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Questions tagged [paging]

Questions about memory-management techniques where the computer manages and transfers data between main memory and secondary storage in pages -- discrete chunks of a fixed size. Operating systems often use paging to implement virtual memory.

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Can someone explain this diagram about Slab Allocation?

I'm trying to understand how Slab Allocation works and why it is different or better than ordinary paging. I found this diagram which I believe would be helpful if it had more explanation. Some questions: What do the 3KB and 7KB items represent?…
CodyBugstein
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Are there any garbage collectors that take into account paging?

Garbage collections have to visit all objects that are alive, so as to find the memory that can be reclaimed. (Having many generations’ just delays this a bit) All things being equal, it is clearly better to first visit the object that are…
Ian Ringrose
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Swap space management during pure demand paging

The following is a doubt that I came across while doing a OS home assignment - however, it seems more concept-based than a straightforward coding question, so IMHO I don't think the homework tag is appropriate for this. In a pure demand paging…
TCSGrad
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Is page size always equal to frame size?

I'm learning about paging. My book says that the logical addresses generated by the CPU are in the form |p|d|(page number, page offset) and the physical addresses are in the form |f|d|(frame number, frame offset). It is also specifically mentioned…
Fuel
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Clock page replacement algorithm - Already existing pages

When simulating the clock page replacement algorithm, when a reference comes in which is already in memory, does the clock hand still increment? Here is an example: With 4 slots, using the clock page replacement algorithm Reference list: 1 2 3 4 1 2…
slaughterize
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Look Ahead buffer vs Translation Look aside buffer

I know that Translation look aside buffer is used for address translation in paging to achieve better performance. I came across term called Look Ahead buffer in a document which said it implements Temporal locality. I tried searching for Look…
eshi14
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How does increasing the page size affect the number of page faults?

If we let the physical memory size remain constant, What effect does the size of the page have on the number of frames? What effect does the number of frames have on the number of page faults? Also, please provide reference strings as an example.…
Anil Muppalla
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How to interpret "Windows - Virtual Memory minimum too low" from a CS student point of view?

On my old 256MB RAM, pc I get this message. (I guess it is quite common) Windows - Virtual Memory minimum too low Your system is low on virtual memory. Windows is increasing the size of your virtual memory paging file. During this process, memory…
user1182
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Page Table Size in a 4 Level Hierarchical Page Table

An Intel 64 bit CPU uses a four-level hierarchical page table. Each of the four levels of the page table can contain 512 entries, and the page table size is 4KB. You should be able to see that it cannot actually address 2^64 bytes of virtual…
George Robinson
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How does a TLB lookup compare all keys simultaneously?

I am reading OS Concepts dinosaur book which says, "Each entry in the TLB consists of two parts: a key (or tag) and a value. When the associative memory is presented with an item, the item is compared with all keys simultaneously." I checked How…
mLstudent33
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How to work out physical address corresponding to logical address?

I am looking to calculate the physical address corresponding to a logical address in a paging memory management scheme. I just want to make sure I am getting the calculation right, as I fear I could be wrong somewhere. So, the data I have is as…
Ciaran Gallagher
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Paging: Does the page table of a process also gets swapped out when the process gets swapped out from main memory?

Does a process's page table too gets swapped out to secondary storage from main memory when the process gets swapped out to secondary storage from main memory? And gets swapped back in when the process is swapped in? I tried to find the answer in…
Meathead
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Best design of a software controlled page table: to echo the TLB?

I am building some simple system software for the Microblaze FPGA (actually being run on OVPsim at least for now). The system is to experiment with various memory management regimes. The first system I want needs to have a very simple paging…
adrianmcmenamin
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What's the difference between Clock and Second Chance Page-Replacement Algorithm?

I know that they both have reference bit, but I only understand the Second Chance but not the Clock Page-Replacement algorithm. could anyone help me understand?
Sino Ka
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What is the difference between LRU implemented for a cache and for page replacement?

I have read that true LRU page replacement requires significant hardware support, so only approximation of LRU is implemented for page replacement. So I wanted to contrast LRU that is implemented for cache, and that for page replacement. Like - Is…
Vinayak Garg
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