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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7answers
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cron Vs. sleep - which is the better one in terms of efficient cpu/memory utilization?

The Case: I need to run some commands/script at certain intervals of time and for this I have two options - 1. set up a cron-job or, 2. implement a loop with sleep in the script itself. Question: ...
1
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0answers
29 views

About the usage of Memory in a linux server [duplicate]

I find my server's memory usage is so high, part of the output of command free is shown below: total used free shared buffers cached Mem: 82446460 81961412 ...
3
votes
1answer
41 views

program executing for 2 days

I have a java program which implements the Hungarian algorithm. I made changes to the existing code in such a way that the input is read from file. I have a pretty huge input around 32,000 rows for ...
1
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0answers
26 views

Set memory allocation for applications in Ubuntu [duplicate]

I have an application running under Ubuntu that tries to consume all available memory. Is there a way to specify and restrict the allocations available for a given application?
1
vote
0answers
159 views

How to cause memory fragmentation on a Linux based embedded device?

Hardware ARM What am I trying to do: Answer: I am trying to create memory fragmentation on a Linux 2.6.31 based swapless embedded device. Why: Answer:I am trying to port some patches to Linux ...
3
votes
1answer
2k views

How to measure on Linux the peak memory of an application after has ended

How do I measure the peak memory of an application running on Linux? I run this app in batch so I cannot use RSS since, it reports the current memory. I need the peak memory that the application has ...
2
votes
0answers
69 views

Why does the kernel boot faster with less memory allocated?

This is not a important question, I'm just curious. Something strange happened, which isn't quiet clear to me: In the kernel command line, the amount of the memory can be set statically with the ...
4
votes
3answers
133 views

What happens in UNIX/Linux when a program is bigger then size of memory?

I was wondering how embedded systems are able run programs bigger than the size of memory. If I had 1 GB of memory and the program was 1.5 GB, would the program load? Are there systems that only use ...
2
votes
2answers
628 views

Are limits in linux (like those controlled by ulimit or /etc/security/limits.conf) per user or per user per process?

I saw three copies of a process running and one of them cored in what seems like memory issue. Each individually occupies about 3-4 GB of memory..would a limit account for killing one of them? And if ...
16
votes
1answer
4k views

What is maximum RAM supportable by Linux?

What is the maximum supportable RAM by Linux? Assume that hardware is/supports 64-bit. Among all Linux distros. Does it go up to 16 exabytes, or is it limited like with Windows which I believe is 192 ...
3
votes
1answer
1k views

Optimised ZFS in low RAM environment feasibility?

I am currently setting up a file server and have come to the point of actually setting up the data drives. The system has 4 drives (one OS disk, 3 data disks). The OS disk is formatted as ext4 and ...
0
votes
1answer
152 views

mdadm large memory consumption [closed]

I am building a RAID 6 with mdadm (8 WD Red 3 Tb) on Ubuntu 13.10x64 server with ext4 filesystem. When I download torrent on the array, server RAM is filled for maximum cap (8 Gb) memory is free when ...
1
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0answers
466 views

dovecot. Can't allocate memory, but free -m show available memory

I trying to send mail with PHP (engine - Drupal). But it can't send mail and write message about it in to log (nothing more that adressed). Part of /var/log/mail.err : Feb 14 19:55:30 hivede13-3220 ...
3
votes
3answers
950 views

Why does MemTotal in /proc/meminfo change?

I monitor value from /proc/meminfo file, namely the MemTotal: number. It changes if a ram module breaks, roughly by size of the memory module - this is obvious. I know the definition for the field ...
5
votes
2answers
804 views

Turning off swapping for only one process with cgroups?

