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Merge pull request #1233 from lightpanda-io/zigdom-factory-allocators
`zigdom` Factory Slab Allocator
This commit is contained in:
muki
@@ -24,6 +24,8 @@ const IS_DEBUG = builtin.mode == .Debug;
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const log = @import("../log.zig");
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const String = @import("../string.zig").String;
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const SlabAllocator = @import("../slab.zig").SlabAllocator;
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const Page = @import("Page.zig");
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const Node = @import("webapi/Node.zig");
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const Event = @import("webapi/Event.zig");
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@@ -46,48 +48,12 @@ const MemoryPoolAligned = std.heap.MemoryPoolAligned;
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// (and alignment) based pools.
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const Factory = @This();
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_page: *Page,
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_size_8_8: MemoryPoolAligned([8]u8, .@"8"),
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_size_16_8: MemoryPoolAligned([16]u8, .@"8"),
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_size_24_8: MemoryPoolAligned([24]u8, .@"8"),
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_size_32_8: MemoryPoolAligned([32]u8, .@"8"),
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_size_32_16: MemoryPoolAligned([32]u8, .@"16"),
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_size_40_8: MemoryPoolAligned([40]u8, .@"8"),
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_size_48_16: MemoryPoolAligned([48]u8, .@"16"),
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_size_56_8: MemoryPoolAligned([56]u8, .@"8"),
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_size_64_16: MemoryPoolAligned([64]u8, .@"16"),
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_size_80_16: MemoryPoolAligned([80]u8, .@"16"),
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_size_88_8: MemoryPoolAligned([88]u8, .@"8"),
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_size_96_16: MemoryPoolAligned([96]u8, .@"16"),
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_size_128_8: MemoryPoolAligned([128]u8, .@"8"),
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_size_144_8: MemoryPoolAligned([144]u8, .@"8"),
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_size_152_8: MemoryPoolAligned([152]u8, .@"8"),
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_size_160_8: MemoryPoolAligned([160]u8, .@"8"),
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_size_184_8: MemoryPoolAligned([184]u8, .@"8"),
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_size_232_8: MemoryPoolAligned([232]u8, .@"8"),
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_size_648_8: MemoryPoolAligned([648]u8, .@"8"),
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_slab: SlabAllocator,
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pub fn init(page: *Page) Factory {
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return .{
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._page = page,
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._size_8_8 = MemoryPoolAligned([8]u8, .@"8").init(page.arena),
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._size_16_8 = MemoryPoolAligned([16]u8, .@"8").init(page.arena),
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._size_24_8 = MemoryPoolAligned([24]u8, .@"8").init(page.arena),
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._size_32_8 = MemoryPoolAligned([32]u8, .@"8").init(page.arena),
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._size_32_16 = MemoryPoolAligned([32]u8, .@"16").init(page.arena),
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._size_40_8 = MemoryPoolAligned([40]u8, .@"8").init(page.arena),
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._size_48_16 = MemoryPoolAligned([48]u8, .@"16").init(page.arena),
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._size_56_8 = MemoryPoolAligned([56]u8, .@"8").init(page.arena),
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._size_64_16 = MemoryPoolAligned([64]u8, .@"16").init(page.arena),
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._size_80_16 = MemoryPoolAligned([80]u8, .@"16").init(page.arena),
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._size_88_8 = MemoryPoolAligned([88]u8, .@"8").init(page.arena),
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._size_96_16 = MemoryPoolAligned([96]u8, .@"16").init(page.arena),
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._size_128_8 = MemoryPoolAligned([128]u8, .@"8").init(page.arena),
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._size_144_8 = MemoryPoolAligned([144]u8, .@"8").init(page.arena),
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._size_152_8 = MemoryPoolAligned([152]u8, .@"8").init(page.arena),
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._size_160_8 = MemoryPoolAligned([160]u8, .@"8").init(page.arena),
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._size_184_8 = MemoryPoolAligned([184]u8, .@"8").init(page.arena),
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._size_232_8 = MemoryPoolAligned([232]u8, .@"8").init(page.arena),
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._size_648_8 = MemoryPoolAligned([648]u8, .@"8").init(page.arena),
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._slab = SlabAllocator.init(page.arena, 128),
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};
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}
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@@ -246,28 +212,8 @@ pub fn create(self: *Factory, value: anytype) !*@TypeOf(value) {
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}
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pub fn createT(self: *Factory, comptime T: type) !*T {
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const SO = @sizeOf(T);
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if (comptime SO == 8) return @ptrCast(try self._size_8_8.create());
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if (comptime SO == 16) return @ptrCast(try self._size_16_8.create());
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if (comptime SO == 24) return @ptrCast(try self._size_24_8.create());
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if (comptime SO == 32) {
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if (comptime @alignOf(T) == 8) return @ptrCast(try self._size_32_8.create());
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if (comptime @alignOf(T) == 16) return @ptrCast(try self._size_32_16.create());
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}
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if (comptime SO == 40) return @ptrCast(try self._size_40_8.create());
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if (comptime SO == 48) return @ptrCast(try self._size_48_16.create());
