// Copyright 2019 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 runtime_test
import (
"fmt"
"internal/goos"
"math/rand"
. "runtime"
"testing"
)
// makePallocData produces an initialized PallocData by setting
// the ranges of described in alloc and scavenge.
func makePallocData(alloc, scavenged []BitRange) *PallocData {
b := new(PallocData)
for _, v := range alloc {
if v.N == 0 {
// Skip N==0. It's harmless and allocRange doesn't
// handle this case.
continue
}
b.AllocRange(v.I, v.N)
}
for _, v := range scavenged {
if v.N == 0 {
// See the previous loop.
continue
}
b.ScavengedSetRange(v.I, v.N)
}
return b
}
func TestFillAligned(t *testing.T) {
fillAlignedSlow := func(x uint64, m uint) uint64 {
if m == 1 {
return x
}
out := uint64(0)
for i := uint(0); i < 64; i += m {
for j := uint(0); j < m; j++ {
if x&(uint64(1)<<(i+j)) != 0 {
out |= ((uint64(1) << m) - 1) << i
break
}
}
}
return out
}
check := func(x uint64, m uint) {
want := fillAlignedSlow(x, m)
if got := FillAligned(x, m); got != want {
t.Logf("got: %064b", got)
t.Logf("want: %064b", want)
t.Errorf("bad fillAligned(%016x, %d)", x, m)
}
}
for m := uint(1); m <= 64; m *= 2 {
tests := []uint64{
0x0000000000000000,
0x00000000ffffffff,
0xffffffff00000000,
0x8000000000000001,
0xf00000000000000f,
0xf00000010050000f,
0xffffffffffffffff,
0x0000000000000001,
0x0000000000000002,
0x0000000000000008,
uint64(1) << (m - 1),
uint64(1) << m,
// Try a few fixed arbitrary examples.
0xb02b9effcf137016,
0x3975a076a9fbff18,
0x0f8c88ec3b81506e,
0x60f14d80ef2fa0e6,
}
for _, test := range tests {
check(test, m)
}
for i := 0; i < 1000; i++ {
// Try a pseudo-random numbers.
check(rand.Uint64(), m)
if m > 1 {
// For m != 1, let's construct a slightly more interesting
// random test. Generate a bitmap which is either 0 or
// randomly set bits for each m-aligned group of m bits.
val := uint64(0)
for n := uint(0); n < 64; n += m {
// For each group of m bits, flip a coin:
// * Leave them as zero.
// * Set them randomly.
if rand.Uint64()%2 == 0 {
val |= (rand.Uint64() & ((1 << m) - 1)) << n
}
}
check(val, m)
}
}
}
}
func TestPallocDataFindScavengeCandidate(t *testing.T) {
type test struct {
alloc, scavenged []BitRange
min, max uintptr
want BitRange
}
tests := map[string]test{
"MixedMin1": {
alloc: []BitRange{{0, 40}, {42, PallocChunkPages - 42}},
scavenged: []BitRange{{0, 41}, {42, PallocChunkPages - 42}},
min: 1,
max: PallocChunkPages,
want: BitRange{41, 1},
},
"MultiMin1": {
alloc: []BitRange{{0, 63}, {65, 20}, {87, PallocChunkPages - 87}},
scavenged: []BitRange{{86, 1}},
min: 1,
max: PallocChunkPages,
want: BitRange{85, 1},
},
}
// Try out different page minimums.
