mm

package
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 Go to latest Published: Dec 10, 2024 License: Apache-2.0, MIT Imports: 30 Imported by: 23

Documentation

Overview

Package mm provides a memory management subsystem. See README.md for a detailed overview.

Lock order: 

fs locks, except for memmap.Mappable locks
	mm.MemoryManager.metadataMu
		mm.MemoryManager.mappingMu
			Locks taken by memmap.MappingIdentity and memmap.Mappable methods other
			than Translate
				kernel.TaskSet.mu
					mm.MemoryManager.activeMu
						Locks taken by memmap.Mappable.Translate
							platform.AddressSpace locks
								memmap.File locks
				mm.aioManager.mu
					mm.AIOContext.mu

Only mm.MemoryManager.Fork is permitted to lock mm.MemoryManager.activeMu in multiple mm.MemoryManagers, as it does so in a well-defined order (forked child first).

Index

Constants

View Source 
const SpecialMappableenableLogging = false

enableLogging indicates whether reference-related events should be logged (with stack traces). This is false by default and should only be set to true for debugging purposes, as it can generate an extremely large amount of output and drastically degrade performance.

Variables

This section is empty.

Functions

func Unpin 

func Unpin(prs []PinnedRange)

Unpin releases the reference held by prs.

Types

type AIOContext 

type AIOContext struct {
	// contains filtered or unexported fields
}

AIOContext is a single asynchronous I/O context.

+stateify savable

func (*AIOContext) CancelPendingRequest 

func (aio *AIOContext) CancelPendingRequest()

CancelPendingRequest forgets about a request that hasn't yet completed.

func (*AIOContext) Dead 

func (aio *AIOContext) Dead() bool

Dead returns true if the context has been destroyed.

func (*AIOContext) Drain 

func (aio *AIOContext) Drain()

Drain drops all completed requests. Pending requests remain untouched.

func (*AIOContext) FinishRequest 

func (aio *AIOContext) FinishRequest(data any)

FinishRequest finishes a pending request. It queues up the data and notifies listeners.

func (*AIOContext) PopRequest 

func (aio *AIOContext) PopRequest() (any, bool)

PopRequest pops a completed request if available, this function does not do any blocking. Returns false if no request is available.

func (*AIOContext) Prepare 

func (aio *AIOContext) Prepare() error

Prepare reserves space for a new request, returning nil if available. Returns EAGAIN if the context is busy and EINVAL if the context is dead.

func (*AIOContext) StateFields 

func (aio *AIOContext) StateFields() []string

func (*AIOContext) StateLoad 

func (aio *AIOContext) StateLoad(ctx context.Context, stateSourceObject state.Source)

+checklocksignore

func (*AIOContext) StateSave 

func (aio *AIOContext) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*AIOContext) StateTypeName 

func (aio *AIOContext) StateTypeName() string

func (*AIOContext) WaitChannel 

func (aio *AIOContext) WaitChannel() chan struct{}

WaitChannel returns a channel that is notified when an AIO request is completed. Returns nil if the context is destroyed and there are no more outstanding requests.

type Dumpability 

type Dumpability int

Dumpability describes if and how core dumps should be created. 

const (
	// NotDumpable indicates that core dumps should never be created.
	NotDumpable Dumpability = iota

	// UserDumpable indicates that core dumps should be created, owned by
	// the current user.
	UserDumpable

	// RootDumpable indicates that core dumps should be created, owned by
	// root.
	RootDumpable
)

type MLockAllOpts 

type MLockAllOpts struct {
	// If Current is true, change the memory-locking behavior of all mappings
	// to Mode. If Future is true, upgrade the memory-locking behavior of all
	// future mappings to Mode. At least one of Current or Future must be true.
	Current bool
	Future  bool
	Mode    memmap.MLockMode
}

MLockAllOpts holds options to MLockAll.

type MRemapMoveMode 

type MRemapMoveMode int

MRemapMoveMode controls MRemap's moving behavior. 

const (
	// MRemapNoMove prevents MRemap from moving the remapped mapping.
	MRemapNoMove MRemapMoveMode = iota

	// MRemapMayMove allows MRemap to move the remapped mapping.
	MRemapMayMove

	// MRemapMustMove requires MRemap to move the remapped mapping to
	// MRemapOpts.NewAddr, replacing any existing mappings in the remapped
	// range.
	MRemapMustMove
)

type MRemapOpts 

type MRemapOpts struct {
	// Move controls whether MRemap moves the remapped mapping to a new address.
	Move MRemapMoveMode

