mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-15 19:56:38 +00:00
477 lines
14 KiB
Go
477 lines
14 KiB
Go
// Copyright 2017 The Memory 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 memory implements a memory allocator.
|
|
//
|
|
// # Build status
|
|
//
|
|
// available at https://modern-c.appspot.com/-/builder/?importpath=modernc.org%2fmemory
|
|
//
|
|
// # Changelog
|
|
//
|
|
// 2017-10-03 Added alternative, unsafe.Pointer-based API.
|
|
//
|
|
// Package memory implements a memory allocator.
|
|
//
|
|
// # Changelog
|
|
//
|
|
// 2017-10-03 Added alternative, unsafe.Pointer-based API.
|
|
//
|
|
// # Benchmarks
|
|
//
|
|
// jnml@3900x:~/src/modernc.org/memory$ date ; go version ; go test -run @ -bench . -benchmem |& tee log
|
|
// Mon Sep 25 16:02:02 CEST 2023
|
|
// go version go1.21.1 linux/amd64
|
|
// goos: linux
|
|
// goarch: amd64
|
|
// pkg: modernc.org/memory
|
|
// cpu: AMD Ryzen 9 3900X 12-Core Processor
|
|
// BenchmarkFree16-24 123506772 9.802 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkFree32-24 73853230 15.08 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkFree64-24 43070334 25.15 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkCalloc16-24 59353304 18.92 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkCalloc32-24 39415004 29.00 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkCalloc64-24 35825725 32.02 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkGoCalloc16-24 38274313 26.99 ns/op 16 B/op 1 allocs/op
|
|
// BenchmarkGoCalloc32-24 44590477 33.06 ns/op 32 B/op 1 allocs/op
|
|
// BenchmarkGoCalloc64-24 44233016 37.20 ns/op 64 B/op 1 allocs/op
|
|
// BenchmarkMalloc16-24 145736911 7.720 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkMalloc32-24 128898334 7.887 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkMalloc64-24 149569483 7.994 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrFree16-24 117043012 9.205 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrFree32-24 77399617 14.20 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrFree64-24 48770785 25.04 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrCalloc16-24 79257636 15.44 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrCalloc32-24 49644562 23.62 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrCalloc64-24 39854710 28.22 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrMalloc16-24 252987727 4.525 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrMalloc32-24 241423840 4.433 ns/op 0 B/op 0 allocs/op
|
|
// BenchmarkUintptrMalloc64-24 256450324 4.669 ns/op 0 B/op 0 allocs/op
|
|
// PASS
|
|
// ok modernc.org/memory 93.178s
|
|
// jnml@3900x:~/src/modernc.org/memory$
|
|
package memory // import "modernc.org/memory"
|
|
|
|
import (
|
|
"fmt"
|
|
"math/bits"
|
|
"os"
|
|
"reflect"
|
|
"unsafe"
|
|
)
|
|
|
|
const (
|
|
headerSize = unsafe.Sizeof(page{})
|
|
mallocAllign = 2 * unsafe.Sizeof(uintptr(0))
|
|
maxSlotSize = 1 << maxSlotSizeLog
|
|
maxSlotSizeLog = pageSizeLog - 2
|
|
pageAvail = pageSize - headerSize
|
|
pageMask = pageSize - 1
|
|
pageSize = 1 << pageSizeLog
|
|
)
|
|
|
|
func init() {
|
|
if unsafe.Sizeof(page{})%mallocAllign != 0 {
|
|
panic("internal error")
|
|
}
|
|
}
|
|
|
|
// if n%m != 0 { n += m-n%m }. m must be a power of 2.
|
|
func roundup(n, m int) int { return (n + m - 1) &^ (m - 1) }
|
|
|
|
type node struct {
|
|
prev, next uintptr // *node
|
|
}
|
|
|
|
type page struct {
|
|
brk int
|
|
log uint
|
|
size int
|
|
used int
|
|
}
|
|
|
|
// Allocator allocates and frees memory. Its zero value is ready for use. The
|
|
// exported counters are updated only when build tag memory.counters is
|
|
// present.
|
|
type Allocator struct {
|
|
Allocs int // # of allocs.
|
|
Bytes int // Asked from OS.
|
|
cap [64]int
|
|
lists [64]uintptr // *node
|
|
Mmaps int // Asked from OS.