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if (comptime SO == 56) return @ptrCast(try self._size_56_8.create());
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if (comptime SO == 64) return @ptrCast(try self._size_64_16.create());
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if (comptime SO == 80) return @ptrCast(try self._size_80_16.create());
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if (comptime SO == 88) return @ptrCast(try self._size_88_8.create());
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if (comptime SO == 96) return @ptrCast(try self._size_96_16.create());
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if (comptime SO == 128) return @ptrCast(try self._size_128_8.create());
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if (comptime SO == 152) return @ptrCast(try self._size_152_8.create());
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if (comptime SO == 160) return @ptrCast(try self._size_160_8.create());
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if (comptime SO == 184) return @ptrCast(try self._size_184_8.create());
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if (comptime SO == 232) return @ptrCast(try self._size_232_8.create());
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if (comptime SO == 648) return @ptrCast(try self._size_648_8.create());
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@compileError(std.fmt.comptimePrint("No pool configured for @sizeOf({d}), @alignOf({d}): ({s})", .{ SO, @alignOf(T), @typeName(T) }));
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const allocator = self._slab.allocator();
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return try allocator.create(T);
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}
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pub fn destroy(self: *Factory, value: anytype) void {
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@@ -291,6 +237,8 @@ pub fn destroy(self: *Factory, value: anytype) void {
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fn destroyChain(self: *Factory, value: anytype, comptime first: bool) void {
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const S = reflect.Struct(@TypeOf(value));
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const allocator = self._slab.allocator();
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// This is initially called from a deinit. We don't want to call that
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// same deinit. So when this is the first time destroyChain is called
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// we don't call deinit (because we're in that deinit)
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@@ -311,7 +259,7 @@ fn destroyChain(self: *Factory, value: anytype, comptime first: bool) void {
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} else if (@hasDecl(S, "JsApi")) {
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// Doesn't have a _proto, but has a JsApi.
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if (self._page.js.removeTaggedMapping(@intFromPtr(value))) |tagged| {
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self._size_24_8.destroy(@ptrCast(tagged));
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allocator.destroy(tagged);
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}
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}
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@@ -319,31 +267,7 @@ fn destroyChain(self: *Factory, value: anytype, comptime first: bool) void {
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// (which makes sense when the @sizeOf(Leaf) == 8). These don't need to
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// be (cannot be) freed. But we'll still free the chain.
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if (comptime wasAllocated(S)) {
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switch (@sizeOf(S)) {
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8 => self._size_8_8.destroy(@ptrCast(@alignCast(value))),
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16 => self._size_16_8.destroy(@ptrCast(value)),
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24 => self._size_24_8.destroy(@ptrCast(value)),
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32 => {
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if (comptime @alignOf(S) == 8) {
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self._size_32_8.destroy(@ptrCast(value));
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} else if (comptime @alignOf(S) == 16) {
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self._size_32_16.destroy(@ptrCast(value));
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}
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},
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40 => self._size_40_8.destroy(@ptrCast(value)),
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48 => self._size_48_16.destroy(@ptrCast(@alignCast(value))),
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56 => self._size_56_8.destroy(@ptrCast(value)),
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64 => self._size_64_16.destroy(@ptrCast(@alignCast(value))),
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80 => self._size_80_16.destroy(@ptrCast(@alignCast(value))),
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88 => self._size_88_8.destroy(@ptrCast(@alignCast(value))),
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96 => self._size_96_16.destroy(@ptrCast(@alignCast(value))),
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128 => self._size_128_8.destroy(@ptrCast(value)),
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144 => self._size_144_8.destroy(@ptrCast(value)),
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152 => self._size_152_8.destroy(@ptrCast(value)),
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160 => self._size_160_8.destroy(@ptrCast(value)),
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648 => self._size_648_8.destroy(@ptrCast(value)),
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else => |SO| @compileError(std.fmt.comptimePrint("Don't know what I'm being asked to destroy @sizeOf({d}), @alignOf({d}): ({s})", .{ SO, @alignOf(S), @typeName(S) })),
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}
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allocator.destroy(value);
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}
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}
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@@ -174,7 +174,12 @@ pub fn init(arena: Allocator, call_arena: Allocator, session: *Session) !*Page {
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pub fn deinit(self: *Page) void {
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if (comptime IS_DEBUG) {
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log.debug(.page, "page.deinit", .{ .url = self.url });
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// Uncomment if you want slab statistics to print.
