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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How do I check how much total memory my VM has? [closed]

I've tried /proc/meminfo but my permission has been denied.
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186 views

What is the usual Allocation unit for a process on Linux?

I'm currently studying memory management in Operating Systems. Allocation Unit is the smallest unit of memory the OS will give to any process. I've read in this page, in the 'Memory allocation ...
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404 views

find: cannot fork: Cannot allocate memory

I want to delete 1 file at a time from my directory which contains so many files,So i want to remove 1 file at a time. Just to avoid too many reads and failed at too many arguments. find ...
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46 views

What does it mean when a private VM page is none of `rwx`?

UPDATE: It's a padding: every such non-rwx area is preceded with a readable and/or writable area and together they constitute a 64Mb segment (for 64bit architecture). A relevant question on SO: ...
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54 views

Shared memory v/s physical memory

I have a C++ process which is using shared memory to store and transfer data between its child processes. I want to check the shared memory usage while the parent process is executing just like top ...
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1answer
157 views

How can two identical virtual addresses point to different physical addresses?

Following a fork() call in Linux, two processes (one being a child of the other) will share allocated heap memory. These allocated pages are marked COW (copy-on-write) and will remain shared until ...
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61 views

Finding memory corruption bugs in Linux and FreeBSD

In windows, we can enable page heap verification using gflags to catch memory corruption bugs more easily. Is there a similar service/program for Linux and FreeBSD operating systems?
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1answer
37 views

difference between inactive and free memory in output of FreeBSD top utility?

top -d1 displays following SDRAM usage statistics on one of my older machines: 125M Active, 42M Inact, 51M Wired, 17M Cache, 34M Buf, 2720K Free In total, there is 256MiB of memory installed. ...
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88 views

SOLVED Linux mint 17.1 keeps crashing

MODERATOR PLEASE CLOSE I have recently installed Linux Mint 17.1 Cinnamon on an Compaq presario c700 w/intel pentium dual core. It is dual booting with windows vista. The partition size is 19gb. I ...
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wProcess killed by OOM killer when plenty of memory apparently free

I'm working on an embedded ARM-based platform. 32-bit, 512MB of RAM, no swap. Linux 3.10.53 (some variety of Ubuntu, if that's relevant). Some code I'm working on is getting consistently oom-killed, ...
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41 views

Hardware specs for Linux machine for cluster administration [closed]

I have just started as cluster system administrator and was asked to choose some features to get bought a personal machine to work on, and most intensive calculations will be perform in the cluster. I ...
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26 views

Debian - Memory usage [closed]

I all, I'd like to understand what happens in this system. Running top I get: KiB Mem: 496948 total, 460012 used, 36936 free, 68604 buffers and in the process list the process that ...
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1answer
457 views

What happens after a page fault?

When a page fault occurs in a Linux system, the interrupt-handler has to figure out the reason why the page fault happened. But how ? Is there anywhere a special number for that !? If yes, where is ...
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1answer
66 views

How to read .vma files?

I am trying to read a .vma file but no luck finding an application to do it on Linux.. I tried to google it but it didn't work out.. The file was produced by Volatility on Ubuntu Linux 12.04 using ...
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60 views

Memory consumption over variable period of time

There are a number of questions on this StackExchange about memory consumption, notably: How to check which process is using most memory How to display top results sorted by memory usage in real ...
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0answers
172 views

Portable way to parse /proc/meminfo

I'm having trouble finding a generic code that work, here, for both CentOS 5/6 and CentOS 7 versions pc the /proc/meminfo file. I Want to compute the "Real Used memory" like free does. (amounts ...
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87 views

Dump XEN guest memory image

I am new into memory forensics thing and I am trying to dump a memory image from a XEN guest (Ubuntu 12.04 x64 - domU) in order to analyze it on dom0 (Ubuntu server 12.04 x64) with volatility . For ...
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704 views

Bash session errors on commands: “fork: Cannot allocate memory”

I have a bash session open to a remote server and something is wrong. I created a directory "test" and touched the files inside touch 1 2 3 4 5. I then tried to copy the directory cp test/ test2/ and ...
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1answer
41 views

Is there a brief way to view the top resource usage(CPU, memory or even bandwidth) of a program after its running?

