Kernel space memory layout [closed] - linux

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Closed 4 years ago.
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How is kernel space sections? and how do they locate?
For example, user space has some sections (.data, .text, stack ...).
I want to know kernel space's memory layout image.
Please tell me it or related site.

The user space is not laid out like this:
For example, user space has some sections(.data, .text, stack ...).
Sections only exist in the executable file. The user space is just memory. There is no "stack" section. The stack is just read/write memory that happens to be used as a stack. A process can have multiple user-mode stacks when there is threading.
Unfortunately dreadful operating system books persist in confusing people this way.
The kernel is also just memory. It can be organized however the operating system wants it to be.

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Cannot allocate memory [closed]

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Closed 6 years ago.
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I'm using a virtual machine to do the work.
I given the volume capacity to be 32MB. According to "cat /proc/meminfo", i have approximately of 1.4GB for the memory available. It is more than enough to be mounted.
However, whenever it mounted, it will automatically unmounted as it cannot allocate memory (as seen on below pic). I tried to adjust the heap size but the result is still the same.
Please take a look at the pic
I solved the problem. Assign more memory to the virtual machine even though it is already more than sufficient to hold the volume capacity

What are the memory segments? File descriptors? [closed]

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Closed 7 years ago.
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1.What are the memory segments needed when executing a process?
Is it connected to virtual memory?
2. What are the open file descriptors that exist in all Unix processes?
thanks in advance
Memory Segments: Text, Data, BSS, Heap and Stack
File Descriptors: Standard Input (0), Standard Output (1) and Standard Error (2) and... they do not necessarily exists in ALL Unix processes (you can close them).

What does it mean to break user space? [closed]

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Closed 8 years ago.
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This may be a simple question but, I heard that the only rule in working on the kernel is that you don't break "user space". So I was wondering what that means: To break user space and how does it happen?
Edit
It has been pointed out to me that this question is not suited for Stack Over Flow by #lurker so I will move it to Super User as #lurker suggests. (See below)
"Questions about general computing hardware and software are off-topic for Stack Overflow unless they directly involve tools used primarily for programming. You may be able to get help on Super User." – lurker, jww, SilentKiller
You're referring to Linus Torvald's first rule of kernel development. This note explains it: https://lkml.org/lkml/2012/12/23/75. I.e., when maintaining the kernel, do not do something which breaks user programs/applications. In other words, when making kernel changes, it is very bad to cause problems in the user's application "space". That doesn't literally mean memory. That means anything that impacts the user applications in a way that negatively affects its behavior (causes the program to malfunction). The note I cite also indicates at least one example.

why Inode number is different from computer to computer [closed]

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Closed 9 years ago.
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I made a folder and file in it (in linux) and then I used the following command to get the Inode number of each file and directory:
ls -i -R
but when I use another computer with the same task I get different numbers for each inode, I know that it is reasonable but can everyone explain the reason of that? I mean why is the results different from computer to computer?
An inode (or index node) is a pointer/identifier used within the internal data-structure of a filesystem.
As such, different computers have different filesystems - talking about the data, not the type/implementation! - and thus have different inodes values for a resource. An inode is an internal identifier while the path is the external identifier.
As an analogy, imagine a C program in a modern operating system that mallocs a new object. The malloc returns a unique pointer within the process. However, many processes can share the same pointer value (when viewed as an integer address) while referring to completely unrelated objects.

Is there something like USN Journal on Linux filesystem? [closed]

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Closed 9 years ago.
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I often use Everything (a search tool) on Windows. It uses USN Journal to speed file name search.
Do Linux filesystems (ext4, xfs, btrfs, etc.) have a similar function to USN Journal?
The USN journal lets a Windows program keep track of changes to files.
An program on Linux can do the same by using inotify. It allows a program to be notified about every change to the files.
It is not a function of any particular filesystem, but of the kernel's filesystem layer, so it works with any filesystem.

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