mirror of
https://github.com/ziglang/zig.git
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1416 lines
58 KiB
Zig
1416 lines
58 KiB
Zig
//! # General Purpose Allocator
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//!
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//! ## Design Priorities
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//!
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//! ### `OptimizationMode.debug` and `OptimizationMode.release_safe`:
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//!
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//! * Detect double free, and emit stack trace of:
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//! - Where it was first allocated
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//! - Where it was freed the first time
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//! - Where it was freed the second time
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//!
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//! * Detect leaks and emit stack trace of:
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//! - Where it was allocated
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//!
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//! * When a page of memory is no longer needed, give it back to resident memory
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//! as soon as possible, so that it causes page faults when used.
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//!
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//! * Do not re-use memory slots, so that memory safety is upheld. For small
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//! allocations, this is handled here; for larger ones it is handled in the
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//! backing allocator (by default `std.heap.page_allocator`).
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//!
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//! * Make pointer math errors unlikely to harm memory from
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//! unrelated allocations.
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//!
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//! * It's OK for these mechanisms to cost some extra overhead bytes.
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//!
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//! * It's OK for performance cost for these mechanisms.
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//!
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//! * Rogue memory writes should not harm the allocator's state.
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//!
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//! * Cross platform. Operates based on a backing allocator which makes it work
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//! everywhere, even freestanding.
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//!
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//! * Compile-time configuration.
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//!
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//! ### `OptimizationMode.release_fast` (note: not much work has gone into this use case yet):
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//!
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//! * Low fragmentation is primary concern
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//! * Performance of worst-case latency is secondary concern
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//! * Performance of average-case latency is next
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//! * Finally, having freed memory unmapped, and pointer math errors unlikely to
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//! harm memory from unrelated allocations are nice-to-haves.
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//!
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//! ### `OptimizationMode.release_small` (note: not much work has gone into this use case yet):
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//!
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//! * Small binary code size of the executable is the primary concern.
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//! * Next, defer to the `.release_fast` priority list.
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//!
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//! ## Basic Design:
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//!
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//! Small allocations are divided into buckets:
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//!
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//! ```
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//! index obj_size
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//! 0 1
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//! 1 2
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//! 2 4
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//! 3 8
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//! 4 16
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//! 5 32
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//! 6 64
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//! 7 128
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//! 8 256
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//! 9 512
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//! 10 1024
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//! 11 2048
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//! ```
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//!
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//! The main allocator state has an array of all the "current" buckets for each
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//! size class. Each slot in the array can be null, meaning the bucket for that
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//! size class is not allocated. When the first object is allocated for a given
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//! size class, it allocates 1 page of memory from the OS. This page is
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//! divided into "slots" - one per allocated object. Along with the page of memory
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//! for object slots, as many pages as necessary are allocated to store the
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//! BucketHeader, followed by "used bits", and two stack traces for each slot
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//! (allocation trace and free trace).
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//!
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//! The "used bits" are 1 bit per slot representing whether the slot is used.
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//! Allocations use the data to iterate to find a free slot. Frees assert that the
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//! corresponding bit is 1 and set it to 0.
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//!
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//! Buckets have prev and next pointers. When there is only one bucket for a given
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//! size class, both prev and next point to itself. When all slots of a bucket are
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//! used, a new bucket is allocated, and enters the doubly linked list. The main
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//! allocator state tracks the "current" bucket for each size class. Leak detection
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//! currently only checks the current bucket.
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//!
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//! Resizing detects if the size class is unchanged or smaller, in which case the same
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//! pointer is returned unmodified. If a larger size class is required,
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//! `error.OutOfMemory` is returned.
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//!
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//! Large objects are allocated directly using the backing allocator and their metadata is stored
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//! in a `std.HashMap` using the backing allocator.
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const std = @import("std");
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const builtin = @import("builtin");
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const log = std.log.scoped(.gpa);
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const math = std.math;
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const assert = std.debug.assert;
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const mem = std.mem;
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const Allocator = std.mem.Allocator;
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const page_size = std.mem.page_size;
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const StackTrace = std.builtin.StackTrace;
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/// Integer type for pointing to slots in a small allocation
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const SlotIndex = std.meta.Int(.unsigned, math.log2(page_size) + 1);
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const default_test_stack_trace_frames: usize = if (builtin.is_test) 8 else 4;
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const default_sys_stack_trace_frames: usize = if (std.debug.sys_can_stack_trace) default_test_stack_trace_frames else 0;
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const default_stack_trace_frames: usize = switch (builtin.mode) {
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.Debug => default_sys_stack_trace_frames,
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else => 0,
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};
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pub const Config = struct {
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/// Number of stack frames to capture.
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stack_trace_frames: usize = default_stack_trace_frames,
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/// If true, the allocator will have two fields:
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/// * `total_requested_bytes` which tracks the total allocated bytes of memory requested.
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/// * `requested_memory_limit` which causes allocations to return `error.OutOfMemory`
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/// when the `total_requested_bytes` exceeds this limit.
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/// If false, these fields will be `void`.
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enable_memory_limit: bool = false,
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/// Whether to enable safety checks.
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safety: bool = std.debug.runtime_safety,
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/// Whether the allocator may be used simultaneously from multiple threads.
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thread_safe: bool = !builtin.single_threaded,
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/// What type of mutex you'd like to use, for thread safety.
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/// when specified, the mutex type must have the same shape as `std.Thread.Mutex` and
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/// `DummyMutex`, and have no required fields. Specifying this field causes
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/// the `thread_safe` field to be ignored.
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///
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/// when null (default):
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/// * the mutex type defaults to `std.Thread.Mutex` when thread_safe is enabled.
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/// * the mutex type defaults to `DummyMutex` otherwise.
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MutexType: ?type = null,
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/// This is a temporary debugging trick you can use to turn segfaults into more helpful
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/// logged error messages with stack trace details. The downside is that every allocation
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/// will be leaked, unless used with retain_metadata!
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never_unmap: bool = false,
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/// This is a temporary debugging aid that retains metadata about allocations indefinitely.
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/// This allows a greater range of double frees to be reported. All metadata is freed when
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/// deinit is called. When used with never_unmap, deliberately leaked memory is also freed
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/// during deinit. Currently should be used with never_unmap to avoid segfaults.
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/// TODO https://github.com/ziglang/zig/issues/4298 will allow use without never_unmap
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retain_metadata: bool = false,
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/// Enables emitting info messages with the size and address of every allocation.
