zombie mutation

[Programming] C language Linux system programming-waiting for termination of sub-processes (zombie processes), linux stiff 1. subprocesses awaiting termination (zombie processes ): If a child process ends before the parent process, the kernel sets the child process to a special State. A process in this state is called a zombie process. After the parent process ob

I recently read Steven S's "Unix environment programming". Chapter 8 describes process control, which contains descriptions of zombie processes, but I still don't know much about it. There is an article about the defunct process of UNIX on the InternetArticleThe description of its principles is more detailed and useful, so it is reprinted here. From: http://www2.ccw.com.cn Author: Zhang daoxin Zhao Guoming In UNIX system management, when th

Note: There is a key issue here that is not resolved, how is quota information handled? It's easy to see how many quotas a zombie instance occupies, but how do you release those quotas back?I can only manually calculate the instance, cores, and RAM values after deletion, and then go to reservations and quota_usages table to modify.This method is two short, and easy to make mistakes, but there is no better way, but also look at the passing of the prede

Orphan processThe parent process dies first, and the child process Tuogu to a process#include #include#includeintMainvoid) {pid_t pid; PID=Fork (); if(-1==pid) { return 0; } if(0==pid) {Sleep ( -); } if(PID >0) { ; } return 0;}Zombie ProcessThe child process dies first, the parent process has not yet had time to corpse#include #include#includeintMainvoid) {pid_t pid; PID=Fork (); if(-1==pid) { return 0; } if(0==pid)

In the fork ()/execve () process, assume that the parent process still exists at the end of the Child process, and the parent process fork () has not installed the sigchld signal processing function to call waitpid () when the sub-process ends and the signal is not explicitly ignored, the sub-process becomes a zombie and cannot end normally. In this case, even the root identity kill-9 cannot kill the zombie

.Example Two#!/usr/bin/python3import osimport Time #创建子进程之前声明的变量source = 10try: pid = os.fork () if pid = = 0: #子进程 print (' I am Child process (%s) and my parent is%s. '% (Os.getpid (), Os.getppid ())) #在子进程中source自减1 Source-= 1 time . Sleep (1) else: #父进程 print (' I (%s) just created a child process (%s). '% (Os.getpid (), PID)) print (source) time.sleep (2) except OSError as E: print ("exception", E) ####### results ####### #I (12807)

First to transcribe a description of the zombie process on the Web:Zombie Process: A process uses fork to create a child process, assuming that the child process exits, and the parent process does not call wait or waitpid to get state information for the child process, then the process descriptive descriptor of the child process is still stored in the system.Such a process is called a zombie process. At the

How is the zombie process generated in the title Unix/linux system? What's the harm? How to avoid it?When a process calls the Exit command to end its own life, he is not actually destroyed, but rather leaves behind a data structure called the zombie process (Zombie) (System call exit, whose role is to make the process exit, but only a normal process becomes a

Linux On the server , there are some zombie processes that show how to quickly find and destroy these zombie processesFirst, we can use the top command to see if the server currently has a zombie process, in which you can see the number of zombie process hints, if the number is greater than 0, it means that the server

normal size of the stick need to shorten it, the practice is:1. First create a short stick in the original stick position, but set it to be invisible, because there is also a shorter animation effect;2. Create a stick node without a physical object and perform a shorter animation;3. Delete itself at the end of the animation and make the short stick visible. Note that animation time needs to be moderate, neither too long nor too short. This will be detailed in the iOS Game Development Series blo

The syntax for a function is: Function Definition Method Copy the Code code as follows: Function "Function_name" (Arg1, arg2 ...){[Code to execute]return [Final_result];} where [Final_result] usually returns the value of a variable from a function. Let's look at an example Copy the Code code as follows: function Double_this_number ($input _number){return $input _number*2;} Calling methods Copy the Code code as follows: $x = 10;$y = Double_this_number ($x);Print $y; The output value is 10 Well

bit of a problem, it can be seen how good autoload ah, hehe ... But I have to remind you that there are several aspects that must be noted. 1. If the class has an inheritance relationship (for example: ClassB extends ClassA), and ClassA is not in the directory where ClassB is located Using the __autoload magic function to instantiate a CLASSB can be a fatal error: Fatal error:class ' CLASSD ' not found in ... Classb.php on line 2, Workaround: Place all classes that have extends relationships in

The core server ran a bunch of scripts, procedures, it is inevitable that sometimes zombie process, dead or alive in the occupied resources there, initially just wrote a keyword to kill the process of the Linux shell script, and later found that many times when the process died there is actually the internal call to the child process when there is a problem , the process of killing the father does not solve the fundamental problem. For example, when r

For multi-process concurrent programming with PHP, it is unavoidable to encounter the problem of zombie process.The zombie process refers to the parent process that has exited,And the process dead after the process is not accepted,It becomes the zombie process (zombie) process. Any process that exits before exiting (us

Reprint: http://blog.csdn.net/shanzhizi/article/details/47320595On linux servers, there are some zombie processes , and here's how to quickly find and destroy these zombie processesFirst, we can use the top command to see if the server currently has a zombie process, in which you can see the number of zombie process hi

For multi-process concurrent programming with PHP, it is unavoidable to encounter the problem of zombie process.A zombie process is a zombie process (zombie) process in which a parent process has exited, and the process dead after it has not been accepted by the process. Any process that exits before exiting (using exi

is the internal value of the PS application, not just the pseudo value for some output formats. The Sort keys list is shown in table 4-3. Sort Key List C Cmd Executable Simple Name C CmdLine Full command line F Flags Long mode flag G Pgrp Process Group ID G Tpgid Controlling the TTY process group ID J Cutime Cumulative User Time J Cstime Cumulative system time K Utime User Time K Stime System time M Min_flt Secondary page fault Find

.*/ Result: Current process ID: 1995A = 8PID = 1, 1996Ppid = 1995AA = 9Child pid = 1996Parent pid = 1995 Generation of zombie processes: /*========================================================== ==========================================Name: jianshiprocess. cAuthor:Version:Copyright: Your copyright noticeDescription: Hello world in C, ANSI-style========================================================== ==========================================*

In the Wikipedia explanation:In the operating system realm, the orphan process refers to a class of processes that continue to run after the parent process finishes or is terminated.In a Unix-like system, a zombie process is the completion of execution (via the exit system call, or a fatal error at run time or a termination signal), but there is still one table entry in the operating system's process table ( process control block PCB), The process of

TCP/IP network programming (transcription note 3) – Zombie process and multitasking concurrent server table of Contents The production of zombie processes Avoid zombie processes Signal Multi-tasking Concurrent server The production of zombie processes Child process exits first, parent