Added atomic min and max operations. These can be used e.g.
to maintain high and low water marks of an another atomic counter.
These use relaxed memory order.
Signed-off-by: Petri Savolainen <petri.savolai...@nokia.com>
---
include/odp/api/atomic.h | 44 ++++++++++++++++++++++++++
platform/linux-generic/include/odp/atomic.h | 48 +++++++++++++++++++++++++++++
2 files changed, 92 insertions(+)
diff --git a/include/odp/api/atomic.h b/include/odp/api/atomic.h
index 957d304..b79a50a 100644
--- a/include/odp/api/atomic.h
+++ b/include/odp/api/atomic.h
@@ -136,6 +136,28 @@ uint32_t odp_atomic_fetch_dec_u32(odp_atomic_u32_t *atom);
void odp_atomic_dec_u32(odp_atomic_u32_t *atom);
/**
+ * Update maximum value of atomic uint32 variable
+ *
+ * Compares value of atomic variable to the new maximum value. If the new value
+ * is greater than the current value, writes the new value into the variable.
+ *
+ * @param atom Pointer to atomic variable
+ * @param new_max New maximum value to be written into the atomic variable
+ */
+void odp_atomic_max_u32(odp_atomic_u32_t *atom, uint32_t new_max);
+
+/**
+ * Update minimum value of atomic uint32 variable
+ *
+ * Compares value of atomic variable to the new minimum value. If the new value
+ * is less than the current value, writes the new value into the variable.
+ *
+ * @param atom Pointer to atomic variable
+ * @param new_min New minimum value to be written into the atomic variable
+ */
+void odp_atomic_min_u32(odp_atomic_u32_t *atom, uint32_t new_min);
+
+/**
* Compare and swap atomic uint32 variable
*
* Compares value of atomic variable to the value pointed by 'old_val'.
@@ -248,6 +270,28 @@ uint64_t odp_atomic_fetch_dec_u64(odp_atomic_u64_t *atom);
void odp_atomic_dec_u64(odp_atomic_u64_t *atom);
/**
+ * Update maximum value of atomic uint64 variable
+ *
+ * Compares value of atomic variable to the new maximum value. If the new value
+ * is greater than the current value, writes the new value into the variable.
+ *
+ * @param atom Pointer to atomic variable
+ * @param new_max New maximum value to be written into the atomic variable
+ */
+void odp_atomic_max_u64(odp_atomic_u64_t *atom, uint64_t new_max);
+
+/**
+ * Update minimum value of atomic uint64 variable
+ *
+ * Compares value of atomic variable to the new minimum value. If the new value
+ * is less than the current value, writes the new value into the variable.
+ *
+ * @param atom Pointer to atomic variable
+ * @param new_min New minimum value to be written into the atomic variable
+ */
+void odp_atomic_min_u64(odp_atomic_u64_t *atom, uint64_t new_min);
+
+/**
* Compare and swap atomic uint64 variable
*
* Compares value of atomic variable to the value pointed by 'old_val'.
diff --git a/platform/linux-generic/include/odp/atomic.h
b/platform/linux-generic/include/odp/atomic.h
index 5b13e02..b2bc5c4 100644
--- a/platform/linux-generic/include/odp/atomic.h
+++ b/platform/linux-generic/include/odp/atomic.h
@@ -94,6 +94,30 @@ static inline int odp_atomic_cas_u32(odp_atomic_u32_t *atom,
uint32_t *old_val,
__ATOMIC_RELAXED);
}
+static inline void odp_atomic_max_u32(odp_atomic_u32_t *atom, uint32_t new_max)
+{
+ uint32_t old_val;
+
+ old_val = odp_atomic_load_u32(atom);
+
+ while (new_max > old_val) {
+ if (odp_atomic_cas_u32(atom, &old_val, new_max))
+ break;
+ }
+}
+
+static inline void odp_atomic_min_u32(odp_atomic_u32_t *atom, uint32_t new_min)
+{
+ uint32_t old_val;
+
+ old_val = odp_atomic_load_u32(atom);
+
+ while (new_min < old_val) {
+ if (odp_atomic_cas_u32(atom, &old_val, new_min))
+ break;
+ }
+}
+
static inline void odp_atomic_init_u64(odp_atomic_u64_t *atom, uint64_t val)
{
atom->v = val;
@@ -210,6 +234,30 @@ static inline int odp_atomic_cas_u64(odp_atomic_u64_t
*atom, uint64_t *old_val,
#endif
}
+static inline void odp_atomic_max_u64(odp_atomic_u64_t *atom, uint64_t new_max)
+{
+ uint64_t old_val;
+
+ old_val = odp_atomic_load_u64(atom);
+
+ while (new_max > old_val) {
+ if (odp_atomic_cas_u64(atom, &old_val, new_max))
+ break;
+ }
+}
+
+static inline void odp_atomic_min_u64(odp_atomic_u64_t *atom, uint64_t new_min)
+{
+ uint64_t old_val;
+
+ old_val = odp_atomic_load_u64(atom);
+
+ while (new_min < old_val) {
+ if (odp_atomic_cas_u64(atom, &old_val, new_min))
+ break;
+ }
+}
+
/**
* @}
*/
--
2.6.2
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