diff options
Diffstat (limited to 'pkg')
| -rw-r--r-- | pkg/abi/linux/linux_abi_autogen_unsafe.go | 8 | ||||
| -rw-r--r-- | pkg/sentry/pgalloc/pgalloc.go | 215 | ||||
| -rw-r--r-- | pkg/sentry/pgalloc/pgalloc_state_autogen.go | 55 | ||||
| -rw-r--r-- | pkg/sentry/pgalloc/reclaim_set.go | 1643 | ||||
| -rw-r--r-- | pkg/sentry/pgalloc/usage_set.go | 2 |
5 files changed, 1817 insertions, 106 deletions
diff --git a/pkg/abi/linux/linux_abi_autogen_unsafe.go b/pkg/abi/linux/linux_abi_autogen_unsafe.go index 8518d61be..62090b192 100644 --- a/pkg/abi/linux/linux_abi_autogen_unsafe.go +++ b/pkg/abi/linux/linux_abi_autogen_unsafe.go @@ -124,12 +124,12 @@ func (s *Statx) UnmarshalBytes(src []byte) { // Packed implements marshal.Marshallable.Packed. //go:nosplit func (s *Statx) Packed() bool { - return s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() + return s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() } // MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe. func (s *Statx) MarshalUnsafe(dst []byte) { - if s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() { + if s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() { safecopy.CopyIn(dst, unsafe.Pointer(s)) } else { s.MarshalBytes(dst) @@ -148,7 +148,7 @@ func (s *Statx) UnmarshalUnsafe(src []byte) { // CopyOutN implements marshal.Marshallable.CopyOutN. //go:nosplit func (s *Statx) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) { - if !s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() { + if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() { // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes. buf := task.CopyScratchBuffer(s.SizeBytes()) // escapes: okay. s.MarshalBytes(buf) // escapes: fallback. @@ -204,7 +204,7 @@ func (s *Statx) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) { // WriteTo implements io.WriterTo.WriteTo. func (s *Statx) WriteTo(w io.Writer) (int64, error) { - if !s.Ctime.Packed() && s.Mtime.Packed() && s.Atime.Packed() && s.Btime.Packed() { + if !s.Atime.Packed() && s.Btime.Packed() && s.Ctime.Packed() && s.Mtime.Packed() { // Type Statx doesn't have a packed layout in memory, fall back to MarshalBytes. buf := make([]byte, s.SizeBytes()) s.MarshalBytes(buf) diff --git a/pkg/sentry/pgalloc/pgalloc.go b/pkg/sentry/pgalloc/pgalloc.go index 2b11ea4ae..c8d9facc2 100644 --- a/pkg/sentry/pgalloc/pgalloc.go +++ b/pkg/sentry/pgalloc/pgalloc.go @@ -108,12 +108,6 @@ type MemoryFile struct { usageSwapped uint64 usageLast time.Time - // minUnallocatedPage is the minimum page that may be unallocated. - // i.e., there are no unallocated pages below minUnallocatedPage. - // - // minUnallocatedPage is protected by mu. - minUnallocatedPage uint64 - // fileSize is the size of the backing memory file in bytes. fileSize is // always a power-of-two multiple of chunkSize. // @@ -146,11 +140,9 @@ type MemoryFile struct { // is protected by mu. reclaimable bool - // minReclaimablePage is the minimum page that may be reclaimable. - // i.e., all reclaimable pages are >= minReclaimablePage. - // - // minReclaimablePage is protected by mu. - minReclaimablePage uint64 + // relcaim is the collection of regions for reclaim. relcaim is protected + // by mu. + reclaim reclaimSet // reclaimCond is signaled (with mu locked) when reclaimable or destroyed // transitions from false to true. @@ -273,12 +265,10 @@ type evictableMemoryUserInfo struct { } const ( - chunkShift = 24 - chunkSize = 1 << chunkShift // 16 MB + chunkShift = 30 + chunkSize = 1 << chunkShift // 1 GB chunkMask = chunkSize - 1 - initialSize = chunkSize - // maxPage is the highest 64-bit page. maxPage = math.MaxUint64 &^ (usermem.PageSize - 1) ) @@ -302,19 +292,12 @@ func NewMemoryFile(file *os.File, opts MemoryFileOpts) (*MemoryFile, error) { if err := file.Truncate(0); err != nil { return nil, err } - if err := file.Truncate(initialSize); err != nil { - return nil, err - } f := &MemoryFile{ - opts: opts, - fileSize: initialSize, - file: file, - // No pages are reclaimable. DecRef will always be able to - // decrease minReclaimablePage from this point. - minReclaimablePage: maxPage, - evictable: make(map[EvictableMemoryUser]*evictableMemoryUserInfo), + opts: opts, + file: file, + evictable: make(map[EvictableMemoryUser]*evictableMemoryUserInfo), } - f.mappings.Store(make([]uintptr, initialSize/chunkSize)) + f.mappings.Store(make([]uintptr, 0)) f.reclaimCond.L = &f.mu if f.opts.DelayedEviction == DelayedEvictionEnabled && f.opts.UseHostMemcgPressure { @@ -404,39 +387,28 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi alignment = usermem.HugePageSize } - start, minUnallocatedPage := findUnallocatedRange(&f.usage, f.minUnallocatedPage, length, alignment) - end := start + length - // File offsets are int64s. Since length must be strictly positive, end - // cannot legitimately be 0. - if end < start || int64(end) <= 0 { + // Find a range in the underlying file. + fr, ok := findAvailableRange(&f.usage, f.fileSize, length, alignment) + if !ok { return platform.FileRange{}, syserror.ENOMEM } - // Expand the file if needed. Double the file size on each expansion; - // uncommitted pages have effectively no cost. - fileSize := f.fileSize - for int64(end) > fileSize { - if fileSize >= 2*fileSize { - // fileSize overflow. - return platform.FileRange{}, syserror.ENOMEM - } - fileSize *= 2 - } - if fileSize > f.fileSize { - if err := f.file.Truncate(fileSize); err != nil { + // Expand the file if needed. Note that findAvailableRange will + // appropriately double the fileSize when required. + if int64(fr.End) > f.fileSize { + if err := f.file.Truncate(int64(fr.End)); err != nil { return platform.FileRange{}, err } - f.fileSize = fileSize + f.fileSize = int64(fr.End) f.mappingsMu.Lock() oldMappings := f.mappings.Load().([]uintptr) - newMappings := make([]uintptr, fileSize>>chunkShift) + newMappings := make([]uintptr, f.fileSize>>chunkShift) copy(newMappings, oldMappings) f.mappings.Store(newMappings) f.mappingsMu.Unlock() } // Mark selected pages as in use. - fr := platform.FileRange{start, end} if f.opts.ManualZeroing { if err := f.forEachMappingSlice(fr, func(bs []byte) { for i := range bs { @@ -453,49 +425,71 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi panic(fmt.Sprintf("allocating %v: failed to insert into usage set:\n%v", fr, &f.usage)) } - if minUnallocatedPage < start { - f.minUnallocatedPage = minUnallocatedPage - } else { - // start was the first unallocated page. The next must be - // somewhere beyond end. - f.minUnallocatedPage = end - } - return fr, nil } -// findUnallocatedRange returns the first unallocated page in usage of the -// specified length and alignment beginning at page start and the first single -// unallocated page. -func findUnallocatedRange(usage *usageSet, start, length, alignment uint64) (uint64, uint64) { - // Only searched until the first page is found. - firstPage := start - foundFirstPage := false - alignMask := alignment - 1 - for seg := usage.LowerBoundSegment(start); seg.Ok(); seg = seg.NextSegment() { - r := seg.Range() +// findAvailableRange returns an available range in the usageSet. +// +// Note that scanning for available slots takes place from end first backwards, +// then forwards. This heuristic has important consequence for how sequential +// mappings can be merged in the host VMAs, given that addresses for both +// application and sentry mappings are allocated top-down (from higher to +// lower addresses). The file is also grown expoentially in order to create +// space for mappings to be allocated downwards. +// +// Precondition: alignment must be a power of 2. +func findAvailableRange(usage *usageSet, fileSize int64, length, alignment uint64) (platform.FileRange, bool) { + alignmentMask := alignment - 1 + for gap := usage.UpperBoundGap(uint64(fileSize)); gap.Ok(); gap = gap.PrevLargeEnoughGap(length) { + // Start searching only at end of file. + end := gap.End() + if end > uint64(fileSize) { + end = uint64(fileSize) + } - if !foundFirstPage && r.Start > firstPage { - foundFirstPage = true + // Start at the top and align downwards. + start := end - length + if start > end { + break // Underflow. } + start &^= alignmentMask - if start >= r.End { - // start was rounded up to an alignment boundary from the end - // of a previous segment and is now beyond r.End. + // Is the gap still sufficient? + if start < gap.Start() { continue } - // This segment represents allocated or reclaimable pages; only the - // range from start to the segment's beginning is allocatable, and the - // next allocatable range begins after the segment. - if r.Start > start && r.Start-start >= length { - break + + // Allocate in the given gap. + return platform.FileRange{start, start + length}, true + } + + // Check that it's possible to fit this allocation at the end of a file of any size. + min := usage.LastGap().Start() + min = (min + alignmentMask) &^ alignmentMask + if min+length < min { + // Overflow. + return platform.FileRange{}, false + } + + // Determine the minimum file size required to fit this allocation