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linux allocate physical memory page 1, Physical memory allocation overview In the linux kernel, the page allocator can allocate one or more consecutive physical pages. The number of allocated pages can only be an integer power of 2; Allocating continuous physical pages is more beneficial to alleviate the memory fragmentation of the system ...

preface Virtual file system is a huge architecture. If you want to analyze everything, it will be particularly complex and clumsy. If you look at it, you won't know what to say (of course, it's mainly the author's food). Therefore, this blog tries to analyze the operation mechanism of VFS file system with the open() function as the startin ...

Hadoop environment configuration (Linux virtual machine) This semester, I chose the course of big data management and analysis, which mainly uses Hadoop framework for data analysis and application development. First, I will configure the environment be careful It's better to put JDK and Hadoop under / usr/local When adding environment ...

Text 3: swordsman and find wildcard Match file name *: Match 0 or more characters ?: Match any character [list]: matching list Any single character in [c1-c2]: matching c1-c2 Any single character in [^c1-c2]/[!c1-c2]: Mismatch c1-c2 Any character in {string1,string2,...}: matching{}Any single string in find file lookup Complete the file s ...

The virtual machine only installs ssh and can only connect to other servers. After installing openssh server, you can use ssh to connect to other terminalsRemote file transferCopy from local to remotescp local_file remote_username@remote_ip:remote_folder perhaps scp local_file remote_username@remote_ip:remote_file perhaps scp local_file rem ...

1. Database yum -y install mysql mysql-server mysql-devel MySQL (client), MySQL-server (server), mysql-devel (library) Start MySQL:service mysql start Confirm installation success: mysql-u root-p View the database: show databases; Use the database: use mysql; Query from the user table for all users that can log in and the host that suppo ...

1. Preface This article is the second part of the introduction of UBOOT command, and then the last article introduces the usage of the remaining commands. The main commands involved are: disk partition, disk file loading, kernel boot, binary file loading, jump command, disk file system format, etc. 2. UBOOT command 2.1 fatls – lists ...

1. Signal Signals are software interrupts that provide a way to handle asynchronous events The simplest interface of unix signaling mechanism is the signal function /* * sign Signal integer * func Function pointer * return : Function pointer (a function address, function has an integer parameter, no return value) */ void (* signal(int ...

Reprint and: Linux system directory structure | rookie tutorial The file directory structure is a tree structure starting from '/'! FHS (File System Hierarchy Standard); 1, Four interactive forms of directory Shareable, which can be shared to the directory used by other systems;unshared, device files running on your own mac ...

KVM mirror operation QEMU img command Create mirror qemu-img create # Create an image with a device space of 10G qemu-img create -f qcow2 centos7-guest.qcow2 10G # Based on backing_file creates an image with a size of 20G. Use the - b parameter and - F to specify backing_file format qemu-img create -F qcow2 -b /path/to/backing-kvm.img -f qco ...