for m := uintptr(1); m <= 64; m *= 2 {
suffix := fmt.Sprintf("Min%d", m)
tests["AllFree"+suffix] = test{
min: m,
max: PallocChunkPages,
want: BitRange{0, PallocChunkPages},
}
tests["AllScavenged"+suffix] = test{
scavenged: []BitRange{{0, PallocChunkPages}},
min: m,
max: PallocChunkPages,
want: BitRange{0, 0},
}
tests["NoneFree"+suffix] = test{
alloc: []BitRange{{0, PallocChunkPages}},
scavenged: []BitRange{{PallocChunkPages / 2, PallocChunkPages / 2}},
min: m,
max: PallocChunkPages,
want: BitRange{0, 0},
}
tests["StartFree"+suffix] = test{
alloc: []BitRange{{uint(m), PallocChunkPages - uint(m)}},
min: m,
max: PallocChunkPages,
want: BitRange{0, uint(m)},
}
tests["EndFree"+suffix] = test{
alloc: []BitRange{{0, PallocChunkPages - uint(m)}},
min: m,
max: PallocChunkPages,
want: BitRange{PallocChunkPages - uint(m), uint(m)},
}
tests["Straddle64"+suffix] = test{
alloc: []BitRange{{0, 64 - uint(m)}, {64 + uint(m), PallocChunkPages - (64 + uint(m))}},
min: m,
max: 2 * m,
want: BitRange{64 - uint(m), 2 * uint(m)},
}
tests["BottomEdge64WithFull"+suffix] = test{
alloc: []BitRange{{64, 64}, {128 + 3*uint(m), PallocChunkPages - (128 + 3*uint(m))}},
scavenged: []BitRange{{1, 10}},
min: m,
max: 3 * m,
want: BitRange{128, 3 * uint(m)},
}
tests["BottomEdge64WithPocket"+suffix] = test{
alloc: []BitRange{{64, 62}, {127, 1}, {128 + 3*uint(m), PallocChunkPages - (128 + 3*uint(m))}},
scavenged: []BitRange{{1, 10}},
min: m,
max: 3 * m,
want: BitRange{128, 3 * uint(m)},
}
tests["Max0"+suffix] = test{
scavenged: []BitRange{{0, PallocChunkPages - uint(m)}},
min: m,
max: 0,
want: BitRange{PallocChunkPages - uint(m), uint(m)},
}
if m <= 8 {
tests["OneFree"] = test{
alloc: []BitRange{{0, 40}, {40 + uint(m), PallocChunkPages - (40 + uint(m))}},
min: m,
max: PallocChunkPages,
want: BitRange{40, uint(m)},
}
tests["OneScavenged"] = test{
alloc: []BitRange{{0, 40}, {40 + uint(m), PallocChunkPages - (40 + uint(m))}},
scavenged: []BitRange{{40, 1}},
min: m,
max: PallocChunkPages,
want: BitRange{0, 0},
}
}
if m > 1 {
tests["MaxUnaligned"+suffix] = test{
scavenged: []BitRange{{0, PallocChunkPages - uint(m*2-1)}},
min: m,
max: m - 2,
want: BitRange{PallocChunkPages - uint(m), uint(m)},
}
tests["SkipSmall"+suffix] = test{
alloc: []BitRange{{0, 64 - uint(m)}, {64, 5}, {70, 11}, {82, PallocChunkPages - 82}},
min: m,
max: m,
want: BitRange{64 - uint(m), uint(m)},
}
tests["SkipMisaligned"+suffix] = test{
alloc: []BitRange{{0, 64 - uint(m)}, {64, 63}, {127 + uint(m), PallocChunkPages - (127 + uint(m))}},
min: m,
max: m,
want: BitRange{64 - uint(m), uint(m)},
}
tests["MaxLessThan"+suffix] = test{
scavenged: []BitRange{{0, PallocChunkPages - uint(m)}},
min: m,
max: 1,
want: BitRange{PallocChunkPages - uint(m), uint(m)},
}
}
}
if PhysHugePageSize > uintptr(PageSize) {
// Check hugepage preserving behavior.
bits := uint(PhysHugePageSize / uintptr(PageSize))
if bits < PallocChunkPages {
tests["PreserveHugePageBottom"] = test{
alloc: []BitRange{{bits + 2, PallocChunkPages - (bits + 2)}},
min: 1,
max: 3, // Make it so that max would have us try to break the huge page.
want: BitRange{0, bits + 2},
}
if 3*bits < PallocChunkPages {
// We need at least 3 huge pages in a chunk for this test to make sense.
tests["PreserveHugePageMiddle"] = test{
alloc: []BitRange{{0, bits - 10}, {2*bits + 10, PallocChunkPages - (2*bits + 10)}},
min: 1,
max: 12, // Make it so that max would have us try to break the huge page.
want: BitRange{bits, bits + 10},
}
}
tests["PreserveHugePageTop"] = test{
alloc: []BitRange{{0, PallocChunkPages - bits}},
min: 1,
max: 1, // Even one page would break a huge page in this case.
want: BitRange{PallocChunkPages - bits, bits},
}
} else if bits == PallocChunkPages {
tests["PreserveHugePageAll"] = test{
min: 1,
max: 1, // Even one page would break a huge page in this case.
want: BitRange{0, PallocChunkPages},
}
} else {
// The huge page size is greater than pallocChunkPages, so it should
// be effectively disabled. There's no way we can possible scavenge
// a huge page out of this bitmap chunk.
tests["PreserveHugePageNone"] = test{
min: 1,
max: 1,
want: BitRange{PallocChunkPages - 1, 1},
}
}
}
for name, v := range tests {
v := v
t.Run(name, func(t *testing.T) {
b := makePallocData(v.alloc, v.scavenged)
start, size := b.FindScavengeCandidate(PallocChunkPages-1, v.min, v.max)
got := BitRange{start, size}
if !(got.N == 0 && v.want.N == 0) && got != v.want {
t.Fatalf("candidate mismatch: got %v, want %v", got, v.want)
}
})
}
}
// Tests end-to-end scavenging on a pageAlloc.
