NAME
get_mempolicy - Retrieve NUMA memory policy for a process
SYNOPSIS
#include <numaif.h>
I int get_mempolicy(int * policy , unsigned long * nodemask ,
I unsigned long maxnode , unsigned long addr ,
I unsigned long flags );
DESCRIPTION
R get_mempolicy ()
retrieves the NUMA policy of the calling process or of a memory address,
depending on the setting of
R flags .
A NUMA machine has different
memory controllers with different distances to specific CPUs.
The memory policy defines in which node memory is allocated for
the process.
If
R flags
is specified as 0,
then information about the calling process's default policy
(as set by
set_mempolicy(2))
is returned.
If
flags
specifies
R MPOL_F_ADDR ,
then information is returned about the policy governing the memory
address given in
R addr .
This policy may be different from the process's default policy if
set_mempolicy(2)
has been used to establish a policy for the page containing
R addr .
If
policy
is not NULL, then it is used to return the policy.
If
R nodemask
is not NULL, then it is used to return the nodemask associated
with the policy.
maxnode
is the maximum bit number plus one that can be stored into
R nodemask .
The bit number is always rounded to a multiple of
R unsigned long .
For an overview of the possible policies see
set_mempolicy(2).
RETURN VALUE
On success,
R get_mempolicy ()
returns 0;
on error, -1 is returned and
errno
is set to indicate the error.
CONFORMING TO
This system call is Linux specific.
NOTES
This manual page is incomplete:
it does not document the details the
R MPOL_F_NODE
flag,
which modifies the operation of
R get_mempolicy ().
This is deliberate: this flag is not intended for application use,
and its operation may change or it may be removed altogether in
future kernel versions.
Do not use it.
Versions and Library Support
See
mbind(2).
SEE ALSO