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// const stats = self._factory._slab.getStats(self.arena) catch unreachable;
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// stats.print() catch unreachable;
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}
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self.js.deinit();
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self._script_manager.shutdown = true;
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self._session.browser.http_client.abort();
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824
src/slab.zig
Normal file
824
src/slab.zig
Normal file
@@ -0,0 +1,824 @@
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const std = @import("std");
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const assert = std.debug.assert;
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const Allocator = std.mem.Allocator;
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const Alignment = std.mem.Alignment;
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const Slab = struct {
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alignment: Alignment,
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item_size: usize,
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max_slot_count: usize,
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bitset: std.bit_set.DynamicBitSetUnmanaged,
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chunks: std.ArrayListUnmanaged([]u8),
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pub fn init(
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allocator: Allocator,
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alignment: Alignment,
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item_size: usize,
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max_slot_count: usize,
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) !Slab {
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return .{
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.alignment = alignment,
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.item_size = item_size,
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.bitset = try .initFull(allocator, 0),
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.chunks = .empty,
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.max_slot_count = max_slot_count,
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};
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}
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pub fn deinit(self: *Slab, allocator: Allocator) void {
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self.bitset.deinit(allocator);
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for (self.chunks.items) |chunk| {
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allocator.rawFree(chunk, self.alignment, @returnAddress());
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}
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self.chunks.deinit(allocator);
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}
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inline fn calculateChunkSize(self: *Slab, chunk_index: usize) usize {
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const safe_index: u6 = @intCast(@min(std.math.maxInt(u6), chunk_index));
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const exponential = @as(usize, 1) << safe_index;
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return @min(exponential, self.max_slot_count);
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}
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inline fn toBitsetIndex(self: *Slab, chunk_index: usize, slot_index: usize) usize {
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var offset: usize = 0;
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for (0..chunk_index) |i| {
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const chunk_size = self.calculateChunkSize(i);
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offset += chunk_size;
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}
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return offset + slot_index;
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}
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inline fn toChunkAndSlotIndices(self: *Slab, bitset_index: usize) struct { usize, usize } {
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var offset: usize = 0;
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var chunk_index: usize = 0;
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while (chunk_index < self.chunks.items.len) : (chunk_index += 1) {
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const chunk_size = self.calculateChunkSize(chunk_index);
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if (bitset_index < offset + chunk_size) {
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return .{ chunk_index, bitset_index - offset };
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}
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offset += chunk_size;
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}
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unreachable;
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}
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fn alloc(self: *Slab, allocator: Allocator) ![]u8 {
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if (self.bitset.findFirstSet()) |index| {
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const chunk_index, const slot_index = self.toChunkAndSlotIndices(index);
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// if we have a free slot
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self.bitset.unset(index);
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const chunk = self.chunks.items[chunk_index];
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const offset = slot_index * self.item_size;
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return chunk.ptr[offset..][0..self.item_size];
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} else {
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const old_capacity = self.bitset.bit_length;
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// if we have don't have a free slot
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try self.allocateChunk(allocator);
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const first_slot_index = old_capacity;
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self.bitset.unset(first_slot_index);
