| // Copyright 2026 The Fuchsia Authors |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #![no_std] |
| |
| use core::sync::atomic::{AtomicU64, Ordering}; |
| |
| // Decrease the likelihood of collisions with zero-based userspace flow ID |
| // generators by starting in the second half of the flow ID space. |
| const FIRST_KERNEL_FLOW_ID: u64 = 1 << 63; |
| |
| static FLOW_ID_GENERATOR: AtomicU64 = AtomicU64::new(FIRST_KERNEL_FLOW_ID); |
| |
| /// Generates globally unique 64-bit flow IDs for tracing. |
| pub fn generate() -> u64 { |
| FLOW_ID_GENERATOR.fetch_add(1, Ordering::Relaxed) |
| } |
| |
| /// Generates globally unique 64-bit flow IDs for tracing (C-exported). |
| #[unsafe(no_mangle)] |
| pub extern "C" fn flow_id_generate() -> u64 { |
| generate() |
| } |
