92 lines
2.7 KiB
Go
92 lines
2.7 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fsutil
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import (
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"math"
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"gvisor.dev/gvisor/pkg/sentry/memmap"
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"gvisor.dev/gvisor/pkg/sentry/usage"
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)
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// FrameRefSetFunctions implements segment.Functions for FrameRefSet.
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type FrameRefSetFunctions struct{}
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// MinKey implements segment.Functions.MinKey.
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func (FrameRefSetFunctions) MinKey() uint64 {
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return 0
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}
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// MaxKey implements segment.Functions.MaxKey.
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func (FrameRefSetFunctions) MaxKey() uint64 {
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return math.MaxUint64
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}
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// ClearValue implements segment.Functions.ClearValue.
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func (FrameRefSetFunctions) ClearValue(val *uint64) {
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}
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// Merge implements segment.Functions.Merge.
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func (FrameRefSetFunctions) Merge(_ memmap.FileRange, val1 uint64, _ memmap.FileRange, val2 uint64) (uint64, bool) {
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if val1 != val2 {
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return 0, false
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}
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return val1, true
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}
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// Split implements segment.Functions.Split.
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func (FrameRefSetFunctions) Split(_ memmap.FileRange, val uint64, _ uint64) (uint64, uint64) {
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return val, val
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}
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// IncRefAndAccount adds a reference on the range fr. All newly inserted segments
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// are accounted as host page cache memory mappings.
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func (refs *FrameRefSet) IncRefAndAccount(fr memmap.FileRange) {
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seg, gap := refs.Find(fr.Start)
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for {
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switch {
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case seg.Ok() && seg.Start() < fr.End:
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seg = refs.Isolate(seg, fr)
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seg.SetValue(seg.Value() + 1)
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seg, gap = seg.NextNonEmpty()
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case gap.Ok() && gap.Start() < fr.End:
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newRange := gap.Range().Intersect(fr)
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usage.MemoryAccounting.Inc(newRange.Length(), usage.Mapped)
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seg, gap = refs.InsertWithoutMerging(gap, newRange, 1).NextNonEmpty()
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default:
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refs.MergeAdjacent(fr)
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return
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}
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}
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}
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// DecRefAndAccount removes a reference on the range fr and untracks segments
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// that are removed from memory accounting.
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func (refs *FrameRefSet) DecRefAndAccount(fr memmap.FileRange) {
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seg := refs.FindSegment(fr.Start)
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for seg.Ok() && seg.Start() < fr.End {
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seg = refs.Isolate(seg, fr)
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if old := seg.Value(); old == 1 {
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usage.MemoryAccounting.Dec(seg.Range().Length(), usage.Mapped)
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seg = refs.Remove(seg).NextSegment()
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} else {
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seg.SetValue(old - 1)
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seg = seg.NextSegment()
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}
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}
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refs.MergeAdjacent(fr)
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}
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