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    The following form allows you to view linux man pages.

    Command:

    get_mempolicy

    
    
    

    SYNOPSIS

           #include <numaif.h>
    
           int get_mempolicy(int *mode, unsigned long *nodemask,
                             unsigned long maxnode, unsigned long addr,
                             unsigned long flags);
    
           Link with -lnuma.
    
    
    

    DESCRIPTION

           get_mempolicy()  retrieves the NUMA policy of the calling process or of
           a memory address, depending on the setting of flags.
    
           A NUMA machine has different memory  controllers  with  different  dis-
           tances  to  specific  CPUs.   The memory policy defines from which node
           memory is allocated for the process.
    
           If flags is specified as 0, then information  about  the  calling  pro-
           cess's  default  policy  (as set by set_mempolicy(2)) is returned.  The
           policy returned [mode and nodemask] may be used  to  restore  the  pro-
           cess's  policy  to its state at the time of the call to get_mempolicy()
           using set_mempolicy(2).
    
           If flags specifies MPOL_F_MEMS_ALLOWED (available since Linux  2.6.24),
           the  mode  argument is ignored and the set of nodes [memories] that the
           process is allowed to  specify  in  subsequent  calls  to  mbind(2)  or
           set_mempolicy(2)  [in  the  absence  of  any mode flags] is returned in
           nodemask.  It is not  permitted  to  combine  MPOL_F_MEMS_ALLOWED  with
           either MPOL_F_ADDR or MPOL_F_NODE.
    
           If  flags specifies MPOL_F_ADDR, then information is returned about the
           policy governing the memory address given in addr.  This policy may  be
           different  from  the process's default policy if mbind(2) or one of the
           helper functions described in numa(3) has been used to establish a pol-
           icy for the memory range containing addr.
    
           If  the  mode argument is not NULL, then get_mempolicy() will store the
           policy mode and any optional mode flags of the requested NUMA policy in
           the  location  pointed  to  by this argument.  If nodemask is not NULL,
           then the nodemask associated with the policy  will  be  stored  in  the
           location  pointed to by this argument.  maxnode specifies the number of
           node IDs that can be stored into nodemask--that is, the maximum node  ID
           plus one.  The value specified by maxnode is always rounded to a multi-
           ple of sizeof(unsigned long).
    
           If flags specifies both MPOL_F_NODE  and  MPOL_F_ADDR,  get_mempolicy()
           will  return the node ID of the node on which the address addr is allo-
           cated into the location pointed to by mode.  If no page  has  yet  been
           allocated  for  the  specified address, get_mempolicy() will allocate a
           page as if the process had performed  a  read  [load]  access  to  that
           address, and return the ID of the node where that page was allocated.
    
           On success, get_mempolicy() returns 0; on error,  -1  is  returned  and
           errno is set to indicate the error.
    
    
    

    ERRORS

           EFAULT Part  of all of the memory range specified by nodemask and maxn-
                  ode points outside your accessible address space.
    
           EINVAL The value specified by maxnode is less than the number  of  node
                  IDs  supported  by  the system.  Or flags specified values other
                  than MPOL_F_NODE or MPOL_F_ADDR; or flags specified  MPOL_F_ADDR
                  and  addr is NULL, or flags did not specify MPOL_F_ADDR and addr
                  is  not  NULL.   Or,  flags  specified   MPOL_F_NODE   but   not
                  MPOL_F_ADDR  and  the  current process policy is not MPOL_INTER-
                  LEAVE.  Or,  flags  specified  MPOL_F_MEMS_ALLOWED  with  either
                  MPOL_F_ADDR or MPOL_F_NODE.  (And there are other EINVAL cases.)
    
    
    

    VERSIONS

           The get_mempolicy() system call was added to the Linux kernel  in  ver-
           sion 2.6.7.
    
    
    

    CONFORMING TO

           This system call is Linux-specific.
    
    
    

    NOTES

           For information on library support, see numa(7).
    
    
    

    SEE ALSO

           getcpu(2),   mbind(2),  mmap(2),  set_mempolicy(2),  numa(3),  numa(7),
           numactl(8)
    
    
    

    Linux 2008-08-15 GET_MEMPOLICY(2)

    
    
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