[dpdk-dev] [PATCH] eal: fix 64bit address alignment in 32-bit builds

Bruce Richardson bruce.richardson at intel.com
Fri Apr 28 10:15:51 CEST 2017

On i686 builds, the uint64_t type is 64-bits in size but is aligned to
32-bits only. This causes mbuf fields for rearm_data to not be 16-byte
aligned on 32-bit builds, which causes errors with some vector PMDs which
expect the rearm data to be aligned as on 64-bit.

Given that we cannot use the extra space in the data structures anyway, as
it's already used on 64-bit builds, we can just force alignment of physical
address structure members to 8-bytes in all cases. This has no effect on
64-bit systems, but fixes the updated PMDs on 32-bit.

Fixes: f4356d7ca168 ("net/i40e: eliminate mbuf write on rearm")
Fixes: f160666a1073 ("net/ixgbe: eliminate mbuf write on rearm")

Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
 lib/librte_eal/common/include/rte_memory.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
index 4aa5d1f..ad14875 100644
--- a/lib/librte_eal/common/include/rte_memory.h
+++ b/lib/librte_eal/common/include/rte_memory.h
@@ -98,7 +98,8 @@ enum rte_page_sizes {
 #define __rte_cache_min_aligned __rte_aligned(RTE_CACHE_LINE_MIN_SIZE)
-typedef uint64_t phys_addr_t; /**< Physical address definition. */
+/** Physical address definition. */
+typedef uint64_t phys_addr_t __rte_aligned(sizeof(uint64_t));
 #define RTE_BAD_PHYS_ADDR ((phys_addr_t)-1)

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