最好的建设网站,网站上传图片尺寸,高端品牌网站,500强室内设计公司排名flink版本: flink-1.11.2
代码位置: org.apache.flink.runtime.util.EnvironmentInformation#getMaxJvmHeapMemory
如果设置了-Xmx参数#xff0c;就返回这个参数#xff0c;如果没设置就返回机器物理内存的1/4. 这里主要看各个机器内存的获取方法。 /*** The maximum JVM…flink版本: flink-1.11.2
代码位置: org.apache.flink.runtime.util.EnvironmentInformation#getMaxJvmHeapMemory
如果设置了-Xmx参数就返回这个参数如果没设置就返回机器物理内存的1/4. 这里主要看各个机器内存的获取方法。 /*** The maximum JVM heap size, in bytes.** pThis method uses the i-Xmx/i value of the JVM, if set. If not set, it returns (as* a heuristic) 1/4th of the physical memory size.** return The maximum JVM heap size, in bytes.*/public static long getMaxJvmHeapMemory() {final long maxMemory Runtime.getRuntime().maxMemory();if(maxMemory ! Long.MAX_VALUE) {// we have the proper max memoryreturn maxMemory;} else {// max JVM heap size is not set - use the heuristic to use 1/4th of the physical memoryfinal long physicalMemory Hardware.getSizeOfPhysicalMemory();if(physicalMemory ! -1) {// got proper value for physical memoryreturn physicalMemory / 4;} else {throw new RuntimeException(Could not determine the amount of free memory.\n Please set the maximum memory for the JVM, e.g. -Xmx512M for 512 megabytes.);}}}
进入getSizeOfPhysicalMemory()方法里面有获取各种操作系统物理内存的方法:
/** Licensed to the Apache Software Foundation (ASF) under one* or more contributor license agreements. See the NOTICE file* distributed with this work for additional information* regarding copyright ownership. The ASF licenses this file* to you under the Apache License, Version 2.0 (the* License); you may not use this file except in compliance* with the License. You may obtain a copy of the License at** http://www.apache.org/licenses/LICENSE-2.0** Unless required by applicable law or agreed to in writing, software* distributed under the License is distributed on an AS IS BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.* See the License for the specific language governing permissions and* limitations under the License.*/package org.apache.flink.runtime.util;import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.management.ManagementFactory;
import java.lang.management.OperatingSystemMXBean;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.regex.Matcher;
import java.util.regex.Pattern;import org.apache.flink.util.OperatingSystem;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** Convenience class to extract hardware specifics of the computer executing the running JVM.*/
public class Hardware {private static final Logger LOG LoggerFactory.getLogger(Hardware.class);private static final String LINUX_MEMORY_INFO_PATH /proc/meminfo;private static final Pattern LINUX_MEMORY_REGEX Pattern.compile(^MemTotal:\\s*(\\d)\\skB$);// ------------------------------------------------------------------------/*** Gets the number of CPU cores (hardware contexts) that the JVM has access to.* * return The number of CPU cores.*/public static int getNumberCPUCores() {// TODO_MA 注释 获取 Cpu Coresreturn Runtime.getRuntime().availableProcessors();}/*** Returns the size of the physical memory in bytes.* * return the size of the physical memory in bytes or {code -1}, if* the size could not be determined.*/public static long getSizeOfPhysicalMemory() {// first try if the JVM can directly tell us what the system memory is// this works only on Oracle JVMstry {Class? clazz Class.forName(com.sun.management.OperatingSystemMXBean);Method method clazz.getMethod(getTotalPhysicalMemorySize);OperatingSystemMXBean operatingSystemMXBean ManagementFactory.getOperatingSystemMXBean();// someone may install different beans, so we need to check whether the bean// is in fact the sun management beanif (clazz.isInstance(operatingSystemMXBean)) {return (Long) method.invoke(operatingSystemMXBean);}}catch (ClassNotFoundException e) {// this happens on non-Oracle JVMs, do nothing and use the alternative code paths}catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {LOG.warn(Access to physical memory size: com.sun.management.OperatingSystemMXBean incompatibly changed., e);}// we now try the OS specific access pathsswitch (OperatingSystem.getCurrentOperatingSystem()) {case LINUX:return getSizeOfPhysicalMemoryForLinux();case WINDOWS:return getSizeOfPhysicalMemoryForWindows();case MAC_OS:return getSizeOfPhysicalMemoryForMac();case FREE_BSD:return getSizeOfPhysicalMemoryForFreeBSD();case UNKNOWN:LOG.error(Cannot determine size of physical memory for unknown operating system);return -1;default:LOG.error(Unrecognized OS: OperatingSystem.getCurrentOperatingSystem());return -1;}}/*** Returns the size of the physical memory in bytes on a Linux-based* operating system.