In computing, memory refers to the state information of a computing system, as it is kept active in some physical structure.

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Questions on Linux kernel internals

I was reading "Linux device drivers, 3rd edition" and faced a few kernel items I don't quite understand. Hope gurus on this forum will help me out. Does the Linux kernel internally operate with ...
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3answers
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How do I read from /proc/$pid/mem under Linux?

The Linux proc(5) man page tells me that /proc/$pid/mem “can be used to access the pages of a process's memory”. But a straightforward attempt to use it only gives me $ cat /proc/$$/mem ...
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4answers
6k views

How to re-load all running applications from swap space into RAM?

If my desktop run out of memory and swaps a lot then I free or kill the application wasting my RAM. But, after that, all my desktop/applications have been swapped and are horribly slow, do you know a ...
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6answers
3k views

Is there a tool that allows logging of memory usage?

I want to monitor memory usage of a process, and I want this data to be logged. Does such a tool exist?
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2answers
1k views

How to find out how much memory a program taking

I use htop to watch my processes, but most of services ran are multi threaded, so they are shown on several lines with a % of memory use which in some cases is the same for all, sometimes it varies ...
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votes
1answer
2k views

What are shmpages in laymans terms?

What exactly are shmpages in the grand scheme of kernel and memory terminology. If I'm hitting a shmpages limit, what does that mean? I'm also curious if this applies to more than linux
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2answers
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Is it possible to execute code in heap space?

I would like to know if i can execute a code piece sitting inside the heap space?
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2answers
247 views

How to reuse Physical memory in the absence of swapping?

How can I reuse physical memory in the absence of swapping?
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votes
3answers
704 views

Is it possible to support multiple processes without support for Virtual memory?

Is it possible to support multiple processes without support for virtual memory? I would like to know more about it if so.
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votes
2answers
1k views

ZONE_NORMAL and it's association with Kernel/User-pages?

Above is presented a case where I have only 512 MB of physical memory. What I have read up so far, is that ZONE_NORMAL is mapped to the kernel virtual address space as shown. Essentially I have a ...
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2answers
973 views

Kernel Panic because of RAM stick?

one of my RAM sticks causes a Kernel Panic on my Ubuntu 10.10 (something like "not syncing" with a lot of memory adresses shown on screen). It's definitely this one RAM stick and not its socket ...
12
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1answer
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What does the Virtual kernel Memory Layout in dmesg imply?

While going through the "Output of dmesg" I could see a list of values which i am not able to understand properly. Memory: 2047804k/2086248k available (3179k kernel code, 37232k reserved, 1935k ...
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6answers
63k views

How to find which processes are taking all the memory?

I'm looking for somthing like top is to CPU usage. Is there a command line argument for top that does this? Currently, my memory is so full that even 'man top' fails with out of memory :)
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4answers
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Shell command to read device registers?

On a single-board computer running Linux, is there a way to read the contents of the device configuration registers that control hardware? I think it would be a wrapper for inw(), more or less. I'm ...
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5answers
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What are high memory and low memory on Linux?

I'm interested in the difference between Highmem and Lowmem: Why is there such a differentiation? What do we gain by doing so? What features does each have?
11
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1answer
494 views

What is the difference between shared memory in early unix systems vs modern unix systems?

How could processes share memory in early versions of UNIX version modern implementations of shared memory?
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2answers
3k views

How does cached memory work for executables?

I always understood cached memory in Linux (as in free -m) as pages of memory that can be reused if they are needed again, or quickly freed if more memory is needed by new applications (I found this ...
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4answers
7k views

What is “System Memory ” displayed in nmon in AIX?

I have a host with AIX 6.1 (6100-04-02-1007) upgraded from AIX 5.1 with Veritas Storage Foundation 5.1. Since the upgrade from AIX 5.3 to 6.1, Run vx services means a lots of memory consumed that I ...
4
votes
3answers
255 views

Randomise or shred memory of an application

Is it possible to randomise or shred memory of a particular application just after its life ends, or better, whenever it deallocates some memory? A command-line utility like this would be perfect: ...
2
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1answer
316 views

Kernel memory allocator patch

Is there any patch for Linux kernel to use different memory allocators, such as ned allocator or TLSF allocator?
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6answers
6k views

Is there a way to limit the amount of memory a particular process can use in Unix?

I need to test a process for memory management. I do not have the source, so I need to do all the testing from the OS side. I want to be able to say something like limitmemory 400k -p <pid> ...
5
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5answers
2k views

How do you free up resources in Ubuntu?

What steps do you take to make a vanilla Ubuntu system run faster and use less memory? I'm using Ubuntu as the OS for my general purpose PC, but it's on slightly older hardware and I want to get as ...
7
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3answers
556 views

How to track down memory spikes?

I have an app running on rackspace cloud (ubuntu 10.04). For some reason, over the last 3 nights, the memory has been spiking and then leveling off for about 7 hours before eventually falling off. ...