I know I can use top to view the overall real-time CPU & Memory usage, and nload for overall real-time bandwidth usage. But I wish to view the maximum(or average) CPU, Memory, & bandwidth ...
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1answer
39 views

Cached Memory but swap is being used [duplicate]

I've got a VM with 16gb of memory and recently it's been using some of the swap space. At first I thought this was because it was using all the memory but then I read some articles about the Cached ...
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1answer
158 views

Shared library mappings in /proc/pid/maps

Why does /proc/pid/maps contain a few records for the same library ? Here is an example: 7fae7db9f000-7fae7dc8f000 r-xp 00000000 08:05 536861 ...
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1answer
21 views

upstart jobs - privileged vs unprivileged

On one of my VMs, some upstart jobs were failing, and when I checked df, showed that I had run out of disk-space (Use% was 100 on /dev/sda1). What I did not get is: the jobs which were running with ...
2
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1answer
60 views

Why is IO so high when almost out of memory

On my work laptop with an SSD and no swap, I sometimes run out of memory when running RAM-expensive applications (virtual machine, etc). When that happens, the system becomes slow (expected) but what ...
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1answer
122 views

Memory usage of a given process (using Linux proc filesystem)

I want to know which files from /proc directory and which fields of these files I need to calculate the memory usage of a given pid. I've been using the "stat" file and the "vsize" parameter that is ...
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4answers
131 views

How do see the memory used by a program in ubuntu?

How can I see the raw memory data used by an application ? Like , suppose I have a file name something.sh . Now I run the command ./something.sh , and then I want see all the data its accessing in ram ...
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How to troubleshoot High VIRT and RES memory on a Standby Server

We currently run TIBCO EMS on our RHEL6 servers, it is Active-Passive setup, for some reason we are seeing a really high VIRT and RES usage by the standby instance (approx 198GB). The application ...
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1answer
25 views

tstime and memory usage

So I am interested in measuring the high-water memory usage of a process. I would love to be able to use tstime but am having troubles figuring it out. Does it work in Unix? When I go to ...
3
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1answer
122 views

How to run free command by crontab

I want to run this command: free && sync && echo 3 > /proc/sys/vm/drop_caches && free -m by cron. That way I can free my RAM and cache in an Ubuntu system. I'm using ...
3
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2answers
240 views

Memory usage of an infinitely looping shell script

So, I have a shell script for updating a MySQL database that looks something like this: #!/bin/sh mysql -h "localhost" -u "root" "-p********" "database" < "update.sql" sleep 5 sh $0 It sleeps ...
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2answers
227 views

Physical Address Extension - how do virtual addresses work?

I'm running Debian Linux. uname -m says i686 which means 32-bit architecture machine with pae flag enabled. getconf LONG_BIT is 32. Installed RAM capacity is 6GB. My /proc/cpuinfo has an entry ...
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1answer
72 views

Storage allocator out of space error on unix shell script

While running the script called abc.sh, following errors are thrown. abc.sh: line 226: storage allocator out of space on 64946176 byte request ( region 64329285632 segments 1981 busy ...
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49 views

Why process is killed while a lot of memory is free?

I am running a python script in ipython. This script will take about 8GB RAM. The system has more than 80 GB free RAM but the swap is nearly 0. My script was killed after it runned for a while. I want ...
2
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1answer
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Can I trust in memory information of dmicode?