at its end. + for { + if fileSize >= 2*fileSize { + // Is this because it's initially empty? + if fileSize == 0 { + fileSize += chunkSize + } else { + // fileSize overflow. + return platform.FileRange{}, false + } + } else { + // Double the current fileSize. + fileSize *= 2 } - start = (r.End + alignMask) &^ alignMask - if !foundFirstPage { - firstPage = r.End + start := (uint64(fileSize) - length) &^ alignmentMask + if start >= min { + return platform.FileRange{start, start + length}, true } } - return start, firstPage } // AllocateAndFill allocates memory of the given kind and fills it by calling @@ -616,6 +610,7 @@ func (f *MemoryFile) DecRef(fr platform.FileRange) { } val.refs-- if val.refs == 0 { + f.reclaim.Add(seg.Range(), reclaimSetValue{}) freed = true // Reclassify memory as System, until it's freed by the reclaim // goroutine. @@ -628,10 +623,6 @@ func (f *MemoryFile) DecRef(fr platform.FileRange) { f.usage.MergeAdjacent(fr) if freed { - if fr.Start < f.minReclaimablePage { - // We've freed at least one lower page. - f.minReclaimablePage = fr.Start - } f.reclaimable = true f.reclaimCond.Signal() } @@ -1030,6 +1021,7 @@ func (f *MemoryFile) String() string { // for allocation. func (f *MemoryFile) runReclaim() { for { + // N.B. We must call f.markReclaimed on the returned FrameRange. fr, ok := f.findReclaimable() if !ok { break @@ -1085,6 +1077,10 @@ func (f *MemoryFile) runReclaim() { } } +// findReclaimable finds memory that has been marked for reclaim. +// +// Note that there returned range will be removed from tracking. It +// must be reclaimed (removed from f.usage) at this point. func (f *MemoryFile) findReclaimable() (platform.FileRange, bool) { f.mu.Lock() defer f.mu.Unlock() @@ -1103,18 +1099,15 @@ func (f *MemoryFile) findReclaimable() (platform.FileRange, bool) { } f.reclaimCond.Wait() } - // Allocate returns the first usable range in offset order and is - // currently a linear scan, so reclaiming from the beginning of the - // file minimizes the expected latency of Allocate. - for seg := f.usage.LowerBoundSegment(f.minReclaimablePage); seg.Ok(); seg = seg.NextSegment() { - if seg.ValuePtr().refs == 0 { - f.minReclaimablePage = seg.End() - return seg.Range(), true - } + // Allocate works from the back of the file inwards, so reclaim + // preserves this order to minimize the cost of the search. + if seg := f.reclaim.LastSegment(); seg.Ok() { + fr := seg.Range() + f.reclaim.Remove(seg) + return fr, true } - // No pages are reclaimable. + // Nothing is reclaimable. f.reclaimable = false - f.minReclaimablePage = maxPage } } @@ -1122,8 +1115,8 @@ func (f *MemoryFile) markReclaimed(fr platform.FileRange) { f.mu.Lock() defer f.mu.Unlock() seg := f.usage.FindSegment(fr.Start) - // All of fr should be mapped to a single uncommitted reclaimable segment - // accounted to System. + // All of fr should be mapped to a single uncommitted reclaimable + // segment accounted to System. if !seg.Ok() { panic(fmt.Sprintf("reclaimed pages %v include unreferenced pages:\n%v", fr, &f.usage)) } @@ -1137,14 +1130,10 @@ func (f *MemoryFile) markReclaimed(fr platform.FileRange) { }); got != want { panic(fmt.Sprintf("reclaimed pages %v in segment %v has incorrect state %v, wanted %v:\n%v", fr, seg.Range(), got, want, &f.usage)) } - // Deallocate reclaimed pages. Even though all of seg is reclaimable, the - // caller of markReclaimed may not have decommitted it, so we can only mark - // fr as reclaimed. + // Deallocate reclaimed pages. Even though all of seg is reclaimable, + // the caller of markReclaimed may not have decommitted it, so we can + // only mark fr as reclaimed. f.usage.Remove(f.usage.Isolate(seg, fr)) - if fr.Start < f.minUnallocatedPage { - // We've deallocated at least one lower page. - f.minUnallocatedPage = fr.Start - } } // StartEvictions requests that f evict all evictable allocations. It does not @@ -1255,3 +1244,27 @@ func (evictableRangeSetFunctions) Merge(_ EvictableRange, _ evictableRangeSetVal func (evictableRangeSetFunctions) Split(_ EvictableRange, _ evictableRangeSetValue, _ uint64) (evictableRangeSetValue, evictableRangeSetValue) { return evictableRangeSetValue{}, evictableRangeSetValue{} } + +// reclaimSetValue is the value type of reclaimSet. +type reclaimSetValue struct{} + +type reclaimSetFunctions struct{} + +func (reclaimSetFunctions) MinKey() uint64 { + return 0 +} + +func (reclaimSetFunctions) MaxKey() uint64 { + return math.MaxUint64 +} + +func (reclaimSetFunctions) ClearValue(val *reclaimSetValue) { +} + +func (reclaimSetFunctions) Merge(_ platform.FileRange, _ reclaimSetValue, _ platform.FileRange, _ reclaimSetValue) (reclaimSetValue, bool) { + return reclaimSetValue{}, true +} + +func (reclaimSetFunctions) Split(_ platform.FileRange, _ reclaimSetValue, _ uint64) (reclaimSetValue, reclaimSetValue) { + return reclaimSetValue{}, reclaimSetValue{} +} diff --git a/pkg/sentry/pgalloc/pgalloc_state_autogen.go b/pkg/sentry/pgalloc/pgalloc_state_autogen.go index 469630448..e9f37b729 100644 --- a/pkg/sentry/pgalloc/pgalloc_state_autogen.go +++ b/pkg/sentry/pgalloc/pgalloc_state_autogen.go @@ -86,6 +86,58 @@ func (x *usageInfo) load(m state.Map) { m.Load("refs", &x.refs) } +func (x *reclaimSet) beforeSave() {} +func (x *reclaimSet) save(m state.Map) { + x.beforeSave() + var root *reclaimSegmentDataSlices = x.saveRoot() + m.SaveValue("root", root) +} + +func (x *reclaimSet) afterLoad() {} +func (x *reclaimSet) load(m state.Map) { + m.LoadValue("root", new(*reclaimSegmentDataSlices), func(y interface{}) { x.loadRoot(y.(*reclaimSegmentDataSlices)) }) +} + +func (x *reclaimnode) beforeSave() {} +func (x *reclaimnode) save(m state.Map) { + x.beforeSave() + m.Save("nrSegments", &x.nrSegments) + m.Save("parent", &x.parent) + m.Save("parentIndex", &x.parentIndex) + m.Save("hasChildren", &x.hasChildren) + m.Save("maxGap", &x.maxGap) + m.Save("keys", &x.keys) + m.Save("values", &x.values) + m.Save("children", &x.children) +} + +func (x *reclaimnode) afterLoad() {} +func (x *reclaimnode) load(m state.Map) { + m.Load("nrSegments", &x.nrSegments) + m.Load("parent", &x.parent) + m.Load("parentIndex", &x.parentIndex) + m.Load("hasChildren", &x.hasChildren) + m.Load("maxGap", &x.maxGap) + m.Load("keys", &x.keys) + m.Load("values", &x.values) + m.Load("children", &x.children) +} + +func (x *reclaimSegmentDataSlices) beforeSave() {} +func (x *reclaimSegmentDataSlices) save(m state.Map) { + x.beforeSave() + m.Save("Start", &x.Start) + m.Save("End", &x.End) + m.Save("Values", &x.Values) +} + +func (x *reclaimSegmentDataSlices) afterLoad() {} +func (x *reclaimSegmentDataSlices) load(m state.Map) { + m.Load("Start", &x.Start) + m.Load("End", &x.End) + m.Load("Values", &x.Values) +} + func (x *usageSet) beforeSave() {} func (x *usageSet) save(m state.Map) { x.beforeSave() @@ -144,6 +196,9 @@ func init() { state.Register("pkg/sentry/pgalloc.evictableRangenode", (*evictableRangenode)(nil), state.Fns{Save: (*evictableRangenode).save, Load: (*evictableRangenode).load}) state.Register("pkg/sentry/pgalloc.evictableRangeSegmentDataSlices", (*evictableRangeSegmentDataSlices)(nil), state.Fns{Save: (*evictableRangeSegmentDataSlices).save, Load: (*evictableRangeSegmentDataSlices).load}) state.Register("pkg/sentry/pgalloc.usageInfo", (*usageInfo)(nil), state.Fns{Save: (*usageInfo).save, Load: (*usageInfo).load}) + state.Register("pkg/sentry/pgalloc.reclaimSet", (*reclaimSet)(nil), state.Fns{Save: (*reclaimSet).save, Load: (*reclaimSet).load}) + state.Register("pkg/sentry/pgalloc.reclaimnode", (*reclaimnode)(nil), state.Fns{Save: (*reclaimnode).save, Load: (*reclaimnode).load}) + state.Register("pkg/sentry/pgalloc.reclaimSegmentDataSlices", (*reclaimSegmentDataSlices)(nil), state.Fns{Save: (*reclaimSegmentDataSlices).save, Load: (*reclaimSegmentDataSlices).load}) state.Register("pkg/sentry/pgalloc.usageSet", (*usageSet)(nil), state.Fns{Save: (*usageSet).save, Load: (*usageSet).load}) state.Register("pkg/sentry/pgalloc.usagenode", (*usagenode)(nil), state.Fns{Save: (*usagenode).save, Load: (*usagenode).load}) state.Register("pkg/sentry/pgalloc.usageSegmentDataSlices", (*usageSegmentDataSlices)(nil), state.Fns{Save: (*usageSegmentDataSlices).save, Load: (*usageSegmentDataSlices).load}) diff --git a/pkg/sentry/pgalloc/reclaim_set.go b/pkg/sentry/pgalloc/reclaim_set.go new file mode 100644 index 000000000..a1805ed27 --- /dev/null +++ b/pkg/sentry/pgalloc/reclaim_set.go @@ -0,0 +1,1643 @@ +package pgalloc + +import ( + __generics_imported0 "gvisor.dev/gvisor/pkg/sentry/platform" +) + +import ( + "bytes" + "fmt" +) + +// trackGaps is an optional parameter. +// +// If trackGaps is 1, the Set will track maximum gap size recursively, +// enabling the GapIterator.