memalloc_attr(3)					     Library Functions Manual						  memalloc_attr(3)

NAME

       memalloc_attr - Query the memory allocation policy and attributes (libnuma library)

SYNOPSIS

       #include <numa.h>

       int memalloc_attr(
	       vm_offset_t va, memalloc_attr_t *attr );

PARAMETERS

       The  user  virtual address for which the memory allocation policy is requested.	Points to a buffer to receive the memory allocation policy
       and attributes for the page containing the specified virtual address.

DESCRIPTION

       The memalloc_attr() function returns the current memory allocation policy and associated attributes in the buffer pointed to  by  attr  for
       the address specified by va.

       If  radset  information	about the memory allocation policy is desired, a radset must be allocated through the radsetcreate() function, and
       the mattr_radset element of the attr argument must point to that radset. Otherwise, a 0 must be specified for the mattr_radset.

EXAMPLE

       #include <numa.h> main() {
	   vm_offset_t va;
	   memalloc_attr_t attr;
	   int id;
	   int flags = SET_CURSOR_CONSUME;
	   rad_cursor_t cursor = SET_CURSOR_INIT;
	   radsetcreate(&attr.mattr_radset);
	   va = (vm_offset_t)&attr;

	   /* no policy in effect - return zeroes */
	   if (memalloc_attr(va, &attr) == -1) {
	       perror("memalloc_attr");
	       radsetdestroy(&attr.mattr_radset); return 0;
	   }
	   printf("mattr_policy = 0x%lx
", attr.mattr_policy);
	   printf("mattr_rad = 0x%lx
", attr.mattr_rad);
	   printf("mattr_stride = 0x%lx
", attr.mattr_stride);
	   printf("mattr_distance = 0x%lx
", attr.mattr_distance);
	   printf("mattr_pagesz = 0x%lx

", attr.mattr_pagesz);

	   /* set policy */
	   attr.mattr_policy = MPOL_DIRECTED;
	   attr.mattr_rad = 0;
	   if (nmadvise((void *)va, sizeof(memalloc_attr_t), 0, &attr) == -1)  {
	       perror("nmadvise");
	       radsetdestroy(&attr.mattr_radset); return 0;
	   }

	   if (memalloc_attr(va, &attr) == -1) {
	       perror("memalloc_attr");
	       radsetdestroy(&attr.mattr_radset);
	       return 0;
	   }
	   printf("mattr_policy = 0x%lx
", attr.mattr_policy);
	   printf("mattr_rad = 0x%lx
", attr.mattr_rad);
	   printf("mattr_stride = 0x%lx
", attr.mattr_stride);
	   printf("mattr_distance = 0x%lx
", attr.mattr_distance);
	   printf("mattr_pagesz = 0x%lx
", attr.mattr_pagesz);

	   /* enumerate the mattr_radset */
	   printf("
Enumerating radset members:
");
	   while ((id = rad_foreach(attr.mattr_radset, flags, &cursor)) != RAD_NONE) {
	       if ((id % 8) == 0)
		   printf("
");
	   printf("%3d, ", id);
	   }
	   printf("
"); }

RETURN VALUES

       Success. In this case, the function stores the requested memory allocation policy and attributes in the buffer pointed to by  attr.  If	no
       memory  allocation  policy  has	been set for the specified virtual address (e.g., madvise() or nmadvise()) not called for that address), a
       zeroed attr structure is returned.  Failure. In this case, the function sets errno to indicate the error.

ERRORS

       If the memalloc_attr() function fails, it sets errno to one of the following values: The address pointed to by va, attr, or mattr_radset is
       invalid.   The  mattr_radset  element  of  the attr argument points to an invalid RAD set, possibly one that has not been created by a rad-
       setcreate() call.

SEE ALSO

       Functions: numa_intro(3)

       Files: numa_types(4)

																  memalloc_attr(3)