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const new_chunk = self.chunks.items[self.chunks.items.len - 1];
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return new_chunk.ptr[0..self.item_size];
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}
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}
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fn free(self: *Slab, ptr: [*]u8) void {
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const addr = @intFromPtr(ptr);
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for (self.chunks.items, 0..) |chunk, i| {
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const chunk_start = @intFromPtr(chunk.ptr);
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const chunk_end = chunk_start + chunk.len;
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if (addr >= chunk_start and addr < chunk_end) {
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const offset = addr - chunk_start;
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const slot_index = offset / self.item_size;
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const bitset_index = self.toBitsetIndex(i, slot_index);
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assert(!self.bitset.isSet(bitset_index));
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self.bitset.set(bitset_index);
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return;
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}
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}
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unreachable;
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}
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fn allocateChunk(self: *Slab, allocator: Allocator) !void {
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const next_chunk_size = self.calculateChunkSize(self.chunks.items.len);
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const chunk_len = self.item_size * next_chunk_size;
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const chunk_ptr = allocator.rawAlloc(
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chunk_len,
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self.alignment,
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@returnAddress(),
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) orelse return error.FailedChildAllocation;
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const chunk = chunk_ptr[0..chunk_len];
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try self.chunks.append(allocator, chunk);
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const new_capacity = self.bitset.bit_length + next_chunk_size;
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try self.bitset.resize(allocator, new_capacity, true);
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}
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const Stats = struct {
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key: SlabKey,
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item_size: usize,
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chunk_count: usize,
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total_slots: usize,
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slots_in_use: usize,
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slots_free: usize,
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bytes_allocated: usize,
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bytes_in_use: usize,
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bytes_free: usize,
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utilization_ratio: f64,
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};
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fn getStats(self: *const Slab, key: SlabKey) Stats {
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const total_slots = self.bitset.bit_length;
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const free_slots = self.bitset.count();
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const used_slots = total_slots - free_slots;
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const bytes_allocated = total_slots * self.item_size;
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const bytes_in_use = used_slots * self.item_size;
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const utilization_ratio = if (bytes_allocated > 0)
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@as(f64, @floatFromInt(bytes_in_use)) / @as(f64, @floatFromInt(bytes_allocated))
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else
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0.0;
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return .{
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.key = key,
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.item_size = self.item_size,
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.chunk_count = self.chunks.items.len,
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.total_slots = total_slots,
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.slots_in_use = used_slots,
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.slots_free = free_slots,
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.bytes_allocated = bytes_allocated,
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.bytes_in_use = bytes_in_use,
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.bytes_free = free_slots * self.item_size,
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.utilization_ratio = utilization_ratio,
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};
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}
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};
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const SlabKey = struct {
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size: usize,
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alignment: Alignment,
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};
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pub const SlabAllocator = struct {
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const Self = @This();
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child_allocator: Allocator,
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max_slot_count: usize,
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slabs: std.ArrayHashMapUnmanaged(SlabKey, Slab, struct {
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const Context = @This();
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pub fn hash(_: Context, key: SlabKey) u32 {
