[dpdk-dev] [PATCH RFC 05/11] mbuf: merge physaddr and buf_len in a bitfield

[Olivier Matz <olivier.matz@6wind.com>]

The physical address is never greater than (1 << 48) = 256 TB.
We can win 2 bytes in the mbuf structure by merging the physical
address and the buffer length in the same bitfield.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 lib/librte_mbuf/rte_mbuf.c | 3 ++-
 lib/librte_mbuf/rte_mbuf.h | 7 ++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index c229525..9879095 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -104,7 +104,8 @@ rte_pktmbuf_init(struct rte_mempool *mp,
 	m->buf_len = (uint16_t)buf_len;
 
 	/* keep some headroom between start of buffer and data */
-	m->data = (char*) m->buf_addr + RTE_MIN(RTE_PKTMBUF_HEADROOM, m->buf_len);
+	m->data = (char*) m->buf_addr + RTE_MIN(RTE_PKTMBUF_HEADROOM,
+		(uint16_t)m->buf_len);
 
 	/* init some constant fields */
 	m->pool = mp;
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 803b223..275f6b2 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -130,8 +130,8 @@ union rte_vlan_macip {
 struct rte_mbuf {
 	struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
 	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. */
+	uint64_t buf_physaddr:48; /**< Physical address of segment buffer. */
+	uint64_t buf_len:16;      /**< Length of segment buffer. */
 #ifdef RTE_MBUF_REFCNT
 	/**
 	 * 16-bit Reference counter.
@@ -148,8 +148,9 @@ struct rte_mbuf {
 #else
 	uint16_t refcnt_reserved;     /**< Do not use this field */
 #endif
-	uint16_t reserved;             /**< Unused field. Required for padding. */
+
 	uint16_t ol_flags;            /**< Offload features. */
+	uint32_t reserved;             /**< Unused field. Required for padding. */
 
 	/* valid for any segment */
 	struct rte_mbuf *next;  /**< Next segment of scattered packet. */
-- 
1.9.2