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Diffstat (limited to 'pkg/sentry/pgalloc/pgalloc.go')
-rw-r--r--pkg/sentry/pgalloc/pgalloc.go124
1 files changed, 66 insertions, 58 deletions
diff --git a/pkg/sentry/pgalloc/pgalloc.go b/pkg/sentry/pgalloc/pgalloc.go
index 46f19d218..3243d7214 100644
--- a/pkg/sentry/pgalloc/pgalloc.go
+++ b/pkg/sentry/pgalloc/pgalloc.go
@@ -33,14 +33,14 @@ import (
"gvisor.dev/gvisor/pkg/log"
"gvisor.dev/gvisor/pkg/safemem"
"gvisor.dev/gvisor/pkg/sentry/hostmm"
- "gvisor.dev/gvisor/pkg/sentry/platform"
+ "gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/usage"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/usermem"
)
-// MemoryFile is a platform.File whose pages may be allocated to arbitrary
+// MemoryFile is a memmap.File whose pages may be allocated to arbitrary
// users.
type MemoryFile struct {
// opts holds options passed to NewMemoryFile. opts is immutable.
@@ -372,7 +372,7 @@ func (f *MemoryFile) Destroy() {
// to Allocate.
//
// Preconditions: length must be page-aligned and non-zero.
-func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.FileRange, error) {
+func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (memmap.FileRange, error) {
if length == 0 || length%usermem.PageSize != 0 {
panic(fmt.Sprintf("invalid allocation length: %#x", length))
}
@@ -390,7 +390,7 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi
// Find a range in the underlying file.
fr, ok := findAvailableRange(&f.usage, f.fileSize, length, alignment)
if !ok {
- return platform.FileRange{}, syserror.ENOMEM
+ return memmap.FileRange{}, syserror.ENOMEM
}
// Expand the file if needed.
@@ -398,7 +398,7 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi
// Round the new file size up to be chunk-aligned.
newFileSize := (int64(fr.End) + chunkMask) &^ chunkMask
if err := f.file.Truncate(newFileSize); err != nil {
- return platform.FileRange{}, err
+ return memmap.FileRange{}, err
}
f.fileSize = newFileSize
f.mappingsMu.Lock()
@@ -416,7 +416,7 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi
bs[i] = 0
}
}); err != nil {
- return platform.FileRange{}, err
+ return memmap.FileRange{}, err
}
}
if !f.usage.Add(fr, usageInfo{
@@ -439,56 +439,64 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi
// 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) {
+func findAvailableRange(usage *usageSet, fileSize int64, length, alignment uint64) (memmap.FileRange, bool) {
alignmentMask := alignment - 1
- for gap := usage.UpperBoundGap(uint64(fileSize)); gap.Ok(); gap = gap.PrevLargeEnoughGap(length) {
- // Start searching only at end of file.
+
+ // Search for space in existing gaps, starting at the current end of the
+ // file and working backward.
+ lastGap := usage.LastGap()
+ gap := lastGap
+ for {
end := gap.End()
if end > uint64(fileSize) {
end = uint64(fileSize)
}
- // Start at the top and align downwards.
- start := end - length
- if start > end {
- break // Underflow.
+ // Try to allocate from the end of this gap, with the start of the
+ // allocated range aligned down to alignment.
+ unalignedStart := end - length
+ if unalignedStart > end {
+ // Negative overflow: this and all preceding gaps are too small to
+ // accommodate length.
+ break
}
- start &^= alignmentMask
-
- // Is the gap still sufficient?
- if start < gap.Start() {
- continue
+ if start := unalignedStart &^ alignmentMask; start >= gap.Start() {
+ return memmap.FileRange{start, start + length}, true
}
- // Allocate in the given gap.
- return platform.FileRange{start, start + length}, true
+ gap = gap.PrevLargeEnoughGap(length)
+ if !gap.Ok() {
+ break
+ }
}
// Check that it's possible to fit this allocation at the end of a file of any size.
- min := usage.LastGap().Start()
+ min := lastGap.Start()
min = (min + alignmentMask) &^ alignmentMask
if min+length < min {
- // Overflow.
- return platform.FileRange{}, false
+ // Overflow: allocation would exceed the range of uint64.
+ return memmap.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
+ newFileSize := 2 * fileSize
+ if newFileSize <= fileSize {
+ if fileSize != 0 {
+ // Overflow: allocation would exceed the range of int64.
