1 /*
   2  * Copyright (c) 2020, Red Hat Inc.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.internal.platform;
  27 
  28 import java.io.IOException;
  29 import java.lang.System.Logger;
  30 import java.lang.System.Logger.Level;
  31 import java.nio.file.Paths;
  32 import java.util.HashMap;
  33 import java.util.List;
  34 import java.util.Map;
  35 
  36 import jdk.internal.platform.cgroupv1.CgroupV1Subsystem;
  37 import jdk.internal.platform.cgroupv2.CgroupV2Subsystem;
  38 
  39 class CgroupSubsystemFactory {
  40 
  41     private static final String CPU_CTRL = "cpu";
  42     private static final String CPUACCT_CTRL = "cpuacct";
  43     private static final String CPUSET_CTRL = "cpuset";
  44     private static final String BLKIO_CTRL = "blkio";
  45     private static final String MEMORY_CTRL = "memory";
  46 
  47     static CgroupMetrics create() {
  48         Map<String, CgroupInfo> infos = new HashMap<>();
  49         try {
  50             List<String> lines = CgroupUtil.readAllLinesPrivileged(Paths.get("/proc/cgroups"));
  51             for (String line : lines) {
  52                 if (line.startsWith("#")) {
  53                     continue;
  54                 }
  55                 CgroupInfo info = CgroupInfo.fromCgroupsLine(line);
  56                 switch (info.getName()) {
  57                 case CPU_CTRL:      infos.put(CPU_CTRL, info); break;
  58                 case CPUACCT_CTRL:  infos.put(CPUACCT_CTRL, info); break;
  59                 case CPUSET_CTRL:   infos.put(CPUSET_CTRL, info); break;
  60                 case MEMORY_CTRL:   infos.put(MEMORY_CTRL, info); break;
  61                 case BLKIO_CTRL:    infos.put(BLKIO_CTRL, info); break;
  62                 }
  63             }
  64         } catch (IOException e) {
  65             return null;
  66         }
  67 
  68         // For cgroups v1 all controllers need to have non-zero hierarchy id
  69         boolean isCgroupsV2 = true;
  70         boolean anyControllersEnabled = false;
  71         boolean anyCgroupsV2Controller = false;
  72         boolean anyCgroupsV1Controller = false;
  73         for (CgroupInfo info: infos.values()) {
  74             anyCgroupsV1Controller = anyCgroupsV1Controller || info.getHierarchyId() != 0;
  75             anyCgroupsV2Controller = anyCgroupsV2Controller || info.getHierarchyId() == 0;
  76             isCgroupsV2 = isCgroupsV2 && info.getHierarchyId() == 0;
  77             anyControllersEnabled = anyControllersEnabled || info.isEnabled();
  78         }
  79 
  80         // If no controller is enabled, return no metrics.
  81         if (!anyControllersEnabled) {
  82             return null;
  83         }
  84         // Warn about mixed cgroups v1 and cgroups v2 controllers. The code is
  85         // not ready to deal with that on a per-controller basis. Return no metrics
  86         // in that case
  87         if (anyCgroupsV1Controller && anyCgroupsV2Controller) {
  88             Logger logger = System.getLogger("jdk.internal.platform");
  89             logger.log(Level.DEBUG, "Mixed cgroupv1 and cgroupv2 not supported. Metrics disabled.");
  90             return null;
  91         }
  92 
  93         if (isCgroupsV2) {
  94             CgroupSubsystem subsystem = CgroupV2Subsystem.getInstance();
  95             return subsystem != null ? new CgroupMetrics(subsystem) : null;
  96         } else {
  97             CgroupV1Subsystem subsystem = CgroupV1Subsystem.getInstance();
  98             return subsystem != null ? new CgroupV1MetricsImpl(subsystem) : null;
  99         }
 100     }
 101 }