Questions tagged [virtual-memory]
Questions about techniques for providing the appearance of an isolated, contiguous address space to each process. The size of the address spaces may be made to appear larger than the size of main memory by moving pages or segments between main memory and a larger backing store.
176 questions
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Is kernel memory mapped once or repeatedly for each spawned process
In virtually every picture of the memory layout of a running process there is a segment reserved for kernel memory e.g. https://unix.stackexchange.com/questions/31407/how-does-forking-affect-a-...
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In OS is it possible for 2 processes to share the entire physical memory image of a process- including code, data, heap & stack -not just parts of it?
I came across a question that asked:
“Can two running processes share the complete process image in physical memory (not just parts of it)?”
At first, I thought the answer was No, since each process ...
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How does GPU page table and TLB management differ from CPUs?
While reading the paper "Fine-grain Quantitative Analysis of Demand Paging in Unified Virtual Memory", I came across the following statements:
It says:
GPU page table updates and TLB ...
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I cant understand memory references in memory trace of valgrind with lackey
i am executing this command on terminal
valgrind --tool=lackey --trace-mem=yes ls 2> trace.txt
looking at some of the memory trace
...
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Spatial locality and virtual vs physical memory
I want to make sure that I correctly understand spatial locality & how it relates to hardware with an example:
Assume that we have two objects in memory in a program running on a modern 64-bit ...
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What is the physical address for a given logical address?
What is the physical address for logical address 23?
I am not really sure how to solve this? I mean how do I access logical address 23 when all I can see is between 0 to 3?
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Is this David Patterson 'Computer Architecture A Quantitative Approach' scheme right?
My guess is that L1 cache tag is also 28 bits as the L1 tag compare adress.
Another question is why the offset is going to CPU?
And the last one What other improvements and errors does this memory ...
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Are they talking about virtual memory in this article?
I am reading this Wikipedia article:
https://en.wikipedia.org/wiki/Memory_segmentation
And I am in this paragraph:
Segmentation with paging
Instead of a memory location, the segment information ...
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Who and how generate the virtual/logical addresses? Confusion if it's the compiler, the linker, the loader
I know that when I compile a program and then I inspect with objdump, I have addresses. These are relative addresses.
But if it's a C program and I printf with <...
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How does virtualization handle modern TLBs?
In an answer to this question:
For instance, modern Intel TLBs have a process context ID (PCID); each TLB entry is tagged with the PCID of the process that the page mapping is for, and the processor ...
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Do I need a multilevel page table in the following design?
I am practicing paging in virtual memory and came across a question with the following details
44-bit address space
16KB page size
16 Bytes Page table entry (PTE)
If I understand paging correctly ...
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Cache Miss in First Private Cache but Hit in Shared LEvel 2 Cache: Does it Result in a Penalty?
In the context of Shared Memory Multiprocessor (SMP) systems with different cache levels, if a cache miss occurs in the first private cache but is followed by a hit in the second shared cache, would ...
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Can a MMU be emulated entirely in software?
I'm curious about the viability of creating memory isolated processes on a processor without an MMU.
While it would be inefficient I'm wondering if it's possible to basically create a virtual machine ...
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What is the reason or motivation for having 128-bit pointers?
I read here that the reason that intptr_t and uintptr_t are optional in C is because there might be a platform where pointers ...
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Page fault, virtual memory
I am reading the book: Digital Design and Computer Architecture: ARM Edition
I am on the chapter about virtual memory. I am wondering, when a page fault occurs, is it the processor or the OS that &...
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