Added 32 bit acquire load/cas and release store/add/sub calls.
These are the minimum set of non-relaxed calls that are needed
for building lock-free algorithms. 64 bit versions can be added
later.
Signed-off-by: Petri Savolainen <petri.savolai...@nokia.com>
---
include/odp/api/atomic.h | 80 ++++++++++++++++++++++++++++-
platform/linux-generic/include/odp/atomic.h | 32 ++++++++++++
2 files changed, 111 insertions(+), 1 deletion(-)
diff --git a/include/odp/api/atomic.h b/include/odp/api/atomic.h
index b79a50a..316f13a 100644
--- a/include/odp/api/atomic.h
+++ b/include/odp/api/atomic.h
@@ -21,7 +21,7 @@ extern "C" {
/**
* @defgroup odp_atomic ODP ATOMIC
* @details
- * <b> Atomic integers </b>
+ * <b> Atomic integers using relaxed memory ordering </b>
*
* Atomic integer types (odp_atomic_u32_t and odp_atomic_u64_t) can be used to
* implement e.g. shared counters. If not otherwise documented, operations in
@@ -31,6 +31,18 @@ extern "C" {
* before or after the operation), only atomicity of the operation itself is
* guaranteed.
*
+ * <b> Operations with other than relaxed memory ordering </b>
+ *
+ * <b> An operation with RELEASE </b> memory ordering
(odp_atomic_xxx_rls_xxx())
+ * ensures that other threads loading the same atomic variable with ACQUIRE
+ * memory ordering see all stores (from the calling thread) that happened
before
+ * this releasing store.
+ *
+ * <b> An operation with ACQUIRE </b> memory ordering
(odp_atomic_xxx_acq_xxx())
+ * ensures that the calling thread sees all stores (done by the releasing
+ * thread) that happened before a RELEASE memory ordered store to the same
+ * atomic variable.
+ *
* @{
*/
@@ -309,6 +321,72 @@ void odp_atomic_min_u64(odp_atomic_u64_t *atom, uint64_t
new_min);
int odp_atomic_cas_u64(odp_atomic_u64_t *atom, uint64_t *old_val,
uint64_t new_val);
+/*
+ * Operations with other than relaxed memory ordering
+ * --------------------------------------------------
+ */
+
+/**
+ * Load value of atomic uint32 variable using ACQUIRE memory ordering
+ *
+ * Otherwise identical to odp_atomic_load_u32() but ensures ACQUIRE memory
+ * ordering.
+ *
+ * @param atom Pointer to atomic variable
+ *
+ * @return Value of the variable
+ */
+uint32_t odp_atomic_load_acq_u32(odp_atomic_u32_t *atom);
+
+/**
+ * Compare and swap atomic uint32 variable using ACQUIRE memory ordering
+ *
+ * Otherwise identical to odp_atomic_cas_u32() but ensures ACQUIRE memory
+ * ordering.
+ *
+ * @param atom Pointer to atomic variable
+ * @param[in,out] old_val Pointer to the old value of the atomic variable.
+ * Operation updates this value on failure.
+ * @param new_val New value to be written into the atomic variable
+ *
+ * @return 0 on failure, !0 on success
+ */
+int odp_atomic_cas_acq_u32(odp_atomic_u32_t *atom, uint32_t *old_val,
+ uint32_t new_val);
+
+/**
+ * Store value to atomic uint32 variable using RELEASE memory ordering
+ *
+ * Otherwise identical to odp_atomic_store_u32() but ensures RELEASE memory
+ * ordering.
+ *
+ * @param atom Pointer to atomic variable
+ * @param val Value to store in the variable
+ */
+void odp_atomic_store_rls_u32(odp_atomic_u32_t *atom, uint32_t val);
+
+/**
+ * Add to atomic uint32 variable using RELEASE memory ordering
+ *
+ * Otherwise identical to odp_atomic_add_u32() but ensures RELEASE memory
+ * ordering.
+ *
+ * @param atom Pointer to atomic variable
+ * @param val Value to be added to the variable
+ */
+void odp_atomic_add_rls_u32(odp_atomic_u32_t *atom, uint32_t val);
+
+/**
+ * Subtract from atomic uint32 variable using RELEASE memory ordering
+ *
+ * Otherwise identical to odp_atomic_sub_u32() but ensures RELEASE memory
+ * ordering.
+ *
+ * @param atom Pointer to atomic variable
+ * @param val Value to be subtracted from the variable
+ */
+void odp_atomic_sub_rls_u32(odp_atomic_u32_t *atom, uint32_t val);
+
/**
* @}
*/
diff --git a/platform/linux-generic/include/odp/atomic.h
b/platform/linux-generic/include/odp/atomic.h
index b2bc5c4..005a0cd 100644
--- a/platform/linux-generic/include/odp/atomic.h
+++ b/platform/linux-generic/include/odp/atomic.h
@@ -258,6 +258,38 @@ static inline void odp_atomic_min_u64(odp_atomic_u64_t
*atom, uint64_t new_min)
}
}
+static inline uint32_t odp_atomic_load_acq_u32(odp_atomic_u32_t *atom)
+{
+ return __atomic_load_n(&atom->v, __ATOMIC_ACQUIRE);
+}
+
+static inline int odp_atomic_cas_acq_u32(odp_atomic_u32_t *atom,
+ uint32_t *old_val, uint32_t new_val)
+{
+ return __atomic_compare_exchange_n(&atom->v, old_val, new_val,
+ 0 /* strong */,
+ __ATOMIC_ACQUIRE,
+ __ATOMIC_RELAXED);
+}
+
+static inline void odp_atomic_store_rls_u32(odp_atomic_u32_t *atom,
+ uint32_t val)
+{
+ __atomic_store_n(&atom->v, val, __ATOMIC_RELEASE);
+}
+
+static inline void odp_atomic_add_rls_u32(odp_atomic_u32_t *atom,
+ uint32_t val)
+{
+ (void)__atomic_fetch_add(&atom->v, val, __ATOMIC_RELEASE);
+}
+
+static inline void odp_atomic_sub_rls_u32(odp_atomic_u32_t *atom,
+ uint32_t val)
+{
+ (void)__atomic_fetch_sub(&atom->v, val, __ATOMIC_RELEASE);
+}
+
/**
* @}
*/
--
2.6.2
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