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verbose_log: bool = false,
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};
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pub const Check = enum { ok, leak };
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pub fn GeneralPurposeAllocator(comptime config: Config) type {
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return struct {
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backing_allocator: Allocator = std.heap.page_allocator,
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buckets: [small_bucket_count]?*BucketHeader = [1]?*BucketHeader{null} ** small_bucket_count,
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large_allocations: LargeAllocTable = .{},
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small_allocations: if (config.safety) SmallAllocTable else void = if (config.safety) .{} else {},
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empty_buckets: if (config.retain_metadata) ?*BucketHeader else void =
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if (config.retain_metadata) null else {},
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total_requested_bytes: @TypeOf(total_requested_bytes_init) = total_requested_bytes_init,
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requested_memory_limit: @TypeOf(requested_memory_limit_init) = requested_memory_limit_init,
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mutex: @TypeOf(mutex_init) = mutex_init,
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const Self = @This();
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const total_requested_bytes_init = if (config.enable_memory_limit) @as(usize, 0) else {};
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const requested_memory_limit_init = if (config.enable_memory_limit) @as(usize, math.maxInt(usize)) else {};
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const mutex_init = if (config.MutexType) |T|
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T{}
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else if (config.thread_safe)
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std.Thread.Mutex{}
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else
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DummyMutex{};
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const DummyMutex = struct {
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fn lock(_: *DummyMutex) void {}
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fn unlock(_: *DummyMutex) void {}
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};
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const stack_n = config.stack_trace_frames;
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const one_trace_size = @sizeOf(usize) * stack_n;
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const traces_per_slot = 2;
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pub const Error = mem.Allocator.Error;
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const small_bucket_count = math.log2(page_size);
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const largest_bucket_object_size = 1 << (small_bucket_count - 1);
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const SmallAlloc = struct {
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requested_size: usize,
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log2_ptr_align: u8,
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};
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const LargeAlloc = struct {
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bytes: []u8,
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requested_size: if (config.enable_memory_limit) usize else void,
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stack_addresses: [trace_n][stack_n]usize,
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freed: if (config.retain_metadata) bool else void,
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log2_ptr_align: if (config.never_unmap and config.retain_metadata) u8 else void,
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const trace_n = if (config.retain_metadata) traces_per_slot else 1;
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fn dumpStackTrace(self: *LargeAlloc, trace_kind: TraceKind) void {
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std.debug.dumpStackTrace(self.getStackTrace(trace_kind));
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}
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fn getStackTrace(self: *LargeAlloc, trace_kind: TraceKind) std.builtin.StackTrace {
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assert(@intFromEnum(trace_kind) < trace_n);
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const stack_addresses = &self.stack_addresses[@intFromEnum(trace_kind)];
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var len: usize = 0;
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while (len < stack_n and stack_addresses[len] != 0) {
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len += 1;
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}
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return .{
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.instruction_addresses = stack_addresses,
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.index = len,
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};
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}
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fn captureStackTrace(self: *LargeAlloc, ret_addr: usize, trace_kind: TraceKind) void {
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assert(@intFromEnum(trace_kind) < trace_n);
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const stack_addresses = &self.stack_addresses[@intFromEnum(trace_kind)];
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collectStackTrace(ret_addr, stack_addresses);
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}
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};
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const LargeAllocTable = std.AutoHashMapUnmanaged(usize, LargeAlloc);
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const SmallAllocTable = std.AutoHashMapUnmanaged(usize, SmallAlloc);
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// Bucket: In memory, in order:
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// * BucketHeader
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// * bucket_used_bits: [N]u8, // 1 bit for every slot; 1 byte for every 8 slots
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// * stack_trace_addresses: [N]usize, // traces_per_slot for every allocation
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const BucketHeader = struct {
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prev: *BucketHeader,
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next: *BucketHeader,
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page: [*]align(page_size) u8,
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alloc_cursor: SlotIndex,
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used_count: SlotIndex,
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fn usedBits(bucket: *BucketHeader, index: usize) *u8 {
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return @as(*u8, @ptrFromInt(@intFromPtr(bucket) + @sizeOf(BucketHeader) + index));
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}
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fn stackTracePtr(
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bucket: *BucketHeader,
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size_class: usize,
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slot_index: SlotIndex,
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trace_kind: TraceKind,
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) *[stack_n]usize {
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const start_ptr = @as([*]u8, @ptrCast(bucket)) + bucketStackFramesStart(size_class);
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const addr = start_ptr + one_trace_size * traces_per_slot * slot_index +
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@intFromEnum(trace_kind) * @as(usize, one_trace_size);
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return @ptrCast(@alignCast(addr));
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}
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fn captureStackTrace(
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bucket: *BucketHeader,
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ret_addr: usize,
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size_class: usize,
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slot_index: SlotIndex,
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trace_kind: TraceKind,
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) void {
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// Initialize them to 0. When determining the count we must look
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// for non zero addresses.
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const stack_addresses = bucket.stackTracePtr(size_class, slot_index, trace_kind);
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collectStackTrace(ret_addr, stack_addresses);
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}
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};
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pub fn allocator(self: *Self) Allocator {
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return .{
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.ptr = self,
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.vtable = &.{
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.alloc = alloc,
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.resize = resize,
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.free = free,
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},
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};
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}
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fn bucketStackTrace(
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bucket: *BucketHeader,
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size_class: usize,
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slot_index: SlotIndex,
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trace_kind: TraceKind,
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) StackTrace {
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const stack_addresses = bucket.stackTracePtr(size_class, slot_index, trace_kind);
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var len: usize = 0;
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while (len < stack_n and stack_addresses[len] != 0) {
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len += 1;
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}
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return StackTrace{
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.instruction_addresses = stack_addresses,
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.index = len,
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};
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}
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fn bucketStackFramesStart(size_class: usize) usize {
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return mem.alignForward(
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usize,
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@sizeOf(BucketHeader) + usedBitsCount(size_class),
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@alignOf(usize),
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);
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}
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fn bucketSize(size_class: usize) usize {
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const slot_count = @divExact(page_size, size_class);
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return bucketStackFramesStart(size_class) + one_trace_size * traces_per_slot * slot_count;
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}
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fn usedBitsCount(size_class: usize) usize {
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const slot_count = @divExact(page_size, size_class);
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if (slot_count < 8) return 1;
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return @divExact(slot_count, 8);
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}
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fn detectLeaksInBucket(
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bucket: *BucketHeader,
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size_class: usize,
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used_bits_count: usize,
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) bool {
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var leaks = false;
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var used_bits_byte: usize = 0;
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while (used_bits_byte < used_bits_count) : (used_bits_byte += 1) {
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const used_byte = bucket.usedBits(used_bits_byte).*;
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if (used_byte != 0) {
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var bit_index: u3 = 0;
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while (true) : (bit_index += 1) {
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const is_used = @as(u1, @truncate(used_byte >> bit_index)) != 0;
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if (is_used) {
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const slot_index = @as(SlotIndex, @intCast(used_bits_byte * 8 + bit_index));
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const stack_trace = bucketStackTrace(bucket, size_class, slot_index, .alloc);
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const addr = bucket.page + slot_index * size_class;
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log.err("memory address 0x{x} leaked: {}", .{
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@intFromPtr(addr), stack_trace,
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});
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leaks = true;
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}
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if (bit_index == math.maxInt(u3))
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break;
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}
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}
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}
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return leaks;
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}
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/// Emits log messages for leaks and then returns whether there were any leaks.
