Struct AllocStats 

#[non_exhaustive]
pub struct AllocStats {
    pub total_allocations: CachePadded<AtomicUsize>,
    pub total_deallocations: CachePadded<AtomicUsize>,
    pub bytes_allocated: CachePadded<AtomicUsize>,
    pub bytes_peak: CachePadded<AtomicUsize>,
    pub failures: CachePadded<AtomicUsize>,
    pub corruption_events: CachePadded<AtomicUsize>,
}

Snapshot of allocation activity. All counters are atomic; reading is Ordering::Relaxed because counter values are advisory (operators read them for diagnostics, not for ordering guarantees).

Each counter is wrapped in CachePadded so concurrent updates from different code paths (alloc / dealloc / failure) don’t ping-pong as a single cache line when Statistics wraps a multi-thread allocator (e.g. Statistics<SharedBumpArena>). The public field type therefore reads as CachePadded<AtomicUsize>; auto-deref keeps the call sites (stats.total_allocations.fetch_add(...)) unchanged.

Width: AtomicUsize, not AtomicU64

Each counter is AtomicUsize so this crate compiles on 32-bit bare-metal targets (Cortex-M3/M4, thumbv7em-none-eabihf, wasm32-unknown-unknown without the atomics feature) that lack native 64-bit atomic ops. The convenience helpers (current_bytes, peak_bytes, live_count) widen each load to u64 at the boundary so the public read-API is uniform across host widths.

Practical impact on 32-bit:

• bytes_allocated / bytes_peak: capped at usize::MAX (4 GiB on 32-bit), which equals the address-space ceiling anyway — a tighter cap is impossible on these targets.
• total_allocations / total_deallocations / failures: cap at u32::MAX ≈ 4.3 B. For long-running 32-bit deployments, the counter wraps after that many ops; values are advisory only.
• corruption_events: cap at u32::MAX. Even at one event per microsecond (already an unrealistic attack rate) the counter would not wrap for ~71 minutes; real workloads see ≪1 event/year.

Marked #[non_exhaustive] so additional observability counters can be added in future releases without a breaking change.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

total_allocations: CachePadded<AtomicUsize>

Total successful allocate calls observed by this wrapper.

total_deallocations: CachePadded<AtomicUsize>

Total deallocate calls observed by this wrapper.

bytes_allocated: CachePadded<AtomicUsize>

Bytes currently held by live allocations.

bytes_peak: CachePadded<AtomicUsize>

High-water mark of bytes_allocated.

failures: CachePadded<AtomicUsize>

Failed allocate calls (returned AllocError).

corruption_events: CachePadded<AtomicUsize>

Detected freelist / metadata corruption events, mirrored from the inner allocator’s Allocator::corruption_events counter via fetch_max on each allocate/deallocate call through this wrapper.

The inner allocator is the source of truth (each corruption- detection site bumps its allocator-local counter at the moment of detection); this mirror lets readers of AllocStats see the corruption count alongside the other counters without needing to reach through to the inner.

Eventually consistent: between calls to this wrapper, the inner counter may have advanced. The mirror is updated on every allocate and deallocate through this wrapper.

Implementations

impl AllocStats

pub const fn new() -> Self

Construct fresh zeroed counters.

pub fn current_bytes(&self) -> u64

Bytes currently in use. Widened to u64 at the boundary so callers get a uniform read-API across 32-bit and 64-bit hosts; the underlying counter is AtomicUsize (capped at usize::MAX).

pub fn peak_bytes(&self) -> u64

Peak bytes ever in use during the wrapper’s lifetime. Widened to u64 at the boundary — see current_bytes.

pub fn live_count(&self) -> i64

Net live allocation count (allocations − deallocations).

Trait Implementations

impl Debug for AllocStats

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for AllocStats

fn default() -> Self

Returns the “default value” for a type.