> From: Tyler Retzlaff [mailto:roret...@linux.microsoft.com]
> Sent: Tuesday, 13 February 2024 07.46
>
> Replace the use of RTE_MARKER<x> with C11 anonymous unions to improve
> code portability between toolchains.
How about combining the cacheline 0 marker and padding, like this:
struct rte_mbuf {
- RTE_MARKER cacheline0;
+ union {
+ char cacheline0[RTE_CACHE_LINE_MIN_SIZE];
+ struct {
- void *buf_addr; /**< Virtual address of segment buffer. */
+ void *buf_addr; /**< Virtual address of segment buffer.
*/
#if RTE_IOVA_IN_MBUF
You could do the same with the cacheline1 marker:
/* second cache line - fields only used in slow path or on TX */
- RTE_MARKER cacheline1 __rte_cache_min_aligned;
+ union {
+ char cacheline1[RTE_CACHE_LINE_MIN_SIZE];
+ struct {
#if RTE_IOVA_IN_MBUF
- /**
- * Next segment of scattered packet. Must be NULL in the last
- * segment or in case of non-segmented packet.
- */
- struct rte_mbuf *next;
+ /**
+ * Next segment of scattered packet. Must be NULL in
the last
+ * segment or in case of non-segmented packet.
+ */
+ struct rte_mbuf *next;
#else
It also avoids the weird union between cacheline0 and buf_addr at the beginning
of the structure, and between cacheline1 and next/dynfield2 at the beginning of
the second cache line.
And then you can omit the pad_cacheline0 array at the end of the first part of
the structure.
BTW: char is a weaker type than uint8_t - i.e. it is easier to cast to another
type.
It might be a personal preference, but I would use char instead of uint8_t for
the padding array.