I would like to turn off swapping for only one process. Swap should work as usual for the other processes. How I can implement this with cgroups?
1
vote
1answer
84 views

Limiting processes by memory under Linux

We must launch several hungry processes on a Linux system. These processes often need several Go (~5Go) of memory to run (total memory: 16Go RAM + 2Go swap). At first, when the system was running ...
2
votes
1answer
3k views

htop reporting much higher memory usage than free or top

The following three outputs were taken essentially simultaneously: top: top - 02:54:36 up 2 days, 13:50, 3 users, load average: 0.05, 0.05, 0.09 Tasks: 181 total, 1 running, 179 sleeping, 0 ...
16
votes
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> ...
0
votes
1answer
1k views

Limit CPU and memory usage for PHP-FPM and Nginx processes in CentOS

I want to limit CPU and memory usage for PHP-FPM and Nginx processes in CentOS. I came across following tools cpulimit cggroups memory resource locater which will more efficient and how can I ...
5
votes
1answer
2k views

Does kernel: EDAC MC0: UE page 0x0 point to bad memory, a driver, or something else?

kernel: EDAC MC0: UE page 0x0, offset 0x0, grain 0, row 7, labels ":": i3200 UE All of a sudden today, our CentOS release 6.4 (Final) system started throwing EDAC errors. I rebooted, and the errors ...
1
vote
1answer
1k views

What's exactly Compile time, Load time, and Execution time? [closed]

It's said, Compile time -- When it is known at compile time where the process will reside, compile time binding is used to generate the absolute code. Here I'm not sure what is the absolute code? ...
0
votes
1answer
103 views

Preventing a new instance of a program to open when calling it

My problem is with FBI (frame buffer image viewer) for Linux, but my question and any answers are perhaps applicable to more than only that program. I don't know. Anyway… While things are loading on ...
1
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0answers
17 views

Amount of memory transfer on a running Linux

Can I determinate the amount of RAM exchange (between the CPU and the RAM) on a running Linux system? I'm not looking for the max RAM speed (then memtest would be valid answer). I'm looking for the ...
74
votes
11answers
30k views

How to fill 90% of the free memory?

I want to do some low-resources testing and for that I need to have 90% of the free memory full. How can I do this on a *nix system?
4
votes
2answers
1k views

Is it possible to trigger OOM-killer on forced swapping?

Is it possible to have the system preemptively swap out inactive pages (vm.swappiness), but invoke the oom-killer when the system runs out of RAM (as opposed to running out of memory) and is forced to ...
19
votes
1answer
14k views

Getting information about a process' memory usage from /proc/pid/smaps

For a given process in /proc/<pid>/smaps, for a given mapping entry what are: Shared_Clean Shared_Dirty Private_Clean Private_Dirty Is Shared_Clean + Shared_Dirty the amount of memory that ...
0
votes
1answer
46 views

Is this method safe or recommended for moving a /home directory?

I have my linux install on a small disk. I want to put the home directory on a different hard-drive. I was thinking of using this and then this. Would this work? Is there a better way? Should I just ...
0
votes
1answer
166 views

Is there something wrong with df output? [duplicate]

I'm using the command df -h to check disk usage on CentOS 6.4. I see an inconsistency with the output. look at the line Filesystem: total 490Gb, used 55Gb, and Available 411Gb. What is it mean? I ...
0
votes
2answers
7k views

Memory usage on SunOS and Linux

I have some doubts with memory usage. Currently I have nagios check who measures used memory from free -m command on Linux. I added another script for memory usage from ...
0
votes
0answers
34 views

How to install memusg tool

I've tried with yum install memusg but returned: Loaded plugins: fastestmirror, security Setting up Install Process No package memusg available Error: nothing to do Any solution
4
votes
1answer
297 views

Why do the data and code segments completely overlap in Linux?

Context: I'm reading "Understanding the Linux kernel, 3d ed", which uses the 2.6.11 kernel. Question: As I understand, the physical address is obtained by translating the linear address, which is ...
1
vote
0answers
41 views

memory consumption alert

My VPS has reported a memory consumption alert says reached 273% and I cannot access any of my sites. But I checked on the terminal today and it does not look like a memory problem. Am I correct in ...
-2
votes
1answer
82 views

Loading a kernel driver to a specific memory address

How can I load a kernel driver at a specific memory address? How could it be done with the following methods? commands/scripts like insmod or modprobe using C code (not sure if there may exist ...
5
votes
3answers
672 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.
1
vote
1answer
580 views

Worker MPM or Prefork?

