source: CIVL/examples/omp/HydroC/hydro_numa.c@ 1aaefd4

/*
  NUMA helper functions
  (C) Romain Dolbeau : CAPS
*/
/*

This software is governed by the CeCILL license under French law and
abiding by the rules of distribution of free software.  You can  use, 
modify and/ or redistribute the software under the terms of the CeCILL
license as circulated by CEA, CNRS and INRIA at the following URL
"http://www.cecill.info". 

As a counterpart to the access to the source code and  rights to copy,
modify and redistribute granted by the license, users are provided only
with a limited warranty  and the software's author,  the holder of the
economic rights,  and the successive licensors  have only  limited
liability. 

In this respect, the user's attention is drawn to the risks associated
with loading,  using,  modifying and/or developing or reproducing the
software by the user in light of its specific status of free software,
that may mean  that it is complicated to manipulate,  and  that  also
therefore means  that it is reserved for developers  and  experienced
professionals having in-depth computer knowledge. Users are therefore
encouraged to load and test the software's suitability as regards their
requirements in conditions enabling the security of their systems and/or 
data to be ensured and,  more generally, to use and operate it in the 
same conditions as regards security. 

The fact that you are presently reading this means that you have had
knowledge of the CeCILL license and that you accept its terms.

*/

#include "hydro_numa.h"
#include <stdlib.h>
#include <stdio.h>
#include <numaif.h>
#include <errno.h>

#define ASSUMED_PAGE_SIZE 4096
void force_move_pages(const void* data_, const size_t n, const size_t selem,
                      const enum numa_distrib_type distrib, const size_t distrib_parameter) {
  const char* data = (const char*)data_;
  const size_t elem_per_page = ASSUMED_PAGE_SIZE/selem;
  const size_t np = n / elem_per_page;
  int status[np];
  int nodes[np];
  const char* pages[np];
  size_t i;
  long res;

#ifndef __MIC__
  const int nmn = numa_num_configured_nodes();

  // fprintf(stderr, "%s:%d elem_per_page = %zd, nmn = %d ; np = %zd\n", __PRETTY_FUNCTION__, __LINE__, elem_per_page, nmn, np);
  
  for (i = 0 ; i < np ; i++) {
    pages[i] = data + i * ASSUMED_PAGE_SIZE;
    switch (distrib) {
    case HYDRO_NUMA_NONE:
      nodes[i] = -1;
      break;
    case HYDRO_NUMA_INTERLEAVED:
      nodes[i] = i % nmn;
      break;
    case HYDRO_NUMA_ONE_BLOCK_PER_NODE: {
      const size_t ppernode = np / nmn;
      size_t nnode = i / ppernode;
      if (nnode > (nmn-1))
        nnode = nmn - 1;
      nodes[i] = nnode;
    } break;
    case HYDRO_NUMA_SIZED_BLOCK_RR: {
      const size_t numb = i / (distrib_parameter/elem_per_page);
      size_t nnode = numb % nmn;
      nodes[i] = nnode;
    } break;
    }
  }
  
  if (HYDRO_NUMA_NONE != distrib) {
    res = move_pages(0, np, (void**)pages, nodes, status, MPOL_MF_MOVE);
  } else {
    res = move_pages(0, np, (void**)pages, NULL , status, MPOL_MF_MOVE);
  }
  
  if (res != 0) {
    fprintf(stderr, "%s:%d: move_pages -> errno = %d\n", __PRETTY_FUNCTION__, __LINE__, errno);
  } else {
    int last_node = status[0];
    const char* last;
    const char* cur = data;
    // fprintf(stderr, "%s:%d: move_pages for %p of %zd elements (%zd bytes)\n", __PRETTY_FUNCTION__, __LINE__, data, n, n * selem);
    // fprintf(stderr, "\t%d: %p ... ", last_node, cur );
    last = cur;
    for (i = 1 ; i < np ; i++) {
      if (status[i] != last_node) {
        cur += ASSUMED_PAGE_SIZE;
        // fprintf(stderr, "%p (%llu)\n", cur, (unsigned long long)cur - (unsigned long long)last);
        last_node = status[i];
        // fprintf(stderr, "\t%d: %p ... ", last_node, cur);
        last = cur;
      } else {
        cur += ASSUMED_PAGE_SIZE;
      }
    }
    // fprintf(stderr, "%p (%llu)\n", cur, (unsigned long long)cur - (unsigned long long)last);
  }
#endif
}