到其中的一个子进程退出,此时函数返回该子进程的PID。
When you release the process descriptor, you need to call Release_task ().
3.5.2 Orphan Process
Overview: The parent process exits before the process, leaving behind the child process, the orphan process
The workaround:
Finds a new parent process within the current thread group for the orphan process, or directly with Init as its parent process
Call Order:
- do_exit()-- - >forget_original_parent()- - >find_new_p
entries that do not copy the parent process.The implementation of the Vfork () system call is done by passing a special flag to the clone () system call.3.4 Implementation of threads in Linux3.4.1 Creating ThreadsCreating a thread is similar to creating a normal process, except that you need to pass some parameter flags when invoking clone () to indicate which resources need to be shared:Clone (CLONE_VM | Clone_fs | Clone_files | clone_sighand,0);The parameter flags passed to clone () determine
like user spaceThe memory in the kernel is not paged.
Difficult to perform floating-point arithmetic during kernel programming
The kernel gives each process only a small fixed-length stack
Because the kernel supports asynchronous interrupts, preemption, and SMP, you must always be aware of synchronization and concurrencySMP: Symmetric multi-processing system. Common ways to solve competition: spin locks and semaphores.
To consider the importance of portabilitysuch as keeping the
_ Get _ priority _ Max () returns the maximum and minimum precedence for a given scheduling policy
2. System calls related to processor bindings
Linux Scheduler provides mandatory processor binding mechanism
In a CPUs _ allowed bitmask in a task _ struct
Sched_setaffinity () sets a bitmask of different combinations of one or several bits
Sched _ Getaffinity () returns the current cpus_ allowed bit mask
3. Discard Processor TimeSched_yield () lets the process expli
-danger">67class="Form-group FORM-GROUP-LG">8 for="Input.shelfname">9class="Form-control FORM-CONTROL-LG"asp- for="Input.shelfname"Autocomplete="if">Ten for="Input.shelfname" class="Text-danger"> One Aclass="Form-group text-right"> -class="btn btn-warning Btn-lg"Type="Submit">Save - theFill in the information of the study:Click the Save button to submit, OK, the normal submission and jump.See if the following DB has data:Haha, everything looks normal.Development of small program for developing p
Tags: enc ret bin cover BSP PNG work split SelectI woke up in the morning and changed a bit: Mainly, the non-common information is all split out, so that the table as small as possible to continue to split, so that the db logic is distinguished. Added Filebank storage book cover picture, unified management of picture resources. The newly added type-related script: 1 CREATE FUNCTION [Base].[Booknbr#type] ()
2 RETURNS TABLE
3 withSCHEMABINDING, encry
In this chapter, let's use the SP framework to create a simple message Program (why is this the most simple one? It can also reflect the speedphp function. I personally think that simplicity is beautiful, can also be understood more quickly ~),It is very effective to use instances to learn program development. At the same time, we can also understand the development process of the actual network project.This example will be provided for you to download later ~
First, let's take a look at the req
: Linux private dishes from brother BirdIn addition to using the test command to make conditional judgments, I can also use [] (the syntax of the brackets to judge the test parameters and tests).[] The syntax requires a space between all the quantities in [], eg:[B "$name" B==b "Xiaoyi" b] #b都表示空格Three Complex scripts3.1 Article Statementsif Else 's standard format:If [conditional judgment 1]; Then command1elif [conditional judgment 2]; then command2else Command3fiWhere conditions can be
queue, and then call Schedule () to select and execute a different process.The process of waking up is just the opposite of the process being set to executable state, and then moving from the wait queue to the executable red-black tree.4.6 Preemption and Context switching4.6.1 User preemptionArises in the following cases:When the user space is returned from the system, when the user space is returned from the interrupt handler;4.6.2 kernel preemptionOccurs in the following situations:The interr
Design first, we make a message thin, first make an input screen interface effect, that is, generate the Message Input screen HTML page, and then in these HTML source code to add ASP script, I get the HTML code below.
* FileName: book.htm
The The The
E-Mail
You can click here to look at the effect of this interface (you need to emphasize that the HTML code is still completely non-functional) you can save it as a book.htm, and then open it
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