* * return the size of the physical memory in bytes or {code -1}, if* the size could not be determined*/private static long getSizeOfPhysicalMemoryForLinux() {try (BufferedReader lineReader new BufferedReader(new FileReader(LINUX_MEMORY_INFO_PATH))) {String line;while ((line lineReader.readLine()) ! null) {Matcher matcher LINUX_MEMORY_REGEX.matcher(line);if (matcher.matches()) {String totalMemory matcher.group(1);return Long.parseLong(totalMemory) * 1024L; // Convert from kilobyte to byte}}// expected line did not comeLOG.error(Cannot determine the size of the physical memory for Linux host (using /proc/meminfo). Unexpected format.);return -1;}catch (NumberFormatException e) {LOG.error(Cannot determine the size of the physical memory for Linux host (using /proc/meminfo). Unexpected format.);return -1;}catch (Throwable t) {LOG.error(Cannot determine the size of the physical memory for Linux host (using /proc/meminfo) , t);return -1;}}/*** Returns the size of the physical memory in bytes on a Mac OS-based* operating system* * return the size of the physical memory in bytes or {code -1}, if* the size could not be determined*/private static long getSizeOfPhysicalMemoryForMac() {BufferedReader bi null;try {Process proc Runtime.getRuntime().exec(sysctl hw.memsize);bi new BufferedReader(new InputStreamReader(proc.getInputStream()));String line;while ((line bi.readLine()) ! null) {if (line.startsWith(hw.memsize)) {long memsize Long.parseLong(line.split(:)[1].trim());bi.close();proc.destroy();return memsize;}}} catch (Throwable t) {LOG.error(Cannot determine physical memory of machine for MacOS host, t);return -1;} finally {if (bi ! null) {try {bi.close();} catch (IOException ignored) {}}}return -1;}/*** Returns the size of the physical memory in bytes on FreeBSD.* * return the size of the physical memory in bytes or {code -1}, if* the size could not be determined*/private static long getSizeOfPhysicalMemoryForFreeBSD() {BufferedReader bi null;try {Process proc Runtime.getRuntime().exec(sysctl hw.physmem);bi new BufferedReader(new InputStreamReader(proc.getInputStream()));String line;while ((line bi.readLine()) ! null) {if (line.startsWith(hw.physmem)) {long memsize Long.parseLong(line.split(:)[1].trim());bi.close();proc.destroy();return memsize;}}LOG.error(Cannot determine the size of the physical memory for FreeBSD host (using sysctl hw.physmem).);return -1;}catch (Throwable t) {LOG.error(Cannot determine the size of the physical memory for FreeBSD host (using sysctl hw.physmem), t);return -1;}finally {if (bi ! null) {try {bi.close();} catch (IOException ignored) {}}}}/*** Returns the size of the physical memory in bytes on Windows.* * return the size of the physical memory in bytes or {code -1}, if* the size could not be determined*/private static long getSizeOfPhysicalMemoryForWindows() {BufferedReader bi null;try {Process proc Runtime.getRuntime().exec(wmic memorychip get capacity);bi new BufferedReader(new InputStreamReader(proc.getInputStream()));String line bi.readLine();if (line null) {return -1L;}if (!line.startsWith(Capacity)) {return -1L;}long sizeOfPhyiscalMemory 0L;while ((line bi.readLine()) ! null) {if (line.isEmpty()) {continue;}line line.replaceAll( , );sizeOfPhyiscalMemory Long.parseLong(line);}return sizeOfPhyiscalMemory;}catch (Throwable t) {LOG.error(Cannot determine the size of the physical memory for Windows host (using wmic memorychip), t);return -1L;}finally {if (bi ! null) {try {bi.close();} catch (Throwable ignored) {}}}}// --------------------------------------------------------------------------------------------private Hardware() {}
}另外注意try catch的这种用法: try (BufferedReader lineReader new BufferedReader(new FileReader(LINUX_MEMORY_INFO_PATH))) {String line;while ((line lineReader.readLine()) ! null) {Matcher matcher LINUX_MEMORY_REGEX.matcher(line);if (matcher.matches()) {String totalMemory matcher.group(1);return Long.parseLong(totalMemory) * 1024L; // Convert from kilobyte to byte}}// expected line did not comeLOG.error(Cannot determine the size of the physical memory for Linux host (using /proc/meminfo). Unexpected format.);return -1;}catch (NumberFormatException e) {LOG.error(Cannot determine the size of the physical memory for Linux host (using /proc/meminfo). Unexpected format.);return -1;}
