src/hotspot/os_cpu/linux_x86/gc/z/zNUMA_linux_x86.cpp

/*
 * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include "gc/z/zErrno.hpp"
#include "gc/z/zCPU.hpp"
#include "gc/z/zNUMA.hpp"
#include "runtime/os.hpp"
#include "utilities/debug.hpp"

#include <unistd.h>
#include <sys/syscall.h>

#ifndef MPOL_F_NODE
#define MPOL_F_NODE     (1<<0)  // Return next IL mode instead of node mask
#endif

#ifndef MPOL_F_ADDR
#define MPOL_F_ADDR     (1<<1)  // Look up VMA using address
#endif

static int z_get_mempolicy(uint32_t* mode, const unsigned long *nmask, unsigned long maxnode, uintptr_t addr, int flags) {
  return syscall(__NR_get_mempolicy, mode, nmask, maxnode, addr, flags);
}

void ZNUMA::initialize_platform() {
  _enabled = UseNUMA;
}

uint32_t ZNUMA::count() {
  if (!_enabled) {
    // NUMA support not enabled
    return 1;
  }

  return os::Linux::numa_max_node() + 1;
}

uint32_t ZNUMA::id() {
  if (!_enabled) {
    // NUMA support not enabled
    return 0;
  }

  return os::Linux::get_node_by_cpu(ZCPU::id());
}

uint32_t ZNUMA::memory_id(uintptr_t addr) {
  if (!_enabled) {
    // NUMA support not enabled, assume everything belongs to node zero
    return 0;
  }

  uint32_t id = (uint32_t)-1;

  if (z_get_mempolicy(&id, NULL, 0, addr, MPOL_F_NODE | MPOL_F_ADDR) == -1) {
    ZErrno err;
    fatal("Failed to get NUMA id for memory at " PTR_FORMAT " (%s)", addr, err.to_string());
  }

  assert(id < count(), "Invalid NUMA id");

  return id;
}