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Split LockFreeQueue into base and notifying variants to reduce memory usage

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J. Nick Koston 2025-07-05 08:59:19 -05:00
parent e173b7f0c2
commit dfcc3206f7
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1 changed files with 8 additions and 8 deletions
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16
esphome/core/lock_free_queue.h
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@ -38,12 +38,13 @@ template<class T, uint8_t SIZE> class LockFreeQueue {
bool push(T *element) {
bool was_empty;
return push_internal_(element, was_empty);
uint8_t old_tail;
return push_internal_(element, was_empty, old_tail);
}
protected:
// Internal push that reports if queue was empty - for use by derived classes
bool push_internal_(T *element, bool &was_empty) {
// Internal push that reports queue state - for use by derived classes
bool push_internal_(T *element, bool &was_empty, uint8_t &old_tail) {
if (element == nullptr)
return false;
@ -60,6 +61,7 @@ template<class T, uint8_t SIZE> class LockFreeQueue {
}
was_empty = (current_tail == head_before);
old_tail = current_tail;
buffer_[current_tail] = element;
tail_.store(next_tail, std::memory_order_release);
@ -116,7 +118,8 @@ template<class T, uint8_t SIZE> class NotifyingLockFreeQueue : public LockFreeQu
bool push(T *element) {
bool was_empty;
bool result = this->push_internal_(element, was_empty);
uint8_t old_tail;
bool result = this->push_internal_(element, was_empty, old_tail);
// Notify optimization: only notify if we need to
if (result && task_to_notify_ != nullptr) {
@ -125,11 +128,8 @@ template<class T, uint8_t SIZE> class NotifyingLockFreeQueue : public LockFreeQu
xTaskNotifyGive(task_to_notify_);
} else {
// Queue wasn't empty - check if consumer has caught up to previous tail
uint8_t current_tail = this->tail_.load(std::memory_order_relaxed);
uint8_t head_after = this->head_.load(std::memory_order_acquire);
// We just pushed, so go back one position to get the old tail
uint8_t previous_tail = (current_tail + SIZE - 1) % SIZE;
if (head_after == previous_tail) {
if (head_after == old_tail) {
// Consumer just caught up to where tail was - might go to sleep, must notify
// Note: There's a benign race here - between reading head_after and calling
// xTaskNotifyGive(), the consumer could advance further. This would result