+ return memmap.FileRange{}, false
}
- } else {
- // Double the current fileSize.
- fileSize *= 2
+ newFileSize = chunkSize
+ }
+ fileSize = newFileSize
+
+ unalignedStart := uint64(fileSize) - length
+ if unalignedStart > uint64(fileSize) {
+ // Negative overflow: fileSize is still inadequate.
+ continue
}
- start := (uint64(fileSize) - length) &^ alignmentMask
- if start >= min {
- return platform.FileRange{start, start + length}, true
+ if start := unalignedStart &^ alignmentMask; start >= min {
+ return memmap.FileRange{start, start + length}, true
}
}
}
@@ -500,22 +508,22 @@ func findAvailableRange(usage *usageSet, fileSize int64, length, alignment uint6
// by r.ReadToBlocks(), it returns that error.
//
// Preconditions: length > 0. length must be page-aligned.
-func (f *MemoryFile) AllocateAndFill(length uint64, kind usage.MemoryKind, r safemem.Reader) (platform.FileRange, error) {
+func (f *MemoryFile) AllocateAndFill(length uint64, kind usage.MemoryKind, r safemem.Reader) (memmap.FileRange, error) {
fr, err := f.Allocate(length, kind)
if err != nil {
- return platform.FileRange{}, err
+ return memmap.FileRange{}, err
}
dsts, err := f.MapInternal(fr, usermem.Write)
if err != nil {
f.DecRef(fr)
- return platform.FileRange{}, err
+ return memmap.FileRange{}, err
}
n, err := safemem.ReadFullToBlocks(r, dsts)
un := uint64(usermem.Addr(n).RoundDown())
if un < length {
// Free unused memory and update fr to contain only the memory that is
// still allocated.
- f.DecRef(platform.FileRange{fr.Start + un, fr.End})
+ f.DecRef(memmap.FileRange{fr.Start + un, fr.End})
fr.End = fr.Start + un
}
return fr, err
@@ -532,7 +540,7 @@ const (
// will read zeroes.
//
// Preconditions: fr.Length() > 0.
-func (f *MemoryFile) Decommit(fr platform.FileRange) error {
+func (f *MemoryFile) Decommit(fr memmap.FileRange) error {
if !fr.WellFormed() || fr.Length() == 0 || fr.Start%usermem.PageSize != 0 || fr.End%usermem.PageSize != 0 {
panic(fmt.Sprintf("invalid range: %v", fr))
}
@@ -552,7 +560,7 @@ func (f *MemoryFile) Decommit(fr platform.FileRange) error {
return nil
}
-func (f *MemoryFile) markDecommitted(fr platform.FileRange) {
+func (f *MemoryFile) markDecommitted(fr memmap.FileRange) {
f.mu.Lock()
defer f.mu.Unlock()
// Since we're changing the knownCommitted attribute, we need to merge
@@ -573,8 +581,8 @@ func (f *MemoryFile) markDecommitted(fr platform.FileRange) {
f.usage.MergeRange(fr)
}
-// IncRef implements platform.File.IncRef.
-func (f *MemoryFile) IncRef(fr platform.FileRange) {
+// IncRef implements memmap.File.IncRef.
+func (f *MemoryFile) IncRef(fr memmap.FileRange) {
if !fr.WellFormed() || fr.Length() == 0 || fr.Start%usermem.PageSize != 0 || fr.End%usermem.PageSize != 0 {
panic(fmt.Sprintf("invalid range: %v", fr))
}
@@ -592,8 +600,8 @@ func (f *MemoryFile) IncRef(fr platform.FileRange) {
f.usage.MergeAdjacent(fr)
}
-// DecRef implements platform.File.DecRef.
-func (f *MemoryFile) DecRef(fr platform.FileRange) {
+// DecRef implements memmap.File.DecRef.
+func (f *MemoryFile) DecRef(fr memmap.FileRange) {
if !fr.WellFormed() || fr.Length() == 0 || fr.Start%usermem.PageSize != 0 || fr.End%usermem.PageSize != 0 {
panic(fmt.Sprintf("invalid range: %v", fr))
}
@@ -629,8 +637,8 @@ func (f *MemoryFile) DecRef(fr platform.FileRange) {
}
}
-// MapInternal implements platform.File.MapInternal.
