Persistence

摘要： The thundering herd problem occurs when a large number of processes waiting for an event are woken whenthat event occurs, but only one process can pro... 阅读全文

摘要： One final hardware primitive is the fetch-and-add instruction, which atomically increments a value while returningthe old value at a partucular addres... 阅读全文

摘要： Tasklets are the preferred way to implement deferrable functions in I/O drivers. As already explained,tasklets are built on top of two softirqs named ... 阅读全文

摘要： In recent kernel versions, each CPU has its own ksoftirqd/n kernel thread (where n is thelogical number of CPU). Each ksoftirqd/n kernel thread runs t... 阅读全文

摘要： We mentioned earlier in the section "Interrupt Handling" that several tasks among those executedby the kernel are not critical: they can be deferred f... 阅读全文

摘要： Every interrupt or exception gives rise to a kernel control path or separate sequence of instructions thatexecute in Kernel Mode on behalf of the curr... 阅读全文

摘要： A system table called Interrupt Descriptor Table (IDT) associates each interrupt or exception vector withthe address of the corresponding interrupt or... 阅读全文

摘要： 中外圣哲都教导我们：“己所不欲，勿施于人。” 这是要我们将心比心，不把自己视为恶、痛苦、灾祸的东西强加于人。己所不欲却施与人，损人利己，把自己的快乐建立在别人的痛苦之上，这种行径当然是对别人的严重侵犯。然而，这只是事情的一个方面。另一方面，自己视为善、快乐、幸福的东西，难道就可以强加于人了吗？要是别... 阅读全文

摘要： 如果我是一个从前的哲人，来到今天的世界，我会最怀念什么？一定是这六个字：善良、丰富、高贵。看到医院拒收付不起医疗费的穷人，听凭危急病人死去，看到商人出售加药和伪劣食品，制造急性和慢性死亡，看到矿难频繁，矿主用工人的生命换取高额利润，看到每天发生的许多凶杀案，往往为了很少的一点钱或一个很小的缘由夺走一... 阅读全文

摘要： 人活世上，除吃睡之外，不外乎做事情和与人交往，它们构成了生活的主要内容。做事情，包括为谋生需要而做的，即所谓本职业务，也包括出于兴趣、爱好、志向、野心、使命感等等而做的，即所谓事业。与人交往，包括同事、邻里、朋友关系以及一般所谓的公共关系，也包括由性和血缘所联接的爱情、婚姻、家庭等关系。这两者都是人... 阅读全文

摘要： Some platforms provide a pair of instructions that work in concert to help build critical sections.On the MIPS architecture, for example, the load-lin... 阅读全文

摘要： Each hardware device controller capable of issuing interrupt requests usually has a singleoutput line designed as the Interrupt ReQuest (IRQ) line. Al... 阅读全文

摘要： The Intel documentation classifies interrupts and exceptions as follows:1. Interrupts:Maskable interrupts: All Interrupt ReQuests (IRQs) issued by I/O... 阅读全文

摘要： Given our basic spin lock, we can now evaluate how effective it is along our previously describedaxes. The most important aspect of a lock is correctn... 阅读全文

摘要： An interrupt is usually defined as an event that alters the sequence of instructions executed by aprocessor. Such events correspond to electrical sign... 阅读全文