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nsg_init(3)
NAME
  nsg_init - Look up or create a NUMA Scheduling Group (libnuma library)

SYNOPSIS
  #include <numa.h>

  nsgid_t nsg_init(
	  key_t key,
	  ulong_t flags );

PARAMETERS
  key Specifies the key that identifies the NUMA Scheduling Group (NSG). This
      value may be one of the following:

	·  An arbitrary binary value other than zero

	·  If the NSG_GETBYPID flag is set, the process ID of a member
	   process of the requested NSG

  flags
      Specifies lookup or creation flags. The following options are defined
      for the flags argument:

      NSG_CREATE
	      Creates the NSG and return its identifier.  If NSG_CREATE and
	      NSG_EXCL are both specified, an error will be returned if the
	      NSG identified by key already exists.

      NSG_GETBYPID
	      If set, then the key parameter is the process ID (pid_t) of a
	      process that is currently a member of the requested NSG.
	      Otherwise, key is an arbitrary binary value that identifies the
	      requested NSG.

	      If the NSG identified by key does not already exist, an error
	      will be returned unless the NSG_CREATE flag is specified. If
	      the NSG_GETBYPID flag is set and the process identified by the
	      value of key does not exist, an error is returned.

	      If both the NSG_CREATE and the NSG_GETBYPID flags are set, and
	      the process identified by the value of key exists but is not
	      currently a member of an NSG, a new NSG will be created using
	      the value of key (the process's ID) and the process will be
	      attached to the new NSG. This establishes the "home RAD" of the
	      process as the home RAD for the NSG.

      NSG_NO_INHERIT
	      A child process will not inherit the NSG of the parent and,
	      therefore, can be assigned to any eligible RAD on the system.
	      This flag is valid only if both NSG_CREATE and NSG_GETBYPID are
	      also specified.

      NSG_CLEANUP
	      The NSG will be marked for automatic deletion when the
	      nsg_perm.nattach member of the associated nsgid_ds structure
	      transitions from nonzero to zero.

DESCRIPTION
  The nsg_init() function looks up and possibly creates the NSG identified by
  the key parameter.  The flags parameter supplies options for the lookup or
  create operation.

  After creating a new NSG, the nsg_init() function initializes an associated
  nsgid_ds structure as follows:

    ·  The nsg_perm.cuid and nsg_perm.uid members are set equal to the
       effective user ID of the calling process.

    ·  The nsg_perm.cgid and nsg_perm.gid members are set equal to the
       effective group ID of the calling process.

    ·  The low order nine bits of nsg_perm.mode are set equal to the low
       order nine bits of flags.

    ·  The nsg_perm.nattach member is set to zero (or 1 if NSG_GETBYPID is
       specified in flags).

  The nsg_perm.mode permissions control operations on NSGs as follows:

    ·  Write permission is required to destroy the NSG or to set the owner
       IDs and permissions.

    ·  Read permission is required to query the NSG status or membership
       roster.

    ·  Execute permission is required to attach processes or threads to an
       NSG.

RETURN VALUES
  NSG identifier of the NUMA Scheduling Group
      Success.

  -1  Failure. In this case, errno is set to indicate the error.

ERRORS
  If the nsg_init() function fails, it sets errno to one of the following
  values for the specified condition:

  [EACCES]
      An NSG already exists for the specified key, but the caller does not
      have access based on the NSG's current permissions.

  [EEXIST]
      An NSG already exists for the specified key, but NSG_CREATE and
      NSG_EXCL flags were specified.

  [ENOENT]
      No NSG exists for the specified key, and the NSG_CREATE flag was not
      specified.

  [ENOSPC]
      No space exists for the new NSG specified by NSG_CREATE.

  [ESRCH]
      The NSG_GETBYPID flag was set and the process identified by key was not
      found.

  [EINVAL]
      One or more illegal values for flags was set.

SEE ALSO
  Functions: nsg_attach_pid(3), nsg_attach_thread(3), numa_intro(3)

  Files: numa_types(4)

Index for Section 3

Alphabetical listing for N

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