-func (f *MemoryFile) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
+// MapInternal implements memmap.File.MapInternal.
+func (f *MemoryFile) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
if !fr.WellFormed() || fr.Length() == 0 {
panic(fmt.Sprintf("invalid range: %v", fr))
}
@@ -656,7 +664,7 @@ func (f *MemoryFile) MapInternal(fr platform.FileRange, at usermem.AccessType) (
// forEachMappingSlice invokes fn on a sequence of byte slices that
// collectively map all bytes in fr.
-func (f *MemoryFile) forEachMappingSlice(fr platform.FileRange, fn func([]byte)) error {
+func (f *MemoryFile) forEachMappingSlice(fr memmap.FileRange, fn func([]byte)) error {
mappings := f.mappings.Load().([]uintptr)
for chunkStart := fr.Start &^ chunkMask; chunkStart < fr.End; chunkStart += chunkSize {
chunk := int(chunkStart >> chunkShift)
@@ -936,7 +944,7 @@ func (f *MemoryFile) updateUsageLocked(currentUsage uint64, checkCommitted func(
continue
case !populated && populatedRun:
// Finish the run by changing this segment.
- runRange := platform.FileRange{
+ runRange := memmap.FileRange{
Start: r.Start + uint64(populatedRunStart*usermem.PageSize),
End: r.Start + uint64(i*usermem.PageSize),
}
@@ -1001,7 +1009,7 @@ func (f *MemoryFile) File() *os.File {
return f.file
}
-// FD implements platform.File.FD.
+// FD implements memmap.File.FD.
func (f *MemoryFile) FD() int {
return int(f.file.Fd())
}
@@ -1082,13 +1090,13 @@ func (f *MemoryFile) runReclaim() {
//
// 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) {
+func (f *MemoryFile) findReclaimable() (memmap.FileRange, bool) {
f.mu.Lock()
defer f.mu.Unlock()
for {
for {
if f.destroyed {
- return platform.FileRange{}, false
+ return memmap.FileRange{}, false
}
if f.reclaimable {
break
@@ -1112,7 +1120,7 @@ func (f *MemoryFile) findReclaimable() (platform.FileRange, bool) {
}
}
-func (f *MemoryFile) markReclaimed(fr platform.FileRange) {
+func (f *MemoryFile) markReclaimed(fr memmap.FileRange) {
f.mu.Lock()
defer f.mu.Unlock()
seg := f.usage.FindSegment(fr.Start)
@@ -1214,11 +1222,11 @@ func (usageSetFunctions) MaxKey() uint64 {
func (usageSetFunctions) ClearValue(val *usageInfo) {
}
-func (usageSetFunctions) Merge(_ platform.FileRange, val1 usageInfo, _ platform.FileRange, val2 usageInfo) (usageInfo, bool) {
+func (usageSetFunctions) Merge(_ memmap.FileRange, val1 usageInfo, _ memmap.FileRange, val2 usageInfo) (usageInfo, bool) {
return val1, val1 == val2
}
-func (usageSetFunctions) Split(_ platform.FileRange, val usageInfo, _ uint64) (usageInfo, usageInfo) {
+func (usageSetFunctions) Split(_ memmap.FileRange, val usageInfo, _ uint64) (usageInfo, usageInfo) {
return val, val
}
@@ -1262,10 +1270,10 @@ func (reclaimSetFunctions) MaxKey() uint64 {
func (reclaimSetFunctions) ClearValue(val *reclaimSetValue) {
}
-func (reclaimSetFunctions) Merge(_ platform.FileRange, _ reclaimSetValue, _ platform.FileRange, _ reclaimSetValue) (reclaimSetValue, bool) {
+func (reclaimSetFunctions) Merge(_ memmap.FileRange, _ reclaimSetValue, _ memmap.FileRange, _ reclaimSetValue) (reclaimSetValue, bool) {
return reclaimSetValue{}, true
}
-func (reclaimSetFunctions) Split(_ platform.FileRange, _ reclaimSetValue, _ uint64) (reclaimSetValue, reclaimSetValue) {
+func (reclaimSetFunctions) Split(_ memmap.FileRange, _ reclaimSetValue, _ uint64) (reclaimSetValue, reclaimSetValue) {
return reclaimSetValue{}, reclaimSetValue{}
}
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-09 07:31:48 +0000