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

[Neil Horman <nhorman@tuxdriver.com>]

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



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;