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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2answers
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Bash script that automatically kills processes when CPU/memory usage gets too high

I have created a script that kills processes if CPU and/or memory usage hits 80%. It creates a list of killed processes when this happens. What can I do to improve it? while [ 1 ]; do echo echo ...
5
votes
1answer
30 views

How the network packets are transferred to the memory on linux?

Is there some command or tool for monitoring network packets and how those packets are handled by the memory and than proceeded to the CPU on linux platform? Using tcpdump I can capture many apache ...
1
vote
1answer
221 views

How to reduce ClamAV memory usage?

I'm running a Ubuntu based web server (Apache, MySQL) on a 512MB VPS. This is more than sufficient for the website it is running (small forum). As I wanted to add some protection against viruses I ...
35
votes
4answers
28k views

Limit memory usage for a single Linux process

I'm running pdftoppm to convert a user-provided PDF into a 300DPI image. This works great, except if the user provides an PDF with a very large page size. pdftoppm will allocate enough memory to ...
9
votes
2answers
146 views

On system memory… specifically the difference between `tmpfs,` `shm,` and `hugepages…`

I've been curious lately about the various Linux kernel memory based filesystems. Note: As far as I'm concerned, the questions below should be considered more or less optional when compared with a ...
1
vote
2answers
676 views

Discrepancy between reported used memory and sum of application memory usage

I'm running a desktop system that quite regularly suffers from lack of memory, this prompted me to investigate what causes the issue in the first place. Problem is, there's no single process that ...
2
votes
0answers
67 views

Debian 64-bit sees less than 4GB of RAM

I have a Debian wheezy (7.4) amd64 virtual machine running under VirtualBox 4.3.10 on a Win7 x64 host with AMD A10-5700 processor. The virtual machine is configured with 16GB of memory (the host has ...
0
votes
1answer
9 views

Configure the OOM to avoid having the system grind to a halt

I have an SSD and therefore no swap. However, when I open a lot of tabs in the browser, the system tends to grind to a halt. If I'm lucky, I can close one or two tabs before the system is completely ...
5
votes
1answer
121 views

can initramfs be paged out to swap disk?

I am using initramfs to boot Centos via PXE. The initramfs used memory is listed within the "cached" value in /proc/meminfo or via free. Since I need to calculate performance data, I need to know ...
1
vote
1answer
441 views

Can I use pmap to find out Memory utilization?

I want to measure memory utilization of my Apache Server. Can I use the pmap command and pass all the process IDs of httpd and take that as total utilization? pmap PID1 PID2 .... It seems that pmap ...
1
vote
1answer
71 views

Why is swap used when a lot of memory is still free? [duplicate]

In the below 2.6.18 Linux Kernel (Red Hat) server, there is a lot of free memory, but I see some swap is used. I always thought of swap as an overflow when memory has been depleted. Why would it ...
0
votes
1answer
52 views

Can continually assigning a variable in a shell script cause a memory leak?

I've written a short script to copy Apache's server status to a log: #Save date and time to a variable dt=$(date) #Echo date and time to the log file as it's not included in server-status echo "Time ...
0
votes
1answer
250 views

Does sync command remove the dirty cache in the memory?

I am aware that sync command flushes the dirty cache into disk. I have run free command first, then sync, and then free again. The result of latter free command shows more free memory available than ...
0
votes
1answer
20 views

Having an independent console to kill rogue process?

Sometimes a flash plugin starts using all the mem and CPU or an app is also behaving "naughtily" and my system starts to crawl until i finally get a terminal with htop up and kill the rogue process, ...
0
votes
1answer
208 views

Java/malloc memory corruption error when running SDK Android Manager

I want to install Android SDK, so I manually installed Java JDK 7u51, downloaded SDK ADT bundle for Linux x64, and tried to run it. When I run android, the SDK manager windows hangs halfway through ...
1
vote
0answers
18 views

What is the structure of Libvirt Qemu VM dump/save files?

I need to do some exploration of Qemu-KVM virtual machines physical memory (particularly I need to check the fact of the physical memory intersection). In order to do that I'm trying to save VM's ...
2
votes
2answers
215 views

How to remove cache device from bcache?

I believe, that once I made sure my cache device state is "clean": $ sudo cat /sys/block/bcache0/bcache/state I can just physically remove it from the machine when it is powered off or boot with ...
2
votes
0answers
20 views

Set up OS and Runnig app using x32-ABI

Intro I just moved to a 64bit installation and I'm experiencing big difference in memory usage ( especially for app like chrome, firefox, mysql and java apps ): - While before 4gb were enough now they ...
2
votes
2answers
369 views

Measuring CPU and Memory per user to distribute “cost” of a server

How should I implement approximately correct per-user monitoring on a server? I want a way to split the cost of a server between the users based on their usage. On newer machines (RHEL6) I would use ...
10
votes
1answer
229 views

Loading of shared libraries and RAM usage

I'm wondering about the way Linux manages shared libraries. (actually I'm talking about Maemo Fremantle, a Debian-based distro released in 2009 running on 256MB RAM). Let's assume we have two ...
0
votes
1answer
26 views

What happens to the files when they are being decrypted?

I have the server's webroot directory mounted on a partition which is being protected with LUKS encryption. I want to know what happens to the files within when that partition is being decrypted. Does ...
5
votes
1answer
267 views

Virtual kernel memory layout: negative values [closed]

i'm porting drivers for omap3-board to 3.5 kernel. When I start board I see it: Memory: 256MB = 256MB total Memory: 253564k/253564k available, 8580k reserved, 3226106074K highmem Virtual kernel ...
2
votes
0answers
29 views

Automatically memtest and then boot

Is there some way to reboot server, so it runs memtest (say, 1 or 2 passes) and then reboots back to Linux and writes report to some log? This feature in Windows Server 2012 helped me to diagnose bad ...
7
votes
7answers
903 views

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
vote
0answers
27 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 ...
1
vote
1answer
110 views

How to dump memory image from linux system?

I know to dump memory images in Window. (eg-dumpit) But I don't know how to dump memory images in Linux. I wanna get memory images in Linux and from linux to linux with ssh connection or something. ...
1
vote
3answers
452 views

Linux / JVM - OutOfMemoryError: unable to create new native thread

I have a memory problem with a Linux server (CentOS). It is a VM. Below is the context. It has 70Gb of RAM. There are 2 tomcat running on it. One tomcat is given a heap of 13Gb and the other one a ...
3
votes
1answer
35 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
25 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?
0
votes
0answers
54 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 ...
2
votes
1answer
1k 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
53 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
87 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
45 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
1k 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
88 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
45 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
vote
0answers
75 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 ...
6
votes
3answers
2k views

How to display meminfo in megabytes in top?

Sometimes it is not comfortable to see meminfo in kilobytes while you have several gigs of RAM. In Linux it looks like that: And here is how it looks in Mac OS X: Is there a way to display ...
3
votes
3answers
173 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 ...
4
votes
2answers
292 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
62 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 ...
1
vote
1answer
2k 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 ...
13
votes
6answers
4k 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
705 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 ...
4
votes
1answer
662 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 ...
0
votes
1answer
54 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
17 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 ...
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vote
0answers
13 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 ...
70
votes
12answers
25k 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?