src/runtime/_mkmalloc/constants.go

// Copyright 2025 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

const (
	// Constants that we use and will transfer to the runtime.
	minHeapAlign = 8
	maxSmallSize = 32 << 10
	smallSizeDiv = 8
	smallSizeMax = 1024
	largeSizeDiv = 128
	pageShift    = 13
	tinySize     = 16

	// Derived constants.
	pageSize = 1 << pageShift
)

const (
	maxPtrSize = max(4, 8)
	maxPtrBits = 8 * maxPtrSize

	// Maximum size smallScanNoHeader would be called for, which is the
	// maximum value gc.MinSizeForMallocHeader can have on any platform.
	// gc.MinSizeForMallocHeader is defined as goarch.PtrSize * goarch.PtrBits.
	smallScanNoHeaderMax = maxPtrSize * maxPtrBits
)