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

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

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
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;
>