func TestPageAllocScavenge(t *testing.T) {
if GOOS == "openbsd" && testing.Short() {
t.Skip("skipping because virtual memory is limited; see #36210")
}
type test struct {
request, expect uintptr
}
minPages := PhysPageSize / PageSize
if minPages < 1 {
minPages = 1
}
type setup struct {
beforeAlloc map[ChunkIdx][]BitRange
beforeScav map[ChunkIdx][]BitRange
expect []test
afterScav map[ChunkIdx][]BitRange
}
tests := map[string]setup{
"AllFreeUnscavExhaust": {
beforeAlloc: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 1: {},
BaseChunkIdx + 2: {},
},
beforeScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 1: {},
BaseChunkIdx + 2: {},
},
expect: []test{
{^uintptr(0), 3 * PallocChunkPages * PageSize},
},
afterScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{0, PallocChunkPages}},
BaseChunkIdx + 1: {{0, PallocChunkPages}},
BaseChunkIdx + 2: {{0, PallocChunkPages}},
},
},
"NoneFreeUnscavExhaust": {
beforeAlloc: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{0, PallocChunkPages}},
BaseChunkIdx + 1: {},
BaseChunkIdx + 2: {{0, PallocChunkPages}},
},
beforeScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 1: {{0, PallocChunkPages}},
BaseChunkIdx + 2: {},
},
expect: []test{
{^uintptr(0), 0},
},
afterScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 1: {{0, PallocChunkPages}},
BaseChunkIdx + 2: {},
},
},
"ScavHighestPageFirst": {
beforeAlloc: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
},
beforeScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
},
expect: []test{
{1, minPages * PageSize},
},
afterScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(minPages)}},
},
},
"ScavMultiple": {
beforeAlloc: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
},
beforeScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
},
expect: []test{
{minPages * PageSize, minPages * PageSize},
{minPages * PageSize, minPages * PageSize},
},
afterScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{0, PallocChunkPages}},
},
},
"ScavMultiple2": {
beforeAlloc: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 1: {},
},
beforeScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
BaseChunkIdx + 1: {{0, PallocChunkPages - uint(2*minPages)}},
},
expect: []test{
{2 * minPages * PageSize, 2 * minPages * PageSize},
{minPages * PageSize, minPages * PageSize},
{minPages * PageSize, minPages * PageSize},
},
afterScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{0, PallocChunkPages}},
BaseChunkIdx + 1: {{0, PallocChunkPages}},
},
},
"ScavDiscontiguous": {
beforeAlloc: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 0xe: {},
},
beforeScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{uint(minPages), PallocChunkPages - uint(2*minPages)}},
BaseChunkIdx + 0xe: {{uint(2 * minPages), PallocChunkPages - uint(2*minPages)}},
},
expect: []test{
{2 * minPages * PageSize, 2 * minPages * PageSize},
{^uintptr(0), 2 * minPages * PageSize},
{^uintptr(0), 0},
},
afterScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{0, PallocChunkPages}},
BaseChunkIdx + 0xe: {{0, PallocChunkPages}},
},
},
}
// Disable these tests on iOS since we have a small address space.
// See #46860.
if PageAlloc64Bit != 0 && goos.IsIos == 0 {
tests["ScavAllVeryDiscontiguous"] = setup{
beforeAlloc: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 0x1000: {},
},
beforeScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {},
BaseChunkIdx + 0x1000: {},
},
expect: []test{
{^uintptr(0), 2 * PallocChunkPages * PageSize},
{^uintptr(0), 0},
},
afterScav: map[ChunkIdx][]BitRange{
BaseChunkIdx: {{0, PallocChunkPages}},
BaseChunkIdx + 0x1000: {{0, PallocChunkPages}},
},
}
}
for name, v := range tests {
v := v
t.Run(name, func(t *testing.T) {
b := NewPageAlloc(v.beforeAlloc, v.beforeScav)
defer FreePageAlloc(b)
for iter, h := range v.expect {
if got := b.Scavenge(h.request); got != h.expect {
t.Fatalf("bad scavenge #%d: want %d, got %d", iter+1, h.expect, got)
}
}
want := NewPageAlloc(v.beforeAlloc, v.afterScav)
defer FreePageAlloc(want)
checkPageAlloc(t, want, b)
})
}
}