	// NewAddr is the new address for the remapping. NewAddr is ignored unless
	// Move is MMRemapMustMove.
	NewAddr hostarch.Addr
}

MRemapOpts specifies options to MRemap.

type MSyncOpts 

type MSyncOpts struct {
	// Sync has the semantics of MS_SYNC.
	Sync bool

	// Invalidate has the semantics of MS_INVALIDATE.
	Invalidate bool
}

MSyncOpts holds options to MSync.

type MapsCallbackFunc 

type MapsCallbackFunc func(start, end hostarch.Addr, permissions hostarch.AccessType, private string, offset uint64, devMajor, devMinor uint32, inode uint64, path string)

MapsCallbackFunc has all the parameters required for populating an entry of /proc/[pid]/maps.

type MemoryManager 

type MemoryManager struct {
	// contains filtered or unexported fields
}

MemoryManager implements a virtual address space.

+stateify savable

func NewMemoryManager 

func NewMemoryManager(p platform.Platform, mf *pgalloc.MemoryFile, sleepForActivation bool) *MemoryManager

NewMemoryManager returns a new MemoryManager with no mappings and 1 user.

func (*MemoryManager) Activate 

func (mm *MemoryManager) Activate(ctx context.Context) error

Activate ensures this MemoryManager has a platform.AddressSpace.

The caller must not hold any locks when calling Activate.

When this MemoryManager is no longer needed by a task, it should call Deactivate to release the reference.

func (*MemoryManager) AddressSpace 

func (mm *MemoryManager) AddressSpace() platform.AddressSpace

AddressSpace returns the platform.AddressSpace bound to mm.

Preconditions: The caller must have called mm.Activate().

func (*MemoryManager) ArgvEnd 

func (mm *MemoryManager) ArgvEnd() hostarch.Addr

ArgvEnd returns the end of the application argument vector.

There is no guarantee that this value is sensible w.r.t. ArgvStart.

func (*MemoryManager) ArgvStart 

func (mm *MemoryManager) ArgvStart() hostarch.Addr

ArgvStart returns the start of the application argument vector.

There is no guarantee that this value is sensible w.r.t. ArgvEnd.

func (*MemoryManager) Auxv 

func (mm *MemoryManager) Auxv() arch.Auxv

Auxv returns the current map of auxiliary vectors.

func (*MemoryManager) Brk 

func (mm *MemoryManager) Brk(ctx context.Context, addr hostarch.Addr) (hostarch.Addr, error)

Brk implements the semantics of Linux's brk(2), except that it returns an error on failure.

func (*MemoryManager) BrkSetup 

func (mm *MemoryManager) BrkSetup(ctx context.Context, addr hostarch.Addr)

BrkSetup sets mm's brk address to addr and its brk size to 0.

func (*MemoryManager) CheckIORange 

func (mm *MemoryManager) CheckIORange(addr hostarch.Addr, length int64) (hostarch.AddrRange, bool)

CheckIORange is similar to hostarch.Addr.ToRange, but applies bounds checks consistent with Linux's arch/x86/include/asm/uaccess.h:access_ok().

Preconditions: length >= 0.

func (*MemoryManager) CompareAndSwapUint32 

func (mm *MemoryManager) CompareAndSwapUint32(ctx context.Context, addr hostarch.Addr, old, new uint32, opts usermem.IOOpts) (uint32, error)

CompareAndSwapUint32 implements usermem.IO.CompareAndSwapUint32.

func (*MemoryManager) CopyIn 

func (mm *MemoryManager) CopyIn(ctx context.Context, addr hostarch.Addr, dst []byte, opts usermem.IOOpts) (int, error)

CopyIn implements usermem.IO.CopyIn.

func (*MemoryManager) CopyInTo 

func (mm *MemoryManager) CopyInTo(ctx context.Context, ars hostarch.AddrRangeSeq, dst safemem.Writer, opts usermem.IOOpts) (int64, error)

CopyInTo implements usermem.IO.CopyInTo.

func (*MemoryManager) CopyOut 

func (mm *MemoryManager) CopyOut(ctx context.Context, addr hostarch.Addr, src []byte, opts usermem.IOOpts) (int, error)

CopyOut implements usermem.IO.CopyOut.

