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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package pgalloc
import (
"testing"
"gvisor.dev/gvisor/pkg/hostarch"
)
const (
page = hostarch.PageSize
hugepage = hostarch.HugePageSize
topPage = (1 << 63) - page
)
func TestFindUnallocatedRange(t *testing.T) {
for _, test := range []struct {
desc string
usage *usageSegmentDataSlices
fileSize int64
length uint64
alignment uint64
start uint64
expectFail bool
}{
{
desc: "Initial allocation succeeds",
usage: &usageSegmentDataSlices{},
length: page,
alignment: page,
start: chunkSize - page, // Grows by chunkSize, allocate down.
},
{
desc: "Allocation finds empty space at start of file",
usage: &usageSegmentDataSlices{
Start: []uint64{page},
End: []uint64{2 * page},
Values: []usageInfo{{refs: 1}},
},
fileSize: 2 * page,
length: page,
alignment: page,
start: 0,
},
{
desc: "Allocation finds empty space at end of file",
usage: &usageSegmentDataSlices{
Start: []uint64{0},
End: []uint64{page},
Values: []usageInfo{{refs: 1}},
},
fileSize: 2 * page,
length: page,
alignment: page,
start: page,
},
{
desc: "In-use frames are not allocatable",
usage: &usageSegmentDataSlices{
Start: []uint64{0, page},
End: []uint64{page, 2 * page},
Values: []usageInfo{{refs: 1}, {refs: 2}},
},
fileSize: 2 * page,
length: page,
alignment: page,
start: 3 * page, // Double fileSize, allocate top-down.
},
{
desc: "Reclaimable frames are not allocatable",
usage: &usageSegmentDataSlices{
Start: []uint64{0, page, 2 * page},
End: []uint64{page, 2 * page, 3 * page},
Values: []usageInfo{{refs: 1}, {refs: 0}, {refs: 1}},
},
fileSize: 3 * page,
length: page,
alignment: page,
start: 5 * page, // Double fileSize, grow down.
},
{
desc: "Gaps between in-use frames are allocatable",
usage: &usageSegmentDataSlices{
Start: []uint64{0, 2 * page},
End: []uint64{page, 3 * page},
Values: []usageInfo{{refs: 1}, {refs: 1}},
},
fileSize: 3 * page,
length: page,
alignment: page,
start: page,
},
{
desc: "Inadequately-sized gaps are rejected",
usage: &usageSegmentDataSlices{
Start: []uint64{0, 2 * page},
End: []uint64{page, 3 * page},
Values: []usageInfo{{refs: 1}, {refs: 1}},
},
fileSize: 3 * page,
length: 2 * page,
alignment: page,
start: 4 * page, // Double fileSize, grow down.
},
{
desc: "Alignment is honored at end of file",
usage: &usageSegmentDataSlices{
Start: []uint64{0, hugepage + page},
// Hugepage-sized gap here that shouldn't be allocated from
// since it's incorrectly aligned.
End: []uint64{page, hugepage + 2*page},
Values: []usageInfo{{refs: 1}, {refs: 1}},
},
fileSize: hugepage + 2*page,
length: hugepage,
alignment: hugepage,
start: 3 * hugepage, // Double fileSize until alignment is satisfied, grow down.
},
{
desc: "Alignment is honored before end of file",
usage: &usageSegmentDataSlices{
Start: []uint64{0, 2*hugepage + page},
// Page will need to be shifted down from top.
End: []uint64{page, 2*hugepage + 2*page},
Values: []usageInfo{{refs: 1}, {refs: 1}},
},
fileSize: 2*hugepage + 2*page,
length: hugepage,
alignment: hugepage,
start: hugepage,
},
{
desc: "Allocation doubles file size more than once if necessary",
usage: &usageSegmentDataSlices{},
fileSize: page,
length: 4 * page,
alignment: page,
start: 0,
},
{
desc: "Allocations are compact if possible",
usage: &usageSegmentDataSlices{
Start: []uint64{page, 3 * page},
End: []uint64{2 * page, 4 * page},
Values: []usageInfo{{refs: 1}, {refs: 2}},
},
fileSize: 4 * page,
length: page,
alignment: page,
start: 2 * page,
},
{
desc: "Top-down allocation within one gap",
usage: &usageSegmentDataSlices{
Start: []uint64{page, 4 * page, 7 * page},
End: []uint64{2 * page, 5 * page, 8 * page},
Values: []usageInfo{{refs: 1}, {refs: 2}, {refs: 1}},
},
fileSize: 8 * page,
length: page,
alignment: page,
start: 6 * page,
},
{
desc: "Top-down allocation between multiple gaps",
usage: &usageSegmentDataSlices{
Start: []uint64{page, 3 * page, 5 * page},
End: []uint64{2 * page, 4 * page, 6 * page},
Values: []usageInfo{{refs: 1}, {refs: 2}, {refs: 1}},
},
fileSize: 6 * page,
length: page,
alignment: page,
start: 4 * page,
},
{
desc: "Top-down allocation with large top gap",
usage: &usageSegmentDataSlices{
Start: []uint64{page, 3 * page},
End: []uint64{2 * page, 4 * page},
Values: []usageInfo{{refs: 1}, {refs: 2}},
},
fileSize: 8 * page,
length: page,
alignment: page,
start: 7 * page,
},
{
desc: "Gaps found with possible overflow",
usage: &usageSegmentDataSlices{
Start: []uint64{page, topPage - page},
End: []uint64{2 * page, topPage},
Values: []usageInfo{{refs: 1}, {refs: 1}},
},
fileSize: topPage,
length: page,
alignment: page,
start: topPage - 2*page,
},
{
desc: "Overflow detected",
usage: &usageSegmentDataSlices{
Start: []uint64{page},
End: []uint64{topPage},
Values: []usageInfo{{refs: 1}},
},
fileSize: topPage,
length: 2 * page,
alignment: page,
expectFail: true,
},
} {
t.Run(test.desc, func(t *testing.T) {
var usage usageSet
if err := usage.ImportSortedSlices(test.usage); err != nil {
t.Fatalf("Failed to initialize usage from %v: %v", test.usage, err)
}
fr, ok := findAvailableRange(&usage, test.fileSize, test.length, test.alignment)
if !test.expectFail && !ok {
t.Fatalf("findAvailableRange(%v, %x, %x, %x): got %x, false wanted %x, true", test.usage, test.fileSize, test.length, test.alignment, fr.Start, test.start)
}
if test.expectFail && ok {
t.Fatalf("findAvailableRange(%v, %x, %x, %x): got %x, true wanted %x, false", test.usage, test.fileSize, test.length, test.alignment, fr.Start, test.start)
}
if ok && fr.Start != test.start {
t.Errorf("findAvailableRange(%v, %x, %x, %x): got start=%x, wanted %x", test.usage, test.fileSize, test.length, test.alignment, fr.Start, test.start)
}
if ok && fr.End != test.start+test.length {
t.Errorf("findAvailableRange(%v, %x, %x, %x): got end=%x, wanted %x", test.usage, test.fileSize, test.length, test.alignment, fr.End, test.start+test.length)
}
})
}
}
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