|
|
pages [64]uintptr // *page
|
|
regs map[uintptr]struct{} // map[*page]struct{}
|
|
}
|
|
|
|
func (a *Allocator) mmap(size int) (uintptr /* *page */, error) {
|
|
p, size, err := mmap(size)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
if counters {
|
|
a.Mmaps++
|
|
a.Bytes += size
|
|
}
|
|
if a.regs == nil {
|
|
a.regs = map[uintptr]struct{}{}
|
|
}
|
|
(*page)(unsafe.Pointer(p)).size = size
|
|
a.regs[p] = struct{}{}
|
|
return p, nil
|
|
}
|
|
|
|
func (a *Allocator) newPage(size int) (uintptr /* *page */, error) {
|
|
size += int(headerSize)
|
|
p, err := a.mmap(size)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
(*page)(unsafe.Pointer(p)).log = 0
|
|
return p, nil
|
|
}
|
|
|
|
func (a *Allocator) newSharedPage(log uint) (uintptr /* *page */, error) {
|
|
if a.cap[log] == 0 {
|
|
a.cap[log] = int(pageAvail) / (1 << log)
|
|
}
|
|
size := int(headerSize) + a.cap[log]<<log
|
|
p, err := a.mmap(size)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
a.pages[log] = p
|
|
(*page)(unsafe.Pointer(p)).log = log
|
|
return p, nil
|
|
}
|
|
|
|
func (a *Allocator) unmap(p uintptr /* *page */) error {
|
|
delete(a.regs, p)
|
|
if counters {
|
|
a.Mmaps--
|
|
}
|
|
return unmap(p, (*page)(unsafe.Pointer(p)).size)
|
|
}
|
|
|
|
// UintptrCalloc is like Calloc except it returns an uintptr.
|
|
func (a *Allocator) UintptrCalloc(size int) (r uintptr, err error) {
|
|
if trace {
|
|
defer func() {
|
|
fmt.Fprintf(os.Stderr, "Calloc(%#x) %#x, %v\n", size, r, err)
|
|
}()
|
|
}
|
|
if r, err = a.UintptrMalloc(size); r == 0 || err != nil {
|
|
return 0, err
|
|
}
|
|
b := ((*rawmem)(unsafe.Pointer(r)))[:size:size]
|
|
for i := range b {
|
|
b[i] = 0
|
|
}
|
|
return r, nil
|
|
}
|
|
|
|
// UintptrFree is like Free except its argument is an uintptr, which must have
|
|
// been acquired from UintptrCalloc or UintptrMalloc or UintptrRealloc.
|
|
func (a *Allocator) UintptrFree(p uintptr) (err error) {
|
|
if trace {
|
|
defer func() {
|
|
fmt.Fprintf(os.Stderr, "Free(%#x) %v\n", p, err)
|
|
}()
|
|
}
|
|
if p == 0 {
|
|
return nil
|
|
}
|
|
|
|
if counters {
|
|
a.Allocs--
|
|
}
|
|
pg := p &^ uintptr(pageMask)
|
|
log := (*page)(unsafe.Pointer(pg)).log
|
|
if log == 0 {
|
|
if counters {
|
|
a.Bytes -= (*page)(unsafe.Pointer(pg)).size
|
|
}
|
|
return a.unmap(pg)
|
|
}
|
|
|
|
(*node)(unsafe.Pointer(p)).prev = 0
|
|
(*node)(unsafe.Pointer(p)).next = a.lists[log]
|
|
if next := (*node)(unsafe.Pointer(p)).next; next != 0 {
|
|
(*node)(unsafe.Pointer(next)).prev = p
|
|
}
|
|
a.lists[log] = p
|
|
(*page)(unsafe.Pointer(pg)).used--
|
|
if (*page)(unsafe.Pointer(pg)).used != 0 {
|
|
return nil
|
|
}
|
|
|
|
for i := 0; i < (*page)(unsafe.Pointer(pg)).brk; i++ {
|
|
n := pg + headerSize + uintptr(i)<<log
|
|
next := (*node)(unsafe.Pointer(n)).next
|
|
prev := (*node)(unsafe.Pointer(n)).prev
|
|
switch {
|
|
case prev == 0:
|
|
a.lists[log] = next
|
|
if next != 0 {
|
|
(*node)(unsafe.Pointer(next)).prev = 0
|
|
}
|
|
case next == 0:
|
|
(*node)(unsafe.Pointer(prev)).next = 0
|
|
default:
|
|
(*node)(unsafe.Pointer(prev)).next = next
|
|
(*node)(unsafe.Pointer(next)).prev = prev
|
|
}
|
|
}
|
|
|
|
if a.pages[log] == pg {
|
|
a.pages[log] = 0
|
|
}
|
|
if counters {
|
|
a.Bytes -= (*page)(unsafe.Pointer(pg)).size
|
|
}
|
|
return a.unmap(pg)
|
|
}
|
|
|
|
// UintptrMalloc is like Malloc except it returns an uinptr.
