Use C11 atomic builtins with explicit ordering instead of rte_atomic
ops which enforce unnecessary barriers on aarch64.
Suggested-by: Olivier Matz <olivier.m...@6wind.com>
Suggested-by: Dodji Seketeli <do...@redhat.com>
Signed-off-by: Phil Yang <phil.y...@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
Acked-by: Olivier Matz <olivier.m...@6wind.com>
---
v5:
1. Change built-ins to builtins.
2. Ignore updates of rte_mbuf_ext_shared_info refcnt_atomic in ABI
checker.
v4:
1. Add union for refcnt_atomic and refcnt in rte_mbuf_ext_shared_info
to avoid ABI breakage. (Olivier)
2. Add notice of refcnt_atomic deprecation. (Honnappa)
v3:
1.Fix ABI breakage.
2.Simplify data type cast.
v2:
Fix ABI issue: revert the rte_mbuf_ext_shared_info struct refcnt field
to refcnt_atomic.
devtools/libabigail.abignore | 4 ++++
lib/librte_mbuf/rte_mbuf.c | 1 -
lib/librte_mbuf/rte_mbuf.h | 19 ++++++++++---------
lib/librte_mbuf/rte_mbuf_core.h | 6 +++++-
4 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/devtools/libabigail.abignore b/devtools/libabigail.abignore
index daa4631..9fea822 100644
--- a/devtools/libabigail.abignore
+++ b/devtools/libabigail.abignore
@@ -52,6 +52,10 @@
[suppress_type]
type_kind = struct
name = rte_epoll_event
+; Ignore updates of rte_mbuf_ext_shared_info refcnt_atomic
+[suppress_type]
+ name = rte_mbuf_ext_shared_info
+ has_data_member_inserted_between = {offset_of(refcnt_atomic),
offset_of(refcnt_atomic)}
;;;;;;;;;;;;;;;;;;;;;;
; Temporary exceptions till DPDK 20.11
diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index ae91ae2..8a456e5 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -22,7 +22,6 @@
#include <rte_eal.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>
-#include <rte_atomic.h>
#include <rte_branch_prediction.h>
#include <rte_mempool.h>
#include <rte_mbuf.h>
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index f8e492e..7259575 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -37,7 +37,6 @@
#include <rte_config.h>
#include <rte_mempool.h>
#include <rte_memory.h>
-#include <rte_atomic.h>
#include <rte_prefetch.h>
#include <rte_branch_prediction.h>
#include <rte_byteorder.h>
@@ -365,7 +364,7 @@ rte_pktmbuf_priv_flags(struct rte_mempool *mp)
static inline uint16_t
rte_mbuf_refcnt_read(const struct rte_mbuf *m)
{
- return (uint16_t)(rte_atomic16_read(&m->refcnt_atomic));
+ return __atomic_load_n(&m->refcnt, __ATOMIC_RELAXED);
}
/**
@@ -378,14 +377,15 @@ rte_mbuf_refcnt_read(const struct rte_mbuf *m)
static inline void
rte_mbuf_refcnt_set(struct rte_mbuf *m, uint16_t new_value)
{
- rte_atomic16_set(&m->refcnt_atomic, (int16_t)new_value);
+ __atomic_store_n(&m->refcnt, new_value, __ATOMIC_RELAXED);
}
/* internal */
static inline uint16_t
__rte_mbuf_refcnt_update(struct rte_mbuf *m, int16_t value)
{
- return (uint16_t)(rte_atomic16_add_return(&m->refcnt_atomic, value));
+ return __atomic_add_fetch(&m->refcnt, (uint16_t)value,
+ __ATOMIC_ACQ_REL);
}
/**
@@ -466,7 +466,7 @@ rte_mbuf_refcnt_set(struct rte_mbuf *m, uint16_t new_value)
static inline uint16_t
rte_mbuf_ext_refcnt_read(const struct rte_mbuf_ext_shared_info *shinfo)
{
- return (uint16_t)(rte_atomic16_read(&shinfo->refcnt_atomic));
+ return __atomic_load_n(&shinfo->refcnt, __ATOMIC_RELAXED);
}
/**
@@ -481,7 +481,7 @@ static inline void
rte_mbuf_ext_refcnt_set(struct rte_mbuf_ext_shared_info *shinfo,
uint16_t new_value)
{
- rte_atomic16_set(&shinfo->refcnt_atomic, (int16_t)new_value);
+ __atomic_store_n(&shinfo->refcnt, new_value, __ATOMIC_RELAXED);
}
/**
@@ -505,7 +505,8 @@ rte_mbuf_ext_refcnt_update(struct rte_mbuf_ext_shared_info
*shinfo,
return (uint16_t)value;
}
- return (uint16_t)rte_atomic16_add_return(&shinfo->refcnt_atomic, value);
+ return __atomic_add_fetch(&shinfo->refcnt, (uint16_t)value,
+ __ATOMIC_ACQ_REL);
}
/** Mbuf prefetch */
@@ -1304,8 +1305,8 @@ static inline int
__rte_pktmbuf_pinned_extbuf_decref(struct rte_mbuf *m)
* Direct usage of add primitive to avoid
* duplication of comparing with one.
*/
- if (likely(rte_atomic16_add_return
- (&shinfo->refcnt_atomic, -1)))
+ if (likely(__atomic_add_fetch(&shinfo->refcnt, (uint16_t)-1,
+ __ATOMIC_ACQ_REL)))
return 1;
/* Reinitialize counter before mbuf freeing. */
diff --git a/lib/librte_mbuf/rte_mbuf_core.h b/lib/librte_mbuf/rte_mbuf_core.h
index 16600f1..8cd7137 100644
--- a/lib/librte_mbuf/rte_mbuf_core.h
+++ b/lib/librte_mbuf/rte_mbuf_core.h
@@ -679,7 +679,11 @@ typedef void (*rte_mbuf_extbuf_free_callback_t)(void
*addr, void *opaque);
struct rte_mbuf_ext_shared_info {
rte_mbuf_extbuf_free_callback_t free_cb; /**< Free callback function */
void *fcb_opaque; /**< Free callback argument */
- rte_atomic16_t refcnt_atomic; /**< Atomically accessed refcnt */
+ RTE_STD_C11
+ union {
+ rte_atomic16_t refcnt_atomic; /**< Atomically accessed refcnt */
+ uint16_t refcnt;
+ };
};
/**< Maximum number of nb_segs allowed. */
--
2.7.4
