Hi Ilya:
> -----Original Message-----
> From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Ilya Maximets
> Sent: Friday, August 31, 2018 8:40 PM
> To: dev@dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo...@intel.com>; Ananyev, Konstantin
> <konstantin.anan...@intel.com>; Laurent Hardy
> <laurent.ha...@6wind.com>; Dai, Wei <wei....@intel.com>; Ilya Maximets
> <i.maxim...@samsung.com>; sta...@dpdk.org
> Subject: [dpdk-dev] [PATCH] net/ixgbe: fix busy polling while fiber link
> update
>
> If the multispeed fiber link is in DOWN state, ixgbe_setup_link could take
> around a second of busy polling. This is highly inconvenient for the case
> where
> single thread periodically checks the link statuses. For example, OVS main
> thread periodically updates the link statuses and hangs for a really long time
> busy waiting on ixgbe_setup_link() for a DOWN fiber ports. For case with 3
> down ports it hangs for a 3 seconds and unable to do anything including
> packet processing.
> Fix that by shifting that workaround to a separate thread by alarm handler
> that
> will try to set up link if it is DOWN.
Does that mean we will block the interrupt thread for 3 seconds?
Also, can we guarantee there will not be any race condition if we call
ixgbe_setup_link at another thread, the base code API is not assumed to be
thread-safe as I know.
Regards
Qi
>
> Fixes: c12d22f65b13 ("net/ixgbe: ensure link status is updated")
> CC: sta...@dpdk.org
>
> Signed-off-by: Ilya Maximets <i.maxim...@samsung.com>
> ---
> drivers/net/ixgbe/ixgbe_ethdev.c | 43 ++++++++++++++++++++++++--------
> 1 file changed, 32 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
> b/drivers/net/ixgbe/ixgbe_ethdev.c
> index 26b192737..a33b9a6e8 100644
> --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> @@ -221,6 +221,8 @@ static int ixgbe_dev_interrupt_action(struct
> rte_eth_dev *dev,
> struct rte_intr_handle *handle); static
> void
> ixgbe_dev_interrupt_handler(void *param); static void
> ixgbe_dev_interrupt_delayed_handler(void *param);
> +static void ixgbe_dev_setup_link_alarm_handler(void *param);
> +
> static int ixgbe_add_rar(struct rte_eth_dev *dev, struct ether_addr
> *mac_addr,
> uint32_t index, uint32_t pool);
> static void ixgbe_remove_rar(struct rte_eth_dev *dev, uint32_t index); @@
> -2791,6 +2793,8 @@ ixgbe_dev_stop(struct rte_eth_dev *dev)
>
> PMD_INIT_FUNC_TRACE();
>
> + rte_eal_alarm_cancel(ixgbe_dev_setup_link_alarm_handler, dev);
> +
> /* disable interrupts */
> ixgbe_disable_intr(hw);
>
> @@ -3969,6 +3973,25 @@ ixgbevf_check_link(struct ixgbe_hw *hw,
> ixgbe_link_speed *speed,
> return ret_val;
> }
>
> +static void
> +ixgbe_dev_setup_link_alarm_handler(void *param) {
> + struct rte_eth_dev *dev = (struct rte_eth_dev *)param;
> + struct ixgbe_hw *hw =
> IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> + struct ixgbe_interrupt *intr =
> + IXGBE_DEV_PRIVATE_TO_INTR(dev->data->dev_private);
> + u32 speed;
> + bool autoneg = false;
> +
> + speed = hw->phy.autoneg_advertised;
> + if (!speed)
> + ixgbe_get_link_capabilities(hw, &speed, &autoneg);
> +
> + ixgbe_setup_link(hw, speed, true);
> +
> + intr->flags &= ~IXGBE_FLAG_NEED_LINK_CONFIG; }
> +
> /* return 0 means link status changed, -1 means not changed */ int
> ixgbe_dev_link_update_share(struct rte_eth_dev *dev, @@ -3981,9 +4004,7
> @@ ixgbe_dev_link_update_share(struct rte_eth_dev *dev,
> IXGBE_DEV_PRIVATE_TO_INTR(dev->data->dev_private);
> int link_up;
> int diag;
> - u32 speed = 0;
> int wait = 1;
> - bool autoneg = false;
>
> memset(&link, 0, sizeof(link));
> link.link_status = ETH_LINK_DOWN;
> @@ -3993,13 +4014,8 @@ ixgbe_dev_link_update_share(struct rte_eth_dev
> *dev,
>
> hw->mac.get_link_status = true;
>
> - if ((intr->flags & IXGBE_FLAG_NEED_LINK_CONFIG) &&
> - ixgbe_get_media_type(hw) == ixgbe_media_type_fiber) {
> - speed = hw->phy.autoneg_advertised;
> - if (!speed)
> - ixgbe_get_link_capabilities(hw, &speed, &autoneg);
> - ixgbe_setup_link(hw, speed, true);
> - }
> + if (intr->flags & IXGBE_FLAG_NEED_LINK_CONFIG)
> + return rte_eth_linkstatus_set(dev, &link);
>
> /* check if it needs to wait to complete, if lsc interrupt is enabled */
> if (wait_to_complete == 0 || dev->data->dev_conf.intr_conf.lsc != 0) @@
> -4017,11 +4033,14 @@ ixgbe_dev_link_update_share(struct rte_eth_dev *dev,
> }
>
> if (link_up == 0) {
> - intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
> + if (ixgbe_get_media_type(hw) == ixgbe_media_type_fiber) {
> + intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
> + rte_eal_alarm_set(10,
> + ixgbe_dev_setup_link_alarm_handler, dev);
> + }
> return rte_eth_linkstatus_set(dev, &link);
> }
>
> - intr->flags &= ~IXGBE_FLAG_NEED_LINK_CONFIG;
> link.link_status = ETH_LINK_UP;
> link.link_duplex = ETH_LINK_FULL_DUPLEX;
>
> @@ -5128,6 +5147,8 @@ ixgbevf_dev_stop(struct rte_eth_dev *dev)
>
> PMD_INIT_FUNC_TRACE();
>
> + rte_eal_alarm_cancel(ixgbe_dev_setup_link_alarm_handler, dev);
> +
> ixgbevf_intr_disable(dev);
>
> hw->adapter_stopped = 1;
> --
> 2.17.1