func (*MemoryManager) CopyOutFrom 

func (mm *MemoryManager) CopyOutFrom(ctx context.Context, ars hostarch.AddrRangeSeq, src safemem.Reader, opts usermem.IOOpts) (int64, error)

CopyOutFrom implements usermem.IO.CopyOutFrom.

func (*MemoryManager) Deactivate 

func (mm *MemoryManager) Deactivate()

Deactivate releases a reference to the MemoryManager.

func (*MemoryManager) DebugString 

func (mm *MemoryManager) DebugString(ctx context.Context) string

DebugString returns a string containing information about mm for debugging.

func (*MemoryManager) DecUsers 

func (mm *MemoryManager) DecUsers(ctx context.Context)

DecUsers decrements mm's user count. If the user count reaches 0, all mappings in mm are unmapped.

func (*MemoryManager) Decommit 

func (mm *MemoryManager) Decommit(addr hostarch.Addr, length uint64) error

Decommit implements the semantics of Linux's madvise(MADV_DONTNEED).

func (*MemoryManager) DestroyAIOContext 

func (mm *MemoryManager) DestroyAIOContext(ctx context.Context, id uint64) *AIOContext

DestroyAIOContext destroys an asynchronous I/O context. It returns the destroyed context. nil if the context does not exist.

func (*MemoryManager) DetachShm 

func (mm *MemoryManager) DetachShm(ctx context.Context, addr hostarch.Addr) error

DetachShm unmaps a sysv shared memory segment.

func (*MemoryManager) Dumpability 

func (mm *MemoryManager) Dumpability() Dumpability

Dumpability returns the dumpability.

func (*MemoryManager) EnableMembarrierPrivate 

func (mm *MemoryManager) EnableMembarrierPrivate()

EnableMembarrierPrivate causes future calls to IsMembarrierPrivateEnabled to return true.

func (*MemoryManager) EnableMembarrierRSeq 

func (mm *MemoryManager) EnableMembarrierRSeq()

EnableMembarrierRSeq causes future calls to IsMembarrierRSeqEnabled to return true.

func (*MemoryManager) EnsurePMAsExist 

func (mm *MemoryManager) EnsurePMAsExist(ctx context.Context, addr hostarch.Addr, length int64, opts usermem.IOOpts) (int64, error)

EnsurePMAsExist attempts to ensure that PMAs exist for the given addr with the requested length. It returns the length to which it was able to either initialize PMAs for, or ascertain that PMAs exist for. If this length is smaller than the requested length it returns an error explaining why.

func (*MemoryManager) EnvvEnd 

func (mm *MemoryManager) EnvvEnd() hostarch.Addr

EnvvEnd returns the end of the application environment vector.

There is no guarantee that this value is sensible w.r.t. EnvvStart.

func (*MemoryManager) EnvvStart 

func (mm *MemoryManager) EnvvStart() hostarch.Addr

EnvvStart returns the start of the application environment vector.

There is no guarantee that this value is sensible w.r.t. EnvvEnd.

func (*MemoryManager) Executable 

func (mm *MemoryManager) Executable() *vfs.FileDescription

Executable returns the executable, if available.

An additional reference will be taken in the case of a non-nil executable, which must be released by the caller.

func (*MemoryManager) FindVMAByName 

func (mm *MemoryManager) FindVMAByName(ar hostarch.AddrRange, name string) (hostarch.Addr, uint64, error)

FindVMAByName finds a vma with the specified name and returns its start address and offset.

func (*MemoryManager) Fork 

func (mm *MemoryManager) Fork(ctx context.Context) (*MemoryManager, error)

Fork creates a copy of mm with 1 user, as for Linux syscalls fork() or clone() (without CLONE_VM).

func (*MemoryManager) GetSharedFutexKey 

func (mm *MemoryManager) GetSharedFutexKey(ctx context.Context, addr hostarch.Addr) (futex.Key, error)

GetSharedFutexKey is used by kernel.Task.GetSharedKey.

func (*MemoryManager) HandleUserFault 

func (mm *MemoryManager) HandleUserFault(ctx context.Context, addr hostarch.Addr, at hostarch.AccessType, sp hostarch.Addr) error

HandleUserFault handles an application page fault. sp is the faulting application thread's stack pointer.