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var hasher = std.hash.Wyhash.init(0);
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std.hash.autoHash(&hasher, key.size);
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std.hash.autoHash(&hasher, key.alignment);
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return @truncate(hasher.final());
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}
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pub fn eql(_: Context, a: SlabKey, b: SlabKey, _: usize) bool {
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return a.size == b.size and a.alignment == b.alignment;
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}
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}, false) = .empty,
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pub fn init(child_allocator: Allocator, max_slot_count: usize) Self {
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assert(std.math.isPowerOfTwo(max_slot_count));
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return .{
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.child_allocator = child_allocator,
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.slabs = .empty,
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.max_slot_count = max_slot_count,
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};
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}
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pub fn deinit(self: *Self) void {
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for (self.slabs.values()) |*slab| {
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slab.deinit(self.child_allocator);
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}
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self.slabs.deinit(self.child_allocator);
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}
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pub const ResetKind = enum {
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/// Free all chunks and release all memory.
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clear,
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/// Keep all chunks, reset trees to reuse memory.
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retain_capacity,
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};
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/// This clears all of the stored memory, freeing the currently used chunks.
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pub fn reset(self: *Self, kind: ResetKind) void {
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switch (kind) {
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.clear => {
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for (self.slabs.values()) |*slab| {
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for (slab.chunks.items) |chunk| {
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self.child_allocator.free(chunk);
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}
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slab.chunks.clearAndFree(self.child_allocator);
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slab.bitset.deinit(self.child_allocator);
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}
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self.slabs.clearAndFree(self.child_allocator);
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},
|
||||
.retain_capacity => {
|
||||
for (self.slabs.values()) |*slab| {
|
||||
slab.bitset.setAll();
|
||||
}
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
const Stats = struct {
|
||||
total_allocated_bytes: usize,
|
||||
bytes_in_use: usize,
|
||||
bytes_free: usize,
|
||||
slab_count: usize,
|
||||
total_chunks: usize,
|
||||
total_slots: usize,
|
||||
slots_in_use: usize,
|
||||
slots_free: usize,
|
||||
fragmentation_ratio: f64,
|
||||
utilization_ratio: f64,
|
||||
slabs: []const Slab.Stats,
|
||||
|
||||
pub fn print(self: *const Stats) !void {
|
||||
std.debug.print("\n", .{});
|
||||
std.debug.print("\n=== Slab Allocator Statistics ===\n", .{});
|
||||
std.debug.print("Overall Memory:\n", .{});
|
||||
std.debug.print(" Total allocated: {} bytes ({d:.2} MB)\n", .{
|
||||
self.total_allocated_bytes,
|
||||
@as(f64, @floatFromInt(self.total_allocated_bytes)) / 1_048_576.0,
|
||||
});
|
||||
std.debug.print(" In use: {} bytes ({d:.2} MB)\n", .{
|
||||
self.bytes_in_use,
|
||||
@as(f64, @floatFromInt(self.bytes_in_use)) / 1_048_576.0,
|
||||
});
|
||||
std.debug.print(" Free: {} bytes ({d:.2} MB)\n", .{
|
||||
self.bytes_free,
|
||||
@as(f64, @floatFromInt(self.bytes_free)) / 1_048_576.0,
|
||||
});
|
||||
|
||||
std.debug.print("\nOverall Structure:\n", .{});
|
||||
std.debug.print(" Slab Count: {}\n", .{self.slab_count});
|
||||
std.debug.print(" Total chunks: {}\n", .{self.total_chunks});
|
||||
std.debug.print(" Total slots: {}\n", .{self.total_slots});
|
||||
std.debug.print(" Slots in use: {}\n", .{self.slots_in_use});
|
||||
std.debug.print(" Slots free: {}\n", .{self.slots_free});
|
||||
|
||||
std.debug.print("\nOverall Efficiency:\n", .{});
|
||||
std.debug.print(" Utilization: {d:.1}%\n", .{self.utilization_ratio * 100.0});
|
||||
std.debug.print(" Fragmentation: {d:.1}%\n", .{self.fragmentation_ratio * 100.0});
|
||||
|
||||
if (self.slabs.len > 0) {
|
||||
std.debug.print("\nPer-Slab Breakdown:\n", .{});
|
||||
std.debug.print(
|
||||
" {s:>5} | {s:>4} | {s:>6} | {s:>6} | {s:>6} | {s:>10} | {s:>6}\n",
|
||||
.{ "Size", "Algn", "Chunks", "Slots", "InUse", "Bytes", "Util%" },
|
||||
);
|
||||
std.debug.print(
|
||||
" {s:-<5}-+-{s:-<4}-+-{s:-<6}-+-{s:-<6}-+-{s:-<6}-+-{s:-<10}-+-{s:-<6}\n",
|
||||
.{ "", "", "", "", "", "", "" },
|
||||
);
|
||||
|
||||
for (self.slabs) |slab| {
|
||||
std.debug.print(" {d:5} | {d:4} | {d:6} | {d:6} | {d:6} | {d:10} | {d:5.1}%\n", .{
|
||||
slab.key.size,
|
||||
@intFromEnum(slab.key.alignment),
|
||||
slab.chunk_count,
|
||||
slab.total_slots,
|
||||
slab.slots_in_use,
|
||||
slab.bytes_allocated,
|
||||
slab.utilization_ratio * 100.0,
|
||||
});
|
||||
}
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
pub fn getStats(self: *Self, a: std.mem.Allocator) !Stats {
|
||||
var slab_stats: std.ArrayList(Slab.Stats) = try .initCapacity(a, self.slabs.entries.len);
|
||||
errdefer slab_stats.deinit(a);
|
||||
|
||||
var stats = Stats{
|
||||
.total_allocated_bytes = 0,
|
||||
.bytes_in_use = 0,
|
||||
.bytes_free = 0,
|
||||
.slab_count = self.slabs.count(),
|
||||
.total_chunks = 0,
|
||||
