smiklosovic commented on code in PR #2842: URL: https://github.com/apache/cassandra/pull/2842#discussion_r1373893156
########## src/java/org/apache/cassandra/utils/SystemInfo.java: ########## @@ -0,0 +1,214 @@ +/* + * 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.cassandra.utils; + +import java.io.IOException; +import java.nio.file.FileSystems; +import java.nio.file.Files; +import java.nio.file.Path; +import java.util.List; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.config.CassandraRelevantProperties; +import oshi.PlatformEnum; + +/** + * An abstraction of System information, this class provides access to system information without specifying how + * it is retrieved. + */ +public class SystemInfo +{ + + private static long INFINITY = -1l; + private static long EXPECTED_MIN_NOFILE = 10000l; // number of files that can be opened + private static long EXPECTED_NPROC = 32768l; // number of processes + private static long EXPECTED_AS = 0x7FFFFFFFl; // address space + /** + * The default number of processes that are reported if the actual value can not be retrieved. + */ + public static long DEFAULT_MAX_PROCESSES = 1024; + + private Logger logger = LoggerFactory.getLogger(SystemInfo.class); + + /* The oshi.SystemInfo has the following note: + * Platform-specific Hardware and Software objects are retrieved via memoized suppliers. To conserve memory at the + * cost of additional processing time, create a new version of SystemInfo() for subsequent calls. To conserve + * processing time at the cost of additional memory usage, re-use the same {@link SystemInfo} object for future + * queries. + * + * We are opting for minimal memory footprint. */ + private oshi.SystemInfo si ; + + public SystemInfo() { + si = new oshi.SystemInfo(); + } + + /** + * + * @return The name of the current platform. (e.g. Linux) + */ + public String platform() + { + return oshi.SystemInfo.getCurrentPlatform().name(); + } + + /** + * Gets the maximum number of processes the user can create. + * Note: if not on a Linux system this always return the + * @{code DEFAULT_MAX_PROCESSES} value. + * @return The maximum number of processes. + * @see #DEFAULT_MAX_PROCESSES + */ + long getMaxProcess() { + // this check only works on Linux systems. + if (oshi.SystemInfo.getCurrentPlatform() == PlatformEnum.LINUX) { + Path p = FileSystems.getDefault().getPath("/proc", Long.toString(getPid()), "limits"); + try + { + List<String> lines = Files.readAllLines(p); + for (String s : lines) + { + if (s.startsWith("Max processes")) + { + String[] parts = s.split("\s+"); + String limit = parts[2]; + if ("unlimited".equals(limit)) + { + return INFINITY; + } + return Long.parseLong(limit); + } + } + logger.error("'Max processes' not found in " + p); + } + catch (IOException e) + { + logger.error("Unable to read "+p, e); + } + } + /* return the default value for non-Linux systems. + * can not return 0 as we know there is at least 1 process (this one) and + * -1 historically represents infinity. + */ + return DEFAULT_MAX_PROCESSES; + } + + /** + * + * @return The maximum number of open files allowd to the current process/user. + */ + long getMaxOpenFiles() { + // ulimit -H -n + return si.getOperatingSystem().getCurrentProcess().getHardOpenFileLimit(); + } + + /** + * Gets the Virtual Memory Size (VSZ). Includes all memory that the process can access, including memory that is swapped out and memory that is from shared libraries. + * @return The amount of virtual memory allowed to be allocatedby the current process/user. + */ + long getVirtualMemoryMax() { + return si.getOperatingSystem().getCurrentProcess().getVirtualSize(); + } + + /** + * + * @return The amount of swap space allocated on the system. + */ + long getSwapSize() { + return si.getHardware().getMemory().getVirtualMemory().getSwapTotal(); + } + + /** + * @return the PID of the current system. + */ + public long getPid() { + return si.getOperatingSystem().getProcessId(); + } + + /** + * Checks if a value if valide (i.e. value >= min or value == INFINITY.. + * @param value the value to check. + * @param min the minimum value. + * @return true if value is valid. + */ + private boolean valid(long value, long min) + { + return value >= min || value == INFINITY; + } + + /** + * Tests if the system is running in degraded mode. + * If the system is running in degraded mode this method will log information. + * @return @{code true} if the system is in degraded mode, @{code false} otherwise. + */ + public boolean warnIfRunningInDegradedMode() + { + boolean degraded = false; + StringBuilder sb = new StringBuilder(); + + if (oshi.SystemInfo.getCurrentPlatform() == PlatformEnum.LINUX) Review Comment: I find this logic complicated. Ifs, elses ... degraded set to true etc ... We can do better. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