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pub fn detectLeaks(self: *Self) bool {
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var leaks = false;
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for (self.buckets, 0..) |optional_bucket, bucket_i| {
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const first_bucket = optional_bucket orelse continue;
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const size_class = @as(usize, 1) << @as(math.Log2Int(usize), @intCast(bucket_i));
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const used_bits_count = usedBitsCount(size_class);
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var bucket = first_bucket;
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while (true) {
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leaks = detectLeaksInBucket(bucket, size_class, used_bits_count) or leaks;
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bucket = bucket.next;
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if (bucket == first_bucket)
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break;
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}
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}
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var it = self.large_allocations.valueIterator();
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while (it.next()) |large_alloc| {
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if (config.retain_metadata and large_alloc.freed) continue;
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const stack_trace = large_alloc.getStackTrace(.alloc);
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log.err("memory address 0x{x} leaked: {}", .{
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@intFromPtr(large_alloc.bytes.ptr), stack_trace,
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});
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leaks = true;
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}
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return leaks;
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}
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fn freeBucket(self: *Self, bucket: *BucketHeader, size_class: usize) void {
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const bucket_size = bucketSize(size_class);
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const bucket_slice = @as([*]align(@alignOf(BucketHeader)) u8, @ptrCast(bucket))[0..bucket_size];
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self.backing_allocator.free(bucket_slice);
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}
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fn freeRetainedMetadata(self: *Self) void {
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if (config.retain_metadata) {
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if (config.never_unmap) {
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// free large allocations that were intentionally leaked by never_unmap
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var it = self.large_allocations.iterator();
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while (it.next()) |large| {
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if (large.value_ptr.freed) {
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self.backing_allocator.rawFree(large.value_ptr.bytes, large.value_ptr.log2_ptr_align, @returnAddress());
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}
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}
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}
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// free retained metadata for small allocations
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if (self.empty_buckets) |first_bucket| {
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var bucket = first_bucket;
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while (true) {
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const prev = bucket.prev;
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if (config.never_unmap) {
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// free page that was intentionally leaked by never_unmap
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self.backing_allocator.free(bucket.page[0..page_size]);
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}
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// alloc_cursor was set to slot count when bucket added to empty_buckets
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self.freeBucket(bucket, @divExact(page_size, bucket.alloc_cursor));
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bucket = prev;
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if (bucket == first_bucket)
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break;
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}
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self.empty_buckets = null;
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}
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}
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}
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pub usingnamespace if (config.retain_metadata) struct {
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pub fn flushRetainedMetadata(self: *Self) void {
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self.freeRetainedMetadata();
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// also remove entries from large_allocations
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var it = self.large_allocations.iterator();
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while (it.next()) |large| {
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if (large.value_ptr.freed) {
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_ = self.large_allocations.remove(@intFromPtr(large.value_ptr.bytes.ptr));
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}
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}
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}
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} else struct {};
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/// Returns `Check.leak` if there were leaks; `Check.ok` otherwise.
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pub fn deinit(self: *Self) Check {
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const leaks = if (config.safety) self.detectLeaks() else false;
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if (config.retain_metadata) {
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self.freeRetainedMetadata();
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}
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self.large_allocations.deinit(self.backing_allocator);
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if (config.safety) {
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self.small_allocations.deinit(self.backing_allocator);
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}
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self.* = undefined;
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return @as(Check, @enumFromInt(@intFromBool(leaks)));
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}
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fn collectStackTrace(first_trace_addr: usize, addresses: *[stack_n]usize) void {
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if (stack_n == 0) return;
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@memset(addresses, 0);
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var stack_trace = StackTrace{
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.instruction_addresses = addresses,
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.index = 0,
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};
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std.debug.captureStackTrace(first_trace_addr, &stack_trace);
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}
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fn reportDoubleFree(ret_addr: usize, alloc_stack_trace: StackTrace, free_stack_trace: StackTrace) void {
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var addresses: [stack_n]usize = [1]usize{0} ** stack_n;
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var second_free_stack_trace = StackTrace{
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.instruction_addresses = &addresses,
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.index = 0,
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};
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std.debug.captureStackTrace(ret_addr, &second_free_stack_trace);
|
|
log.err("Double free detected. Allocation: {} First free: {} Second free: {}", .{
|
|
alloc_stack_trace, free_stack_trace, second_free_stack_trace,
|
|
});
|
|
}
|
|
|
|
fn allocSlot(self: *Self, size_class: usize, trace_addr: usize) Error![*]u8 {
|
|
const bucket_index = math.log2(size_class);
|
|
const first_bucket = self.buckets[bucket_index] orelse try self.createBucket(
|
|
size_class,
|
|
bucket_index,
|
|
);
|
|
var bucket = first_bucket;
|
|
const slot_count = @divExact(page_size, size_class);
|
|
while (bucket.alloc_cursor == slot_count) {
|
|
const prev_bucket = bucket;
|
|
bucket = prev_bucket.next;
|
|
if (bucket == first_bucket) {
|
|
// make a new one
|
|
bucket = try self.createBucket(size_class, bucket_index);
|
|
bucket.prev = prev_bucket;
|
|
bucket.next = prev_bucket.next;
|
|
prev_bucket.next = bucket;
|
|
bucket.next.prev = bucket;
|
|
}
|
|
}
|
|
// change the allocator's current bucket to be this one
|
|
self.buckets[bucket_index] = bucket;
|
|
|
|
const slot_index = bucket.alloc_cursor;
|
|
bucket.alloc_cursor += 1;
|
|
|
|
var used_bits_byte = bucket.usedBits(slot_index / 8);
|
|
const used_bit_index: u3 = @as(u3, @intCast(slot_index % 8)); // TODO cast should be unnecessary
|
|
used_bits_byte.* |= (@as(u8, 1) << used_bit_index);
|
|
bucket.used_count += 1;
|
|
bucket.captureStackTrace(trace_addr, size_class, slot_index, .alloc);
|
|
return bucket.page + slot_index * size_class;
|
|
}
|
|
|
|
fn searchBucket(
|
|
bucket_list: ?*BucketHeader,
|
|
addr: usize,
|
|
) ?*BucketHeader {
|
|
const first_bucket = bucket_list orelse return null;
|
|
var bucket = first_bucket;
|
|
while (true) {
|
|
const in_bucket_range = (addr >= @intFromPtr(bucket.page) and
|
|
addr < @intFromPtr(bucket.page) + page_size);
|
|
if (in_bucket_range) return bucket;
|
|
bucket = bucket.prev;
|
|
if (bucket == first_bucket) {
|
|
return null;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// This function assumes the object is in the large object storage regardless
|
|
/// of the parameters.
|
|
fn resizeLarge(
|
|
self: *Self,
|
|
old_mem: []u8,
|
|
log2_old_align: u8,
|
|
new_size: usize,
|
|
ret_addr: usize,
|
|
) bool {
|
|
const entry = self.large_allocations.getEntry(@intFromPtr(old_mem.ptr)) orelse {
|
|
if (config.safety) {
|
|
@panic("Invalid free");
|
|
} else {
|
|
unreachable;
|
|
}
|
|
};
|
|
|
|
if (config.retain_metadata and entry.value_ptr.freed) {
|
|
if (config.safety) {
|
|
reportDoubleFree(ret_addr, entry.value_ptr.getStackTrace(.alloc), entry.value_ptr.getStackTrace(.free));
|
|
@panic("Unrecoverable double free");
|
|
} else {
|
|
unreachable;
|
|
}
|
|
}
|
|
|
|
if (config.safety and old_mem.len != entry.value_ptr.bytes.len) {
|
|
var addresses: [stack_n]usize = [1]usize{0} ** stack_n;
|
|
var free_stack_trace = StackTrace{
|
|
.instruction_addresses = &addresses,
|
|
.index = 0,
|
|
};
|
|
std.debug.captureStackTrace(ret_addr, &free_stack_trace);
|
|
log.err("Allocation size {d} bytes does not match free size {d}. Allocation: {} Free: {}", .{
|
|
entry.value_ptr.bytes.len,
|
|
old_mem.len,
|
|
entry.value_ptr.getStackTrace(.alloc),
|
|
free_stack_trace,
|
|
});
|
|
}
|
|
|
|
// Do memory limit accounting with requested sizes rather than what
|
|
// backing_allocator returns because if we want to return
|
|
// error.OutOfMemory, we have to leave allocation untouched, and
|
|
// that is impossible to guarantee after calling
|
|
// backing_allocator.rawResize.
