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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
  va  The user virtual address for which the memory allocation policy is
      requested.

  attr
      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\n", attr.mattr_policy);
	   printf("mattr_rad = 0x%lx\n", attr.mattr_rad);
	   printf("mattr_stride = 0x%lx\n", attr.mattr_stride);
	   printf("mattr_distance = 0x%lx\n", attr.mattr_distance);
	   printf("mattr_pagesz = 0x%lx\n\n", 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\n", attr.mattr_policy);
	   printf("mattr_rad = 0x%lx\n", attr.mattr_rad);
	   printf("mattr_stride = 0x%lx\n", attr.mattr_stride);
	   printf("mattr_distance = 0x%lx\n", attr.mattr_distance);
	   printf("mattr_pagesz = 0x%lx\n", attr.mattr_pagesz);

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

RETURN VALUES
  0   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.

  -1  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:

  [EFAULT]
      The address pointed to by va, attr, or mattr_radset is invalid.

  [EINVAL]
      The mattr_radset element of the attr argument points to an invalid RAD
      set, possibly one that has not been created by a radsetcreate() call.

SEE ALSO
  Functions: numa_intro(3)

  Files: numa_types(4)

Index for Section 3

Alphabetical listing for M

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