From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrien Mazarguil Subject: Re: [PATCH 2/7] net/mlx4: fix Rx interrupts with multiple ports Date: Fri, 16 Jun 2017 15:39:55 +0200 Message-ID: <20170616133955.GD1758@6wind.com> References: <2407596e1e05260170f8b0b80806b28b63e9255d.1497439616.git.adrien.mazarguil@6wind.com> <08cf1e01-f0b9-9540-9cc5-0b7fb79d8799@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: dev@dpdk.org To: Ferruh Yigit Return-path: Received: from mail-wm0-f54.google.com (mail-wm0-f54.google.com [74.125.82.54]) by dpdk.org (Postfix) with ESMTP id 847B72BD1 for ; Fri, 16 Jun 2017 15:40:06 +0200 (CEST) Received: by mail-wm0-f54.google.com with SMTP id u195so12258740wmd.1 for ; Fri, 16 Jun 2017 06:40:06 -0700 (PDT) Content-Disposition: inline In-Reply-To: <08cf1e01-f0b9-9540-9cc5-0b7fb79d8799@intel.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Fri, Jun 16, 2017 at 02:07:54PM +0100, Ferruh Yigit wrote: > On 6/14/2017 12:49 PM, Adrien Mazarguil wrote: > > Several Ethernet device structures are allocated on top of a common PCI > > device for mlx4 adapters with multiple ports. These inherit a common > > interrupt handle from their parent PCI device, which prevents Rx interrupts > > from working properly on all ports as their configuration is overwritten. > > > > Use a local interrupt handle to address this issue. > > Hi Adrien, > > I am not clear why local copy required, and main concern from my point > of view is if this is a common problem for all PMDs and should be > addressed in higher level? This issue only affects PMDs that handle multiple Ethernet ports through a single PCI device. Such PMDs (like mlx4) identify themselves as PCI drivers that manually have to register multiple rte_eth_dev instances through rte_eth_dev_allocate(), which they then have to initialize. > The variable is already per eth_dev, but this patch moves it the private > data. What overwrites it within eth_dev? Calling rte_eth_copy_pci_info() makes the rte_eth_dev structure inherit the default interrupt handle of the underlying PCI device. By "inherit", I mean eth_dev->intr_handle points to it, in that sense it's not per eth_dev but per PCI device. mlx4 Rx interrupts are associated with a given Verbs context, and each port has its own Verbs context, so they cannot be shared, while other PMDs using other methods for catching interrupts may be perfectly fine with a single vector associated with the PCI device. It depends on the PMD, for instance there is no such problem with mlx5 as exactly one PCI device is associated with a given port. This patch merely allocates a specific interrupt handle associated with the eth_dev itself and makes the eth_dev handle point to that instead of the default PCI handle. This "local" handle is initialized using the PCI handle as a template before modifying the pointer. It's completely safe. > > Fixes: 9f05a4b81809 ("net/mlx4: support user space Rx interrupt event") > > > > Signed-off-by: Adrien Mazarguil > > Acked-by: Moti Haimovsky > > --- > > drivers/net/mlx4/mlx4.c | 9 +++++++++ > > drivers/net/mlx4/mlx4.h | 1 + > > 2 files changed, 10 insertions(+) > > > > diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c > > index 178562e..2b4722f 100644 > > --- a/drivers/net/mlx4/mlx4.c > > +++ b/drivers/net/mlx4/mlx4.c > > @@ -6207,6 +6207,15 @@ mlx4_pci_probe(struct rte_pci_driver *pci_drv, struct rte_pci_device *pci_dev) > > > > eth_dev->device->driver = &mlx4_driver.driver; > > > > + /* > > + * Copy and override interrupt handle to prevent it from > > + * being shared between all ethdev instances of a given PCI > > + * device. This is required to properly handle Rx interrupts > > + * on all ports. > > + */ > > + priv->intr_handle_dev = *eth_dev->intr_handle; > > + eth_dev->intr_handle = &priv->intr_handle_dev; > > + > > priv->dev = eth_dev; > > eth_dev->dev_ops = &mlx4_dev_ops; > > > > diff --git a/drivers/net/mlx4/mlx4.h b/drivers/net/mlx4/mlx4.h > > index c46fc23..b74fbf8 100644 > > --- a/drivers/net/mlx4/mlx4.h > > +++ b/drivers/net/mlx4/mlx4.h > > @@ -345,6 +345,7 @@ struct priv { > > unsigned int txqs_n; /* TX queues array size. */ > > struct rxq *(*rxqs)[]; /* RX queues. */ > > struct txq *(*txqs)[]; /* TX queues. */ > > + struct rte_intr_handle intr_handle_dev; /* Device interrupt handler. */ > > struct rte_intr_handle intr_handle; /* Interrupt handler. */ > > struct rte_flow_drop *flow_drop_queue; /* Flow drop queue. */ > > LIST_HEAD(mlx4_flows, rte_flow) flows; > > > -- Adrien Mazarguil 6WIND