|
|
const prev_req_bytes = self.total_requested_bytes;
|
|
if (config.enable_memory_limit) {
|
|
const new_req_bytes = prev_req_bytes + new_size - entry.value_ptr.requested_size;
|
|
if (new_req_bytes > prev_req_bytes and new_req_bytes > self.requested_memory_limit) {
|
|
return false;
|
|
}
|
|
self.total_requested_bytes = new_req_bytes;
|
|
}
|
|
|
|
if (!self.backing_allocator.rawResize(old_mem, log2_old_align, new_size, ret_addr)) {
|
|
if (config.enable_memory_limit) {
|
|
self.total_requested_bytes = prev_req_bytes;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
if (config.enable_memory_limit) {
|
|
entry.value_ptr.requested_size = new_size;
|
|
}
|
|
|
|
if (config.verbose_log) {
|
|
log.info("large resize {d} bytes at {*} to {d}", .{
|
|
old_mem.len, old_mem.ptr, new_size,
|
|
});
|
|
}
|
|
entry.value_ptr.bytes = old_mem.ptr[0..new_size];
|
|
entry.value_ptr.captureStackTrace(ret_addr, .alloc);
|
|
return true;
|
|
}
|
|
|
|
/// This function assumes the object is in the large object storage regardless
|
|
/// of the parameters.
|
|
fn freeLarge(
|
|
self: *Self,
|
|
old_mem: []u8,
|
|
log2_old_align: u8,
|
|
ret_addr: usize,
|
|
) void {
|
|
const entry = self.large_allocations.getEntry(@intFromPtr(old_mem.ptr)) orelse {
|
|
if (config.safety) {
|
|
@panic("Invalid free");
|
|
} else {
|
|
unreachable;
|
|
}
|
|
};
|
|
|
|
if (config.retain_metadata and entry.value_ptr.freed) {
|
|
if (config.safety) {
|
|
reportDoubleFree(ret_addr, entry.value_ptr.getStackTrace(.alloc), entry.value_ptr.getStackTrace(.free));
|
|
return;
|
|
} else {
|
|
unreachable;
|
|
}
|
|
}
|
|
|
|
if (config.safety and old_mem.len != entry.value_ptr.bytes.len) {
|
|
var addresses: [stack_n]usize = [1]usize{0} ** stack_n;
|
|
var free_stack_trace = StackTrace{
|
|
.instruction_addresses = &addresses,
|
|
.index = 0,
|
|
};
|
|
std.debug.captureStackTrace(ret_addr, &free_stack_trace);
|
|
log.err("Allocation size {d} bytes does not match free size {d}. Allocation: {} Free: {}", .{
|
|
entry.value_ptr.bytes.len,
|
|
old_mem.len,
|
|
entry.value_ptr.getStackTrace(.alloc),
|
|
free_stack_trace,
|
|
});
|
|
}
|
|
|
|
if (!config.never_unmap) {
|
|
self.backing_allocator.rawFree(old_mem, log2_old_align, ret_addr);
|
|
}
|
|
|
|
if (config.enable_memory_limit) {
|
|
self.total_requested_bytes -= entry.value_ptr.requested_size;
|
|
}
|
|
|
|
if (config.verbose_log) {
|
|
log.info("large free {d} bytes at {*}", .{ old_mem.len, old_mem.ptr });
|
|
}
|
|
|
|
if (!config.retain_metadata) {
|
|
assert(self.large_allocations.remove(@intFromPtr(old_mem.ptr)));
|
|
} else {
|
|
entry.value_ptr.freed = true;
|
|
entry.value_ptr.captureStackTrace(ret_addr, .free);
|
|
}
|
|
}
|
|
|
|
pub fn setRequestedMemoryLimit(self: *Self, limit: usize) void {
|
|
self.requested_memory_limit = limit;
|
|
}
|
|
|
|
fn resize(
|
|
ctx: *anyopaque,
|
|
old_mem: []u8,
|
|
log2_old_align_u8: u8,
|
|
new_size: usize,
|
|
ret_addr: usize,
|
|
) bool {
|
|
const self: *Self = @ptrCast(@alignCast(ctx));
|
|
const log2_old_align = @as(Allocator.Log2Align, @intCast(log2_old_align_u8));
|
|
self.mutex.lock();
|
|
defer self.mutex.unlock();
|
|
|
|
assert(old_mem.len != 0);
|
|
|
|
const aligned_size = @max(old_mem.len, @as(usize, 1) << log2_old_align);
|
|
if (aligned_size > largest_bucket_object_size) {
|
|
return self.resizeLarge(old_mem, log2_old_align, new_size, ret_addr);
|
|
}
|
|
const size_class_hint = math.ceilPowerOfTwoAssert(usize, aligned_size);
|
|
|
|
var bucket_index = math.log2(size_class_hint);
|
|
var size_class: usize = size_class_hint;
|
|
const bucket = while (bucket_index < small_bucket_count) : (bucket_index += 1) {
|
|
if (searchBucket(self.buckets[bucket_index], @intFromPtr(old_mem.ptr))) |bucket| {
|
|
// move bucket to head of list to optimize search for nearby allocations
|
|
self.buckets[bucket_index] = bucket;
|
|
break bucket;
|
|
}
|
|
size_class *= 2;
|
|
} else blk: {
|
|
if (config.retain_metadata) {
|
|
if (!self.large_allocations.contains(@intFromPtr(old_mem.ptr))) {
|
|
// object not in active buckets or a large allocation, so search empty buckets
|
|
if (searchBucket(self.empty_buckets, @intFromPtr(old_mem.ptr))) |bucket| {
|
|
// bucket is empty so is_used below will always be false and we exit there
|
|
break :blk bucket;
|
|
} else {
|
|
@panic("Invalid free");
|
|
}
|
|
}
|
|
}
|
|
return self.resizeLarge(old_mem, log2_old_align, new_size, ret_addr);
|
|
};
|
|
const byte_offset = @intFromPtr(old_mem.ptr) - @intFromPtr(bucket.page);
|
|
const slot_index = @as(SlotIndex, @intCast(byte_offset / size_class));
|
|
const used_byte_index = slot_index / 8;
|
|
const used_bit_index = @as(u3, @intCast(slot_index % 8));
|
|
const used_byte = bucket.usedBits(used_byte_index);
|
|
const is_used = @as(u1, @truncate(used_byte.* >> used_bit_index)) != 0;
|
|
if (!is_used) {
|
|
if (config.safety) {
|
|
reportDoubleFree(ret_addr, bucketStackTrace(bucket, size_class, slot_index, .alloc), bucketStackTrace(bucket, size_class, slot_index, .free));
|
|
@panic("Unrecoverable double free");
|
|
} else {
|
|
unreachable;
|
|
}
|
|
}
|
|
|
|
// Definitely an in-use small alloc now.
