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package com.sun.management.internal;

import jdk.internal.platform.Metrics;
import sun.management.BaseOperatingSystemImpl;
import sun.management.VMManagement;

import java.util.concurrent.TimeUnit;
Implementation class for the operating system. Standard and committed hotspot-specific metrics if any. ManagementFactory.getOperatingSystemMXBean() returns an instance of this class.
/** * Implementation class for the operating system. * Standard and committed hotspot-specific metrics if any. * * ManagementFactory.getOperatingSystemMXBean() returns an instance * of this class. */
class OperatingSystemImpl extends BaseOperatingSystemImpl implements com.sun.management.UnixOperatingSystemMXBean { private static final int MAX_ATTEMPTS_NUMBER = 10; private final Metrics containerMetrics; OperatingSystemImpl(VMManagement vm) { super(vm); this.containerMetrics = jdk.internal.platform.Container.metrics(); } public long getCommittedVirtualMemorySize() { return getCommittedVirtualMemorySize0(); } public long getTotalSwapSpaceSize() { if (containerMetrics != null) { long limit = containerMetrics.getMemoryAndSwapLimit(); // The memory limit metrics is not available if JVM runs on Linux host (not in a docker container) // or if a docker container was started without specifying a memory limit (without '--memory=' // Docker option). In latter case there is no limit on how much memory the container can use and // it can use as much memory as the host's OS allows. long memLimit = containerMetrics.getMemoryLimit(); if (limit >= 0 && memLimit >= 0) { // we see a limit == 0 on some machines where "kernel does not support swap limit capabilities" return (limit < memLimit) ? 0 : limit - memLimit; } } return getTotalSwapSpaceSize0(); } public long getFreeSwapSpaceSize() { if (containerMetrics != null) { long memSwapLimit = containerMetrics.getMemoryAndSwapLimit(); long memLimit = containerMetrics.getMemoryLimit(); if (memSwapLimit >= 0 && memLimit >= 0) { long deltaLimit = memSwapLimit - memLimit; // Return 0 when memSwapLimit == memLimit, which means no swap space is allowed. // And the same for memSwapLimit < memLimit. if (deltaLimit <= 0) { return 0; } for (int attempt = 0; attempt < MAX_ATTEMPTS_NUMBER; attempt++) { long memSwapUsage = containerMetrics.getMemoryAndSwapUsage(); long memUsage = containerMetrics.getMemoryUsage(); if (memSwapUsage > 0 && memUsage > 0) { // We read "memory usage" and "memory and swap usage" not atomically, // and it's possible to get the negative value when subtracting these two. // If this happens just retry the loop for a few iterations. long deltaUsage = memSwapUsage - memUsage; if (deltaUsage >= 0) { long freeSwap = deltaLimit - deltaUsage; if (freeSwap >= 0) { return freeSwap; } } } } } } return getFreeSwapSpaceSize0(); } public long getProcessCpuTime() { return getProcessCpuTime0(); } public long getFreeMemorySize() { if (containerMetrics != null) { long usage = containerMetrics.getMemoryUsage(); long limit = containerMetrics.getMemoryLimit(); if (usage > 0 && limit >= 0) { return limit - usage; } } return getFreeMemorySize0(); } public long getTotalMemorySize() { if (containerMetrics != null) { long limit = containerMetrics.getMemoryLimit(); if (limit >= 0) { return limit; } } return getTotalMemorySize0(); } public long getOpenFileDescriptorCount() { return getOpenFileDescriptorCount0(); } public long getMaxFileDescriptorCount() { return getMaxFileDescriptorCount0(); } public double getCpuLoad() { if (containerMetrics != null) { long quota = containerMetrics.getCpuQuota(); if (quota > 0) { long periodLength = containerMetrics.getCpuPeriod(); long numPeriods = containerMetrics.getCpuNumPeriods(); long usageNanos = containerMetrics.getCpuUsage(); if (periodLength > 0 && numPeriods > 0 && usageNanos > 0) { long elapsedNanos = TimeUnit.MICROSECONDS.toNanos(periodLength * numPeriods); double systemLoad = (double) usageNanos / elapsedNanos; // Ensure the return value is in the range 0.0 -> 1.0 systemLoad = Math.max(0.0, systemLoad); systemLoad = Math.min(1.0, systemLoad); return systemLoad; } return -1; } else { // If CPU quotas are not active then find the average system load for // all online CPUs that are allowed to run this container. // If the cpuset is the same as the host's one there is no need to iterate over each CPU if (isCpuSetSameAsHostCpuSet()) { return getCpuLoad0(); } else { int[] cpuSet = containerMetrics.getEffectiveCpuSetCpus(); if (cpuSet != null && cpuSet.length > 0) { double systemLoad = 0.0; for (int cpu : cpuSet) { double cpuLoad = getSingleCpuLoad0(cpu); if (cpuLoad < 0) { return -1; } systemLoad += cpuLoad; } return systemLoad / cpuSet.length; } return -1; } } } return getCpuLoad0(); } public double getProcessCpuLoad() { return getProcessCpuLoad0(); } private boolean isCpuSetSameAsHostCpuSet() { if (containerMetrics != null && containerMetrics.getCpuSetCpus() != null) { return containerMetrics.getCpuSetCpus().length == getHostConfiguredCpuCount0(); } return false; } /* native methods */ private native long getCommittedVirtualMemorySize0(); private native long getFreeMemorySize0(); private native long getFreeSwapSpaceSize0(); private native long getMaxFileDescriptorCount0(); private native long getOpenFileDescriptorCount0(); private native long getProcessCpuTime0(); private native double getProcessCpuLoad0(); private native double getCpuLoad0(); private native long getTotalMemorySize0(); private native long getTotalSwapSpaceSize0(); private native double getSingleCpuLoad0(int cpuNum); private native int getHostConfiguredCpuCount0(); static { initialize0(); } private static native void initialize0(); }