ax_alloc/
tracking.rs

1use alloc::collections::btree_map::BTreeMap;
2use core::{
3    alloc::Layout,
4    ops::Range,
5    sync::atomic::{AtomicBool, Ordering},
6};
7
8use ax_kspin::SpinNoIrq;
9use axbacktrace::Backtrace;
10
11pub(crate) static TRACKING_ENABLED: AtomicBool = AtomicBool::new(false);
12
13#[ax_percpu::def_percpu]
14pub(crate) static IN_GLOBAL_ALLOCATOR: bool = false;
15// Re-entrancy note: `Backtrace::capture()` now uses `InlineFrames` (stack-allocated
16// array, no heap) so it does NOT re-enter the allocator. The `IN_GLOBAL_ALLOCATOR`
17// guard remains as a safety net for any future code paths that might allocate
18// during backtrace capture.
19
20/// Metadata for each allocation made by the global allocator.
21#[derive(Debug)]
22pub struct AllocationInfo {
23    /// Layout of the allocation.
24    pub layout: Layout,
25    /// Backtrace at the time of allocation.
26    pub backtrace: Backtrace,
27    /// Generation at which the allocation was made.
28    pub generation: u64,
29}
30
31pub(crate) struct GlobalState {
32    // FIXME: don't know why using HashMap causes crash
33    pub map: BTreeMap<usize, AllocationInfo>,
34    pub generation: u64,
35}
36
37static STATE: SpinNoIrq<GlobalState> = SpinNoIrq::new(GlobalState {
38    map: BTreeMap::new(),
39    generation: 0,
40});
41
42/// Enables allocation tracking.
43pub fn enable_tracking() {
44    TRACKING_ENABLED.store(true, Ordering::SeqCst);
45}
46
47/// Disables allocation tracking.
48pub fn disable_tracking() {
49    TRACKING_ENABLED.store(false, Ordering::SeqCst);
50}
51
52/// Returns whether allocation tracking is enabled.
53pub fn tracking_enabled() -> bool {
54    TRACKING_ENABLED.load(Ordering::SeqCst)
55}
56
57pub(crate) fn with_state<R>(f: impl FnOnce(Option<&mut GlobalState>) -> R) -> R {
58    IN_GLOBAL_ALLOCATOR.with_current(|in_global| {
59        if *in_global || !tracking_enabled() {
60            f(None)
61        } else {
62            *in_global = true;
63            let mut state = STATE.lock();
64            let result = f(Some(&mut state));
65            *in_global = false;
66            result
67        }
68    })
69}
70
71/// Returns the current generation of the global allocator.
72///
73/// The generation is incremented every time a new allocation is made. It
74/// can be utilized to track the changes in the allocation state over time.
75///
76/// See [`allocations_in`].
77pub fn current_generation() -> u64 {
78    STATE.lock().generation
79}
80
81/// Visits all allocations made by the global allocator within the given
82/// generation range.
83pub fn allocations_in(range: Range<u64>, visitor: impl FnMut(&AllocationInfo)) {
84    with_state(|state| {
85        state
86            .unwrap()
87            .map
88            .values()
89            .filter(move |info| range.contains(&info.generation))
90            .for_each(visitor)
91    });
92}
ax_alloc/tracking.rs

ax_alloc/
tracking.rs