|
|
if (config.safety) {
|
|
const entry = self.small_allocations.getEntry(@intFromPtr(old_mem.ptr)) orelse
|
|
@panic("Invalid free");
|
|
if (old_mem.len != entry.value_ptr.requested_size or log2_old_align != entry.value_ptr.log2_ptr_align) {
|
|
var addresses: [stack_n]usize = [1]usize{0} ** stack_n;
|
|
var free_stack_trace = StackTrace{
|
|
.instruction_addresses = &addresses,
|
|
.index = 0,
|
|
};
|
|
std.debug.captureStackTrace(ret_addr, &free_stack_trace);
|
|
if (old_mem.len != entry.value_ptr.requested_size) {
|
|
log.err("Allocation size {d} bytes does not match resize size {d}. Allocation: {} Resize: {}", .{
|
|
entry.value_ptr.requested_size,
|
|
old_mem.len,
|
|
bucketStackTrace(bucket, size_class, slot_index, .alloc),
|
|
free_stack_trace,
|
|
});
|
|
}
|
|
if (log2_old_align != entry.value_ptr.log2_ptr_align) {
|
|
log.err("Allocation alignment {d} does not match resize alignment {d}. Allocation: {} Resize: {}", .{
|
|
@as(usize, 1) << @as(math.Log2Int(usize), @intCast(entry.value_ptr.log2_ptr_align)),
|
|
@as(usize, 1) << @as(math.Log2Int(usize), @intCast(log2_old_align)),
|
|
bucketStackTrace(bucket, size_class, slot_index, .alloc),
|
|
free_stack_trace,
|
|
});
|
|
}
|
|
}
|
|
}
|
|
const prev_req_bytes = self.total_requested_bytes;
|
|
if (config.enable_memory_limit) {
|
|
const new_req_bytes = prev_req_bytes + new_size - old_mem.len;
|
|
if (new_req_bytes > prev_req_bytes and new_req_bytes > self.requested_memory_limit) {
|
|
return false;
|
|
}
|
|
self.total_requested_bytes = new_req_bytes;
|
|
}
|
|
|
|
const new_aligned_size = @max(new_size, @as(usize, 1) << log2_old_align);
|
|
const new_size_class = math.ceilPowerOfTwoAssert(usize, new_aligned_size);
|
|
if (new_size_class <= size_class) {
|
|
if (old_mem.len > new_size) {
|
|
@memset(old_mem[new_size..], undefined);
|
|
}
|
|
if (config.verbose_log) {
|
|
log.info("small resize {d} bytes at {*} to {d}", .{
|
|
old_mem.len, old_mem.ptr, new_size,
|
|
});
|
|
}
|
|
if (config.safety) {
|
|
const entry = self.small_allocations.getEntry(@intFromPtr(old_mem.ptr)).?;
|
|
entry.value_ptr.requested_size = new_size;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
if (config.enable_memory_limit) {
|
|
self.total_requested_bytes = prev_req_bytes;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
fn free(
|
|
ctx: *anyopaque,
|
|
old_mem: []u8,
|
|
log2_old_align_u8: u8,
|
|
ret_addr: usize,
|
|
) void {
|
|
const self: *Self = @ptrCast(@alignCast(ctx));
|
|
const log2_old_align = @as(Allocator.Log2Align, @intCast(log2_old_align_u8));
|
|
self.mutex.lock();
|
|
defer self.mutex.unlock();
|
|
|
|
assert(old_mem.len != 0);
|
|
|
|
const aligned_size = @max(old_mem.len, @as(usize, 1) << log2_old_align);
|
|
if (aligned_size > largest_bucket_object_size) {
|
|
self.freeLarge(old_mem, log2_old_align, ret_addr);
|
|
return;
|
|
}
|
|
const size_class_hint = math.ceilPowerOfTwoAssert(usize, aligned_size);
|
|
|
|
var bucket_index = math.log2(size_class_hint);
|
|
var size_class: usize = size_class_hint;
|
|
const bucket = while (bucket_index < small_bucket_count) : (bucket_index += 1) {
|
|
if (searchBucket(self.buckets[bucket_index], @intFromPtr(old_mem.ptr))) |bucket| {
|
|
// move bucket to head of list to optimize search for nearby allocations
|
|
self.buckets[bucket_index] = bucket;
|
|
break bucket;
|
|
}
|
|
size_class *= 2;
|
|
} else blk: {
|
|
if (config.retain_metadata) {
|
|
if (!self.large_allocations.contains(@intFromPtr(old_mem.ptr))) {
|
|
// object not in active buckets or a large allocation, so search empty buckets
|
|
if (searchBucket(self.empty_buckets, @intFromPtr(old_mem.ptr))) |bucket| {
|
|
// bucket is empty so is_used below will always be false and we exit there
|
|
break :blk bucket;
|
|
} else {
|
|
@panic("Invalid free");
|
|
}
|
|
}
|
|
}
|
|
self.freeLarge(old_mem, log2_old_align, ret_addr);
|
|
return;
|
|
};
|
|
const byte_offset = @intFromPtr(old_mem.ptr) - @intFromPtr(bucket.page);
|
|
const slot_index = @as(SlotIndex, @intCast(byte_offset / size_class));
|
|
const used_byte_index = slot_index / 8;
|
|
const used_bit_index = @as(u3, @intCast(slot_index % 8));
|
|
const used_byte = bucket.usedBits(used_byte_index);
|
|
const is_used = @as(u1, @truncate(used_byte.* >> used_bit_index)) != 0;
|
|
if (!is_used) {
|
|
if (config.safety) {
|
|
reportDoubleFree(ret_addr, bucketStackTrace(bucket, size_class, slot_index, .alloc), bucketStackTrace(bucket, size_class, slot_index, .free));
|
|
// Recoverable if this is a free.
|
|
return;
|
|
} else {
|
|
unreachable;
|
|
}
|
|
}
|
|
|
|
// Definitely an in-use small alloc now.
|
|
if (config.safety) {
|
|
const entry = self.small_allocations.getEntry(@intFromPtr(old_mem.ptr)) orelse
|
|
@panic("Invalid free");
|
|
if (old_mem.len != entry.value_ptr.requested_size or log2_old_align != entry.value_ptr.log2_ptr_align) {
|
|
var addresses: [stack_n]usize = [1]usize{0} ** stack_n;
|
|
var free_stack_trace = StackTrace{
|
|
.instruction_addresses = &addresses,
|
|
.index = 0,
|
|
};
|
|
std.debug.captureStackTrace(ret_addr, &free_stack_trace);
|
|
if (old_mem.len != entry.value_ptr.requested_size) {
|
|
log.err("Allocation size {d} bytes does not match free size {d}. Allocation: {} Free: {}", .{
|
|
entry.value_ptr.requested_size,
|
|
old_mem.len,
|
|
bucketStackTrace(bucket, size_class, slot_index, .alloc),
|
|
free_stack_trace,
|
|
});
|
|
}
|
|
if (log2_old_align != entry.value_ptr.log2_ptr_align) {
|
|
log.err("Allocation alignment {d} does not match free alignment {d}. Allocation: {} Free: {}", .{
|
|
@as(usize, 1) << @as(math.Log2Int(usize), @intCast(entry.value_ptr.log2_ptr_align)),
|
|
@as(usize, 1) << @as(math.Log2Int(usize), @intCast(log2_old_align)),
|
|
bucketStackTrace(bucket, size_class, slot_index, .alloc),
|
|
free_stack_trace,
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
if (config.enable_memory_limit) {
|
|
self.total_requested_bytes -= old_mem.len;
|
|
}
|
|
|
|
// Capture stack trace to be the "first free", in case a double free happens.
