2011 年 6月随笔档案 - Teddy Yan

Linux Kernel Development (8)

摘要：The Block I/O Layer The smallest addressable unit on a block device is a sector. Sectors come in various powers of two, but 512 bytes is the most common size. although many block devices can operate on multiple sectors at one time. Software has different goals and therefore imposes its own smalles.. 阅读全文

posted @ 2011-06-16 17:23 Teddy Yan 阅读(195) 评论(0) 推荐(0) |

Linux Kernel Development (9)

摘要：The Memory Descriptor Processes may elect to share their address spaces with their children by means of the CLONE_VM flag to clone().The process is then called a thread. Recall from Chapter 3, “Process Management,” that this is essentially the only difference between normal processes and so-called . 阅读全文

posted @ 2011-06-16 17:23 Teddy Yan 阅读(168) 评论(0) 推荐(0) |

Linux Kernel Development (10)

摘要：The Page Cache and Page Writeback In this manner, the page cache contains chunks of recently accessed files. During a page I/O operation, such as read(),2 the kernel checks whether the data resides in the page cache. If the data is in the page cache, the kernel can quickly return the requested p... 阅读全文

posted @ 2011-06-16 17:23 Teddy Yan 阅读(155) 评论(0) 推荐(0) |

Linux Kernel Development (7)

摘要：The Virtual Filesystem The Unix concept of the file is in stark contrast to record-oriented filesystems, such as OpenVMS’s Files-11. Record-oriented filesystems provide a richer, more structured representation of files than Unix’s simple byte-stream abstraction, at the cost of simplicity and flexib. 阅读全文

posted @ 2011-06-16 17:22 Teddy Yan 阅读(137) 评论(0) 推荐(0) |

Linux Kernel development (5)

摘要：An Introduction to Kernel Synchronization A common use of the atomic integer operations is to implement counters. Protecting a sole counter with a complex locking scheme is overkill, so instead developers use atomic_inc() and atomic_dec(), which are much lighter in weight. The fact that a contende.. 阅读全文

posted @ 2011-06-16 17:21 Teddy Yan 阅读(143) 评论(0) 推荐(0) |

Linux Kernel Development (6)

摘要：Timers and Time Management The frequency of the system timer (the tick rate) is programmed on system boot based on a static preprocessor define, HZ The kernel defines the value in . The final agreement is that, at least on modern systems, HZ=1000 does not create unacceptable overhead and the move... 阅读全文

posted @ 2011-06-16 17:21 Teddy Yan 阅读(155) 评论(0) 推荐(0) |

Teddy Yan