{Prev,Next}LargeEnoughGap functions. In this +// case, Key must be an unsigned integer. +// +// trackGaps must be 0 or 1. +const reclaimtrackGaps = 0 + +var _ = uint8(reclaimtrackGaps << 7) // Will fail if not zero or one. + +// dynamicGap is a type that disappears if trackGaps is 0. +type reclaimdynamicGap [reclaimtrackGaps]uint64 + +// Get returns the value of the gap. +// +// Precondition: trackGaps must be non-zero. +func (d *reclaimdynamicGap) Get() uint64 { + return d[:][0] +} + +// Set sets the value of the gap. +// +// Precondition: trackGaps must be non-zero. +func (d *reclaimdynamicGap) Set(v uint64) { + d[:][0] = v +} + +const ( + // minDegree is the minimum degree of an internal node in a Set B-tree. + // + // - Any non-root node has at least minDegree-1 segments. + // + // - Any non-root internal (non-leaf) node has at least minDegree children. + // + // - The root node may have fewer than minDegree-1 segments, but it may + // only have 0 segments if the tree is empty. + // + // Our implementation requires minDegree >= 3. Higher values of minDegree + // usually improve performance, but increase memory usage for small sets. + reclaimminDegree = 10 + + reclaimmaxDegree = 2 * reclaimminDegree +) + +// A Set is a mapping of segments with non-overlapping Range keys. The zero +// value for a Set is an empty set. Set values are not safely movable nor +// copyable. Set is thread-compatible. +// +// +stateify savable +type reclaimSet struct { + root reclaimnode `state:".(*reclaimSegmentDataSlices)"` +} + +// IsEmpty returns true if the set contains no segments. +func (s *reclaimSet) IsEmpty() bool { + return s.root.nrSegments == 0 +} + +// IsEmptyRange returns true iff no segments in the set overlap the given +// range. This is semantically equivalent to s.SpanRange(r) == 0, but may be +// more efficient. +func (s *reclaimSet) IsEmptyRange(r __generics_imported0.FileRange) bool { + switch { + case r.Length() < 0: + panic(fmt.Sprintf("invalid range %v", r)) + case r.Length() == 0: + return true + } + _, gap := s.Find(r.Start) + if !gap.Ok() { + return false + } + return r.End <= gap.End() +} + +// Span returns the total size of all segments in the set. +func (s *reclaimSet) Span() uint64 { + var sz uint64 + for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { + sz += seg.Range().Length() + } + return sz +} + +// SpanRange returns the total size of the intersection of segments in the set +// with the given range. +func (s *reclaimSet) SpanRange(r __generics_imported0.FileRange) uint64 { + switch { + case r.Length() < 0: + panic(fmt.Sprintf("invalid range %v", r)) + case r.Length() == 0: + return 0 + } + var sz uint64 + for seg := s.LowerBoundSegment(r.Start); seg.Ok() && seg.Start() < r.End; seg = seg.NextSegment() { + sz += seg.Range().Intersect(r).Length() + } + return sz +} + +// FirstSegment returns the first segment in the set. If the set is empty, +// FirstSegment returns a terminal iterator. +func (s *reclaimSet) FirstSegment() reclaimIterator { + if s.root.nrSegments == 0 { + return reclaimIterator{} + } + return s.root.firstSegment() +} + +// LastSegment returns the last segment in the set. If the set is empty, +// LastSegment returns a terminal iterator. +func (s *reclaimSet) LastSegment() reclaimIterator { + if s.root.nrSegments == 0 { + return reclaimIterator{} + } + return s.root.lastSegment() +} + +// FirstGap returns the first gap in the set. +func (s *reclaimSet) FirstGap() reclaimGapIterator { + n := &s.root + for n.hasChildren { + n = n.children[0] + } + return reclaimGapIterator{n, 0} +} + +// LastGap returns the last gap in the set. +func (s *reclaimSet) LastGap() reclaimGapIterator { + n := &s.root + for n.hasChildren { + n = n.children[n.nrSegments] + } + return reclaimGapIterator{n, n.nrSegments} +} + +// Find returns the segment or gap whose range contains the given key. If a +// segment is found, the returned Iterator is non-terminal and the +// returned GapIterator is terminal. Otherwise, the returned Iterator is +// terminal and the returned GapIterator is non-terminal. +func (s *reclaimSet) Find(key uint64) (reclaimIterator, reclaimGapIterator) { + n := &s.root + for { + + lower := 0 + upper := n.nrSegments + for lower < upper { + i := lower + (upper-lower)/2 + if r := n.keys[i]; key < r.End { + if key >= r.Start { + return reclaimIterator{n, i}, reclaimGapIterator{} + } + upper = i + } else { + lower = i + 1 + } + } + i := lower + if !n.hasChildren { + return reclaimIterator{}, reclaimGapIterator{n, i} + } + n = n.children[i] + } +} + +// FindSegment returns the segment whose range contains the given key. If no +// such segment exists, FindSegment returns a terminal iterator. +func (s *reclaimSet) FindSegment(key uint64) reclaimIterator { + seg, _ := s.Find(key) + return seg +} + +// LowerBoundSegment returns the segment with the lowest range that contains a +// key greater than or equal to min. If no such segment exists, +// LowerBoundSegment returns a terminal iterator. +func (s *reclaimSet) LowerBoundSegment(min uint64) reclaimIterator { + seg, gap := s.Find(min) + if seg.Ok() { + return seg + } + return gap.NextSegment() +} + +// UpperBoundSegment returns the segment with the highest range that contains a +// key less than or equal to max. If no such segment exists, UpperBoundSegment +// returns a terminal iterator. +func (s *reclaimSet) UpperBoundSegment(max uint64) reclaimIterator { + seg, gap := s.Find(max) + if seg.Ok() { + return seg + } + return gap.PrevSegment() +} + +// FindGap returns the gap containing the given key. If no such gap exists +// (i.e. the set contains a segment containing that key), FindGap returns a +// terminal iterator. +func (s *reclaimSet) FindGap(key uint64) reclaimGapIterator { + _, gap := s.Find(key) + return gap +} + +// LowerBoundGap returns the gap with the lowest range that is greater than or +// equal to min. +func (s *reclaimSet) LowerBoundGap(min uint64) reclaimGapIterator { + seg, gap := s.Find(min) + if gap.Ok() { + return gap + } + return seg.NextGap() +} + +// UpperBoundGap returns the gap with the highest range that is less than or +// equal to max. +func (s *reclaimSet) UpperBoundGap(max uint64) reclaimGapIterator { + seg, gap := s.Find(max) + if gap.Ok() { + return gap + } + return seg.PrevGap() +} + +// Add inserts the given segment into the set and returns true. If the new +// segment can be merged with adjacent segments, Add will do so. If the new +// segment would overlap an existing segment, Add returns false. If Add +// succeeds, all existing iterators are invalidated. +func (s *reclaimSet) Add(r __generics_imported0.FileRange, val reclaimSetValue) bool { + if r.Length() <= 0 { + panic(fmt.Sprintf("invalid segment range %v", r)) + } + gap := s.FindGap(r.Start) + if !gap.Ok() { + return false + } + if r.End > gap.End() { + return false + } + s.Insert(gap, r, val) + return true +} + +// AddWithoutMerging inserts the given segment into the set and returns true. +// If it would overlap an existing segment, AddWithoutMerging does nothing and +// returns false. If AddWithoutMerging succeeds, all existing iterators are +// invalidated. +func (s *reclaimSet) AddWithoutMerging(r __generics_imported0.FileRange, val reclaimSetValue) bool { + if r.Length() <= 0 { + panic(fmt.Sprintf("invalid segment range %v", r)) + } + gap := s.FindGap(r.Start) + if !gap.Ok() { + return false + } + if r.End > gap.End() { + return false + } + s.InsertWithoutMergingUnchecked(gap, r, val) + return true +} + +// Insert inserts the given segment into the given gap. If the new segment can +// be merged with adjacent segments, Insert will do so. Insert returns an +// iterator to the segment containing the inserted value (which may have been +// merged with other values). All existing iterators (including gap, but not +// including the returned iterator) are invalidated. +// +// If the gap cannot accommodate the segment, or if r is invalid, Insert panics. +// +// Insert is semantically equivalent to a InsertWithoutMerging followed by a +// Merge, but may be more efficient. Note that there is no unchecked variant of +// Insert since Insert must retrieve and inspect gap's predecessor and +// successor segments regardless. +func (s *reclaimSet) Insert(gap reclaimGapIterator, r __generics_imported0.FileRange, val reclaimSetValue) reclaimIterator { + if r.Length() <= 0 { + panic(fmt.Sprintf("invalid segment range %v", r)) + } + prev, next := gap.PrevSegment(), gap.NextSegment() + if prev.Ok() && prev.End() > r.Start { + panic(fmt.Sprintf("new segment %v overlaps predecessor %v", r, prev.Range())) + } + if next.Ok() && next.Start() < r.End { + panic(fmt.Sprintf("new segment %v overlaps successor %v", r, next.Range())) + } + if prev.Ok() && prev.End() == r.Start { + if mval, ok := (reclaimSetFunctions{}).Merge(prev.Range(), prev.Value(), r, val); ok { + shrinkMaxGap := reclaimtrackGaps != 0 && gap.Range().Length() == gap.node.maxGap.Get() + prev.SetEndUnchecked(r.End) + prev.SetValue(mval) + if shrinkMaxGap { + gap.node.updateMaxGapLeaf() + } + if next.Ok() && next.Start() == r.End { + val = mval + if mval, ok := (reclaimSetFunctions{}).Merge(prev.Range(), val, next.Range(), next.Value()); ok { + prev.SetEndUnchecked(next.End()) + prev.SetValue(mval) + return s.Remove(next).PrevSegment() + } + } + return prev + } + } + if next.Ok() && next.Start() == r.End { + if mval, ok := (reclaimSetFunctions{}).Merge(r, val, next.Range(), next.Value()); ok { + shrinkMaxGap := reclaimtrackGaps != 0 && gap.Range().Length() == gap.node.maxGap.Get() + next.SetStartUnchecked(r.Start) + next.SetValue(mval) + if shrinkMaxGap { + gap.node.updateMaxGapLeaf() + } + return next + } + } + + return s.InsertWithoutMergingUnchecked(gap, r, val) +} + +// InsertWithoutMerging inserts the given segment into the given gap and +// returns an iterator to the inserted segment. All existing iterators +// (including gap, but not including the returned iterator) are invalidated. +// +// If the gap cannot accommodate the segment, or if r is invalid, +// InsertWithoutMerging panics. +func (s *reclaimSet) InsertWithoutMerging(gap reclaimGapIterator, r __generics_imported0.FileRange, val reclaimSetValue) reclaimIterator { + if r.Length() <= 0 { + panic(fmt.Sprintf("invalid segment range %v", r)) + } + if gr := gap.Range(); !gr.IsSupersetOf(r) { + panic(fmt.Sprintf("cannot insert segment range %v into gap range %v", r, gr)) + } + return s.InsertWithoutMergingUnchecked(gap, r, val) +} + +// InsertWithoutMergingUnchecked inserts the given segment into the given gap +// and returns an iterator to the inserted segment. All existing iterators +// (including gap, but not including the returned iterator) are invalidated. +// +// Preconditions: r.Start >= gap.Start(); r.End <= gap.End(). +func (s *reclaimSet) InsertWithoutMergingUnchecked(gap reclaimGapIterator, r __generics_imported0.FileRange, val reclaimSetValue) reclaimIterator { + gap = gap.node.rebalanceBeforeInsert(gap) + splitMaxGap := reclaimtrackGaps != 0 && (gap.node.nrSegments == 0 || gap.Range().Length() == gap.node.maxGap.Get()) + copy(gap.node.keys[gap.index+1:], gap.node.keys[gap.index:gap.node.nrSegments]) + copy(gap.node.values[gap.index+1:], gap.node.values[gap.index:gap.node.nrSegments]) + gap.node.keys[gap.index] = r + gap.node.values[gap.index] = val + gap.node.nrSegments++ + if splitMaxGap { + gap.node.updateMaxGapLeaf() + } + return reclaimIterator{gap.node, gap.index} +} + +// Remove removes the given segment and returns an iterator to the vacated gap. +// All existing iterators (including seg, but not including the returned +// iterator) are invalidated. +func (s *reclaimSet) Remove(seg reclaimIterator) reclaimGapIterator { + + if seg.node.hasChildren { + + victim := seg.PrevSegment() + + seg.SetRangeUnchecked(victim.Range()) + seg.SetValue(victim.Value()) + + nextAdjacentNode := seg.NextSegment().node + if reclaimtrackGaps != 0 { + nextAdjacentNode.updateMaxGapLeaf() + } + return s.Remove(victim).NextGap() + } + copy(seg.node.keys[seg.index:], seg.node.keys[seg.index+1:seg.node.nrSegments]) + copy(seg.node.values[seg.index:], seg.node.values[seg.index+1:seg.node.nrSegments]) + reclaimSetFunctions{}.ClearValue(&seg.node.values[seg.node.nrSegments-1]) + seg.node.nrSegments-- + if reclaimtrackGaps != 0 { + seg.node.updateMaxGapLeaf() + } + return seg.node.rebalanceAfterRemove(reclaimGapIterator{seg.node, seg.index}) +} + +// RemoveAll removes all segments from the set. All existing iterators are +// invalidated. +func (s *reclaimSet) RemoveAll() { + s.root = reclaimnode{} +} + +// RemoveRange removes all segments in the given range. An iterator to the +// newly formed gap is returned, and all existing iterators are invalidated. +func (s *reclaimSet) RemoveRange(r __generics_imported0.FileRange) reclaimGapIterator { + seg, gap := s.Find(r.Start) + if seg.Ok() { + seg = s.Isolate(seg, r) + gap = s.Remove(seg) + } + for seg = gap.NextSegment(); seg.Ok() && seg.Start() < r.End; seg = gap.NextSegment() { + seg = s.Isolate(seg, r) + gap = s.Remove(seg) + } + return gap +} + +// Merge attempts to merge two neighboring segments. If successful, Merge +// returns an iterator to the merged segment, and all existing iterators are +// invalidated. Otherwise, Merge returns a terminal iterator. +// +// If first is not the predecessor of second, Merge panics. +func (s *reclaimSet) Merge(first, second reclaimIterator) reclaimIterator { + if first.NextSegment() != second { + panic(fmt.Sprintf("attempt to merge non-neighboring segments %v, %v", first.Range(), second.Range())) + } + return s.MergeUnchecked(first, second) +} + +// MergeUnchecked attempts to merge two neighboring segments. If successful, +// MergeUnchecked returns an iterator to the merged segment, and all existing +// iterators are invalidated. Otherwise, MergeUnchecked returns a terminal +// iterator. +// +// Precondition: first is the predecessor of second: first.NextSegment() == +// second, first == second.PrevSegment(). +func (s *reclaimSet) MergeUnchecked(first, second reclaimIterator) reclaimIterator { + if first.End() == second.Start() { + if mval, ok := (reclaimSetFunctions{}).Merge(first.Range(), first.Value(), second.Range(), second.Value()); ok { + + first.SetEndUnchecked(second.End()) + first.SetValue(mval) + + return s.Remove(second).PrevSegment() + } + } + return reclaimIterator{} +} + +// MergeAll attempts to merge all adjacent segments in the set. All existing +// iterators are invalidated. +func (s *reclaimSet) MergeAll() { + seg := s.FirstSegment() + if !seg.Ok() { + return + } + next := seg.NextSegment() + for next.Ok() { + if mseg := s.MergeUnchecked(seg, next); mseg.Ok() { + seg, next = mseg, mseg.NextSegment() + } else { + seg, next = next, next.NextSegment() + } + } +} + +// MergeRange attempts to merge all adjacent segments that contain a key in the +// specific range. All existing iterators are invalidated. +func (s *reclaimSet) MergeRange(r __generics_imported0.FileRange) { + seg := s.LowerBoundSegment(r.Start) + if !seg.Ok() { + return + } + next := seg.NextSegment() + for next.Ok() && next.Range().Start < r.End { + if mseg := s.MergeUnchecked(seg, next); mseg.Ok() { + seg, next = mseg, mseg.NextSegment() + } else { + seg, next = next, next.NextSegment() + } + } +} + +// MergeAdjacent attempts to merge the segment containing r.Start with its +// predecessor, and the segment containing r.End-1 with its successor. +func (s *reclaimSet) MergeAdjacent(r __generics_imported0.FileRange) { + first := s.FindSegment(r.Start) + if first.Ok() { + if prev := first.PrevSegment(); prev.Ok() { + s.Merge(prev, first) + } + } + last := s.FindSegment(r.End - 1) + if last.Ok() { + if next := last.NextSegment(); next.Ok() { + s.Merge(last, next) + } + } +} + +// Split splits the given segment at the given key and returns iterators to the +// two resulting segments. All existing iterators (including seg, but not +// including the returned iterators) are invalidated. +// +// If the segment cannot be split at split (because split is at the start or +// end of the segment's range, so splitting would produce a segment with zero +// length, or because split falls outside the segment's range altogether), +// Split panics. +func (s *reclaimSet) Split(seg reclaimIterator, split uint64) (reclaimIterator, reclaimIterator) { + if !seg.Range().CanSplitAt(split) { + panic(fmt.Sprintf("can't split %v at %v", seg.Range(), split)) + } + return s.SplitUnchecked(seg, split) +} + +// SplitUnchecked splits the given segment at the given key and returns +// iterators to the two resulting segments. All existing iterators (including +// seg, but not including the returned iterators) are invalidated. +// +// Preconditions: seg.Start() < key < seg.End(). +func (s *reclaimSet) SplitUnchecked(seg reclaimIterator, split uint64) (reclaimIterator, reclaimIterator) { + val1, val2 := (reclaimSetFunctions{}).Split(seg.Range(), seg.Value(), split) + end2 := seg.End() + seg.SetEndUnchecked(split) + seg.SetValue(val1) + seg2 := s.InsertWithoutMergingUnchecked(seg.NextGap(), __generics_imported0.FileRange{split, end2}, val2) + + return seg2.PrevSegment(), seg2 +} + +// SplitAt splits the segment straddling split, if one exists. SplitAt returns +// true if a segment was split and false otherwise. If SplitAt splits a +// segment, all existing iterators are invalidated. +func (s *reclaimSet) SplitAt(split uint64) bool { + if seg := s.FindSegment(split); seg.Ok() && seg.Range().CanSplitAt(split) { + s.SplitUnchecked(seg, split) + return true + } + return false +} + +// Isolate ensures that the given segment's range does not escape r by +// splitting at r.Start and r.End if necessary, and returns an updated iterator +// to the bounded segment. All existing iterators (including seg, but not +// including the returned iterators) are invalidated. +func (s *reclaimSet) Isolate(seg reclaimIterator, r __generics_imported0.FileRange) reclaimIterator { + if seg.Range().CanSplitAt(r.Start) { + _, seg = s.SplitUnchecked(seg, r.Start) + } + if seg.Range().CanSplitAt(r.End) { + seg, _ = s.SplitUnchecked(seg, r.End) + } + return seg +} + +// ApplyContiguous applies a function to a contiguous range of segments, +// splitting if necessary. The function is applied until the first gap is +// encountered, at which point the gap is returned. If the function is applied +// across the entire range, a terminal gap is returned. All existing iterators +// are invalidated. +// +// N.B. The Iterator must not be invalidated by the function. +func (s *reclaimSet) ApplyContiguous(r __generics_imported0.FileRange, fn func(seg reclaimIterator)) reclaimGapIterator { + seg, gap := s.Find(r.Start) + if !seg.Ok() { + return gap + } + for { + seg = s.Isolate(seg, r) + fn(seg) + if seg.End() >= r.End { + return reclaimGapIterator{} + } + gap = seg.NextGap() + if !gap.IsEmpty() { + return gap + } + seg = gap.NextSegment() + if !seg.Ok() { + + return reclaimGapIterator{} + } + } +} + +// +stateify savable +type reclaimnode struct { + // An internal binary tree node looks like: + // + // K + // / \ + // Cl Cr + // + // where all keys in the subtree rooted by Cl (the left subtree) are less + // than K (the key of the parent node), and all keys in the subtree rooted + // by Cr (the right subtree) are greater than K. + // + // An internal B-tree node's indexes work out to look like: + // + // K0 K1 K2 ... Kn-1 + // / \/ \/ \ ... / \ + // C0 C1 C2 C3 ... Cn-1 Cn + // + // where n is nrSegments. + nrSegments int + + // parent is a pointer to this node's parent. If this node is root, parent + // is nil. + parent *reclaimnode + + // parentIndex is the index of this node in parent.children. + parentIndex int + + // Flag for internal nodes that is technically redundant with "children[0] + // != nil", but is stored in the first cache line. "hasChildren" rather + // than "isLeaf" because false must be the correct value for an empty root. + hasChildren bool + + // The longest gap within this node. If the node is a leaf, it's simply the + // maximum gap among all the (nrSegments+1) gaps formed by its nrSegments keys + // including the 0th and nrSegments-th gap possibly shared with its upper-level + // nodes; if it's a non-leaf node, it's the max of all children's maxGap. + maxGap reclaimdynamicGap + + // Nodes store keys and values in separate arrays to maximize locality in + // the common case (scanning keys for lookup). + keys [reclaimmaxDegree - 1]__generics_imported0.FileRange + values [reclaimmaxDegree - 1]reclaimSetValue + children [reclaimmaxDegree]*reclaimnode +} + +// firstSegment returns the first segment in the subtree rooted by n. +// +// Preconditions: n.nrSegments != 0. +func (n *reclaimnode) firstSegment() reclaimIterator { + for n.hasChildren { + n = n.children[0] + } + return reclaimIterator{n, 0} +} + +// lastSegment returns the last segment in the subtree rooted by n. +// +// Preconditions: n.nrSegments != 0. +func (n *reclaimnode) lastSegment() reclaimIterator { + for n.hasChildren { + n = n.children[n.nrSegments] + } + return reclaimIterator{n, n.nrSegments - 1} +} + +func (n *reclaimnode) prevSibling() *reclaimnode { + if n.parent == nil || n.parentIndex == 0 { + return nil + } + return n.parent.children[n.parentIndex-1] +} + +func (n *reclaimnode) nextSibling() *reclaimnode { + if n.parent == nil || n.parentIndex == n.parent.nrSegments { + return nil + } + return n.parent.children[n.parentIndex+1] +} + +// rebalanceBeforeInsert splits n and its ancestors if they are full, as +// required for insertion, and returns an updated iterator to the position +// represented by gap. +func (n *reclaimnode) rebalanceBeforeInsert(gap reclaimGapIterator) reclaimGapIterator { + if n.nrSegments < reclaimmaxDegree-1 { + return gap + } + if n.parent != nil { + gap = n.parent.rebalanceBeforeInsert(gap) + } + if n.parent == nil { + + left := &reclaimnode{ + nrSegments: reclaimminDegree - 1, + parent: n, + parentIndex: 0, + hasChildren: n.hasChildren, + } + right := &reclaimnode{ + nrSegments: reclaimminDegree - 1, + parent: n, + parentIndex: 1, + hasChildren: n.hasChildren, + } + copy(left.keys[:reclaimminDegree-1], n.keys[:reclaimminDegree-1]) + copy(left.values[:reclaimminDegree-1], n.values[:reclaimminDegree-1]) + copy(right.keys[:reclaimminDegree-1], n.keys[reclaimminDegree:]) + copy(right.values[:reclaimminDegree-1], n.values[reclaimminDegree:]) + n.keys[0], n.values[0] = n.keys[reclaimminDegree-1], n.values[reclaimminDegree-1] + reclaimzeroValueSlice(n.values[1:]) + if n.hasChildren { + copy(left.children[:reclaimminDegree], n.children[:reclaimminDegree]) + copy(right.children[:reclaimminDegree], n.children[reclaimminDegree:]) + reclaimzeroNodeSlice(n.children[2:]) + for i := 0; i < reclaimminDegree; i++ { + left.children[i].parent = left + left.children[i].parentIndex = i + right.children[i].parent = right + right.children[i].parentIndex = i + } + } + n.nrSegments = 1 + n.hasChildren = true + n.children[0] = left + n.children[1] = right + + if reclaimtrackGaps != 0 { + left.updateMaxGapLocal() + right.updateMaxGapLocal() + } + if gap.node != n { + return gap + } + if gap.index < reclaimminDegree { + return reclaimGapIterator{left, gap.index} + } + return reclaimGapIterator{right, gap.index - reclaimminDegree} + } + + copy(n.parent.keys[n.parentIndex+1:], n.parent.keys[n.parentIndex:n.parent.nrSegments]) + copy(n.parent.values[n.parentIndex+1:], n.parent.values[n.parentIndex:n.parent.nrSegments]) + n.parent.keys[n.parentIndex], n.parent.values[n.parentIndex] = n.keys[reclaimminDegree-1], n.values[reclaimminDegree-1] + copy(n.parent.children[n.parentIndex+2:], n.parent.children[n.parentIndex+1:n.parent.nrSegments+1]) + for i := n.parentIndex + 2; i < n.parent.nrSegments+2; i++ { + n.parent.children[i].parentIndex = i + } + sibling := &reclaimnode{ + nrSegments: reclaimminDegree - 1, + parent: n.parent, + parentIndex: n.parentIndex + 1, + hasChildren: n.hasChildren, + } + n.parent.children[n.parentIndex+1] = sibling + n.parent.nrSegments++ + copy(sibling.keys[:reclaimminDegree-1], n.keys[reclaimminDegree:]) + copy(sibling.values[:reclaimminDegree-1], n.values[reclaimminDegree:]) + reclaimzeroValueSlice(n.values[reclaimminDegree-1:]) + if n.hasChildren { + copy(sibling.children[:reclaimminDegree], n.children[reclaimminDegree:]) + reclaimzeroNodeSlice(n.children[reclaimminDegree:]) + for i := 0; i < reclaimminDegree; i++ { + sibling.children[i].parent = sibling + sibling.children[i].parentIndex = i + } + } + n.nrSegments = reclaimminDegree - 1 + + if reclaimtrackGaps != 0 { + n.updateMaxGapLocal() + sibling.updateMaxGapLocal() + } + + if gap.node != n { + return gap + } + if gap.index < reclaimminDegree { + return gap + } + return reclaimGapIterator{sibling, gap.index - reclaimminDegree} +} + +// rebalanceAfterRemove "unsplits" n and its ancestors if they are deficient +// (contain fewer segments than required by B-tree invariants), as required for +// removal, and returns an updated iterator to the position represented by gap. +// +// Precondition: n is the only node in the tree that may currently violate a +// B-tree invariant. +func (n *reclaimnode) rebalanceAfterRemove(gap reclaimGapIterator) reclaimGapIterator { + for { + if n.nrSegments >= reclaimminDegree-1 { + return gap + } + if n.parent == nil { + + return gap + } + + if sibling := n.prevSibling(); sibling != nil && sibling.nrSegments >= reclaimminDegree { + copy(n.keys[1:], n.keys[:n.nrSegments]) + copy(n.values[1:], n.values[:n.nrSegments]) + n.keys[0] = n.parent.keys[n.parentIndex-1] + n.values[0] = n.parent.values[n.parentIndex-1] + n.parent.keys[n.parentIndex-1] = sibling.keys[sibling.nrSegments-1] + n.parent.values[n.parentIndex-1] = sibling.values[sibling.nrSegments-1] + reclaimSetFunctions{}.ClearValue(&sibling.values[sibling.nrSegments-1]) + if n.hasChildren { + copy(n.children[1:], n.children[:n.nrSegments+1]) + n.children[0] = sibling.children[sibling.nrSegments] + sibling.children[sibling.nrSegments] = nil + n.children[0].parent = n + n.children[0].parentIndex = 0 + for i := 1; i < n.nrSegments+2; i++ { + n.children[i].parentIndex = i + } + } + n.nrSegments++ + sibling.nrSegments-- + + if reclaimtrackGaps != 0 { + n.updateMaxGapLocal() + sibling.updateMaxGapLocal() + } + if gap.node == sibling && gap.index == sibling.nrSegments { + return reclaimGapIterator{n, 0} + } + if gap.node == n { + return reclaimGapIterator{n, gap.index + 1} + } + return gap + } + if sibling := n.nextSibling(); sibling != nil && sibling.nrSegments >= reclaimminDegree { + n.keys[n.nrSegments] = n.parent.keys[n.parentIndex] + n.values[n.nrSegments] = n.parent.values[n.parentIndex] + n.parent.keys[n.parentIndex] = sibling.keys[0] + n.parent.values[n.parentIndex] = sibling.values[0] + copy(sibling.keys[:sibling.nrSegments-1], sibling.keys[1:]) + copy(sibling.values[:sibling.nrSegments-1], sibling.values[1:]) + reclaimSetFunctions{}.ClearValue(&sibling.values[sibling.nrSegments-1]) + if n.hasChildren { + n.children[n.nrSegments+1] = sibling.children[0] + copy(sibling.children[:sibling.nrSegments], sibling.children[1:]) + sibling.children[sibling.nrSegments] = nil + n.children[n.nrSegments+1].parent = n + n.children[n.nrSegments+1].parentIndex = n.nrSegments + 1 + for i := 0; i < sibling.nrSegments; i++ { + sibling.children[i].parentIndex = i + } + } + n.nrSegments++ + sibling.nrSegments-- + + if reclaimtrackGaps != 0 { + n.updateMaxGapLocal() + sibling.updateMaxGapLocal() + } + if gap.node == sibling { + if gap.index == 0 { + return reclaimGapIterator{n, n.nrSegments} + } + return reclaimGapIterator{sibling, gap.index - 1} + } + return gap + } + + p := n.parent + if p.nrSegments == 1 { + + left, right := p.children[0], p.children[1] + p.nrSegments = left.nrSegments + right.nrSegments + 1 + p.hasChildren = left.hasChildren + p.keys[left.nrSegments] = p.keys[0] + p.values[left.nrSegments] = p.values[0] + copy(p.keys[:left.nrSegments], left.keys[:left.nrSegments]) + copy(p.values[:left.nrSegments], left.values[:left.nrSegments]) + copy(p.keys[left.nrSegments+1:], right.keys[:right.nrSegments]) + copy(p.values[left.nrSegments+1:], right.values[:right.nrSegments]) + if left.hasChildren { + copy(p.children[:left.nrSegments+1], left.children[:left.nrSegments+1]) + copy(p.children[left.nrSegments+1:], right.children[:right.nrSegments+1]) + for i := 0; i < p.nrSegments+1; i++ { + p.children[i].parent = p + p.children[i].parentIndex = i + } + } else { + p.children[0] = nil + p.children[1] = nil + } + + if gap.node == left { + return reclaimGapIterator{p, gap.index} + } + if gap.node == right { + return reclaimGapIterator{p, gap.index + left.nrSegments + 1} + } + return gap + } + // Merge n and either sibling, along with the segment separating the + // two, into whichever of the two nodes comes first. This is the + // reverse of the non-root splitting case in + // node.rebalanceBeforeInsert. + var left, right *reclaimnode + if n.parentIndex > 0 { + left = n.prevSibling() + right = n + } else { + left = n + right = n.nextSibling() + } + + if gap.node == right { + gap = reclaimGapIterator{left, gap.index + left.nrSegments + 1} + } + left.keys[left.nrSegments] = p.keys[left.parentIndex] + left.values[left.nrSegments] = p.values[left.parentIndex] + copy(left.keys[left.nrSegments+1:], right.keys[:right.nrSegments]) + copy(left.values[left.nrSegments+1:], right.values[:right.nrSegments]) + if left.hasChildren { + copy(left.children[left.nrSegments+1:], right.children[:right.nrSegments+1]) + for i := left.nrSegments + 1; i < left.nrSegments+right.nrSegments+2; i++ { + left.children[i].parent = left + left.children[i].parentIndex = i + } + } + left.nrSegments += right.nrSegments + 1 + copy(p.keys[left.parentIndex:], p.keys[left.parentIndex+1:p.nrSegments]) + copy(p.values[left.parentIndex:], p.values[left.parentIndex+1:p.nrSegments]) + reclaimSetFunctions{}.ClearValue(&p.values[p.nrSegments-1]) + copy(p.children[left.parentIndex+1:], p.children[left.parentIndex+2:p.nrSegments+1]) + for i := 0; i < p.nrSegments; i++ { + p.children[i].parentIndex = i + } + p.children[p.nrSegments] = nil + p.nrSegments-- + + if reclaimtrackGaps != 0 { + left.updateMaxGapLocal() + } + + n = p + } +} + +// updateMaxGapLeaf updates maxGap bottom-up from the calling leaf until no +// necessary update. +// +// Preconditions: n must be a leaf node, trackGaps must be 1. +func (n *reclaimnode) updateMaxGapLeaf() { + if n.hasChildren { + panic(fmt.Sprintf("updateMaxGapLeaf should always be called on leaf node: %v", n)) + } + max := n.calculateMaxGapLeaf() + if max == n.maxGap.Get() { + + return + } + oldMax := n.maxGap.Get() + n.maxGap.Set(max) + if max > oldMax { + + for p := n.parent; p != nil; p = p.parent { + if p.maxGap.Get() >= max { + + break + } + + p.maxGap.Set(max) + } + return + } + + for p := n.parent; p != nil; p = p.parent { + if p.maxGap.Get() > oldMax { + + break + } + + parentNewMax := p.calculateMaxGapInternal() + if p.maxGap.Get() == parentNewMax { + + break + } + + p.maxGap.Set(parentNewMax) + } +} + +// updateMaxGapLocal updates maxGap of the calling node solely with no +// propagation to ancestor nodes. +// +// Precondition: trackGaps must be 1. +func (n *reclaimnode) updateMaxGapLocal() { + if !n.hasChildren { + + n.maxGap.Set(n.calculateMaxGapLeaf()) + } else { + + n.maxGap.Set(n.calculateMaxGapInternal()) + } +} + +// calculateMaxGapLeaf iterates the gaps within a leaf node and calculate the +// max. +// +// Preconditions: n must be a leaf node. +func (n *reclaimnode) calculateMaxGapLeaf() uint64 { + max := reclaimGapIterator{n, 0}.Range().Length() + for i := 1; i <= n.nrSegments; i++ { + if current := (reclaimGapIterator{n, i}).Range().Length(); current > max { + max = current + } + } + return max +} + +// calculateMaxGapInternal iterates children's maxGap within an internal node n +// and calculate the max. +// +// Preconditions: n must be a non-leaf node. +func (n *reclaimnode) calculateMaxGapInternal() uint64 { + max := n.children[0].maxGap.Get() + for i := 1; i <= n.nrSegments; i++ { + if current := n.children[i].maxGap.Get(); current > max { + max = current + } + } + return max +} + +// searchFirstLargeEnoughGap returns the first gap having at least minSize length +// in the subtree rooted by n. If not found, return a terminal gap iterator. +func (n *reclaimnode) searchFirstLargeEnoughGap(minSize uint64) reclaimGapIterator { + if n.maxGap.Get() < minSize { + return reclaimGapIterator{} + } + if n.hasChildren { + for i := 0; i <= n.nrSegments; i++ { + if largeEnoughGap := n.children[i].searchFirstLargeEnoughGap(minSize); largeEnoughGap.Ok() { + return largeEnoughGap + } + } + } else { + for i := 0; i <= n.nrSegments; i++ { + currentGap := reclaimGapIterator{n, i} + if currentGap.Range().Length() >= minSize { + return currentGap + } + } + } + panic(fmt.Sprintf("invalid maxGap in %v", n)) +} + +// searchLastLargeEnoughGap returns the last gap having at least minSize length +// in the subtree rooted by n. If not found, return a terminal gap iterator. +func (n *reclaimnode) searchLastLargeEnoughGap(minSize uint64) reclaimGapIterator { + if n.maxGap.Get() < minSize { + return reclaimGapIterator{} + } + if n.hasChildren { + for i := n.nrSegments; i >= 0; i-- { + if largeEnoughGap := n.children[i].searchLastLargeEnoughGap(minSize); largeEnoughGap.Ok() { + return largeEnoughGap + } + } + } else { + for i := n.nrSegments; i >= 0; i-- { + currentGap := reclaimGapIterator{n, i} + if currentGap.Range().Length() >= minSize { + return currentGap + } + } + } + panic(fmt.Sprintf("invalid maxGap in %v", n)) +} + +// A Iterator is conceptually one of: +// +// - A pointer to a segment in a set; or +// +// - A terminal iterator, which is a sentinel indicating that the end of +// iteration has been reached. +// +// Iterators are copyable values and are meaningfully equality-comparable. The +// zero value of Iterator is a terminal iterator. +// +// Unless otherwise specified, any mutation of a set invalidates all existing +// iterators into the set. +type reclaimIterator struct { + // node is the node containing the iterated segment. If the iterator is + // terminal, node is nil. + node *reclaimnode + + // index is the index of the segment in node.keys/values. + index int +} + +// Ok returns true if the iterator is not terminal. All other methods are only +// valid for non-terminal iterators. +func (seg reclaimIterator) Ok() bool { + return seg.node != nil +} + +// Range returns the iterated segment's range key. +func (seg reclaimIterator) Range() __generics_imported0.FileRange { + return seg.node.keys[seg.index] +} + +// Start is equivalent to Range().Start, but should be preferred if only the +// start of the range is needed. +func (seg reclaimIterator) Start() uint64 { + return seg.node.keys[seg.index].Start +} + +// End is equivalent to Range().End, but should be preferred if only the end of +// the range is needed. +func (seg reclaimIterator) End() uint64 { + return seg.node.keys[seg.index].End +} + +// SetRangeUnchecked mutates the iterated segment's range key. This operation +// does not invalidate any iterators. +// +// Preconditions: +// +// - r.Length() > 0. +// +// - The new range must not overlap an existing one: If seg.NextSegment().Ok(), +// then r.end <= seg.NextSegment().Start(); if seg.PrevSegment().Ok(), then +// r.start >= seg.PrevSegment().End(). +func (seg reclaimIterator) SetRangeUnchecked(r __generics_imported0.FileRange) { + seg.node.keys[seg.index] = r +} + +// SetRange mutates the iterated segment's range key. If the new range would +// cause the iterated segment to overlap another segment, or if the new range +// is invalid, SetRange panics. This operation does not invalidate any +// iterators. +func (seg reclaimIterator) SetRange(r __generics_imported0.FileRange) { + if r.Length() <= 0 { + panic(fmt.Sprintf("invalid segment range %v", r)) + } + if prev := seg.PrevSegment(); prev.Ok() && r.Start < prev.End() { + panic(fmt.Sprintf("new segment range %v overlaps segment range %v", r, prev.Range())) + } + if next := seg.NextSegment(); next.Ok() && r.End > next.Start() { + panic(fmt.Sprintf("new segment range %v overlaps segment range %v", r, next.Range())) + } + seg.SetRangeUnchecked(r) +} + +// SetStartUnchecked mutates the iterated segment's start. This operation does +// not invalidate any iterators. +// +// Preconditions: The new start must be valid: start < seg.End(); if +// seg.PrevSegment().Ok(), then start >= seg.PrevSegment().End(). +func (seg reclaimIterator) SetStartUnchecked(start uint64) { + seg.node.keys[seg.index].Start = start +} + +// SetStart mutates the iterated segment's start. If the new start value would +// cause the iterated segment to overlap another segment, or would result in an +// invalid range, SetStart panics. This operation does not invalidate any +// iterators. +func (seg reclaimIterator) SetStart(start uint64) { + if start >= seg.End() { + panic(fmt.Sprintf("new start %v would invalidate segment range %v", start, seg.Range())) + } + if prev := seg.PrevSegment(); prev.Ok() && start < prev.End() { + panic(fmt.Sprintf("new start %v would cause segment range %v to overlap segment range %v", start, seg.Range(), prev.Range())) + } + seg.SetStartUnchecked(start) +} + +// SetEndUnchecked mutates the iterated segment's end. This operation does not +// invalidate any iterators. +// +// Preconditions: The new end must be valid: end > seg.Start(); if +// seg.NextSegment().Ok(), then end <= seg.NextSegment().Start(). +func (seg reclaimIterator) SetEndUnchecked(end uint64) { + seg.node.keys[seg.index].End = end +} + +// SetEnd mutates the iterated segment's end. If the new end value would cause +// the iterated segment to overlap another segment, or would result in an +// invalid range, SetEnd panics. This operation does not invalidate any +// iterators. +func (seg reclaimIterator) SetEnd(end uint64) { + if end <= seg.Start() { + panic(fmt.Sprintf("new end %v would invalidate segment range %v", end, seg.Range())) + } + if next := seg.NextSegment(); next.Ok() && end > next.Start() { + panic(fmt.Sprintf("new end %v would cause segment range %v to overlap segment range %v", end, seg.Range(), next.Range())) + } + seg.SetEndUnchecked(end) +} + +// Value returns a copy of the iterated segment's value. +func (seg reclaimIterator) Value() reclaimSetValue { + return seg.node.values[seg.index] +} + +// ValuePtr returns a pointer to the iterated segment's value. The pointer is +// invalidated if the iterator is invalidated. This operation does not +// invalidate any iterators. +func (seg reclaimIterator) ValuePtr() *reclaimSetValue { + return &seg.node.values[seg.index] +} + +// SetValue mutates the iterated segment's value. This operation does not +// invalidate any iterators. +func (seg reclaimIterator) SetValue(val reclaimSetValue) { + seg.node.values[seg.index] = val +} + +// PrevSegment returns the iterated segment's predecessor. If there is no +// preceding segment, PrevSegment returns a terminal iterator. +func (seg reclaimIterator) PrevSegment() reclaimIterator { + if seg.node.hasChildren { + return seg.node.children[seg.index].lastSegment() + } + if seg.index > 0 { + return reclaimIterator{seg.node, seg.index - 1} + } + if seg.node.parent == nil { + return reclaimIterator{} + } + return reclaimsegmentBeforePosition(seg.node.parent, seg.node.parentIndex) +} + +// NextSegment returns the iterated segment's successor. If there is no +// succeeding segment, NextSegment returns a terminal iterator. +func (seg reclaimIterator) NextSegment() reclaimIterator { + if seg.node.hasChildren { + return seg.node.children[seg.index+1].firstSegment() + } + if seg.index < seg.node.nrSegments-1 { + return reclaimIterator{seg.node, seg.index + 1} + } + if seg.node.parent == nil { + return reclaimIterator{} + } + return reclaimsegmentAfterPosition(seg.node.parent, seg.node.parentIndex) +} + +// PrevGap returns the gap immediately before the iterated segment. +func (seg reclaimIterator) PrevGap() reclaimGapIterator { + if seg.node.hasChildren { + + return seg.node.children[seg.index].lastSegment().NextGap() + } + return reclaimGapIterator{seg.node, seg.index} +} + +// NextGap returns the gap immediately after the iterated segment. +func (seg reclaimIterator) NextGap() reclaimGapIterator { + if seg.node.hasChildren { + return seg.node.children[seg.index+1].firstSegment().PrevGap() + } + return reclaimGapIterator{seg.node, seg.index + 1} +} + +// PrevNonEmpty returns the iterated segment's predecessor if it is adjacent, +// or the gap before the iterated segment otherwise. If seg.Start() == +// Functions.MinKey(), PrevNonEmpty will return two terminal iterators. +// Otherwise, exactly one of the iterators returned by PrevNonEmpty will be +// non-terminal. +func (seg reclaimIterator) PrevNonEmpty() (reclaimIterator, reclaimGapIterator) { + gap := seg.PrevGap() + if gap.Range().Length() != 0 { + return reclaimIterator{}, gap + } + return gap.PrevSegment(), reclaimGapIterator{} +} + +// NextNonEmpty returns the iterated segment's successor if it is adjacent, or +// the gap after the iterated segment otherwise. If seg.End() == +// Functions.MaxKey(), NextNonEmpty will return two terminal iterators. +// Otherwise, exactly one of the iterators returned by NextNonEmpty will be +// non-terminal. +func (seg reclaimIterator) NextNonEmpty() (reclaimIterator, reclaimGapIterator) { + gap := seg.NextGap() + if gap.Range().Length() != 0 { + return reclaimIterator{}, gap + } + return gap.NextSegment(), reclaimGapIterator{} +} + +// A GapIterator is conceptually one of: +// +// - A pointer to a position between two segments, before the first segment, or +// after the last segment in a set, called a *gap*; or +// +// - A terminal iterator, which is a sentinel indicating that the end of +// iteration has been reached. +// +// Note that the gap between two adjacent segments exists (iterators to it are +// non-terminal), but has a length of zero. GapIterator.IsEmpty returns true +// for such gaps. An empty set contains a single gap, spanning the entire range +// of the set's keys. +// +// GapIterators are copyable values and are meaningfully equality-comparable. +// The zero value of GapIterator is a terminal iterator. +// +// Unless otherwise specified, any mutation of a set invalidates all existing +// iterators into the set. +type reclaimGapIterator struct { + // The representation of a GapIterator is identical to that of an Iterator, + // except that index corresponds to positions between segments in the same + // way as for node.children (see comment for node.nrSegments). + node *reclaimnode + index int +} + +// Ok returns true if the iterator is not terminal. All other methods are only +// valid for non-terminal iterators. +func (gap reclaimGapIterator) Ok() bool { + return gap.node != nil +} + +// Range returns the range spanned by the iterated gap. +func (gap reclaimGapIterator) Range() __generics_imported0.FileRange { + return __generics_imported0.FileRange{gap.Start(), gap.End()} +} + +// Start is equivalent to Range().Start, but should be preferred if only the +// start of the range is needed. +func (gap reclaimGapIterator) Start() uint64 { + if ps := gap.PrevSegment(); ps.Ok() { + return ps.End() + } + return reclaimSetFunctions{}.MinKey() +} + +// End is equivalent to Range().End, but should be preferred if only the end of +// the range is needed. +func (gap reclaimGapIterator) End() uint64 { + if ns := gap.NextSegment(); ns.Ok() { + return ns.Start() + } + return reclaimSetFunctions{}.MaxKey() +} + +// IsEmpty returns true if the iterated gap is empty (that is, the "gap" is +// between two adjacent segments.) +func (gap reclaimGapIterator) IsEmpty() bool { + return gap.Range().Length() == 0 +} + +// PrevSegment returns the segment immediately before the iterated gap. If no +// such segment exists, PrevSegment returns a terminal iterator. +func (gap reclaimGapIterator) PrevSegment() reclaimIterator { + return reclaimsegmentBeforePosition(gap.node, gap.index) +} + +// NextSegment returns the segment immediately after the iterated gap. If no +// such segment exists, NextSegment returns a terminal iterator. +func (gap reclaimGapIterator) NextSegment() reclaimIterator { + return reclaimsegmentAfterPosition(gap.node, gap.index) +} + +// PrevGap returns the iterated gap's predecessor. If no such gap exists, +// PrevGap returns a terminal iterator. +func (gap reclaimGapIterator) PrevGap() reclaimGapIterator { + seg := gap.PrevSegment() + if !seg.Ok() { + return reclaimGapIterator{} + } + return seg.PrevGap() +} + +// NextGap returns the iterated gap's successor. If no such gap exists, NextGap +// returns a terminal iterator. +func (gap reclaimGapIterator) NextGap() reclaimGapIterator { + seg := gap.NextSegment() + if !seg.Ok() { + return reclaimGapIterator{} + } + return seg.NextGap() +} + +// NextLargeEnoughGap returns the iterated gap's first next gap with larger +// length than minSize. If not found, return a terminal gap iterator (does NOT +// include this gap itself). +// +// Precondition: trackGaps must be 1. +func (gap reclaimGapIterator) NextLargeEnoughGap(minSize uint64) reclaimGapIterator { + if reclaimtrackGaps != 1 { + panic("set is not tracking gaps") + } + if gap.node != nil && gap.node.hasChildren && gap.index == gap.node.nrSegments { + + gap.node = gap.NextSegment().node + gap.index = 0 + return gap.nextLargeEnoughGapHelper(minSize) + } + return gap.nextLargeEnoughGapHelper(minSize) +} + +// nextLargeEnoughGapHelper is the helper function used by NextLargeEnoughGap +// to do the real recursions. +// +// Preconditions: gap is NOT the trailing gap of a non-leaf node. +func (gap reclaimGapIterator) nextLargeEnoughGapHelper(minSize uint64) reclaimGapIterator { + + for gap.node != nil && + (gap.node.maxGap.Get() < minSize || (!gap.node.hasChildren && gap.index == gap.node.nrSegments)) { + gap.node, gap.index = gap.node.parent, gap.node.parentIndex + } + + if gap.node == nil { + return reclaimGapIterator{} + } + + gap.index++ + for gap.index <= gap.node.nrSegments { + if gap.node.hasChildren { + if largeEnoughGap := gap.node.children[gap.index].searchFirstLargeEnoughGap(minSize); largeEnoughGap.Ok() { + return largeEnoughGap + } + } else { + if gap.Range().Length() >= minSize { + return gap + } + } + gap.index++ + } + gap.node, gap.index = gap.node.parent, gap.node.parentIndex + if gap.node != nil && gap.index == gap.node.nrSegments { + + gap.node, gap.index = gap.node.parent, gap.node.parentIndex + } + return gap.nextLargeEnoughGapHelper(minSize) +} + +// PrevLargeEnoughGap returns the iterated gap's first prev gap with larger or +// equal length than minSize. If not found, return a terminal gap iterator +// (does NOT include this gap itself). +// +// Precondition: trackGaps must be 1. +func (gap reclaimGapIterator) PrevLargeEnoughGap(minSize uint64) reclaimGapIterator { + if reclaimtrackGaps != 1 { + panic("set is not tracking gaps") + } + if gap.node != nil && gap.node.hasChildren && gap.index == 0 { + + gap.node = gap.PrevSegment().node + gap.index = gap.node.nrSegments + return gap.prevLargeEnoughGapHelper(minSize) + } + return gap.prevLargeEnoughGapHelper(minSize) +} + +// prevLargeEnoughGapHelper is the helper function used by PrevLargeEnoughGap +// to do the real recursions. +// +// Preconditions: gap is NOT the first gap of a non-leaf node. +func (gap reclaimGapIterator) prevLargeEnoughGapHelper(minSize uint64) reclaimGapIterator { + + for gap.node != nil && + (gap.node.maxGap.Get() < minSize || (!gap.node.hasChildren && gap.index == 0)) { + gap.node, gap.index = gap.node.parent, gap.node.parentIndex + } + + if gap.node == nil { + return reclaimGapIterator{} + } + + gap.index-- + for gap.index >= 0 { + if gap.node.hasChildren { + if largeEnoughGap := gap.node.children[gap.index].searchLastLargeEnoughGap(minSize); largeEnoughGap.Ok() { + return largeEnoughGap + } + } else { + if gap.Range().Length() >= minSize { + return gap + } + } + gap.index-- + } + gap.node, gap.index = gap.node.parent, gap.node.parentIndex + if gap.node != nil && gap.index == 0 { + + gap.node, gap.index = gap.node.parent, gap.node.parentIndex + } + return gap.prevLargeEnoughGapHelper(minSize) +} + +// segmentBeforePosition returns the predecessor segment of the position given +// by n.children[i], which may or may not contain a child. If no such segment +// exists, segmentBeforePosition returns a terminal iterator. +func reclaimsegmentBeforePosition(n *reclaimnode, i int) reclaimIterator { + for i == 0 { + if n.parent == nil { + return reclaimIterator{} + } + n, i = n.parent, n.parentIndex + } + return reclaimIterator{n, i - 1} +} + +// segmentAfterPosition returns the successor segment of the position given by +// n.children[i], which may or may not contain a child. If no such segment +// exists, segmentAfterPosition returns a terminal iterator. +func reclaimsegmentAfterPosition(n *reclaimnode, i int) reclaimIterator { + for i == n.nrSegments { + if n.parent == nil { + return reclaimIterator{} + } + n, i = n.parent, n.parentIndex + } + return reclaimIterator{n, i} +} + +func reclaimzeroValueSlice(slice []reclaimSetValue) { + + for i := range slice { + reclaimSetFunctions{}.ClearValue(&slice[i]) + } +} + +func reclaimzeroNodeSlice(slice []*reclaimnode) { + for i := range slice { + slice[i] = nil + } +} + +// String stringifies a Set for debugging. +func (s *reclaimSet) String() string { + return s.root.String() +} + +// String stringifies a node (and all of its children) for debugging. +func (n *reclaimnode) String() string { + var buf bytes.Buffer + n.writeDebugString(&buf, "") + return buf.String() +} + +func (n *reclaimnode) writeDebugString(buf *bytes.Buffer, prefix string) { + if n.hasChildren != (n.nrSegments > 0 && n.children[0] != nil) { + buf.WriteString(prefix) + buf.WriteString(fmt.Sprintf("WARNING: inconsistent value of hasChildren: got %v, want %v\n", n.hasChildren, !n.hasChildren)) + } + for i := 0; i < n.nrSegments; i++ { + if child := n.children[i]; child != nil { + cprefix := fmt.Sprintf("%s- % 3d ", prefix, i) + if child.parent != n || child.parentIndex != i { + buf.WriteString(cprefix) + buf.WriteString(fmt.Sprintf("WARNING: inconsistent linkage to parent: got (%p, %d), want (%p, %d)\n", child.parent, child.parentIndex, n, i)) + } + child.writeDebugString(buf, fmt.Sprintf("%s- % 3d ", prefix, i)) + } + buf.WriteString(prefix) + if n.hasChildren { + if reclaimtrackGaps != 0 { + buf.WriteString(fmt.Sprintf("- % 3d: %v => %v, maxGap: %d\n", i, n.keys[i], n.values[i], n.maxGap.Get())) + } else { + buf.WriteString(fmt.Sprintf("- % 3d: %v => %v\n", i, n.keys[i], n.values[i])) + } + } else { + buf.WriteString(fmt.Sprintf("- % 3d: %v => %v\n", i, n.keys[i], n.values[i])) + } + } + if child := n.children[n.nrSegments]; child != nil { + child.writeDebugString(buf, fmt.Sprintf("%s- % 3d ", prefix, n.nrSegments)) + } +} + +// SegmentDataSlices represents segments from a set as slices of start, end, and +// values. SegmentDataSlices is primarily used as an intermediate representation +// for save/restore and the layout here is optimized for that. +// +// +stateify savable +type reclaimSegmentDataSlices struct { + Start []uint64 + End []uint64 + Values []reclaimSetValue +} + +// ExportSortedSlice returns a copy of all segments in the given set, in ascending +// key order. +func (s *reclaimSet) ExportSortedSlices() *reclaimSegmentDataSlices { + var sds reclaimSegmentDataSlices + for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { + sds.Start = append(sds.Start, seg.Start()) + sds.End = append(sds.End, seg.End()) + sds.Values = append(sds.Values, seg.Value()) + } + sds.Start = sds.Start[:len(sds.Start):len(sds.Start)] + sds.End = sds.End[:len(sds.End):len(sds.End)] + sds.Values = sds.Values[:len(sds.Values):len(sds.Values)] + return &sds +} + +// ImportSortedSlice initializes the given set from the given slice. +// +// Preconditions: s must be empty. sds must represent a valid set (the segments +// in sds must have valid lengths that do not overlap). The segments in sds +// must be sorted in ascending key order. +func (s *reclaimSet) ImportSortedSlices(sds *reclaimSegmentDataSlices) error { + if !s.IsEmpty() { + return fmt.Errorf("cannot import into non-empty set %v", s) + } + gap := s.FirstGap() + for i := range sds.Start { + r := __generics_imported0.FileRange{sds.Start[i], sds.End[i]} + if !gap.Range().IsSupersetOf(r) { + return fmt.Errorf("segment overlaps a preceding segment or is incorrectly sorted: [%d, %d) => %v", sds.Start[i], sds.End[i], sds.Values[i]) + } + gap = s.InsertWithoutMerging(gap, r, sds.Values[i]).NextGap() + } + return nil +} + +// segmentTestCheck returns an error if s is incorrectly sorted, does not +// contain exactly expectedSegments segments, or contains a segment which +// fails the passed check. +// +// This should be used only for testing, and has been added to this package for +// templating convenience. +func (s *reclaimSet) segmentTestCheck(expectedSegments int, segFunc func(int, __generics_imported0.FileRange, reclaimSetValue) error) error { + havePrev := false + prev := uint64(0) + nrSegments := 0 + for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { + next := seg.Start() + if havePrev && prev >= next { + return fmt.Errorf("incorrect order: key %d (segment %d) >= key %d (segment %d)", prev, nrSegments-1, next, nrSegments) + } + if segFunc != nil { + if err := segFunc(nrSegments, seg.Range(), seg.Value()); err != nil { + return err + } + } + prev = next + havePrev = true + nrSegments++ + } + if nrSegments != expectedSegments { + return fmt.Errorf("incorrect number of segments: got %d, wanted %d", nrSegments, expectedSegments) + } + return nil +} + +// countSegments counts the number of segments in the set. +// +// Similar to Check, this should only be used for testing. +func (s *reclaimSet) countSegments() (segments int) { + for seg := s.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { + segments++ + } + return segments +} +func (s *reclaimSet) saveRoot() *reclaimSegmentDataSlices { + return s.ExportSortedSlices() +} + +func (s *reclaimSet) loadRoot(sds *reclaimSegmentDataSlices) { + if err := s.ImportSortedSlices(sds); err != nil { + panic(err) + } +} diff --git a/pkg/sentry/pgalloc/usage_set.go b/pkg/sentry/pgalloc/usage_set.go index 79db792d9..6df3d12af 100644 --- a/pkg/sentry/pgalloc/usage_set.go +++ b/pkg/sentry/pgalloc/usage_set.go @@ -16,7 +16,7 @@ import ( // case, Key must be an unsigned integer. // // trackGaps must be 0 or 1. -const usagetrackGaps = 0 +const usagetrackGaps = 1 var _ = uint8(usagetrackGaps << 7) // Will fail if not zero or one. |