|
|
bucket.captureStackTrace(ret_addr, size_class, slot_index, .free);
|
|
|
|
used_byte.* &= ~(@as(u8, 1) << used_bit_index);
|
|
bucket.used_count -= 1;
|
|
if (bucket.used_count == 0) {
|
|
if (bucket.next == bucket) {
|
|
// it's the only bucket and therefore the current one
|
|
self.buckets[bucket_index] = null;
|
|
} else {
|
|
bucket.next.prev = bucket.prev;
|
|
bucket.prev.next = bucket.next;
|
|
self.buckets[bucket_index] = bucket.prev;
|
|
}
|
|
if (!config.never_unmap) {
|
|
self.backing_allocator.free(bucket.page[0..page_size]);
|
|
}
|
|
if (!config.retain_metadata) {
|
|
self.freeBucket(bucket, size_class);
|
|
} else {
|
|
// move alloc_cursor to end so we can tell size_class later
|
|
const slot_count = @divExact(page_size, size_class);
|
|
bucket.alloc_cursor = @as(SlotIndex, @truncate(slot_count));
|
|
if (self.empty_buckets) |prev_bucket| {
|
|
// empty_buckets is ordered newest to oldest through prev so that if
|
|
// config.never_unmap is false and backing_allocator reuses freed memory
|
|
// then searchBuckets will always return the newer, relevant bucket
|
|
bucket.prev = prev_bucket;
|
|
bucket.next = prev_bucket.next;
|
|
prev_bucket.next = bucket;
|
|
bucket.next.prev = bucket;
|
|
} else {
|
|
bucket.prev = bucket;
|
|
bucket.next = bucket;
|
|
}
|
|
self.empty_buckets = bucket;
|
|
}
|
|
} else {
|
|
@memset(old_mem, undefined);
|
|
}
|
|
if (config.safety) {
|
|
assert(self.small_allocations.remove(@intFromPtr(old_mem.ptr)));
|
|
}
|
|
if (config.verbose_log) {
|
|
log.info("small free {d} bytes at {*}", .{ old_mem.len, old_mem.ptr });
|
|
}
|
|
}
|
|
|
|
// Returns true if an allocation of `size` bytes is within the specified
|
|
// limits if enable_memory_limit is true
|
|
fn isAllocationAllowed(self: *Self, size: usize) bool {
|
|
if (config.enable_memory_limit) {
|
|
const new_req_bytes = self.total_requested_bytes + size;
|
|
if (new_req_bytes > self.requested_memory_limit)
|
|
return false;
|
|
self.total_requested_bytes = new_req_bytes;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
fn alloc(ctx: *anyopaque, len: usize, log2_ptr_align: u8, ret_addr: usize) ?[*]u8 {
|
|
const self: *Self = @ptrCast(@alignCast(ctx));
|
|
self.mutex.lock();
|
|
defer self.mutex.unlock();
|
|
if (!self.isAllocationAllowed(len)) return null;
|
|
return allocInner(self, len, @as(Allocator.Log2Align, @intCast(log2_ptr_align)), ret_addr) catch return null;
|
|
}
|
|
|
|
fn allocInner(
|
|
self: *Self,
|
|
len: usize,
|
|
log2_ptr_align: Allocator.Log2Align,
|
|
ret_addr: usize,
|
|
) Allocator.Error![*]u8 {
|
|
const new_aligned_size = @max(len, @as(usize, 1) << @as(Allocator.Log2Align, @intCast(log2_ptr_align)));
|
|
if (new_aligned_size > largest_bucket_object_size) {
|
|
try self.large_allocations.ensureUnusedCapacity(self.backing_allocator, 1);
|
|
const ptr = self.backing_allocator.rawAlloc(len, log2_ptr_align, ret_addr) orelse
|
|
return error.OutOfMemory;
|
|
const slice = ptr[0..len];
|
|
|
|
const gop = self.large_allocations.getOrPutAssumeCapacity(@intFromPtr(slice.ptr));
|
|
if (config.retain_metadata and !config.never_unmap) {
|
|
// Backing allocator may be reusing memory that we're retaining metadata for
|
|
assert(!gop.found_existing or gop.value_ptr.freed);
|
|
} else {
|
|
assert(!gop.found_existing); // This would mean the kernel double-mapped pages.
|
|
}
|
|
gop.value_ptr.bytes = slice;
|
|
if (config.enable_memory_limit)
|
|
gop.value_ptr.requested_size = len;
|
|
gop.value_ptr.captureStackTrace(ret_addr, .alloc);
|
|
if (config.retain_metadata) {
|
|
gop.value_ptr.freed = false;
|
|
if (config.never_unmap) {
|
|
gop.value_ptr.log2_ptr_align = log2_ptr_align;
|
|
}
|
|
}
|
|
|
|
if (config.verbose_log) {
|
|
log.info("large alloc {d} bytes at {*}", .{ slice.len, slice.ptr });
|
|
}
|
|
return slice.ptr;
|
|
}
|
|
|
|
if (config.safety) {
|
|
try self.small_allocations.ensureUnusedCapacity(self.backing_allocator, 1);
|
|
}
|
|
const new_size_class = math.ceilPowerOfTwoAssert(usize, new_aligned_size);
|
|
const ptr = try self.allocSlot(new_size_class, ret_addr);
|
|
if (config.safety) {
|
|
const gop = self.small_allocations.getOrPutAssumeCapacity(@intFromPtr(ptr));
|
|
gop.value_ptr.requested_size = len;
|
|
gop.value_ptr.log2_ptr_align = log2_ptr_align;
|
|
}
|
|
if (config.verbose_log) {
|
|
log.info("small alloc {d} bytes at {*}", .{ len, ptr });
|
|
}
|
|
return ptr;
|
|
}
|
|
|
|
fn createBucket(self: *Self, size_class: usize, bucket_index: usize) Error!*BucketHeader {
|
|
const page = try self.backing_allocator.alignedAlloc(u8, page_size, page_size);
|
|
errdefer self.backing_allocator.free(page);
|
|
|
|
const bucket_size = bucketSize(size_class);
|
|
const bucket_bytes = try self.backing_allocator.alignedAlloc(u8, @alignOf(BucketHeader), bucket_size);
|
|
const ptr = @as(*BucketHeader, @ptrCast(bucket_bytes.ptr));
|
|
ptr.* = BucketHeader{
|
|
.prev = ptr,
|
|
.next = ptr,
|
|
.page = page.ptr,
|
|
.alloc_cursor = 0,
|
|
.used_count = 0,
|
|
};
|
|
self.buckets[bucket_index] = ptr;
|
|
// Set the used bits to all zeroes
|
|
@memset(@as([*]u8, @as(*[1]u8, ptr.usedBits(0)))[0..usedBitsCount(size_class)], 0);
|
|
return ptr;
|
|
}
|
|
};
|
|
}
|
|
|
|
const TraceKind = enum {
|
|
alloc,
|
|
free,
|
|
};
|
|
|
|
const test_config = Config{};
|
|
|
|
test "small allocations - free in same order" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var list = std.ArrayList(*u64).init(std.testing.allocator);
|
|
defer list.deinit();
|
|
|
|
var i: usize = 0;
|
|
while (i < 513) : (i += 1) {
|
|
const ptr = try allocator.create(u64);
|
|
try list.append(ptr);
|
|
}
|
|
|
|
for (list.items) |ptr| {
|
|
allocator.destroy(ptr);
|
|
}
|
|
}
|
|
|
|
test "small allocations - free in reverse order" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var list = std.ArrayList(*u64).init(std.testing.allocator);
|
|
defer list.deinit();
|
|
|
|
var i: usize = 0;
|
|
while (i < 513) : (i += 1) {
|
|
const ptr = try allocator.create(u64);
|
|
try list.append(ptr);
|
|
}
|
|
|
|
while (list.popOrNull()) |ptr| {
|
|
allocator.destroy(ptr);
|
|
}
|
|
}
|
|
|
|
test "large allocations" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
const ptr1 = try allocator.alloc(u64, 42768);
|
|
const ptr2 = try allocator.alloc(u64, 52768);
|
|
allocator.free(ptr1);
|
|
const ptr3 = try allocator.alloc(u64, 62768);
|
|
allocator.free(ptr3);
|
|
allocator.free(ptr2);
|
|
}
|
|
|
|
test "very large allocation" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
try std.testing.expectError(error.OutOfMemory, allocator.alloc(u8, math.maxInt(usize)));
|
|
}
|
|
|
|
test "realloc" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var slice = try allocator.alignedAlloc(u8, @alignOf(u32), 1);
|
|
defer allocator.free(slice);
|
|
slice[0] = 0x12;
|
|
|
|
// This reallocation should keep its pointer address.