|
|
func (a *Allocator) UintptrMalloc(size int) (r uintptr, err error) {
|
|
if trace {
|
|
defer func() {
|
|
fmt.Fprintf(os.Stderr, "Malloc(%#x) %#x, %v\n", size, r, err)
|
|
}()
|
|
}
|
|
if size < 0 {
|
|
panic("invalid malloc size")
|
|
}
|
|
|
|
if size == 0 {
|
|
return 0, nil
|
|
}
|
|
|
|
if counters {
|
|
a.Allocs++
|
|
}
|
|
log := uint(bits.Len(uint((size+int(mallocAllign)-1)&^int(mallocAllign-1) - 1)))
|
|
if log > maxSlotSizeLog {
|
|
p, err := a.newPage(size)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return p + headerSize, nil
|
|
}
|
|
|
|
if a.lists[log] == 0 && a.pages[log] == 0 {
|
|
if _, err := a.newSharedPage(log); err != nil {
|
|
return 0, err
|
|
}
|
|
}
|
|
|
|
if p := a.pages[log]; p != 0 {
|
|
(*page)(unsafe.Pointer(p)).used++
|
|
(*page)(unsafe.Pointer(p)).brk++
|
|
if (*page)(unsafe.Pointer(p)).brk == a.cap[log] {
|
|
a.pages[log] = 0
|
|
}
|
|
return p + headerSize + uintptr((*page)(unsafe.Pointer(p)).brk-1)<<log, nil
|
|
}
|
|
|
|
n := a.lists[log]
|
|
p := n &^ uintptr(pageMask)
|
|
a.lists[log] = (*node)(unsafe.Pointer(n)).next
|
|
if next := (*node)(unsafe.Pointer(n)).next; next != 0 {
|
|
(*node)(unsafe.Pointer(next)).prev = 0
|
|
}
|
|
(*page)(unsafe.Pointer(p)).used++
|
|
return n, nil
|
|
}
|
|
|
|
// UintptrRealloc is like Realloc except its first argument is an uintptr,
|
|
// which must have been returned from UintptrCalloc, UintptrMalloc or
|
|
// UintptrRealloc.
|
|
func (a *Allocator) UintptrRealloc(p uintptr, size int) (r uintptr, err error) {
|
|
if trace {
|
|
defer func() {
|
|
fmt.Fprintf(os.Stderr, "UnsafeRealloc(%#x, %#x) %#x, %v\n", p, size, r, err)
|
|
}()
|
|
}
|
|
switch {
|
|
case p == 0:
|
|
return a.UintptrMalloc(size)
|
|
case size == 0 && p != 0:
|
|
return 0, a.UintptrFree(p)
|
|
}
|
|
|
|
us := UintptrUsableSize(p)
|
|
if us >= size {
|
|
return p, nil
|
|
}
|
|
|
|
if r, err = a.UintptrMalloc(size); err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
if us < size {
|
|
size = us
|
|
}
|
|
copy((*rawmem)(unsafe.Pointer(r))[:size:size], (*rawmem)(unsafe.Pointer(p))[:size:size])
|
|
return r, a.UintptrFree(p)
|
|
}
|
|
|
|
// UintptrUsableSize is like UsableSize except its argument is an uintptr,
|
|
// which must have been returned from UintptrCalloc, UintptrMalloc or
|
|
// UintptrRealloc.
|
|
func UintptrUsableSize(p uintptr) (r int) {
|
|
if trace {
|
|
defer func() {
|
|
fmt.Fprintf(os.Stderr, "UsableSize(%#x) %#x\n", p, r)
|
|
}()
|
|
}
|
|
if p == 0 {
|
|
return 0
|
|
}
|
|
|
|
return usableSize(p)
|
|
}
|
|
|
|
func usableSize(p uintptr) (r int) {
|
|
pg := p &^ uintptr(pageMask)
|
|
if log := (*page)(unsafe.Pointer(pg)).log; log != 0 {
|
|
return 1 << log
|
|
}
|
|
|
|
return (*page)(unsafe.Pointer(pg)).size - int(headerSize)
|
|
}
|
|
|
|
// Calloc is like Malloc except the allocated memory is zeroed.
|
|
func (a *Allocator) Calloc(size int) (r []byte, err error) {
|
|
p, err := a.UintptrCalloc(size)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var b []byte
|
|
sh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
|
|
sh.Cap = usableSize(p)
|
|
sh.Data = p
|
|
sh.Len = size
|
|
return b, nil
|
|
}
|
|
|
|
// Close releases all OS resources used by a and sets it to its zero value.
|
|
//
|
|
// It's not necessary to Close the Allocator when exiting a process.
|
|
func (a *Allocator) Close() (err error) {
|
|
for p := range a.regs {
|
|
if e := a.unmap(p); e != nil && err == nil {
|
|
err = e
|
|
}
|
|
}
|
|
*a = Allocator{}
|
|
return err
|
|
}
|
|
|
|
// Free deallocates memory (as in C.free). The argument of Free must have been
|
|
// acquired from Calloc or Malloc or Realloc.
