随笔分类 -  Linux Kernel

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：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：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

摘要：A process switch may occur at just one one well-defined point: the schedule() function, which is discussedat length in Chapter 7. Here, we are only co... 阅读全文

摘要：To control the execution of process, the kernel must be able to suspend the execution of the processrunning on the CPU and resume the execution of som... 阅读全文

摘要：A new wait queue head may be defined by using the DECLARE_WAIT_QUEUE_HEAD(name) macro,which statically declares a new wait queue head variable called ... 阅读全文

摘要：The runqueue lists group all processes in a TASK_RUNNING state. When it comes to groupingprocesses in other states, the various states call for differ... 阅读全文

摘要：Processes created by a program have a parent/child relationship. When a process creates multiple children,these children have sibling relationships. S... 阅读全文

摘要：When looking for a new process to run on a CPU, the kernel has to consider only the runnable processes(that is, the processes in the TASK_RUNNING stat... 阅读全文

摘要：Before moving to and describing how the kernel keeps track of the various processes in the system,we would like to emphasize the role of special data ... 阅读全文

摘要：Processes are dynamic entities whose lifetimes range from a few milliseconds to months. Thus, thekernel must be able to handle many processes at the s... 阅读全文

摘要：As a general rule, each execution context that can be independently scheduled must have its ownprocess descriptor; therefore, even lightweight process... 阅读全文

摘要：The concept of a process is fundamental to any multiprogramming operating system. A processis usually defined as an instance of a program in execution... 阅读全文

摘要：ASIDE: Why System Calls Look Like Procedure Calls?You may wonder why a call to a system call, such as open() or read() looks exactly likea typical pro... 阅读全文

摘要：From the introduction to concurrency, we saw one of the fundamental problems in concurrentprogramming: we would like to execute a series of instructio... 阅读全文