Preconditions: mm.as != nil.

func (*MemoryManager) IncUsers 

func (mm *MemoryManager) IncUsers() bool

IncUsers increments mm's user count and returns true. If the user count is already 0, IncUsers does nothing and returns false.

func (*MemoryManager) Invalidate 

func (mm *MemoryManager) Invalidate(ar hostarch.AddrRange, opts memmap.InvalidateOpts)

Invalidate implements memmap.MappingSpace.Invalidate.

func (*MemoryManager) InvalidateUnsavable 

func (mm *MemoryManager) InvalidateUnsavable(ctx context.Context) error

InvalidateUnsavable invokes memmap.Mappable.InvalidateUnsavable on all Mappables mapped by mm.

func (*MemoryManager) IsMembarrierPrivateEnabled 

func (mm *MemoryManager) IsMembarrierPrivateEnabled() bool

IsMembarrierPrivateEnabled returns true if mm.EnableMembarrierPrivate() has previously been called.

func (*MemoryManager) IsMembarrierRSeqEnabled 

func (mm *MemoryManager) IsMembarrierRSeqEnabled() bool

IsMembarrierRSeqEnabled returns true if mm.EnableMembarrierRSeq() has previously been called.

func (*MemoryManager) LoadUint32 

func (mm *MemoryManager) LoadUint32(ctx context.Context, addr hostarch.Addr, opts usermem.IOOpts) (uint32, error)

LoadUint32 implements usermem.IO.LoadUint32.

func (*MemoryManager) LookupAIOContext 

func (mm *MemoryManager) LookupAIOContext(ctx context.Context, id uint64) (*AIOContext, bool)

LookupAIOContext looks up the given context. It returns false if the context does not exist.

func (*MemoryManager) MLock 

func (mm *MemoryManager) MLock(ctx context.Context, addr hostarch.Addr, length uint64, mode memmap.MLockMode) error

MLock implements the semantics of Linux's mlock()/mlock2()/munlock(), depending on mode.

func (*MemoryManager) MLockAll 

func (mm *MemoryManager) MLockAll(ctx context.Context, opts MLockAllOpts) error

MLockAll implements the semantics of Linux's mlockall()/munlockall(), depending on opts.

func (*MemoryManager) MMap 

func (mm *MemoryManager) MMap(ctx context.Context, opts memmap.MMapOpts) (hostarch.Addr, error)

MMap establishes a memory mapping.

func (*MemoryManager) MProtect 

func (mm *MemoryManager) MProtect(addr hostarch.Addr, length uint64, realPerms hostarch.AccessType, growsDown bool) error

MProtect implements the semantics of Linux's mprotect(2).

func (*MemoryManager) MRemap 

func (mm *MemoryManager) MRemap(ctx context.Context, oldAddr hostarch.Addr, oldSize uint64, newSize uint64, opts MRemapOpts) (hostarch.Addr, error)

MRemap implements the semantics of Linux's mremap(2).

func (*MemoryManager) MSync 

func (mm *MemoryManager) MSync(ctx context.Context, addr hostarch.Addr, length uint64, opts MSyncOpts) error

MSync implements the semantics of Linux's msync().

func (*MemoryManager) MUnmap 

func (mm *MemoryManager) MUnmap(ctx context.Context, addr hostarch.Addr, length uint64) error

MUnmap implements the semantics of Linux's munmap(2).

func (*MemoryManager) MapStack 

func (mm *MemoryManager) MapStack(ctx context.Context) (hostarch.AddrRange, error)

MapStack allocates the initial process stack.

func (*MemoryManager) MapsCallbackFuncForBuffer 

func (mm *MemoryManager) MapsCallbackFuncForBuffer(buf *bytes.Buffer) MapsCallbackFunc

MapsCallbackFuncForBuffer creates a /proc/[pid]/maps entry including the trailing newline.

func (*MemoryManager) MaxResidentSetSize 

func (mm *MemoryManager) MaxResidentSetSize() uint64

MaxResidentSetSize returns the value advertised as mm's max RSS in bytes.

func (*MemoryManager) NewAIOContext 

func (mm *MemoryManager) NewAIOContext(ctx context.Context, events uint32) (uint64, error)

NewAIOContext creates a new context for asynchronous I/O.

