+++ /dev/null
-.\" Copyright 2003,2004 Andi Kleen, SuSE Labs.
-.\" and Copyright 2007 Lee Schermerhorn, Hewlett Packard
-.\"
-.\" %%%LICENSE_START(VERBATIM_PROF)
-.\" Permission is granted to make and distribute verbatim copies of this
-.\" manual provided the copyright notice and this permission notice are
-.\" preserved on all copies.
-.\"
-.\" Permission is granted to copy and distribute modified versions of this
-.\" manual under the conditions for verbatim copying, provided that the
-.\" entire resulting derived work is distributed under the terms of a
-.\" permission notice identical to this one.
-.\"
-.\" Since the Linux kernel and libraries are constantly changing, this
-.\" manual page may be incorrect or out-of-date. The author(s) assume no
-.\" responsibility for errors or omissions, or for damages resulting from
-.\" the use of the information contained herein.
-.\"
-.\" Formatted or processed versions of this manual, if unaccompanied by
-.\" the source, must acknowledge the copyright and authors of this work.
-.\" %%%LICENSE_END
-.\"
-.\" 2006-02-03, mtk, substantial wording changes and other improvements
-.\" 2007-08-27, Lee Schermerhorn <Lee.Schermerhorn@hp.com>
-.\" more precise specification of behavior.
-.\"
-.TH SET_MEMPOLICY 2 2014-05-28 Linux "Linux Programmer's Manual"
-.SH NAME
-set_mempolicy \- set default NUMA memory policy for a process and its children
-.SH SYNOPSIS
-.nf
-.B "#include <numaif.h>"
-.sp
-.BI "long set_mempolicy(int " mode ", const unsigned long *" nodemask ,
-.BI " unsigned long " maxnode );
-.sp
-Link with \fI\-lnuma\fP.
-.fi
-.SH DESCRIPTION
-.BR set_mempolicy ()
-sets the NUMA memory policy of the calling process,
-which consists of a policy mode and zero or more nodes,
-to the values specified by the
-.IR mode ,
-.I nodemask
-and
-.I maxnode
-arguments.
-
-A NUMA machine has different
-memory controllers with different distances to specific CPUs.
-The memory policy defines from which node memory is allocated for
-the process.
-
-This system call defines the default policy for the process.
-The process policy governs allocation of pages in the process's
-address space outside of memory ranges
-controlled by a more specific policy set by
-.BR mbind (2).
-The process default policy also controls allocation of any pages for
-memory-mapped files mapped using the
-.BR mmap (2)
-call with the
-.B MAP_PRIVATE
-flag and that are only read [loaded] from by the process
-and of memory-mapped files mapped using the
-.BR mmap (2)
-call with the
-.B MAP_SHARED
-flag, regardless of the access type.
-The policy is applied only when a new page is allocated
-for the process.
-For anonymous memory this is when the page is first
-touched by the application.
-
-The
-.I mode
-argument must specify one of
-.BR MPOL_DEFAULT ,
-.BR MPOL_BIND ,
-.BR MPOL_INTERLEAVE ,
-or
-.BR MPOL_PREFERRED .
-All modes except
-.B MPOL_DEFAULT
-require the caller to specify via the
-.I nodemask
-argument one or more nodes.
-
-The
-.I mode
-argument may also include an optional
-.IR "mode flag" .
-The supported
-.I "mode flags"
-are:
-.TP
-.BR MPOL_F_STATIC_NODES " (since Linux 2.6.26)"
-A nonempty
-.I nodemask
-specifies physical node ids.
-Linux will not remap the
-.I nodemask
-when the process moves to a different cpuset context,
-nor when the set of nodes allowed by the process's
-current cpuset context changes.
-.TP
-.BR MPOL_F_RELATIVE_NODES " (since Linux 2.6.26)"
-A nonempty
-.I nodemask
-specifies node ids that are relative to the set of
-node ids allowed by the process's current cpuset.
-.PP
-.I nodemask
-points to a bit mask of node IDs that contains up to
-.I maxnode
-bits.
-The bit mask size is rounded to the next multiple of
-.IR "sizeof(unsigned long)" ,
-but the kernel will use bits only up to
-.IR maxnode .
-A NULL value of
-.I nodemask
-or a
-.I maxnode
-value of zero specifies the empty set of nodes.
-If the value of
-.I maxnode
-is zero,
-the
-.I nodemask
-argument is ignored.