I understand that there is a comparison topic between the two modules but this is different. I was contacting cPanel support in order to help me freeing up some memory usage on the VPS. They found ...
1
vote
1answer
1k views

Linux empty buffer cache command permission denied

I'm using the following commands to flush cache: # sync; echo 3 > /proc/sys/vm/drop_caches # sync; echo 2 > /proc/sys/vm/drop_caches # sync; echo 1 > /proc/sys/vm/drop_caches When I use ...
4
votes
1answer
1k views

How can I tell what memory RAM address range is being used by uboot?

I am in uboot and was wondering, how could I tell what RAM address range is being used by uboot. uboot needs memory to run so it might be using some of the RAM. I want to avoid modifying those RAM ...
2
votes
2answers
59 views

Securely viewing an encrypted file

I have a file that is gpg encrypted. I would like to view the content of the file, but leave no trace of the output. Lets say for example that the encrypted file has some passwords, and I don't want ...
1
vote
1answer
272 views

How to see buffered and cached data

~$ free total used free shared buffers cached Mem: 3891076 1044972 2846104 0 82744 463876 -/+ buffers/cache: 498352 3392724 ...
2
votes
3answers
463 views

How can I find the amount of memory consumed by a process?

How can I find the amount of main memory consumed by a process using ps aux? I have a process which runs for half an hour. Is it possible to find the maximum amount of main memory consumed by it ...
17
votes
2answers
4k views

How to blacklist a correct bad RAM sector according to MemTest86+ error indication?

MemTest86+ (the version included with Ubuntu 13.04) says Failing address: 002f796c48 - 759.5 MB What should I specify in the memmap kernel parameter to bypass this area? I've tried running ...
0
votes
1answer
41 views

HDD indicator blinks when I run out of memory, but I have no swap configured [duplicate]

I'm running Arch Linux, with 8 GB memory and no swap defined. Sometimes it ran out of memory, then my system get a little bit stuck, and I can see the HDD indicator blinking. Then I restart X, which ...
2
votes
2answers
115 views

Linux-swap on reboot

I'm wondering what actually happens to a Linux-swap partition reboot. I've been taking a course in computer organization and while installing/partitioning a new drive I became rather curious about ...
0
votes
1answer
67 views

How to create memory-based disk in linux? [duplicate]

I need to have a very fast disk for keeping cache. How can I do that in Linux?
6
votes
3answers
10k views

Swap usage too high?

I have a debian sid box, freshly installed about a month ago, with no desktop apps running at the moment. Any command I try to run (via ssh) makes the hard disk work very hard. The system worked ...
1
vote
0answers
383 views

CentOS memory allocation

I was running my VPS with CentOS on 1G memory, but I saw the memory was getting "full" so I had 1G extra installed. This VPS is one I rent at a hosting company. That company did most of the ...
2
votes
0answers
201 views

Writing to Arbitrary Memory Addresses [closed]

I'm reading "Art of Exploitation 2nd Ed." and I have a question regarding a section on format string attacks. Target program Below code (fmt_vuln.c) is a target program. #include <stdio.h> ...
1
vote
2answers
284 views

Swap bash script pins htop's memory usage

I deployed a hack to add swap space to a VPS that otherwise didn't allow me to use swapon to create a file. Prior to adding and executing the script, I followed the steps outlined here. and ...
15
votes
2answers
2k views

Linux: Total swap used = swap used by processes +?

So, I'm trying to do some investigation on where does swap use come from in a system with high swap usage: # free total used free shared buffers cached Mem: ...
2
votes
2answers
244 views

How to reuse Physical memory in the absence of swapping?

How can I reuse physical memory in the absence of swapping?