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-rw-r--r--src/queue.cpp29
1 files changed, 12 insertions, 17 deletions
diff --git a/src/queue.cpp b/src/queue.cpp
index 5585b772f..05076cfbd 100644
--- a/src/queue.cpp
+++ b/src/queue.cpp
@@ -11,37 +11,32 @@ struct MPSCNode {
template <typename T>
struct MPSCQueue {
gbAllocator allocator;
- std::atomic<isize> count;
+ MPSCNode<T> sentinel;
std::atomic<MPSCNode<T> *> head;
std::atomic<MPSCNode<T> *> tail;
- MPSCNode<T> sentinel;
+ std::atomic<isize> count;
};
-template <typename T> gb_internal void mpsc_init (MPSCQueue<T> *q, gbAllocator const &allocator);
-template <typename T> gb_internal void mpsc_destroy(MPSCQueue<T> *q);
-template <typename T> gb_internal isize mpsc_enqueue(MPSCQueue<T> *q, T const &value);
-template <typename T> gb_internal bool mpsc_dequeue(MPSCQueue<T> *q, T *value_);
-template <typename T> gb_internal MPSCNode<T> *mpsc_tail (MPSCQueue<T> *q);
+template <typename T> gb_internal void mpsc_init (MPSCQueue<T> *q, gbAllocator const &allocator);
+template <typename T> gb_internal void mpsc_destroy(MPSCQueue<T> *q);
+template <typename T> gb_internal isize mpsc_enqueue(MPSCQueue<T> *q, T const &value);
+template <typename T> gb_internal bool mpsc_dequeue(MPSCQueue<T> *q, T *value_);
template <typename T>
gb_internal void mpsc_init(MPSCQueue<T> *q, gbAllocator const &allocator) {
q->allocator = allocator;
- q->count.store(0, std::memory_order_relaxed);
+ q->sentinel.next.store(nullptr, std::memory_order_relaxed);
q->head.store(&q->sentinel, std::memory_order_relaxed);
q->tail.store(&q->sentinel, std::memory_order_relaxed);
-
- q->sentinel.next.store(nullptr, std::memory_order_relaxed);
+ q->count.store(0, std::memory_order_relaxed);
}
template <typename T>
gb_internal void mpsc_destroy(MPSCQueue<T> *q) {
- while (mpsc_dequeue(q, (T *)nullptr)) {}
- // DO NOTHING for the time being
- // free the nodes later
+ GB_ASSERT(q->count.load() == 0);
}
-
template <typename T>
gb_internal MPSCNode<T> *mpsc_alloc_node(MPSCQueue<T> *q, T const &value) {
auto new_node = gb_alloc_item(q->allocator, MPSCNode<T>);
@@ -51,7 +46,7 @@ gb_internal MPSCNode<T> *mpsc_alloc_node(MPSCQueue<T> *q, T const &value) {
template <typename T>
gb_internal void mpsc_free_node(MPSCQueue<T> *q, MPSCNode<T> *node) {
- // TODO(bill): reuse the free nodes
+ // TODO(bill): determine a good way to handle the freed nodes rather than letting them leak
}
template <typename T>
@@ -59,7 +54,7 @@ gb_internal isize mpsc_enqueue(MPSCQueue<T> *q, MPSCNode<T> *node) {
node->next.store(nullptr, std::memory_order_relaxed);
auto prev = q->head.exchange(node, std::memory_order_acq_rel);
prev->next.store(node, std::memory_order_release);
- isize count = 1 + q->count.fetch_add(1, std::memory_order_acq_rel);
+ isize count = 1 + q->count.fetch_add(1, std::memory_order_relaxed);
return count;
}
@@ -77,8 +72,8 @@ gb_internal bool mpsc_dequeue(MPSCQueue<T> *q, T *value_) {
if (next) {
q->tail.store(next, std::memory_order_relaxed);
if (value_) *value_ = next->value;
+ q->count.fetch_sub(1, std::memory_order_relaxed);
mpsc_free_node(q, tail);
- q->count.fetch_sub(1, std::memory_order_acq_rel);
return true;
}
GB_ASSERT(q->count.load(std::memory_order_acquire) == 0);