Re: [dpdk-dev] [PATCH v3] Fix two compile issues with i686 platform

["Qiu, Michael" <michael.qiu@intel.com>]

On 12/8/2014 11:39 AM, Qiu, Michael wrote:
> On 12/8/2014 11:00 AM, Neil Horman wrote:
>> On Mon, Dec 08, 2014 at 02:46:51AM +0000, Qiu, Michael wrote:
>>> On 12/5/2014 11:25 PM, Neil Horman wrote:
>>>> On Fri, Dec 05, 2014 at 03:02:33PM +0000, Bruce Richardson wrote:
>>>>> On Fri, Dec 05, 2014 at 09:22:05AM -0500, Neil Horman wrote:
>>>>>> On Fri, Dec 05, 2014 at 04:31:47PM +0800, Chao Zhu wrote:
>>>>>>> On 2014/12/4 17:12, Michael Qiu wrote:
>>>>>>>> lib/librte_eal/linuxapp/eal/eal_memory.c:324:4: error: comparison
>>>>>>>> is always false due to limited range of data type [-Werror=type-limits]
>>>>>>>>     || (hugepage_sz == RTE_PGSIZE_16G)) {
>>>>>>>>     ^
>>>>>>>> cc1: all warnings being treated as errors
>>>>>>>>
>>>>>>>> lib/librte_eal/linuxapp/eal/eal.c(461): error #2259: non-pointer
>>>>>>>> conversion from "long long" to "void *" may lose significant bits
>>>>>>>>    RTE_PTR_ALIGN_CEIL((uintptr_t)addr, RTE_PGSIZE_16M);
>>>>>>>>
>>>>>>>> This was introuduced by commit b77b5639:
>>>>>>>>         mem: add huge page sizes for IBM Power
>>>>>>>>
>>>>>>>> The root cause is that size_t and uintptr_t are 32-bit in i686
>>>>>>>> platform, but RTE_PGSIZE_16M and RTE_PGSIZE_16G are always 64-bit.
>>>>>>>>
>>>>>>>> Define RTE_PGSIZE_16G only in 64 bit platform to avoid
>>>>>>>> this issue.
>>>>>>>>
>>>>>>>> Signed-off-by: Michael Qiu <michael.qiu@intel.com>
>>>>>>>> ---
>>>>>>>>  v3 ---> v2
>>>>>>>> 	Change RTE_PGSIZE_16G from ULL to UL
>>>>>>>> 	to keep all entries consistent
>>>>>>>>
>>>>>>>>  V2 ---> v1
>>>>>>>> 	Change two type entries to one, and
>>>>>>>> 	leave RTE_PGSIZE_16G only valid for
>>>>>>>> 	64-bit platform
>>>>>>>>
>>>>>> NACK, this is the wrong way to fix this problem.  Pagesizes are independent of
>>>>>> architecutre.  While a system can't have a hugepage size that exceeds its
>>>>>> virtual address limit, theres no need to do per-architecture special casing of
>>>>>> page sizes here.  Instead of littering the code with ifdef RTE_ARCH_64
>>>>>> everytime you want to check a page size, just convert the size_t to a uint64_t
>>>>>> and you can allow all of the enumerated page types on all architecutres, and
>>>>>> save yourself some ifdeffing in the process.
>>>>>>
>>>>>> Neil
>>>>> While I get your point, I find it distasteful to use a uint64_t for memory sizes,
>>>>> when there is the size_t type defined for that particular purpose.
>>>>> However, I suppose that reducing the number of #ifdefs compared to using the
>>>>> "correct" datatypes for objects is a more practical optino - however distastful
>>>>> I find it.
>>>> size_t isn't defined for memory sizes in the sense that we're using them here.
>>>> size_t is meant to address the need for a type to describe object sizes on a
>>>> particular system, and it itself is sized accordingly (32 bits on a 32 bit arch,
>>>> 64 on 64), so that you can safely store a size that the system in question might
>>>> maximally allocate/return.  In this situation we are describing memory sizes
>>>> that might occur no a plurality of arches, and so size_t is inappropriate
>>>> because it as a type is not sized for anything other than the arch it is being
>>>> built for.  The pragmatic benefits of ennumerating page sizes in a single
>>>> canonical location far outweigh the desire to use a misappropriated type to
>>>> describe them.
>>> Neil,
>>>
>>> This patch fix two compile issues, and we need to do *dpdk testing
>>> affairs*,  if it is blocked in build stage, we can do *nothing* for testing.
>>>
>>> I've get you mind and your concern. But we should take care of changing
>>> the type of "hugepage_sz", because lots of places using it.
>>>
>>> Would you mind if we consider this as hot fix, and we can post a better
>>> fix later(like in dpdk 2.0)? Otherwise all test cycle are blocked.
>>>
>> Honestly, no.  Because intels testing schedule shouldn't drive the inclusion of
>> upstream fixes.  Also, I'm not asking for a major redesign of anything, I'm
>> asking for a proper fix for a very straightforward problem.  I've attached the
>> proper fix below.
>>
>> Regards
>> Neil
> We test dpdk upstream now as 1,8 rc2 and rc3 released :)
>
> I know that what you mean. but lots of please using "hugepage_sz" do you

