In computer science, Memory Leakage occurs when a computer software or program consumes required memory but unable to memory after completing its task or when no longer needed to Operating System. There are two types of Memory Leakage. One is Virtual…

FROM: http://cqfish.blog.51cto.com/622299/197230 linux 清除系统cached top查看系统内存使用情况   Mem:    16432180k total, 13737848k used,    2694332k free,     945396k buffers   freem -m [root@mysql ~]# free -m            total      used        free     shared     …

在linux下使用free命令查看内存使用情况,有buffers和cached两项,以下是它们的区别: buffers是为块设备设计的缓冲.比如磁盘读写,把分散的写操作集中进行,减少磁盘I/O,从而提高系统性能.比如入U盘里cp一个文件,但是U盘读写指示灯未闪动,过了一会儿才闪动.卸载时会清空缓冲,所以有时卸载一个设备需要等待几秒. cached是缓存读取过的内容,下次再读时,如果在缓存中命中,则直接从缓存读取,否则读取磁盘.由于缓存空间有限,过一段时间以后没用的缓存会被移动到swap里面,所以…

0.编译环境 Linux: CentOS 5.5 gcc: 4.1.2 1. 安装PostgreSQL 1) 解压postgresql-9.1.7.tar.bz2 #tar jxvf postgresql-9.1.7.tar.bz2 2) 进入解压后的postgresql-9.1.7目录 #cd postgresql-9.1.7 3) 编译postgresql源码 #./configure --prefix=/opt/pgsql-9.1.7 #make #make install 至此,完成po…

A method includes storing, with a first programmable processor, shared variable data to cache lines of a first cache of the first processor. The method further includes executing, with the first programmable processor, a store-with-release operation,…

Page Cache This is used to speed up access to images and data on disk. As pages are read into memory from disk they are cached in the page cache. If they were discarded and then needed again they can quickly be fetched from this cache. 页缓存,为了加速从硬盘当中读…

Linux provides two virtual devices for this purpose, '/dev/mem' and '/dev/kmem', though many distributions disable them by default for security reasons. '/dev/mem' is linked to the physical system memory, whereas '/dev/kmem' maps to the entire virtua…

Blue : User Space 128TBRed : Kernel Space 512MBThe rest of the address space goes to various parts of the system, along with a few unusable holes. ----------- <previous description obsolete, deleted> Virtual memory map with 4 level page tables: 0000…

目录 . Linux通信机制分类简介 . 控制机制 0x1: 竞态条件 0x2: 临界区 . Inter-Process Communication (IPC) mechanisms: 进程间通信机制 0x1: 信号(Signals) 0x2: 管道(Pipes) 0x3: 套接字(Sockets) 0x4: System V通信机制(System V IPC Mechanisms) . 多线程并行中的阻塞和同步 0x1: CPU指令集提供的原子操作(Atomic) 0x2: 操作系统提供的原子…

## Linux kernel memory-faq.txt What is some existing documentation on Linux memory management? Ulrich Drepper (the ex-glibc maintainer) wrote an article series called "What every programmer should know about memory": Part 1: http://lwn.net/Artic…