.total_slots = 0,
|
||||
.slots_in_use = 0,
|
||||
.slots_free = 0,
|
||||
.fragmentation_ratio = 0.0,
|
||||
.utilization_ratio = 0.0,
|
||||
.slabs = &.{},
|
||||
};
|
||||
|
||||
var it = self.slabs.iterator();
|
||||
while (it.next()) |entry| {
|
||||
const key = entry.key_ptr.*;
|
||||
const slab = entry.value_ptr;
|
||||
const slab_stat = slab.getStats(key);
|
||||
|
||||
slab_stats.appendAssumeCapacity(slab_stat);
|
||||
|
||||
stats.total_allocated_bytes += slab_stat.bytes_allocated;
|
||||
stats.bytes_in_use += slab_stat.bytes_in_use;
|
||||
stats.bytes_free += slab_stat.bytes_free;
|
||||
stats.total_chunks += slab_stat.chunk_count;
|
||||
stats.total_slots += slab_stat.total_slots;
|
||||
stats.slots_in_use += slab_stat.slots_in_use;
|
||||
stats.slots_free += slab_stat.slots_free;
|
||||
}
|
||||
|
||||
if (stats.total_allocated_bytes > 0) {
|
||||
stats.fragmentation_ratio = @as(f64, @floatFromInt(stats.bytes_free)) /
|
||||
@as(f64, @floatFromInt(stats.total_allocated_bytes));
|
||||
stats.utilization_ratio = @as(f64, @floatFromInt(stats.bytes_in_use)) /
|
||||
@as(f64, @floatFromInt(stats.total_allocated_bytes));
|
||||
}
|
||||
|
||||
stats.slabs = try slab_stats.toOwnedSlice(a);
|
||||
return stats;
|
||||
}
|
||||
|
||||
pub const vtable = Allocator.VTable{
|
||||
.alloc = alloc,
|
||||
.free = free,
|
||||
.remap = Allocator.noRemap,
|
||||
.resize = Allocator.noResize,
|
||||
};
|
||||
|
||||
pub fn allocator(self: *Self) Allocator {
|
||||
return .{
|
||||
.ptr = self,
|
||||
.vtable = &vtable,
|
||||
};
|
||||
}
|
||||
|
||||
fn alloc(ctx: *anyopaque, len: usize, alignment: Alignment, ret_addr: usize) ?[*]u8 {
|
||||
const self: *Self = @ptrCast(@alignCast(ctx));
|
||||
_ = ret_addr;
|
||||
|
||||
const list_gop = self.slabs.getOrPut(
|
||||
self.child_allocator,
|
||||
SlabKey{ .size = len, .alignment = alignment },
|
||||
) catch return null;
|
||||
|
||||
if (!list_gop.found_existing) {
|
||||
list_gop.value_ptr.* = Slab.init(
|
||||
self.child_allocator,
|
||||
alignment,
|
||||
len,
|
||||
self.max_slot_count,
|
||||
) catch return null;
|
||||
}
|
||||
|
||||
const list = list_gop.value_ptr;
|
||||
const buf = list.alloc(self.child_allocator) catch return null;
|
||||
return buf.ptr;
|
||||
}
|
||||
|
||||
fn free(ctx: *anyopaque, memory: []u8, alignment: Alignment, ret_addr: usize) void {
|
||||
const self: *Self = @ptrCast(@alignCast(ctx));
|
||||
_ = ret_addr;
|
||||
|
||||
const ptr = memory.ptr;
|
||||
const len = memory.len;
|
||||
|
||||
const list = self.slabs.getPtr(.{ .size = len, .alignment = alignment }).?;
|
||||
list.free(ptr);
|
||||
}
|
||||
};
|
||||
|
||||
const testing = std.testing;
|
||||
|
||||
const TestSlabAllocator = SlabAllocator;
|
||||
|
||||
test "slab allocator - basic allocation and free" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate some memory
|
||||
const ptr1 = try allocator.alloc(u8, 100);
|
||||
try testing.expect(ptr1.len == 100);
|
||||
|
||||
// Write to it to ensure it's valid
|
||||
@memset(ptr1, 42);
|
||||
try testing.expectEqual(@as(u8, 42), ptr1[50]);
|
||||
|
||||
// Free it
|
||||
allocator.free(ptr1);
|
||||
}
|
||||
|
||||
test "slab allocator - multiple allocations" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
const ptr1 = try allocator.alloc(u8, 64);
|
||||
const ptr2 = try allocator.alloc(u8, 128);
|
||||
const ptr3 = try allocator.alloc(u8, 256);
|
||||
|
||||
// Ensure they don't overlap
|
||||
const addr1 = @intFromPtr(ptr1.ptr);
|
||||
const addr2 = @intFromPtr(ptr2.ptr);
|
||||
const addr3 = @intFromPtr(ptr3.ptr);
|
||||
|
||||
try testing.expect(addr1 + 64 <= addr2 or addr2 + 128 <= addr1);
|
||||
try testing.expect(addr2 + 128 <= addr3 or addr3 + 256 <= addr2);
|
||||
|
||||
allocator.free(ptr1);
|
||||
allocator.free(ptr2);
|
||||
allocator.free(ptr3);
|
||||
}
|
||||
|
||||
test "slab allocator - no coalescing (different size classes)" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate two blocks of same size
|
||||
const ptr1 = try allocator.alloc(u8, 128);
|
||||
const ptr2 = try allocator.alloc(u8, 128);
|
||||
|
||||
// Free them (no coalescing in slab allocator)
|
||||
allocator.free(ptr1);
|
||||
allocator.free(ptr2);
|
||||
|
||||
// Can't allocate larger block from these freed 128-byte blocks
|
||||
const ptr3 = try allocator.alloc(u8, 256);
|
||||
|
||||
// ptr3 will be from a different size class, not coalesced from ptr1+ptr2
|
||||
const addr1 = @intFromPtr(ptr1.ptr);
|
||||
const addr3 = @intFromPtr(ptr3.ptr);
|
||||
|
||||
// They should NOT be adjacent (different size classes)
|
||||
try testing.expect(addr3 < addr1 or addr3 >= addr1 + 256);
|
||||
|
||||
allocator.free(ptr3);
|
||||
}
|
||||
|
||||
test "slab allocator - reuse freed memory" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
const ptr1 = try allocator.alloc(u8, 64);
|
||||
const addr1 = @intFromPtr(ptr1.ptr);
|
||||
allocator.free(ptr1);
|
||||
|
||||
// Allocate same size, should reuse from same slab
|
||||
const ptr2 = try allocator.alloc(u8, 64);
|
||||
const addr2 = @intFromPtr(ptr2.ptr);
|
||||
|
||||
try testing.expectEqual(addr1, addr2);
|
||||
allocator.free(ptr2);
|
||||
}
|
||||
|
||||
test "slab allocator - multiple size classes" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate various sizes - each creates a new slab
|
||||
var ptrs: [10][]u8 = undefined;
|
||||
const sizes = [_]usize{ 24, 40, 64, 88, 128, 144, 200, 256, 512, 1000 };
|
||||
|
||||
for (&ptrs, sizes) |*ptr, size| {
|
||||
ptr.* = try allocator.alloc(u8, size);
|
||||
@memset(ptr.*, 0xFF);
|
||||
}
|
||||
|
||||
// Should have created multiple slabs
|
||||
try testing.expect(slab_alloc.slabs.count() >= 10);
|
||||
|
||||
// Free all
|
||||
for (ptrs) |ptr| {
|
||||
allocator.free(ptr);
|
||||
}
|
||||
}
|
||||
|
||||
test "slab allocator - various sizes" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Test different sizes (not limited to powers of 2!)
|
||||
const sizes = [_]usize{ 8, 16, 24, 32, 40, 64, 88, 128, 144, 256 };
|
||||
|
||||
for (sizes) |size| {
|
||||
const ptr = try allocator.alloc(u8, size);
|
||||
try testing.expect(ptr.len == size);
|
||||
@memset(ptr, @intCast(size & 0xFF));
|
||||
allocator.free(ptr);
|
||||
}
|
||||
}
|
||||
|
||||
test "slab allocator - exact sizes (no rounding)" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Odd sizes stay exact (unlike buddy which rounds to power of 2)
|
||||
const ptr1 = try allocator.alloc(u8, 100);
|
||||
const ptr2 = try allocator.alloc(u8, 200);
|
||||
const ptr3 = try allocator.alloc(u8, 50);
|
||||
|
||||
// Exact sizes!
