mlockall(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

MLOCKALL(3P)            POSIX Programmer's Manual           MLOCKALL(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       mlockall, munlockall — lock/unlock the address space of a process
       (REALTIME)

SYNOPSIS         top

       #include <sys/mman.h>

       int mlockall(int flags);
       int munlockall(void);

DESCRIPTION         top

       The mlockall() function shall cause all of the pages mapped by
       the address space of a process to be memory-resident until
       unlocked or until the process exits or execs another process
       image. The flags argument determines whether the pages to be
       locked are those currently mapped by the address space of the
       process, those that are mapped in the future, or both. The flags
       argument is constructed from the bitwise-inclusive OR of one or
       more of the following symbolic constants, defined in
       <sys/mman.h>:

       MCL_CURRENT Lock all of the pages currently mapped into the
                   address space of the process.

       MCL_FUTURE  Lock all of the pages that become mapped into the
                   address space of the process in the future, when
                   those mappings are established.

       If MCL_FUTURE is specified, and the automatic locking of future
       mappings eventually causes the amount of locked memory to exceed
       the amount of available physical memory or any other
       implementation-defined limit, the behavior is implementation-
       defined. The manner in which the implementation informs the
       application of these situations is also implementation-defined.

       The munlockall() function shall unlock all currently mapped pages
       of the address space of the process. Any pages that become mapped
       into the address space of the process after a call to
       munlockall() shall not be locked, unless there is an intervening
       call to mlockall() specifying MCL_FUTURE or a subsequent call to
       mlockall() specifying MCL_CURRENT. If pages mapped into the
       address space of the process are also mapped into the address
       spaces of other processes and are locked by those processes, the
       locks established by the other processes shall be unaffected by a
       call by this process to munlockall().

       Upon successful return from the mlockall() function that
       specifies MCL_CURRENT, all currently mapped pages of the address
       space of the process shall be memory-resident and locked.  Upon
       return from the munlockall() function, all currently mapped pages
       of the address space of the process shall be unlocked with
       respect to the address space of the process.  The memory
       residency of unlocked pages is unspecified.

       Appropriate privileges are required to lock process memory with
       mlockall().

RETURN VALUE         top

       Upon successful completion, the mlockall() function shall return
       a value of zero. Otherwise, no additional memory shall be locked,
       and the function shall return a value of -1 and set errno to
       indicate the error. The effect of failure of mlockall() on
       previously existing locks in the address space is unspecified.

       If it is supported by the implementation, the munlockall()
       function shall always return a value of zero. Otherwise, the
       function shall return a value of -1 and set errno to indicate the
       error.

ERRORS         top

       The mlockall() function shall fail if:

       EAGAIN Some or all of the memory identified by the operation
              could not be locked when the call was made.

       EINVAL The flags argument is zero, or includes unimplemented
              flags.

       The mlockall() function may fail if:

       ENOMEM Locking all of the pages currently mapped into the address
              space of the process would exceed an implementation-
              defined limit on the amount of memory that the process may
              lock.

       EPERM  The calling process does not have appropriate privileges
              to perform the requested operation.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       exec(1p), exit(3p), fork(3p), mlock(3p), munmap(3p)

       The Base Definitions volume of POSIX.1‐2017, sys_mman.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                      MLOCKALL(3P)

Pages that refer to this page: sys_mman.h(0p)_Exit(3p)mlock(3p)munlockall(3p)munmap(3p)