Sorry, please/places
> confirm it will not affect other issue?
>
> On other hand, we use 32 bit address in 32 bit platform for better
> performance(some of places also use uintptr_t for address check and
> alignment).
>
> And it should not acceptable in 32 bit platform to use 64-bit platform
> specification affairs(like RTE_PGSIZE_16G).
>
> Thanks,
> Michael
>
>>
>> diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
>> index 412b432..31a391c 100644
>> --- a/lib/librte_eal/common/eal_common_memory.c
>> +++ b/lib/librte_eal/common/eal_common_memory.c
>> @@ -96,7 +96,7 @@ rte_dump_physmem_layout(FILE *f)
>>  
>>  		fprintf(f, "Segment %u: phys:0x%"PRIx64", len:%zu, "
>>  		       "virt:%p, socket_id:%"PRId32", "
>> -		       "hugepage_sz:%zu, nchannel:%"PRIx32", "
>> +		       "hugepage_sz:%llu, nchannel:%"PRIx32", "
>>  		       "nrank:%"PRIx32"\n", i,
>>  		       mcfg->memseg[i].phys_addr,
>>  		       mcfg->memseg[i].len,
>> diff --git a/lib/librte_eal/common/eal_internal_cfg.h b/lib/librte_eal/common/eal_internal_cfg.h
>> index aac6abf..e2ecb0d 100644
>> --- a/lib/librte_eal/common/eal_internal_cfg.h
>> +++ b/lib/librte_eal/common/eal_internal_cfg.h
>> @@ -49,7 +49,7 @@
>>   * mount points of hugepages
>>   */
>>  struct hugepage_info {
>> -	size_t hugepage_sz;   /**< size of a huge page */
>> +	uint64_t hugepage_sz;   /**< size of a huge page */
>>  	const char *hugedir;    /**< dir where hugetlbfs is mounted */
>>  	uint32_t num_pages[RTE_MAX_NUMA_NODES];
>>  				/**< number of hugepages of that size on each socket */
>> diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
>> index 1990833..7f8103f 100644
>> --- a/lib/librte_eal/common/include/rte_memory.h
>> +++ b/lib/librte_eal/common/include/rte_memory.h
>> @@ -92,7 +92,7 @@ struct rte_memseg {
>>  	phys_addr_t ioremap_addr; /**< Real physical address inside the VM */
>>  #endif
>>  	size_t len;               /**< Length of the segment. */
>> -	size_t hugepage_sz;       /**< The pagesize of underlying memory */
>> +	uint64_t hugepage_sz;       /**< The pagesize of underlying memory */
>>  	int32_t socket_id;          /**< NUMA socket ID. */
>>  	uint32_t nchannel;          /**< Number of channels. */
>>  	uint32_t nrank;             /**< Number of ranks. */
>> diff --git a/lib/librte_eal/common/include/rte_memzone.h b/lib/librte_eal/common/include/rte_memzone.h
>> index 7d47bff..3006e81 100644
>> --- a/lib/librte_eal/common/include/rte_memzone.h
>> +++ b/lib/librte_eal/common/include/rte_memzone.h
>> @@ -83,7 +83,7 @@ struct rte_memzone {
>>  #endif
>>  	size_t len;                       /**< Length of the memzone. */
>>  
>> -	size_t hugepage_sz;               /**< The page size of underlying memory */
>> +	uint64_t hugepage_sz;               /**< The page size of underlying memory */
>>  
>>  	int32_t socket_id;                /**< NUMA socket ID. */
>>  
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
>> index e6cb919..bae2507 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
>> @@ -300,7 +300,7 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl,
>>  #endif
>>  
>>  	for (i = 0; i < hpi->num_pages[0]; i++) {
>> -		size_t hugepage_sz = hpi->hugepage_sz;
>> +		uint64_t hugepage_sz = hpi->hugepage_sz;
>>  
>>  		if (orig) {
>>  			hugepg_tbl[i].file_id = i;
>>
>