I want to buy 16gb memory for my notebook. I ran dmicode and found this information: Handle 0x0005, DMI type 5, 20 bytes Memory Controller Information Error Detecting Method: None ...
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25 views

/proc filesystem - getting useful information

I'm trying to understand the values in /proc/PID/status. I want to calculate cpu% & mem% used by PID, similar to top bash command. For Memory percentage usage I can do the following (correct me ...
3
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1answer
81 views

Resource (CPU time and memory) limitation and termination of a process upon violation in Linux

The problem: Given a process, limit the resources it and its child-processes can use. I.e. set CPU time and virtual memory quotas. When the process group exceeds one of the limits, terminate it, ...
2
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1answer
106 views

What does Linux spend memory on other than userland, caches and slab?

I have a system with 1 GB of physical RAM. Right now, free shows the following memory usage: total used free shared buffers cached Mem: 1026360 863660 ...
2
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0answers
48 views

Which process wrote to which memory address? [closed]

Recently, I've been seeing a wide variety of memory-related crashes at work (C++ applications on Ubuntu 14.04). Our applications use a properietary third party library to interface with real time data ...
2
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1answer
101 views

How to find the page size of physical memories from userspace?

I want to understand the page size, sector size, block size (if applicable) of a usb flash drive. Is there a way for me to inspect those with Ubuntu? mount /dev/sda1 /mnt ? umount /dev/sda1 Edit ...
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81 views

Is High Virtual Memory usage a problem or may cause problems?

In our server, we have a python based code that listen ports. The amount of Virtual Memory it uses is increased greatly with time Like: USER PID %CPU %MEM VSZ RSS TTY STAT ...
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How can I profile/benchmark RAM performance?

I would like to know if my memory hardware is a bottleneck of my system performance. I am dealing with really old hardware (late 2000). If there is room for improvement, I would like to upgrade. ...
3
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1answer
108 views

How do I forbid access to physical memory in Linux?

I'm on an embedded system (Zynq from Xilinx. It uses ARMv7, Cortex-A9), and running Linux. I need to ensure that no access to a certain physical memory range is ever made, either accidentally by the ...
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63 views

What is kswapd_low_wmark_hit_quickly from /proc/vmstat

What does this parameter mean? # cat /proc/vmstat | grep low kswapd_low_wmark_hit_quickly 2
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0answers
26 views

Page Fault Frequency Algorithm - Compute number of frames and mean resident set

I'm reading about Page Fault Frequency algorithm but I don't understand how can I compute the number of frames. For example I have my reference string: 112233444412412214432255543 and control ...
0
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1answer
56 views

Substantial portion of memory used is not accounted for by user processes

I recently installed a copy of Ubuntu Server 14.04.2 LTS on a cluster. All appears to be working fine, but a large portion (around half) of our total available RAM is being used. I.e., when I run ...
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0answers
81 views

How to determine the memory usage of a single process?

There a few helpful scripts out there, which give some useful information. But I would like to calculate those values myself. I am interested in values like USS and PSS. I already had my first attempt ...
3
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2answers
85 views

Sum the memory usages of all the processes of a program?

How can we sum the memory usages of all the processes of a program? For example, I have opened many Chrome tabs for webpages, and each tab runs a different process. How can I get the total sum of ...
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8answers
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Memory problems when compressing and transferring a large number of small files (1TB in total)

I have 5 million files which take up about 1TB of storage space. I need to transfer these files to a third party. What's the best way to do this? I have tried reducing the size using .tar.gz, but ...
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2answers
103 views

What unit is used for the memory values from top command in Linux?

I have the following snippet shown as my top command output. One real quick question here being, the values of Mem are shown in what granularity? Are they the number of bytes? Mem: 8191488k total, ...
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1answer
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Memory utiization

I use free -m to check memory status. In this pic we see total used & memory. I want the result in %. Like Used memory - total memory x by 100. And whenever I want to check the memory status, it ...
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3answers
2k views

How to calculate the memory consumed by a “C” program in linux

I have written two C programmes one is using function pointer, and the other without function pointer. Now i want to know the memory consumed by the two programmes , to see how memory can ...