_speed(netdev, ¤t_speed, NULL);
> + netdev_linux_get_speed_locked(netdev_linux_cast(netdev),
> + ¤t_speed, &max_speed);
> hc->max_rate = current_speed ? current_speed / 8 * 1000000ULL
> : NETDEV_DEFAULT_BPS / 8;
> }
> @@ -5424,8 +5430,10 @@ hfsc_parse_qdisc_details__(struct netdev *netdev,
> const struct smap *details,
> uint32_t max_rate = smap_get_ullong(details, "max-rate", 0) / 8;
> if (!max_rate) {
> uint32_t current_speed;
> + uint32_t max_speed OVS_UNUSED;
>
> - netdev_get_speed(netdev, ¤t_speed, NULL);
Oh, wow. This thing not only deadlocks, it also crashes on the NULL, right?
I see we call netdev_get_speed(..., NULL) a lot in other palces. Should
those be fixed as well? Maybe the function should be fixed to allow NULL
instead?
> + netdev_linux_get_speed_locked(netdev_linux_cast(netdev),
> + ¤t_speed, &max_speed);
> max_rate = current_speed ? current_speed / 8 * 1000000ULL
> : NETDEV_DEFAULT_BPS / 8;
> }
> diff --git a/tests/system-traffic.at b/tests/system-traffic.at
> index f363a778c..d90717d1b 100644
> --- a/tests/system-traffic.at
> +++ b/tests/system-traffic.at
> @@ -2458,34 +2458,53 @@ AT_BANNER([QoS])
>
> AT_SETUP([QoS - basic configuration])
> OVS_CHECK_TC_QDISC()
> +AT_SKIP_IF([test $HAVE_ETHTOOL = "no"])
> OVS_TRAFFIC_VSWITCHD_START()
>
> -ADD_NAMESPACES(at_ns0, at_ns1)
> +AT_CHECK([ip tuntap add tap0 mode tap])
> +on_exit 'ip link del tap0'
> +AT_CHECK([ip tuntap add tap1 mode tap])
> +on_exit 'ip link del tap1'
tapN is a fairly common name. Even though we run in a separate
namespace in GHA, it may not be always the case. Maybe rename
the ports into ovs-tapN ?
>
> -ADD_VETH(p0, at_ns0, br0, "10.1.1.1/24")
> -ADD_VETH(p1, at_ns1, br0, "10.1.1.2/24")
> +dnl Set maximum link speed to 5Gb.
> +AT_CHECK([ethtool -s tap0 speed 5000 duplex full])
> +AT_CHECK([ip link set dev tap0 up])
> +AT_CHECK([ethtool -s tap1 speed 5000 duplex full])
> +AT_CHECK([ip link set dev tap1 up])
>
> -dnl Adding a custom qdisc to ovs-p1, ovs-p0 will have the default qdisc.
> -AT_CHECK([tc qdisc add dev ovs-p1 root noqueue])
> -AT_CHECK([tc qdisc show dev ovs-p1 | grep -q noqueue])
> +AT_CHECK([ovs-vsctl add-port br0 tap0 -- set int tap0 type=tap])
> +AT_CHECK([ovs-vsctl add-port br0 tap1 -- set int tap1 type=tap])
>
> -dnl Configure the same QoS for both ports.
> -AT_CHECK([ovs-vsctl set port ovs-p0 qos=@qos -- set port ovs-p1 qos=@qos dnl
> - -- --id=@qos create qos dnl
> - type=linux-htb other-config:max-rate=3000000 queues:0=@queue
> dnl
> - -- --id=@queue create queue dnl
> +dnl Adding a custom qdisc to tap1, tap0 will have the default qdisc.
> +AT_CHECK([tc qdisc add dev tap1 root noqueue])
> +AT_CHECK([tc qdisc show dev tap1 | grep -q noqueue])
> +
> +dnl Configure the same QoS for both ports:
> +dnl queue0 uses fixed max-rate.
> +dnl queue1 relies on underlying link speed.
> +AT_CHECK([ovs-vsctl dnl
> + -- --id=@queue0 create queue dnl
> other_config:min-rate=2000000 other_config:max-rate=3000000
> dnl
> - other_config:burst=3000000],
> + other_config:burst=3000000 dnl
> + -- --id=@queue1 create queue dnl
> + other_config:min-rate=4000000 other_config:burst=4000000 dnl
> + -- --id=@qos create qos dnl
> + type=linux-htb queues:0=@queue0 dnl
> + queues:1=@queue1 -- dnl
> + -- set port tap0 qos=@qos -- set port tap1 qos=@qos],
> [ignore], [ignore])
>
> dnl Wait for qdiscs to be applied.
> -OVS_WAIT_UNTIL([tc qdisc show dev ovs-p0 | grep -q htb])
> -OVS_WAIT_UNTIL([tc qdisc show dev ovs-p1 | grep -q htb])
> +OVS_WAIT_UNTIL([tc qdisc show dev tap0 | grep -q htb])
> +OVS_WAIT_UNTIL([tc qdisc show dev tap1 | grep -q htb])
>
> dnl Check the configuration.
> -m4_define([HTB_CONF], [rate 2Mbit ceil 3Mbit burst 375000b cburst 375000b])
> -AT_CHECK([tc class show dev ovs-p0 | grep -q 'class htb .* HTB_CONF'])
> -AT_CHECK([tc class show dev ovs-p1 | grep -q 'class htb .* HTB_CONF'])
> +m4_define([HTB_CONF0], [rate 2Mbit ceil 3Mbit burst 375000b cburst 375000b])
> +m4_define([HTB_CONF1], [rate 4Mbit ceil 5Gbit burst 500000b cburst 500000b])
> +AT_CHECK([tc class show dev tap0 | grep -q 'class htb .* HTB_CONF0'])
> +AT_CHECK([tc class show dev tap0 | grep -q 'class htb .* HTB_CONF1'])
> +AT_CHECK([tc class show dev tap1 | grep -q 'class htb .* HTB_CONF0'])
> +AT_CHECK([tc class show dev tap1 | grep -q 'class htb .* HTB_CONF1'])
>
> OVS_TRAFFIC_VSWITCHD_STOP
> AT_CLEANUP
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