[dpdk-dev] [PATCH v6 04/11] eal/mem: extract common code for memseg list initialization

[Burakov, Anatoly]

On 10-Jun-20 3:31 PM, Dmitry Kozlyuk wrote:
> On Wed, 10 Jun 2020 11:26:22 +0100
> "Burakov, Anatoly" <anatoly.burakov at intel.com> wrote:
> 
> [snip]
>>>>> +	addr = eal_get_virtual_area(
>>>>> +		msl->base_va, &mem_sz, page_sz, 0, reserve_flags);
>>>>> +	if (addr == NULL) {
>>>>> +#ifndef RTE_EXEC_ENV_WINDOWS
>>>>> +		/* The hint would be misleading on Windows, but this function
>>>>> +		 * is called from many places, including common code,
>>>>> +		 * so don't duplicate the message.
>>>>> +		 */
>>>>> +		if (rte_errno == EADDRNOTAVAIL)
>>>>> +			RTE_LOG(ERR, EAL, "Cannot reserve %llu bytes at [%p] - "
>>>>> +				"please use '--" OPT_BASE_VIRTADDR "' option\n",
>>>>> +				(unsigned long long)mem_sz, msl->base_va);
>>>>> +		else
>>>>> +			RTE_LOG(ERR, EAL, "Cannot reserve memory\n");
>>>>> +#endif
>>>>
>>>> You're left without any error messages on Windows. How about:
>>>>
>>>> const char *err_str = "Cannot reserve memory\n";
>>>> #ifndef RTE_EXEC_ENV_WINDOWS
>>>> if (rte_errno == EADDRNOTAVAIL)
>>>>       err_str = ...
>>>> #endif
>>>> RTE_LOG(ERR, EAL, err_str);
>>>>
>>>> or something like that?
>>>>   
>>>
>>> How about removing generic error message here completely and printing more
>>> specific messages at call sites? In fact, almost all of them already do this.
>>> It would be more helpful in tracking down errors.
>>>    
>>
>> Agreed, let's do that :) We do pass up the rte_errno, correct? So, we
>> should be able to do that.
> 
> Actually, callers don't need rte_errno, because we only have to distinguish
> EADDRNOTAVAIL here, and eal_get_virtual_area() already prints precise
> diagnostics at WARNING and ERR level. rte_errno is preserved, however.
> 

Not sure i agree, we still need the "--base-virtaddr" hint, and we can 
only do that from the caller (without #ifdef-ery here), so we do need 
rte_errno for that.

-- 
Thanks,
Anatoly