[dpdk-dev] mbuff rearm_data aligmenet issue on non x86

[Jerin Jacob]

Hi All,

I would like align mbuff rearm_data field to 8 byte aligned so that
write to mbuf->rearm_data with uint64_t* will be naturally aligned.
I am not sure about IA but some other architecture/implementation has overhead
in non-naturally aligned stores.

Proposed patch is something like this below, But open for any change to
make fit for all other architectures/platform.

Any thoughts ?

➜ [master] [dpdk-master] $ git diff
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 529debb..5a917d0 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -733,10 +733,8 @@ struct rte_mbuf {
        void *buf_addr;           /**< Virtual address of segment
buffer. */
        phys_addr_t buf_physaddr; /**< Physical address of segment
buffer. */
 
-       uint16_t buf_len;         /**< Length of segment buffer. */
-
        /* next 6 bytes are initialised on RX descriptor rearm */
-       MARKER8 rearm_data;
+       MARKER64 rearm_data;
        uint16_t data_off;
 
        /**
@@ -754,6 +752,7 @@ struct rte_mbuf {
        uint8_t nb_segs;          /**< Number of segments. */
        uint8_t port;             /**< Input port. */
 
+       uint16_t buf_len;         /**< Length of segment buffer. */
        uint64_t ol_flags;        /**< Offload features. */
 
        /* remaining bytes are set on RX when pulling packet from
 * descriptor 

/Jerin