NewAIOContext is analogous to Linux's fs/aio.c:ioctx_alloc().

func (*MemoryManager) NumaPolicy 

func (mm *MemoryManager) NumaPolicy(addr hostarch.Addr) (linux.NumaPolicy, uint64, error)

NumaPolicy implements the semantics of Linux's get_mempolicy(MPOL_F_ADDR).

func (*MemoryManager) Pin 

func (mm *MemoryManager) Pin(ctx context.Context, ar hostarch.AddrRange, at hostarch.AccessType, ignorePermissions bool) ([]PinnedRange, error)

Pin returns the memmap.File ranges currently mapped by addresses in ar in mm, acquiring a reference on the returned ranges which the caller must release by calling Unpin. If not all addresses are mapped, Pin returns a non-nil error. Note that Pin may return both a non-empty slice of PinnedRanges and a non-nil error.

Pin does not prevent mapped ranges from changing, making it unsuitable for most I/O. It should only be used in contexts that would use get_user_pages() in the Linux kernel.

Preconditions:

  • ar.Length() != 0.
  • ar must be page-aligned.

func (*MemoryManager) ReadMapsDataInto 

func (mm *MemoryManager) ReadMapsDataInto(ctx context.Context, fn MapsCallbackFunc)

ReadMapsDataInto is called by fsimpl/proc.mapsData.Generate to implement /proc/[pid]/maps.

func (*MemoryManager) ReadSmapsDataInto 

func (mm *MemoryManager) ReadSmapsDataInto(ctx context.Context, buf *bytes.Buffer)

ReadSmapsDataInto is called by fsimpl/proc.smapsData.Generate to implement /proc/[pid]/maps.

func (*MemoryManager) ResidentSetSize 

func (mm *MemoryManager) ResidentSetSize() uint64

ResidentSetSize returns the value advertised as mm's RSS in bytes.

func (*MemoryManager) SetArgvEnd 

func (mm *MemoryManager) SetArgvEnd(a hostarch.Addr)

SetArgvEnd sets the end of the application argument vector.

func (*MemoryManager) SetArgvStart 

func (mm *MemoryManager) SetArgvStart(a hostarch.Addr)

SetArgvStart sets the start of the application argument vector.

func (*MemoryManager) SetAuxv 

func (mm *MemoryManager) SetAuxv(auxv arch.Auxv)

SetAuxv sets the entire map of auxiliary vectors.

func (*MemoryManager) SetDontFork 

func (mm *MemoryManager) SetDontFork(addr hostarch.Addr, length uint64, dontfork bool) error

SetDontFork implements the semantics of madvise MADV_DONTFORK.

Preconditions: addr and length are page-aligned.

func (*MemoryManager) SetDumpability 

func (mm *MemoryManager) SetDumpability(d Dumpability)

SetDumpability sets the dumpability.

func (*MemoryManager) SetEnvvEnd 

func (mm *MemoryManager) SetEnvvEnd(a hostarch.Addr)

SetEnvvEnd sets the end of the application environment vector.

func (*MemoryManager) SetEnvvStart 

func (mm *MemoryManager) SetEnvvStart(a hostarch.Addr)

SetEnvvStart sets the start of the application environment vector.

func (*MemoryManager) SetExecutable 

func (mm *MemoryManager) SetExecutable(ctx context.Context, fd *vfs.FileDescription)

SetExecutable sets the executable.

This takes a reference on d.

func (*MemoryManager) SetMmapLayout 

func (mm *MemoryManager) SetMmapLayout(ac *arch.Context64, r *limits.LimitSet) (arch.MmapLayout, error)

SetMmapLayout initializes mm's layout from the given arch.Context64.

Preconditions: mm contains no mappings and is not used concurrently.

func (*MemoryManager) SetNumaPolicy 

func (mm *MemoryManager) SetNumaPolicy(addr hostarch.Addr, length uint64, policy linux.NumaPolicy, nodemask uint64) error

SetNumaPolicy implements the semantics of Linux's mbind().

func (*MemoryManager) SetVDSOSigReturn 

func (mm *MemoryManager) SetVDSOSigReturn(addr uint64)

SetVDSOSigReturn sets the address of vdso_sigreturn.

func (*MemoryManager) SetVMAAnonName 

func (mm *MemoryManager) SetVMAAnonName(addr hostarch.Addr, length uint64, name string, nameIsNil bool) error

SetVMAAnonName implements the semantics of Linux's prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME).

func (*MemoryManager) StateFields 

func (mm *MemoryManager) StateFields() []string

func (*MemoryManager) StateLoad 

func (mm *MemoryManager) StateLoad(ctx context.Context, stateSourceObject state.Source)

