Linux Kernel API (2.6)
#protect share data
spin_lock/spin_unlock: protect the data during process context(and only at process context), and make sure your code bewteen lock/unlock is fast enough.There may deadlock if the same spin_lock is called at interrupt context.
spin_lock_irq/spin_unlock_irq: call it during interrupt context, make sure the irq is on before calling this function, it will disable irq before accessing share data
spin_lock_irqsave/irqrestore: use at interrupt context, and will save/restort irq registers
The code between spin_lock**/spin_unlock** must not sleep.
The spin_lock** API is defined at include/linux/spinlock_api_up.h for UP architecture.
linux/kernel/spinlock.c is only for SMP.
mutex_lock/mutex_unlock: the similar with down/up, but more efficient
mutex_lock_interruptible: the simlilar with down_interruptiable, can be interruptiable by signal.(like CTRL-C)
the code beween mutex_lock and mutex_unlock can go to sleep
相关文档：
假如上传代码到SVN上，最简单的一种方法就是：进入代码目录，然后$svn import -m "New import" myqwcode http://192.168.0.222/svn/myqwcode就可以了，不需要建立新目录！
1、将文件checkout到本地目录
svn checkout path（path是服务器上的目录）
例如：svn checkout svn://192.168.1.1/pro/domain
......
Linux文件名的长度限制是255个字符
windows下完全限定文件名必须少于260个字符，目录名必须小于248个字符。
linux下文件数、目录数、文件名长度的各种限制
以下测试都是在没有优化或修改内核的前提下测试的结果
1. 测试目的：ext3文件系统下filename最大字符长度
测试平台：RHEL5U3_x64
测试过程：
L ......
首先我的操作系统是Debian Linux，我Debian用的是Xfce桌面环境，昨天我用了命令apt-get install gnome,安装了一堆软件之后重启，就进入不了图形界面了，只能进入字符界面，今天可好折腾了。
上午在网上查资料，可能总结了几个吧
1、在字符界面输入命令startx
2、修改init的默认级，所在文件的位置/etc/initt ......
I learned some experience while Nanjing found 0x03 error. At begining, we don't know why our GSRM(a linux process) hang in a short time 5 seconds sometimes. It didn't handle any message at that time and the interruption is not regularly. So we assume we have Linux OS problem. We did following checks ......
