Method pop_next

nodedb/src/data/executor/core_loop/priority_queues.rs:190–230

Pop the next task according to the 8:4:2 drain ratio. Each call to `pop_next` pulls one task from whichever tier has remaining budget in the current cycle. Once a tier's budget for the cycle is exhausted the next lower tier is tried; if *that* is also exhausted or empty the remaining budget cascades further down. Cycle state is maintained via the mutable `cycle` counter passed by the caller (re

(&mut self, cycle: &mut usize)

    ///
    /// Returns `None` when all tiers are empty.
    pub fn pop_next(&mut self, cycle: &mut usize) -> Option<QueuedTask> {
        // Within a 14-slot window: slots 0–7 = Critical, 8–11 = High, 12–13 = Low.
        // When a preferred tier is empty its slots go to the next lower tier.

        const CYCLE_LEN: usize = BUDGET_CRITICAL + BUDGET_HIGH + BUDGET_LOW; // 14

        let pos = *cycle % CYCLE_LEN;

        // Determine preferred tier based on cycle position.
        let preferred = if pos < BUDGET_CRITICAL {
            TierPref::Critical
        } else if pos < BUDGET_CRITICAL + BUDGET_HIGH {
            TierPref::High
        } else {
            TierPref::Low
        };

        let task = match preferred {
            TierPref::Critical => self
                .critical
                .pop_front()
                .or_else(|| self.high.pop_front())
                .or_else(|| self.low.pop_front()),
            TierPref::High => self
                .high
                .pop_front()
                .or_else(|| self.critical.pop_front())
                .or_else(|| self.low.pop_front()),
            TierPref::Low => self
                .low
                .pop_front()
                .or_else(|| self.high.pop_front())
                .or_else(|| self.critical.pop_front()),
        };

        if task.is_some() {
            *cycle = cycle.wrapping_add(1);
        }

        task
    }
}

impl Default for PriorityQueues {