On Wed, Mar 20, 2024 at 03:01:36PM -0700, Tyler Retzlaff wrote:
> RTE_MARKER typedefs are a GCC extension unsupported by MSVC. Remove
> RTE_MARKER fields from rte_mbuf struct.
>
> Maintain alignment of fields after removed cacheline1 marker by placing
> C11 alignas(RTE_CACHE_LINE_MIN_SIZE).
>
> Provide new rearm_data and rx_descriptor_fields1 fields in anonymous
> unions as single element arrays of with types matching the original
> markers to maintain API compatibility.
>
> Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
> ---
> doc/guides/rel_notes/release_24_03.rst | 2 +
> lib/mbuf/rte_mbuf.h | 4 +-
> lib/mbuf/rte_mbuf_core.h | 188
> ++++++++++++++++++---------------
> 3 files changed, 104 insertions(+), 90 deletions(-)
>
> diff --git a/doc/guides/rel_notes/release_24_03.rst
> b/doc/guides/rel_notes/release_24_03.rst
> index 14826ea..4f18cca 100644
> --- a/doc/guides/rel_notes/release_24_03.rst
> +++ b/doc/guides/rel_notes/release_24_03.rst
> @@ -216,6 +216,8 @@ Removed Items
>
> * acc101: Removed obsolete code for non productized HW variant.
>
> +* mbuf: ``RTE_MARKER`` fields ``cacheline0`` and ``cacheline1``
> + have been removed from ``struct rte_mbuf``.
>
> API Changes
> -----------
> diff --git a/lib/mbuf/rte_mbuf.h b/lib/mbuf/rte_mbuf.h
> index 286b32b..4c4722e 100644
> --- a/lib/mbuf/rte_mbuf.h
> +++ b/lib/mbuf/rte_mbuf.h
> @@ -108,7 +108,7 @@
> static inline void
> rte_mbuf_prefetch_part1(struct rte_mbuf *m)
> {
> - rte_prefetch0(&m->cacheline0);
> + rte_prefetch0(m);
> }
>
> /**
> @@ -126,7 +126,7 @@
> rte_mbuf_prefetch_part2(struct rte_mbuf *m)
> {
> #if RTE_CACHE_LINE_SIZE == 64
> - rte_prefetch0(&m->cacheline1);
> + rte_prefetch0(RTE_PTR_ADD(m, RTE_CACHE_LINE_MIN_SIZE));
> #else
> RTE_SET_USED(m);
> #endif
> diff --git a/lib/mbuf/rte_mbuf_core.h b/lib/mbuf/rte_mbuf_core.h
> index 9f58076..665213c 100644
> --- a/lib/mbuf/rte_mbuf_core.h
> +++ b/lib/mbuf/rte_mbuf_core.h
> @@ -465,8 +465,6 @@ enum {
> * The generic rte_mbuf, containing a packet mbuf.
> */
> struct __rte_cache_aligned rte_mbuf {
> - RTE_MARKER cacheline0;
> -
> void *buf_addr; /**< Virtual address of segment buffer. */
> #if RTE_IOVA_IN_MBUF
> /**
> @@ -488,116 +486,130 @@ struct __rte_cache_aligned rte_mbuf {
> #endif
>
> /* next 8 bytes are initialised on RX descriptor rearm */
> - RTE_MARKER64 rearm_data;
> - uint16_t data_off;
> -
> - /**
> - * Reference counter. Its size should at least equal to the size
> - * of port field (16 bits), to support zero-copy broadcast.
> - * It should only be accessed using the following functions:
> - * rte_mbuf_refcnt_update(), rte_mbuf_refcnt_read(), and
> - * rte_mbuf_refcnt_set(). The functionality of these functions (atomic,
> - * or non-atomic) is controlled by the RTE_MBUF_REFCNT_ATOMIC flag.
> - */
> - RTE_ATOMIC(uint16_t) refcnt;
> + union {
> + uint64_t rearm_data[1];
> + __extension__
> + struct {
> + uint16_t data_off;
> +
> + /**
> + * Reference counter. Its size should at least equal to
> the size
> + * of port field (16 bits), to support zero-copy
> broadcast.
> + * It should only be accessed using the following
> functions:
> + * rte_mbuf_refcnt_update(), rte_mbuf_refcnt_read(), and
> + * rte_mbuf_refcnt_set(). The functionality of these
> functions (atomic,
> + * or non-atomic) is controlled by the
> RTE_MBUF_REFCNT_ATOMIC flag.
> + */
> + RTE_ATOMIC(uint16_t) refcnt;
>
> - /**
> - * Number of segments. Only valid for the first segment of an mbuf
> - * chain.
> - */
> - uint16_t nb_segs;
> + /**
> + * Number of segments. Only valid for the first segment
> of an mbuf
> + * chain.
> + */
> + uint16_t nb_segs;
>
> - /** Input port (16 bits to support more than 256 virtual ports).
> - * The event eth Tx adapter uses this field to specify the output port.
> - */
> - uint16_t port;
> + /** Input port (16 bits to support more than 256
> virtual ports).
> + * The event eth Tx adapter uses this field to specify
> the output port.
> + */
> + uint16_t port;
> + };
> + };
>
> uint64_t ol_flags; /**< Offload features. */
>
> /* remaining bytes are set on RX when pulling packet from descriptor */
> - RTE_MARKER rx_descriptor_fields1;
> -
> - /*
> - * The packet type, which is the combination of outer/inner L2, L3, L4
> - * and tunnel types. The packet_type is about data really present in the
> - * mbuf. Example: if vlan stripping is enabled, a received vlan packet
> - * would have RTE_PTYPE_L2_ETHER and not RTE_PTYPE_L2_VLAN because the
> - * vlan is stripped from the data.
> - */
> union {
> - uint32_t packet_type; /**< L2/L3/L4 and tunnel information. */
> + void *rx_descriptor_fields1[1];
Can we make this array the actual size of all the fields, rather than just
an 8-byte value? That would allow the right think to be done if assigning
the descriptor fields from one mbuf to another, or when using memset or
memcpy on them.
/Bruce
