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Latest commit d965bb6 Mar 20, 2020 History
There are a handful of places where the runtime wants to round up the
result of a division. We just introduced a helper to do this. This CL
replaces all of the hand-coded round-ups (that I could find) with this

Change-Id: I465d152157ff0f3cad40c0aa57491e4f2de510ad
Run-TryBot: Austin Clements <>
TryBot-Result: Gobot Gobot <>
Reviewed-by: Cherry Zhang <>
8 contributors

Users who have contributed to this file

@rsc @randall77 @RLH @mknyszek @dvyukov @davecheney @bradfitz @aclements
25 lines (22 sloc) 777 Bytes
// Copyright 2009 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.
// Malloc small size classes.
// See malloc.go for overview.
// See also mksizeclasses.go for how we decide what size classes to use.
package runtime
// Returns size of the memory block that mallocgc will allocate if you ask for the size.
func roundupsize(size uintptr) uintptr {
if size < _MaxSmallSize {
if size <= smallSizeMax-8 {
return uintptr(class_to_size[size_to_class8[divRoundUp(size, smallSizeDiv)]])
} else {
return uintptr(class_to_size[size_to_class128[divRoundUp(size-smallSizeMax, largeSizeDiv)]])
if size+_PageSize < size {
return size
return alignUp(size, _PageSize)