|
|
func (a *Allocator) Free(b []byte) (err error) {
|
|
if b = b[:cap(b)]; len(b) == 0 {
|
|
return nil
|
|
}
|
|
|
|
return a.UintptrFree(uintptr(unsafe.Pointer(&b[0])))
|
|
}
|
|
|
|
// Malloc allocates size bytes and returns a byte slice of the allocated
|
|
// memory. The memory is not initialized. Malloc panics for size < 0 and
|
|
// returns (nil, nil) for zero size.
|
|
//
|
|
// It's ok to reslice the returned slice but the result of appending to it
|
|
// cannot be passed to Free or Realloc as it may refer to a different backing
|
|
// array afterwards.
|
|
func (a *Allocator) Malloc(size int) (r []byte, err error) {
|
|
p, err := a.UintptrMalloc(size)
|
|
if p == 0 || err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
sh := (*reflect.SliceHeader)(unsafe.Pointer(&r))
|
|
sh.Cap = usableSize(p)
|
|
sh.Data = p
|
|
sh.Len = size
|
|
return r, nil
|
|
}
|
|
|
|
// Realloc changes the size of the backing array of b to size bytes or returns
|
|
// an error, if any. The contents will be unchanged in the range from the
|
|
// start of the region up to the minimum of the old and new sizes. If the
|
|
// new size is larger than the old size, the added memory will not be
|
|
// initialized. If b's backing array is of zero size, then the call is
|
|
// equivalent to Malloc(size), for all values of size; if size is equal to
|
|
// zero, and b's backing array is not of zero size, then the call is equivalent
|
|
// to Free(b). Unless b's backing array is of zero size, it must have been
|
|
// returned by an earlier call to Malloc, Calloc or Realloc. If the area
|
|
// pointed to was moved, a Free(b) is done.
|
|
func (a *Allocator) Realloc(b []byte, size int) (r []byte, err error) {
|
|
var p uintptr
|
|
if b = b[:cap(b)]; len(b) != 0 {
|
|
p = uintptr(unsafe.Pointer(&b[0]))
|
|
}
|
|
if p, err = a.UintptrRealloc(p, size); p == 0 || err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
sh := (*reflect.SliceHeader)(unsafe.Pointer(&r))
|
|
sh.Cap = usableSize(p)
|
|
sh.Data = p
|
|
sh.Len = size
|
|
return r, nil
|
|
}
|
|
|
|
// UsableSize reports the size of the memory block allocated at p, which must
|
|
// point to the first byte of a slice returned from Calloc, Malloc or Realloc.
|
|
// The allocated memory block size can be larger than the size originally
|
|
// requested from Calloc, Malloc or Realloc.
|
|
func UsableSize(p *byte) (r int) { return UintptrUsableSize(uintptr(unsafe.Pointer(p))) }
|
|
|
|
// UnsafeCalloc is like Calloc except it returns an unsafe.Pointer.
|
|
func (a *Allocator) UnsafeCalloc(size int) (r unsafe.Pointer, err error) {
|
|
p, err := a.UintptrCalloc(size)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return unsafe.Pointer(p), nil
|
|
}
|
|
|
|
// UnsafeFree is like Free except its argument is an unsafe.Pointer, which must
|
|
// have been acquired from UnsafeCalloc or UnsafeMalloc or UnsafeRealloc.
|
|
func (a *Allocator) UnsafeFree(p unsafe.Pointer) (err error) { return a.UintptrFree(uintptr(p)) }
|
|
|
|
// UnsafeMalloc is like Malloc except it returns an unsafe.Pointer.
|
|
func (a *Allocator) UnsafeMalloc(size int) (r unsafe.Pointer, err error) {
|
|
p, err := a.UintptrMalloc(size)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return unsafe.Pointer(p), nil
|
|
}
|
|
|
|
// UnsafeRealloc is like Realloc except its first argument is an
|
|
// unsafe.Pointer, which must have been returned from UnsafeCalloc,
|
|
// UnsafeMalloc or UnsafeRealloc.
|
|
func (a *Allocator) UnsafeRealloc(p unsafe.Pointer, size int) (r unsafe.Pointer, err error) {
|
|
q, err := a.UintptrRealloc(uintptr(p), size)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return unsafe.Pointer(q), nil
|
|
}
|
|
|
|
// UnsafeUsableSize is like UsableSize except its argument is an
|
|
// unsafe.Pointer, which must have been returned from UnsafeCalloc,
|
|
// UnsafeMalloc or UnsafeRealloc.
|
|
func UnsafeUsableSize(p unsafe.Pointer) (r int) { return UintptrUsableSize(uintptr(p)) }
|