+checklocksignore

func (*MemoryManager) StateSave 

func (mm *MemoryManager) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*MemoryManager) StateTypeName 

func (mm *MemoryManager) StateTypeName() string

func (*MemoryManager) String 

func (mm *MemoryManager) String() string

String implements fmt.Stringer.String.

func (*MemoryManager) SwapUint32 

func (mm *MemoryManager) SwapUint32(ctx context.Context, addr hostarch.Addr, new uint32, opts usermem.IOOpts) (uint32, error)

SwapUint32 implements usermem.IO.SwapUint32.

func (*MemoryManager) VDSOSigReturn 

func (mm *MemoryManager) VDSOSigReturn() uint64

VDSOSigReturn returns the address of vdso_sigreturn.

func (*MemoryManager) VirtualDataSize 

func (mm *MemoryManager) VirtualDataSize() uint64

VirtualDataSize returns the size of private data segments in mm.

func (*MemoryManager) VirtualMemorySize 

func (mm *MemoryManager) VirtualMemorySize() uint64

VirtualMemorySize returns the combined length in bytes of all mappings in mm.

func (*MemoryManager) VirtualMemorySizeRange 

func (mm *MemoryManager) VirtualMemorySizeRange(ar hostarch.AddrRange) uint64

VirtualMemorySizeRange returns the combined length in bytes of all mappings in ar in mm.

func (*MemoryManager) ZeroOut 

func (mm *MemoryManager) ZeroOut(ctx context.Context, addr hostarch.Addr, toZero int64, opts usermem.IOOpts) (int64, error)

ZeroOut implements usermem.IO.ZeroOut.

type PinnedRange 

type PinnedRange struct {
	// Source is the corresponding range of addresses.
	Source hostarch.AddrRange

	// File is the mapped file.
	File memmap.File

	// Offset is the offset into File at which this PinnedRange begins.
	Offset uint64
}

PinnedRanges are returned by MemoryManager.Pin.

func (PinnedRange) FileRange 

func (pr PinnedRange) FileRange() memmap.FileRange

FileRange returns the memmap.File offsets mapped by pr.

type SpecialMappable 

type SpecialMappable struct {
	SpecialMappableRefs
	// contains filtered or unexported fields
}

SpecialMappable implements memmap.MappingIdentity and memmap.Mappable with semantics similar to Linux's mm/mmap.c:_install_special_mapping(), except that SpecialMappable takes ownership of the memory that it represents (_install_special_mapping() does not.)

+stateify savable 

var SpecialMappableobj *SpecialMappable

obj is used to customize logging. Note that we use a pointer to T so that we do not copy the entire object when passed as a format parameter.

func NewSpecialMappable 

func NewSpecialMappable(name string, mf *pgalloc.MemoryFile, fr memmap.FileRange) *SpecialMappable

NewSpecialMappable returns a SpecialMappable that owns fr, which represents offsets in mfp.MemoryFile() that contain the SpecialMappable's data. The SpecialMappable will use the given name in /proc/[pid]/maps.

Preconditions: fr.Length() != 0.

func (*SpecialMappable) AddMapping 

func (*SpecialMappable) AddMapping(context.Context, memmap.MappingSpace, hostarch.AddrRange, uint64, bool) error

AddMapping implements memmap.Mappable.AddMapping.

func (*SpecialMappable) CopyMapping 

func (*SpecialMappable) CopyMapping(context.Context, memmap.MappingSpace, hostarch.AddrRange, hostarch.AddrRange, uint64, bool) error

CopyMapping implements memmap.Mappable.CopyMapping.

func (*SpecialMappable) DecRef 

func (m *SpecialMappable) DecRef(ctx context.Context)

DecRef implements refs.RefCounter.DecRef.

func (*SpecialMappable) DeviceID 

func (m *SpecialMappable) DeviceID() uint64

DeviceID implements memmap.MappingIdentity.DeviceID.

func (*SpecialMappable) FileRange 

func (m *SpecialMappable) FileRange() memmap.FileRange

FileRange returns the offsets into m.mf that stores the SpecialMappable's contents.

func (*SpecialMappable) InodeID 

func (m *SpecialMappable) InodeID() uint64

InodeID implements memmap.MappingIdentity.InodeID.

func (*SpecialMappable) InvalidateUnsavable 

func (m *SpecialMappable) InvalidateUnsavable(ctx context.Context) error

InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.