-
-Where a
-.I nodemask
-is required, it must contain at least one node that is on-line,
-allowed by the process's current cpuset context,
-[unless the
-.B MPOL_F_STATIC_NODES
-mode flag is specified],
-and contains memory.
-If the
-.B MPOL_F_STATIC_NODES
-is set in
-.I mode
-and a required
-.I nodemask
-contains no nodes that are allowed by the process's current cpuset context,
-the memory policy reverts to
-.IR "local allocation" .
-This effectively overrides the specified policy until the process's
-cpuset context includes one or more of the nodes specified by
-.IR nodemask .
-
-The
-.B MPOL_DEFAULT
-mode specifies that any nondefault process memory policy be removed,
-so that the memory policy "falls back" to the system default policy.
-The system default policy is "local allocation"\(emthat is,
-allocate memory on the node of the CPU that triggered the allocation.
-.I nodemask
-must be specified as NULL.
-If the "local node" contains no free memory, the system will
-attempt to allocate memory from a "near by" node.
-
-The
-.B MPOL_BIND
-mode defines a strict policy that restricts memory allocation to the
-nodes specified in
-.IR nodemask .
-If
-.I nodemask
-specifies more than one node, page allocations will come from
-the node with the lowest numeric node ID first, until that node
-contains no free memory.
-Allocations will then come from the node with the next highest
-node ID specified in
-.I nodemask
-and so forth, until none of the specified nodes contain free memory.
-Pages will not be allocated from any node not specified in the
-.IR nodemask .
-
-.B MPOL_INTERLEAVE
-interleaves page allocations across the nodes specified in
-.I nodemask
-in numeric node ID order.
-This optimizes for bandwidth instead of latency
-by spreading out pages and memory accesses to those pages across
-multiple nodes.
-However, accesses to a single page will still be limited to
-the memory bandwidth of a single node.
-.\" NOTE: the following sentence doesn't make sense in the context
-.\" of set_mempolicy() -- no memory area specified.
-.\" To be effective the memory area should be fairly large,
-.\" at least 1MB or bigger.
-
-.B MPOL_PREFERRED
-sets the preferred node for allocation.
-The kernel will try to allocate pages from this node first
-and fall back to "near by" nodes if the preferred node is low on free
-memory.
-If
-.I nodemask
-specifies more than one node ID, the first node in the
-mask will be selected as the preferred node.
-If the
-.I nodemask
-and
-.I maxnode
-arguments specify the empty set, then the policy
-specifies "local allocation"
-(like the system default policy discussed above).
-
-The process memory policy is preserved across an
-.BR execve (2),
-and is inherited by child processes created using
-.BR fork (2)
-or
-.BR clone (2).
-.SH RETURN VALUE
-On success,
-.BR set_mempolicy ()
-returns 0;
-on error, \-1 is returned and
-.I errno
-is set to indicate the error.
-.SH ERRORS
-.TP
-.B EFAULT
-Part of all of the memory range specified by
-.I nodemask
-and
-.I maxnode
-points outside your accessible address space.
-.TP
-.B EINVAL
-.I mode
-is invalid.
-Or,
-.I mode
-is
-.B MPOL_DEFAULT
-and
-.I nodemask
-is nonempty,
-or
-.I mode
-is
-.B MPOL_BIND
-or
-.B MPOL_INTERLEAVE
-and
-.I nodemask
-is empty.
-Or,
-.I maxnode
-specifies more than a page worth of bits.
-Or,
-.I nodemask
-specifies one or more node IDs that are
-greater than the maximum supported node ID.
-Or, none of the node IDs specified by
-.I nodemask
-are on-line and allowed by the process's current cpuset context,
-or none of the specified nodes contain memory.
-Or, the
-.I mode
-argument specified both
-.B MPOL_F_STATIC_NODES
-and
-.BR MPOL_F_RELATIVE_NODES .
-.TP
-.B ENOMEM
-Insufficient kernel memory was available.
-.SH VERSIONS
-The
-.BR set_mempolicy (),
-system call was added to the Linux kernel in version 2.6.7.
-.SH CONFORMING TO
-This system call is Linux-specific.
-.SH NOTES
-Process policy is not remembered if the page is swapped out.
-When such a page is paged back in, it will use the policy of
-the process or memory range that is in effect at the time the
-page is allocated.
-
-For information on library support, see
-.BR numa (7).
-.SH SEE ALSO
-.BR get_mempolicy (2),
-.BR getcpu (2),
-.BR mbind (2),
-.BR mmap (2),
-.BR numa (3),
-.BR cpuset (7),
-.BR numa (7),
-.BR numactl (8)
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
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