|
||||
try testing.expect(ptr1.len == 100);
|
||||
try testing.expect(ptr2.len == 200);
|
||||
try testing.expect(ptr3.len == 50);
|
||||
|
||||
allocator.free(ptr1);
|
||||
allocator.free(ptr2);
|
||||
allocator.free(ptr3);
|
||||
}
|
||||
|
||||
test "slab allocator - chunk allocation" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate many items of same size to force multiple chunks
|
||||
var ptrs: [100][]u8 = undefined;
|
||||
for (&ptrs) |*ptr| {
|
||||
ptr.* = try allocator.alloc(u8, 64);
|
||||
}
|
||||
|
||||
// Should have allocated multiple chunks (32 items per chunk)
|
||||
const slab = slab_alloc.slabs.getPtr(.{ .size = 64, .alignment = Alignment.@"1" }).?;
|
||||
try testing.expect(slab.chunks.items.len > 1);
|
||||
|
||||
// Free all
|
||||
for (ptrs) |ptr| {
|
||||
allocator.free(ptr);
|
||||
}
|
||||
}
|
||||
|
||||
test "slab allocator - reset with retain_capacity" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate some memory
|
||||
const ptr1 = try allocator.alloc(u8, 128);
|
||||
const ptr2 = try allocator.alloc(u8, 256);
|
||||
_ = ptr1;
|
||||
_ = ptr2;
|
||||
|
||||
const slabs_before = slab_alloc.slabs.count();
|
||||
const slab_128 = slab_alloc.slabs.getPtr(.{ .size = 128, .alignment = Alignment.@"1" }).?;
|
||||
const chunks_before = slab_128.chunks.items.len;
|
||||
|
||||
// Reset but keep chunks
|
||||
slab_alloc.reset(.retain_capacity);
|
||||
|
||||
try testing.expectEqual(slabs_before, slab_alloc.slabs.count());
|
||||
try testing.expectEqual(chunks_before, slab_128.chunks.items.len);
|
||||
|
||||
// Should be able to allocate again
|
||||
const ptr3 = try allocator.alloc(u8, 512);
|
||||
allocator.free(ptr3);
|
||||
}
|
||||
|
||||
test "slab allocator - reset with clear" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate some memory
|
||||
const ptr1 = try allocator.alloc(u8, 128);
|
||||
_ = ptr1;
|
||||
|
||||
try testing.expect(slab_alloc.slabs.count() > 0);
|
||||
|
||||
// Reset and free everything
|
||||
slab_alloc.reset(.clear);
|
||||
|
||||
try testing.expectEqual(@as(usize, 0), slab_alloc.slabs.count());
|
||||
|
||||
// Should still work after reset
|
||||
const ptr2 = try allocator.alloc(u8, 256);
|
||||
allocator.free(ptr2);
|
||||
}
|
||||
|
||||
test "slab allocator - stress test" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
var prng = std.Random.DefaultPrng.init(0);
|
||||
const random = prng.random();
|
||||
|
||||
var ptrs: std.ArrayList([]u8) = .empty;
|
||||
|
||||
defer {
|
||||
for (ptrs.items) |ptr| {
|
||||
allocator.free(ptr);
|
||||
}
|
||||
ptrs.deinit(allocator);
|
||||
}
|
||||
|
||||
// Random allocations and frees
|
||||
var i: usize = 0;
|
||||
while (i < 100) : (i += 1) {
|
||||
if (random.boolean() and ptrs.items.len > 0) {
|
||||
// Free a random allocation
|
||||
const index = random.uintLessThan(usize, ptrs.items.len);
|
||||
allocator.free(ptrs.swapRemove(index));
|
||||
} else {
|
||||
// Allocate random size (8 to 512)
|
||||
const size = random.uintAtMost(usize, 504) + 8;
|
||||
const ptr = try allocator.alloc(u8, size);
|
||||
try ptrs.append(allocator, ptr);
|
||||
|
||||
// Write to ensure it's valid
|
||||
@memset(ptr, @intCast(i & 0xFF));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
test "slab allocator - alignment" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
const ptr1 = try allocator.create(u64);
|
||||
const ptr2 = try allocator.create(u32);
|
||||
const ptr3 = try allocator.create([100]u8);
|
||||
|
||||
allocator.destroy(ptr1);
|
||||
allocator.destroy(ptr2);
|
||||
allocator.destroy(ptr3);
|
||||
}
|
||||
|
||||
test "slab allocator - no resize support" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
const slice = try allocator.alloc(u8, 100);
|
||||
@memset(slice, 42);
|
||||
|
||||
// Resize should fail (not supported)