|
|
const old_slice = slice;
|
|
slice = try allocator.realloc(slice, 2);
|
|
try std.testing.expect(old_slice.ptr == slice.ptr);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
slice[1] = 0x34;
|
|
|
|
// This requires upgrading to a larger size class
|
|
slice = try allocator.realloc(slice, 17);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[1] == 0x34);
|
|
}
|
|
|
|
test "shrink" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var slice = try allocator.alloc(u8, 20);
|
|
defer allocator.free(slice);
|
|
|
|
@memset(slice, 0x11);
|
|
|
|
try std.testing.expect(allocator.resize(slice, 17));
|
|
slice = slice[0..17];
|
|
|
|
for (slice) |b| {
|
|
try std.testing.expect(b == 0x11);
|
|
}
|
|
|
|
try std.testing.expect(allocator.resize(slice, 16));
|
|
slice = slice[0..16];
|
|
|
|
for (slice) |b| {
|
|
try std.testing.expect(b == 0x11);
|
|
}
|
|
}
|
|
|
|
test "large object - grow" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var slice1 = try allocator.alloc(u8, page_size * 2 - 20);
|
|
defer allocator.free(slice1);
|
|
|
|
const old = slice1;
|
|
slice1 = try allocator.realloc(slice1, page_size * 2 - 10);
|
|
try std.testing.expect(slice1.ptr == old.ptr);
|
|
|
|
slice1 = try allocator.realloc(slice1, page_size * 2);
|
|
try std.testing.expect(slice1.ptr == old.ptr);
|
|
|
|
slice1 = try allocator.realloc(slice1, page_size * 2 + 1);
|
|
}
|
|
|
|
test "realloc small object to large object" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var slice = try allocator.alloc(u8, 70);
|
|
defer allocator.free(slice);
|
|
slice[0] = 0x12;
|
|
slice[60] = 0x34;
|
|
|
|
// This requires upgrading to a large object
|
|
const large_object_size = page_size * 2 + 50;
|
|
slice = try allocator.realloc(slice, large_object_size);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[60] == 0x34);
|
|
}
|
|
|
|
test "shrink large object to large object" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var slice = try allocator.alloc(u8, page_size * 2 + 50);
|
|
defer allocator.free(slice);
|
|
slice[0] = 0x12;
|
|
slice[60] = 0x34;
|
|
|
|
if (!allocator.resize(slice, page_size * 2 + 1)) return;
|
|
slice = slice.ptr[0 .. page_size * 2 + 1];
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[60] == 0x34);
|
|
|
|
try std.testing.expect(allocator.resize(slice, page_size * 2 + 1));
|
|
slice = slice[0 .. page_size * 2 + 1];
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[60] == 0x34);
|
|
|
|
slice = try allocator.realloc(slice, page_size * 2);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[60] == 0x34);
|
|
}
|
|
|
|
test "shrink large object to large object with larger alignment" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var debug_buffer: [1000]u8 = undefined;
|
|
var fba = std.heap.FixedBufferAllocator.init(&debug_buffer);
|
|
const debug_allocator = fba.allocator();
|
|
|
|
const alloc_size = page_size * 2 + 50;
|
|
var slice = try allocator.alignedAlloc(u8, 16, alloc_size);
|
|
defer allocator.free(slice);
|
|
|
|
const big_alignment: usize = switch (builtin.os.tag) {
|
|
.windows => page_size * 32, // Windows aligns to 64K.
|
|
else => page_size * 2,
|
|
};
|
|
// This loop allocates until we find a page that is not aligned to the big
|
|
// alignment. Then we shrink the allocation after the loop, but increase the
|
|
// alignment to the higher one, that we know will force it to realloc.
|
|
var stuff_to_free = std.ArrayList([]align(16) u8).init(debug_allocator);
|
|
while (mem.isAligned(@intFromPtr(slice.ptr), big_alignment)) {
|
|
try stuff_to_free.append(slice);
|
|
slice = try allocator.alignedAlloc(u8, 16, alloc_size);
|
|
}
|
|
while (stuff_to_free.popOrNull()) |item| {
|
|
allocator.free(item);
|
|
}
|
|
slice[0] = 0x12;
|
|
slice[60] = 0x34;
|
|
|
|
slice = try allocator.reallocAdvanced(slice, big_alignment, alloc_size / 2);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[60] == 0x34);
|
|
}
|
|
|
|
test "realloc large object to small object" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var slice = try allocator.alloc(u8, page_size * 2 + 50);
|
|
defer allocator.free(slice);
|
|
slice[0] = 0x12;
|
|
slice[16] = 0x34;
|
|
|
|
slice = try allocator.realloc(slice, 19);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[16] == 0x34);
|
|
}
|
|
|
|
test "overridable mutexes" {
|
|
var gpa = GeneralPurposeAllocator(.{ .MutexType = std.Thread.Mutex }){
|
|
.backing_allocator = std.testing.allocator,
|
|
.mutex = std.Thread.Mutex{},
|
|
};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
const ptr = try allocator.create(i32);
|
|
defer allocator.destroy(ptr);
|
|
}
|
|
|
|
test "non-page-allocator backing allocator" {
|
|
var gpa = GeneralPurposeAllocator(.{}){ .backing_allocator = std.testing.allocator };
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
const ptr = try allocator.create(i32);
|
|
defer allocator.destroy(ptr);
|
|
}
|
|
|
|
test "realloc large object to larger alignment" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var debug_buffer: [1000]u8 = undefined;
|
|
var fba = std.heap.FixedBufferAllocator.init(&debug_buffer);
|
|
const debug_allocator = fba.allocator();
|
|
|
|
var slice = try allocator.alignedAlloc(u8, 16, page_size * 2 + 50);
|
|
defer allocator.free(slice);
|
|
|
|
const big_alignment: usize = switch (builtin.os.tag) {
|
|
.windows => page_size * 32, // Windows aligns to 64K.