func (*SpecialMappable) Length 

func (m *SpecialMappable) Length() uint64

Length returns the length of the SpecialMappable.

func (*SpecialMappable) MappedName 

func (m *SpecialMappable) MappedName(ctx context.Context) string

MappedName implements memmap.MappingIdentity.MappedName.

func (*SpecialMappable) Msync 

func (m *SpecialMappable) Msync(ctx context.Context, mr memmap.MappableRange) error

Msync implements memmap.MappingIdentity.Msync.

func (*SpecialMappable) RemoveMapping 

func (*SpecialMappable) RemoveMapping(context.Context, memmap.MappingSpace, hostarch.AddrRange, uint64, bool)

RemoveMapping implements memmap.Mappable.RemoveMapping.

func (*SpecialMappable) StateFields 

func (m *SpecialMappable) StateFields() []string

func (*SpecialMappable) StateLoad 

func (m *SpecialMappable) StateLoad(ctx context.Context, stateSourceObject state.Source)

+checklocksignore

func (*SpecialMappable) StateSave 

func (m *SpecialMappable) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*SpecialMappable) StateTypeName 

func (m *SpecialMappable) StateTypeName() string

func (*SpecialMappable) Translate 

func (m *SpecialMappable) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error)

Translate implements memmap.Mappable.Translate.

type SpecialMappableRefs 

type SpecialMappableRefs struct {
	// contains filtered or unexported fields
}

Refs implements refs.RefCounter. It keeps a reference count using atomic operations and calls the destructor when the count reaches zero.

NOTE: Do not introduce additional fields to the Refs struct. It is used by many filesystem objects, and we want to keep it as small as possible (i.e., the same size as using an int64 directly) to avoid taking up extra cache space. In general, this template should not be extended at the cost of performance. If it does not offer enough flexibility for a particular object (example: b/187877947), we should implement the RefCounter/CheckedObject interfaces manually.

+stateify savable

func (*SpecialMappableRefs) DecRef 

func (r *SpecialMappableRefs) DecRef(destroy func())

DecRef implements refs.RefCounter.DecRef.

Note that speculative references are counted here. Since they were added prior to real references reaching zero, they will successfully convert to real references. In other words, we see speculative references only in the following case: 

A: TryIncRef [speculative increase => sees non-negative references]
B: DecRef [real decrease]
A: TryIncRef [transform speculative to real]

func (*SpecialMappableRefs) IncRef 

func (r *SpecialMappableRefs) IncRef()

IncRef implements refs.RefCounter.IncRef.

func (*SpecialMappableRefs) InitRefs 

func (r *SpecialMappableRefs) InitRefs()

InitRefs initializes r with one reference and, if enabled, activates leak checking.

func (*SpecialMappableRefs) LeakMessage 

func (r *SpecialMappableRefs) LeakMessage() string

LeakMessage implements refs.CheckedObject.LeakMessage.

func (*SpecialMappableRefs) LogRefs 

func (r *SpecialMappableRefs) LogRefs() bool

LogRefs implements refs.CheckedObject.LogRefs.

func (*SpecialMappableRefs) ReadRefs 

func (r *SpecialMappableRefs) ReadRefs() int64

ReadRefs returns the current number of references. The returned count is inherently racy and is unsafe to use without external synchronization.

func (*SpecialMappableRefs) RefType 

func (r *SpecialMappableRefs) RefType() string

RefType implements refs.CheckedObject.RefType.

func (*SpecialMappableRefs) StateFields 

func (r *SpecialMappableRefs) StateFields() []string

func (*SpecialMappableRefs) StateLoad 

func (r *SpecialMappableRefs) StateLoad(ctx context.Context, stateSourceObject state.Source)

+checklocksignore

func (*SpecialMappableRefs) StateSave 

func (r *SpecialMappableRefs) StateSave(stateSinkObject state.Sink)

+checklocksignore

func (*SpecialMappableRefs) StateTypeName 

func (r *SpecialMappableRefs) StateTypeName() string

func (*SpecialMappableRefs) TryIncRef 

func (r *SpecialMappableRefs) TryIncRef() bool

TryIncRef implements refs.TryRefCounter.TryIncRef.

To do this safely without a loop, a speculative reference is first acquired on the object. This allows multiple concurrent TryIncRef calls to distinguish other TryIncRef calls from genuine references held.

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