|
||||
try testing.expect(!allocator.resize(slice, 90));
|
||||
try testing.expect(!allocator.resize(slice, 200));
|
||||
|
||||
allocator.free(slice);
|
||||
}
|
||||
|
||||
test "slab allocator - fragmentation pattern" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate 10 items
|
||||
var items: [10][]u8 = undefined;
|
||||
for (&items) |*item| {
|
||||
item.* = try allocator.alloc(u8, 64);
|
||||
@memset(item.*, 0xFF);
|
||||
}
|
||||
|
||||
// Free every other one
|
||||
allocator.free(items[0]);
|
||||
allocator.free(items[2]);
|
||||
allocator.free(items[4]);
|
||||
allocator.free(items[6]);
|
||||
allocator.free(items[8]);
|
||||
|
||||
// Allocate new items - should reuse freed slots
|
||||
const new1 = try allocator.alloc(u8, 64);
|
||||
const new2 = try allocator.alloc(u8, 64);
|
||||
const new3 = try allocator.alloc(u8, 64);
|
||||
|
||||
// Should get some of the freed slots back
|
||||
const addrs = [_]usize{
|
||||
@intFromPtr(items[0].ptr),
|
||||
@intFromPtr(items[2].ptr),
|
||||
@intFromPtr(items[4].ptr),
|
||||
@intFromPtr(items[6].ptr),
|
||||
@intFromPtr(items[8].ptr),
|
||||
};
|
||||
|
||||
const new1_addr = @intFromPtr(new1.ptr);
|
||||
var found = false;
|
||||
for (addrs) |addr| {
|
||||
if (new1_addr == addr) found = true;
|
||||
}
|
||||
try testing.expect(found);
|
||||
|
||||
// Cleanup
|
||||
allocator.free(items[1]);
|
||||
allocator.free(items[3]);
|
||||
allocator.free(items[5]);
|
||||
allocator.free(items[7]);
|
||||
allocator.free(items[9]);
|
||||
allocator.free(new1);
|
||||
allocator.free(new2);
|
||||
allocator.free(new3);
|
||||
}
|
||||
|
||||
test "slab allocator - many small allocations" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate 1000 small items
|
||||
var ptrs: std.ArrayList([]u8) = .empty;
|
||||
defer {
|
||||
for (ptrs.items) |ptr| {
|
||||
allocator.free(ptr);
|
||||
}
|
||||
ptrs.deinit(allocator);
|
||||
}
|
||||
|
||||
var i: usize = 0;
|
||||
while (i < 1000) : (i += 1) {
|
||||
const ptr = try allocator.alloc(u8, 24);
|
||||
try ptrs.append(allocator, ptr);
|
||||
}
|
||||
|
||||
// Should have created multiple chunks
|
||||
const slab = slab_alloc.slabs.getPtr(.{ .size = 24, .alignment = Alignment.@"1" }).?;
|
||||
try testing.expect(slab.chunks.items.len > 1);
|
||||
}
|
||||
|
||||
test "slab allocator - zero waste for exact sizes" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// These sizes have zero internal fragmentation (unlike buddy)
|
||||
const sizes = [_]usize{ 24, 40, 56, 88, 144, 152, 184, 232, 648 };
|
||||
|
||||
for (sizes) |size| {
|
||||
const ptr = try allocator.alloc(u8, size);
|
||||
|
||||
// Exact size returned!
|
||||
try testing.expectEqual(size, ptr.len);
|
||||
|
||||
@memset(ptr, 0xFF);
|
||||
allocator.free(ptr);
|
||||
}
|
||||
}
|
||||
|
||||
test "slab allocator - different size classes don't interfere" {
|
||||
var slab_alloc = TestSlabAllocator.init(testing.allocator, 16);
|
||||
defer slab_alloc.deinit();
|
||||
|
||||
const allocator = slab_alloc.allocator();
|
||||
|
||||
// Allocate size 64
|
||||
const ptr_64 = try allocator.alloc(u8, 64);
|
||||
const addr_64 = @intFromPtr(ptr_64.ptr);
|
||||
allocator.free(ptr_64);
|
||||
|
||||
// Allocate size 128 - should NOT reuse size-64 slot
|
||||
const ptr_128 = try allocator.alloc(u8, 128);
|
||||
const addr_128 = @intFromPtr(ptr_128.ptr);
|
||||
|
||||
try testing.expect(addr_64 != addr_128);
|
||||
|
||||
// Allocate size 64 again - SHOULD reuse original slot
|
||||
const ptr_64_again = try allocator.alloc(u8, 64);
|
||||
const addr_64_again = @intFromPtr(ptr_64_again.ptr);
|
||||
|
||||
try testing.expectEqual(addr_64, addr_64_again);
|
||||
|
||||
allocator.free(ptr_128);
|
||||
allocator.free(ptr_64_again);
|
||||
}
|
||||
Reference in New Issue
Block a user