Re: [dpdk-dev] [PATCH v1 1/1] bus/pci: probe PCI devices in whitelisted order

[Slava Ovsiienko <viacheslavo@mellanox.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of vattunuru@marvell.com
> Sent: Monday, September 23, 2019 14:57
> To: dev@dpdk.org
> Cc: gaetan.rivet@6wind.com; ferruh.yigit@intel.com;
> anatoly.burakov@intel.com; Thomas Monjalon <thomas@monjalon.net>;
> jerinj@marvell.com; Vamsi Attunuru <vattunuru@marvell.com>
> Subject: [dpdk-dev] [PATCH v1 1/1] bus/pci: probe PCI devices in whitelisted
> order
> 
> From: Vamsi Attunuru <vattunuru@marvell.com>
> 
> Current pci bus driver scans pci devices in the order that it read from sysfs.
> Accordingly all or whitelisted devices are getting probed.
> 
> Patch modifies the probing order of whitelisted pci devices in a sequence the
> devices are whitelisted(using EAL flags).

Thanks, it would be nice to have opportunity to control probing order,
it might be useful for bonded devices and representors either.

Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>

> 
> It ensures the eth devices that application uses are probed in device
> whitelisted sequence, in turn it facilitates the packet forwarding applications
> to work without any packet loss or performance drop when the underneath
> network ports have different bandwidths. By altering the whitelist order
> applications like testpmd, l2fwd can forward the ingress traffic to egress port
> that has of equivalent bandwidth.
> 
> Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
> ---
>  drivers/bus/pci/pci_common.c | 67 ++++++++++++++++++++++++++++++----
> ----------
>  1 file changed, 46 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
> index 6b46b4f..c27a0e9 100644
> --- a/drivers/bus/pci/pci_common.c
> +++ b/drivers/bus/pci/pci_common.c
> @@ -293,32 +293,57 @@ rte_pci_probe(void)
>  	struct rte_pci_device *dev = NULL;
>  	size_t probed = 0, failed = 0;
>  	struct rte_devargs *devargs;
> -	int probe_all = 0;
> +	struct rte_pci_addr addr;
>  	int ret = 0;
> 
> -	if (rte_pci_bus.bus.conf.scan_mode != RTE_BUS_SCAN_WHITELIST)
> -		probe_all = 1;
> -
> -	FOREACH_DEVICE_ON_PCIBUS(dev) {
> -		probed++;
> +	if (rte_pci_bus.bus.conf.scan_mode != RTE_BUS_SCAN_WHITELIST) {
> +		/* Probe all devices */
> +		FOREACH_DEVICE_ON_PCIBUS(dev) {
> +			probed++;
> 
> -		devargs = dev->device.devargs;
> -		/* probe all or only whitelisted devices */
> -		if (probe_all)
>  			ret = pci_probe_all_drivers(dev);
> -		else if (devargs != NULL &&
> -			devargs->policy == RTE_DEV_WHITELISTED)
> -			ret = pci_probe_all_drivers(dev);
> -		if (ret < 0) {
> -			if (ret != -EEXIST) {
> -				RTE_LOG(ERR, EAL, "Requested device "
> -					PCI_PRI_FMT " cannot be used\n",
> -					dev->addr.domain, dev->addr.bus,
> -					dev->addr.devid, dev-
> >addr.function);
> -				rte_errno = errno;
> -				failed++;
> +			if (ret < 0) {
> +				if (ret != -EEXIST) {
> +					RTE_LOG(ERR, EAL, "Requested
> device "
> +						PCI_PRI_FMT " cannot be
> used\n",
> +						dev->addr.domain, dev-
> >addr.bus,
> +						dev->addr.devid,
> +						dev->addr.function);
> +					rte_errno = errno;
> +					failed++;
> +				}
> +				ret = 0;
> +			}
> +		}
> +	} else {
> +		/* Probe only whitelisted devices */
> +		RTE_EAL_DEVARGS_FOREACH("pci", devargs) {
> +			if (devargs->policy != RTE_DEV_WHITELISTED)
> +				continue;
> +
> +			devargs->bus->parse(devargs->name, &addr);
> +
> +			FOREACH_DEVICE_ON_PCIBUS(dev) {
> +				if (rte_pci_addr_cmp(&dev->addr, &addr))
> +					continue;
> +				probed++;
> +				ret = pci_probe_all_drivers(dev);
> +				if (ret < 0) {
> +					if (ret != -EEXIST) {
> +						RTE_LOG(ERR, EAL,
> +							"Requested device "
> +							 PCI_PRI_FMT
> +							"cannot be used\n",
> +							dev->addr.domain,
> +							dev->addr.bus,
> +							dev->addr.devid,
> +							dev->addr.function);
> +						rte_errno = errno;
> +						failed++;
> +					}
> +					ret = 0;
> +				}
>  			}
> -			ret = 0;
>  		}
>  	}
> 
> --
> 2.8.4