[dpdk-dev] Making rte_eal_pci_probe() in rte_eal_init() optional?
Roger B. Melton
rmelton at cisco.com
Wed Nov 18 23:13:51 CET 2015
Hi Thomas, in-line -Roger
On 11/17/15 10:46 AM, Thomas Monjalon wrote:
> 2015-11-17 08:56, Roger B. Melton:
>> Hi David, in-line -Roger
>>
>> On 11/16/15 4:46 AM, David Marchand wrote:
>>> Hello Roger,
>>>
>>> On Sun, Nov 15, 2015 at 3:45 PM, Roger B. Melton <rmelton at cisco.com
>>> <mailto:rmelton at cisco.com>> wrote:
>>>
>>> I like the "-b all" and "-w none" idea, but I think it might be
>>> complicated to implement it the way we would need it to work. The
>>> existing -b and -w options persist for the duration of the
>>> application, and we would need the "-b all"/"-w none" to persists
>>> only through rte_eal_init() time. Otherwise our attempt to to
>>> attach a device at a later time would be blocked by the option.
>>>
>>> I agree, the black/white lists should only apply to initial scan.
>>> I forgot about this problem ...
>>> I had started some cleanup in the pci scan / attach code but this is
>>> too late for 2.2, I will post this in the next merge window.
>>>
>>>
>>> Wouldn't it be simpler to have an option to disable the
>>> rte_eal_init() time the probe. Would that address the issue with
>>> VFIO, prevent automatically attaching to devices while permitting
>>> on demand attach?
>>>
>>>
>>> I suppose we can do this yes (I think Thomas once proposed off-list an
>>> option like --no-pci-scan).
>>> Do you think you can send a patch ?
>> What about --no-pci-init-probe? I know it's long, but it is more
>> descriptive of it's purpose to disable only the init time pci probe.
> Why not a "-b all"?
> Making it work would also solve the case where you to scan only part of
> the devices and initialize the blacklisted ones later.
> .
>
Do you envision "-b all" setting a flag that would be used to block
rte_eal_init() invocation of rte_eal_pci_probe()? e.g. If we have a new
API, *rte_eal_pci_blacklist_all_get()* that returns a non-zero value if
"-b all" was specified, then in rte_eal_init() we would have something like:
...
/* Probe & Initialize PCI devices */
* if (!rte_eal_pci_blacklist_all_get())** <--- New check*
if (rte_eal_pci_probe())
rte_panic("Cannot probe PCI\n");
...
Or setting a flag that would be checked in rte_eal_probe_one() similar
to the existing per device blacklist check? e.g. Again with a new API,
*rte_eal_pci_blacklist_all_get()* that returns a non-zero value if "-b
all" was specified, then in rte_eal_pci_probe_one_driver() we would have
something like:
/* no initialization when blacklisted, return without error */
if (*rte_eal_pci_blacklist_all_get() || <--- New check*
(dev->devargs != NULL &&
dev->devargs->type == RTE_DEVTYPE_BLACKLISTED_PCI)) {
RTE_LOG(DEBUG, EAL, " Device is blacklisted, not
initializing\n");
return 1;
}
The former would work, but I think it would be confusing for "-b all" to
only apply to init.
The latter would be consistent with how "-b <PCI DBDF>" works, but in
order to initialize devices at a later time, we would need a way to
clear the blacklist all state at run time so that
*rte_eal_pci_blacklist_all()* would return false. For example, something
like *rte_eal_pci_blacklist_all_clear()*.
Or do you have something else in mind entirely?
More information about the dev
mailing list