|
|
else => page_size * 2,
|
|
};
|
|
// This loop allocates until we find a page that is not aligned to the big alignment.
|
|
var stuff_to_free = std.ArrayList([]align(16) u8).init(debug_allocator);
|
|
while (mem.isAligned(@intFromPtr(slice.ptr), big_alignment)) {
|
|
try stuff_to_free.append(slice);
|
|
slice = try allocator.alignedAlloc(u8, 16, page_size * 2 + 50);
|
|
}
|
|
while (stuff_to_free.popOrNull()) |item| {
|
|
allocator.free(item);
|
|
}
|
|
slice[0] = 0x12;
|
|
slice[16] = 0x34;
|
|
|
|
slice = try allocator.reallocAdvanced(slice, 32, page_size * 2 + 100);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[16] == 0x34);
|
|
|
|
slice = try allocator.reallocAdvanced(slice, 32, page_size * 2 + 25);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[16] == 0x34);
|
|
|
|
slice = try allocator.reallocAdvanced(slice, big_alignment, page_size * 2 + 100);
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[16] == 0x34);
|
|
}
|
|
|
|
test "large object shrinks to small but allocation fails during shrink" {
|
|
var failing_allocator = std.testing.FailingAllocator.init(std.heap.page_allocator, 3);
|
|
var gpa = GeneralPurposeAllocator(.{}){ .backing_allocator = failing_allocator.allocator() };
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
var slice = try allocator.alloc(u8, page_size * 2 + 50);
|
|
defer allocator.free(slice);
|
|
slice[0] = 0x12;
|
|
slice[3] = 0x34;
|
|
|
|
// Next allocation will fail in the backing allocator of the GeneralPurposeAllocator
|
|
|
|
try std.testing.expect(allocator.resize(slice, 4));
|
|
slice = slice[0..4];
|
|
try std.testing.expect(slice[0] == 0x12);
|
|
try std.testing.expect(slice[3] == 0x34);
|
|
}
|
|
|
|
test "objects of size 1024 and 2048" {
|
|
var gpa = GeneralPurposeAllocator(test_config){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
const slice = try allocator.alloc(u8, 1025);
|
|
const slice2 = try allocator.alloc(u8, 3000);
|
|
|
|
allocator.free(slice);
|
|
allocator.free(slice2);
|
|
}
|
|
|
|
test "setting a memory cap" {
|
|
var gpa = GeneralPurposeAllocator(.{ .enable_memory_limit = true }){};
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
gpa.setRequestedMemoryLimit(1010);
|
|
|
|
const small = try allocator.create(i32);
|
|
try std.testing.expect(gpa.total_requested_bytes == 4);
|
|
|
|
const big = try allocator.alloc(u8, 1000);
|
|
try std.testing.expect(gpa.total_requested_bytes == 1004);
|
|
|
|
try std.testing.expectError(error.OutOfMemory, allocator.create(u64));
|
|
|
|
allocator.destroy(small);
|
|
try std.testing.expect(gpa.total_requested_bytes == 1000);
|
|
|
|
allocator.free(big);
|
|
try std.testing.expect(gpa.total_requested_bytes == 0);
|
|
|
|
const exact = try allocator.alloc(u8, 1010);
|
|
try std.testing.expect(gpa.total_requested_bytes == 1010);
|
|
allocator.free(exact);
|
|
}
|
|
|
|
test "double frees" {
|
|
// use a GPA to back a GPA to check for leaks of the latter's metadata
|
|
var backing_gpa = GeneralPurposeAllocator(.{ .safety = true }){};
|
|
defer std.testing.expect(backing_gpa.deinit() == .ok) catch @panic("leak");
|
|
|
|
const GPA = GeneralPurposeAllocator(.{ .safety = true, .never_unmap = true, .retain_metadata = true });
|
|
var gpa = GPA{ .backing_allocator = backing_gpa.allocator() };
|
|
defer std.testing.expect(gpa.deinit() == .ok) catch @panic("leak");
|
|
const allocator = gpa.allocator();
|
|
|
|
// detect a small allocation double free, even though bucket is emptied
|
|
const index: usize = 6;
|
|
const size_class: usize = @as(usize, 1) << 6;
|
|
const small = try allocator.alloc(u8, size_class);
|
|
try std.testing.expect(GPA.searchBucket(gpa.buckets[index], @intFromPtr(small.ptr)) != null);
|
|
allocator.free(small);
|
|
try std.testing.expect(GPA.searchBucket(gpa.buckets[index], @intFromPtr(small.ptr)) == null);
|
|
try std.testing.expect(GPA.searchBucket(gpa.empty_buckets, @intFromPtr(small.ptr)) != null);
|
|
|
|
// detect a large allocation double free
|
|
const large = try allocator.alloc(u8, 2 * page_size);
|
|
try std.testing.expect(gpa.large_allocations.contains(@intFromPtr(large.ptr)));
|
|
try std.testing.expectEqual(gpa.large_allocations.getEntry(@intFromPtr(large.ptr)).?.value_ptr.bytes, large);
|
|
allocator.free(large);
|
|
try std.testing.expect(gpa.large_allocations.contains(@intFromPtr(large.ptr)));
|
|
try std.testing.expect(gpa.large_allocations.getEntry(@intFromPtr(large.ptr)).?.value_ptr.freed);
|
|
|
|
const normal_small = try allocator.alloc(u8, size_class);
|
|
defer allocator.free(normal_small);
|
|
const normal_large = try allocator.alloc(u8, 2 * page_size);
|
|
defer allocator.free(normal_large);
|
|
|
|
// check that flushing retained metadata doesn't disturb live allocations
|
|
gpa.flushRetainedMetadata();
|
|
try std.testing.expect(gpa.empty_buckets == null);
|
|
try std.testing.expect(GPA.searchBucket(gpa.buckets[index], @intFromPtr(normal_small.ptr)) != null);
|
|
try std.testing.expect(gpa.large_allocations.contains(@intFromPtr(normal_large.ptr)));
|
|
try std.testing.expect(!gpa.large_allocations.contains(@intFromPtr(large.ptr)));
|
|
}
|
|
|
|
test "bug 9995 fix, large allocs count requested size not backing size" {
|
|
// with AtLeast, buffer likely to be larger than requested, especially when shrinking
|
|
var gpa = GeneralPurposeAllocator(.{ .enable_memory_limit = true }){};
|
|
const allocator = gpa.allocator();
|
|
|
|
var buf = try allocator.alignedAlloc(u8, 1, page_size + 1);
|
|
try std.testing.expect(gpa.total_requested_bytes == page_size + 1);
|
|
buf = try allocator.realloc(buf, 1);
|
|
try std.testing.expect(gpa.total_requested_bytes == 1);
|
|
buf = try allocator.realloc(buf, 2);
|
|
try std.testing.expect(gpa.total_requested_bytes == 2);
|
|
}
|