Function init_governor

nodedb/src/memory/startup.rs:23–46

Initialize the memory governor from engine byte budgets. Called once at startup. The returned governor is shared (via `Arc`) across the Control Plane and all Data Plane cores. `budgets` carries a byte limit for **every** [`EngineId`]; the governor reports any engine without a budget as being at Emergency pressure, which rejects that engine's writes with `resources exhausted`, so the full map is

(
    global_ceiling: usize,
    budgets: &EngineByteBudgets,
)

/// [`crate::config::EngineConfig::to_byte_budgets`], which derives one
/// entry per `EngineId::ALL` member.
pub fn init_governor(
    global_ceiling: usize,
    budgets: &EngineByteBudgets,
) -> crate::Result<Arc<MemoryGovernor>> {
    let engine_limits = budgets.as_engine_limits().clone();

    let config = GovernorConfig {
        global_ceiling,
        engine_limits,
    };

    let governor = MemoryGovernor::new(config).map_err(|e| crate::Error::Config {
        detail: format!("failed to initialize memory governor: {e}"),
    })?;

    info!(
        global_ceiling,
        engines = EngineId::ALL.len(),
        total_engine_budget = budgets.total(),
        "memory governor initialized"
    );

    Ok(Arc::new(governor))
}

#[cfg(test)]
mod tests {