gotosocial/vendor/modernc.org/memory/memory.go
kim ed46224573
Add SQLite support, fix un-thread-safe DB caches, small performance f… (#172)
* Add SQLite support, fix un-thread-safe DB caches, small performance fixes

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* add SQLite licenses to README

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* appease the linter, and fix my dumbass-ery

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* make requested changes

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

* add back comment

Signed-off-by: kim (grufwub) <grufwub@gmail.com>
2021-08-29 16:41:41 +02:00

543 lines
18 KiB
Go
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// 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
//
// AMD Ryzen 9 3900X 12-Core Processor × 24
//
// jnml@3900x:~/src/modernc.org/memory$ date ; go version ; go test -run @ -bench . -benchmem |& tee log
// Fri Nov 20 17:23:04 CET 2020
// go version go1.15.5 linux/amd64
// goos: linux
// goarch: amd64
// pkg: modernc.org/memory
// BenchmarkFree16-24 141188362 8.26 ns/op 0 B/op 0 allocs/op
// BenchmarkFree32-24 100000000 11.4 ns/op 0 B/op 0 allocs/op
// BenchmarkFree64-24 67160647 18.3 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc16-24 60612698 19.8 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc32-24 47968105 23.8 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc64-24 40752181 28.6 ns/op 0 B/op 0 allocs/op
// BenchmarkGoCalloc16-24 66487354 17.8 ns/op 16 B/op 1 allocs/op
// BenchmarkGoCalloc32-24 56009206 21.2 ns/op 32 B/op 1 allocs/op
// BenchmarkGoCalloc64-24 52086571 23.4 ns/op 64 B/op 1 allocs/op
// BenchmarkMalloc16-24 113943390 10.2 ns/op 0 B/op 0 allocs/op
// BenchmarkMalloc32-24 113520471 10.2 ns/op 0 B/op 0 allocs/op
// BenchmarkMalloc64-24 108787056 10.7 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree16-24 146110286 7.94 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree32-24 93052707 12.0 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree64-24 69805262 17.3 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc16-24 85282725 13.7 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc32-24 66489789 17.9 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc64-24 53561092 22.7 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc16-24 222978858 5.28 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc32-24 210443384 5.30 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc64-24 213706227 5.47 ns/op 0 B/op 0 allocs/op
// PASS
// ok modernc.org/memory 70.528s
// jnml@3900x:~/src/modernc.org/memory$
//
// Intel® Core™ i5-4670 CPU @ 3.40GHz × 4
//
// ==== jnml@4670:~/src/modernc.org/memory> date ; go version ; go test -run @ -bench . -benchmem |& tee log
// Sat Dec 8 12:56:53 CET 2018
// go version go1.11.2 linux/amd64
// goos: linux
// goarch: amd64
// pkg: modernc.org/memory
// BenchmarkFree16-4 100000000 14.7 ns/op 0 B/op 0 allocs/op
// BenchmarkFree32-4 100000000 20.5 ns/op 0 B/op 0 allocs/op
// BenchmarkFree64-4 50000000 32.8 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc16-4 50000000 24.4 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc32-4 50000000 29.2 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc64-4 50000000 35.7 ns/op 0 B/op 0 allocs/op
// BenchmarkGoCalloc16-4 50000000 27.0 ns/op 16 B/op 1 allocs/op
// BenchmarkGoCalloc32-4 50000000 27.3 ns/op 32 B/op 1 allocs/op
// BenchmarkGoCalloc64-4 30000000 37.9 ns/op 64 B/op 1 allocs/op
// BenchmarkMalloc16-4 100000000 12.9 ns/op 0 B/op 0 allocs/op
// BenchmarkMalloc32-4 100000000 12.9 ns/op 0 B/op 0 allocs/op
// BenchmarkMalloc64-4 100000000 13.2 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree16-4 100000000 12.0 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree32-4 100000000 17.5 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree64-4 50000000 28.9 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc16-4 100000000 17.8 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc32-4 100000000 22.9 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc64-4 50000000 29.6 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc16-4 200000000 7.31 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc32-4 200000000 7.47 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc64-4 200000000 7.68 ns/op 0 B/op 0 allocs/op
// PASS
// ok modernc.org/memory 73.859s
// //
// Intel® Xeon(R) CPU E5-1650 v2 @ 3.50GHz × 12
//
// ==== jnml@e5-1650:~/src/modernc.org/memory> date ; go version ; go test -run @ -bench . -benchmem
// Fri Dec 7 14:18:50 CET 2018
// go version go1.11.2 linux/amd64
// goos: linux
// goarch: amd64
// pkg: modernc.org/memory
// BenchmarkFree16-12 100000000 16.7 ns/op 0 B/op 0 allocs/op
// BenchmarkFree32-12 50000000 25.0 ns/op 0 B/op 0 allocs/op
// BenchmarkFree64-12 30000000 39.7 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc16-12 50000000 26.3 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc32-12 50000000 33.4 ns/op 0 B/op 0 allocs/op
// BenchmarkCalloc64-12 30000000 38.3 ns/op 0 B/op 0 allocs/op
// BenchmarkGoCalloc16-12 50000000 26.6 ns/op 16 B/op 1 allocs/op
// BenchmarkGoCalloc32-12 50000000 26.8 ns/op 32 B/op 1 allocs/op
// BenchmarkGoCalloc64-12 30000000 35.1 ns/op 64 B/op 1 allocs/op
// BenchmarkMalloc16-12 100000000 13.5 ns/op 0 B/op 0 allocs/op
// BenchmarkMalloc32-12 100000000 13.4 ns/op 0 B/op 0 allocs/op
// BenchmarkMalloc64-12 100000000 14.1 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree16-12 100000000 14.4 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree32-12 100000000 21.7 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrFree64-12 50000000 36.7 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc16-12 100000000 20.4 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc32-12 50000000 27.1 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrCalloc64-12 50000000 33.4 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc16-12 200000000 8.02 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc32-12 200000000 8.28 ns/op 0 B/op 0 allocs/op
// BenchmarkUintptrMalloc64-12 200000000 8.29 ns/op 0 B/op 0 allocs/op
// PASS
// ok modernc.org/memory 80.896s
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)) }