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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AIX Memory Limits

I cannot find these numbers anywhere on the IBM Web site or even random blogs that Google finds. Questions What is the maximum physical memory size a POWER7 CPU supports? What is the maximum ...
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How to draw memory consuption plot

I am running one pipeline on ubuntu 12.4 platform and i would like to draw a memory consumption plot. Can anyone give some idea some idea. Thanks advance.
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62 views

How to track down the source of I/O spikes?

I am using Linux as a desktop, and keep getting seemingly random I/O Spikes. The machine becomes unusably slow. At first I thought it was just that I don't have enough memory. But looking at the ...
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42 views

How are the values represented with the “free” command

I am interested in the totals of the 3 lines. Specifcally, if the "used" values can be counted as what's going on in real time, or if that's just a running total since the OS was started? How does ...
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Making Linux read swap back into memory

The Linux kernel swaps out most pages from memory when I run an application that uses most of the 16GB of physical memory. After the application finishes every action (typing commands, switching ...
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58 views

How can I find how much RAM are VMware Player VMs using on Linux?

I am running Debian Jessie 64-bit on a computer with 8 GB of RAM. This is my memory usage according to htop(with a fairly large Firefox session) before starting a guest VM that has 4 GB allocated. ...
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How to Determine the Amount of RAM Slots In Use?

I forgot how many RAM modules are installed on my laptop. I do not want to unscrew it but want to look it up on the console. How do I gather this information?
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is THP good or bad for MySQL Server?

Linux kernel new feature called Transparent Huge Pages (THP) which is by default enabled on CentOS 6.x and above OS. Is THP good for MySQL DB machine? I am trying following to disabled THP but seems ...
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Determining maximum memory usage for an extremely short process

I have a program I am testing and I need to determine the maximum memory used by the process. I know that in general ps -aux can give me this information, but the process runs in under 1/10 seconds ...
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1k views

Fork / Cannot allocate memory

I have a 64-bit server running linux 3.x that reports "bash: fork: cannot allocate memory". This server has plenty of RAM (64G) and swap (128G) and I cannot see a particular process being the culript ...
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62 views

Kernel's cached memory can't be freed, even dropping caches

All host's memory is cached and there's no way it can be freed. /dev/ram1 is used for storing testing files, but after each build we run freeramdisk. $ freeramdisk /dev/ram1 $ echo 3 > ...
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Monitoring process activities using system calls only (without utilities like `top`)

I want to obtain information about memory used by different users and different processes which users are running and statistics about those processes like memory consumption, execution speed, etc., ...
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Out of Memory with unused memory and swap

I have a strange error on my Raspberry Pi2. System is archlinuxarm. Short after boot (about 30 secs), the system states that it is out of memory, resulting in closing many applications, most time ...
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Why am I missing 2% of my ram

I am running grep MemTotal /proc/meminfo to determine the RAM installed on a system, however instead of reporting a number corresponding to an even number of GB, it is slightly off. I.e. on my 64 GB ...
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4answers
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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 ...
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How can I find which process is eating my memory? [duplicate]

My Linux system sometimes reaches 90% memory usage. We are running some Java processes, and top shows overall usage as 45%. If I stop the running processes, usage reduces to 5-10%. I want to list ...
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27 views

Distributing CPU cores between cgroups and outside world

Is it possible to manage access to CPU cores in a similar fashion that memory limiting works? In particular I need to be able to dynamically create and destroy cgroups that will limit a particular ...
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3k 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 ...
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Measuring RAM usage of a program

time is a brilliant command if you want to figure out how much CPU time a given command takes. I am looking for something similar that can measure the max RAM usage of the program and any children. ...
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171 views

Is there any relationship between memory fragmentation and whether or not swap is enabled on a system?

One of the answers to Do I need swap space if I have more than enough amount of RAM? got me wondering if there is any relationship between memory fragmentation as measured by cat /proc/buddyinfo and ...
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Is there any dynamically produced .log file showing up the memory usage on FreeBSD?

I am using FreeBSD 10.1-RELEASE and I was just wondering if there is any .log file produced by default from the system because I am using ELK and I want to pass this file to logstash and then ...
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1answer
240 views

Linux and x32-ABI - How to use?

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 ...
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I seem to be using only some part of my total memory

My Kubuntu laptop $ uname -a Linux jiggs 3.16.0-31-generic #43-Ubuntu SMP Tue Mar 10 17:37:36 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux has 6GiB of memory: # lshw -C memory *-firmware ...
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MMU-less kernel?

I would like to try compile mmu-less kernel. From what I found in configuration there is no option for such a thing. Is it possible to be done?
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268 views

Can I limit the size of the linux file cache?

I am running 64-bit Xubuntu 14.04, linux version 3.8.0-25 with 8GB of RAM. I have a script (in MATLAB, for what it's worth) that loads a large number of data files (~23k) one at a time, for a total ...
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557 views

Spike in swap utilisation without high swap rate

Every Saturday, for reasons unknown to me, one of my servers experiences a spike in swap utilisation. It's not necessarily a problem as there is plenty of free memory available, but I'd still like to ...
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Generate major page faults

Is it possible to generate major page faults in the linux kernel at will? Can a program be written such that it is guaranteed to cause a major page fault on it's execution.
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322 views

How to get the size of GPU memory available for OpenCL?

How is it possible to get the size of the memory on a GPU, which is available for programs with use OpenCL for computations, such as darktable? I know of lspci which gives some general informations, ...
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Changing redis filesystem writing behaviour

The filesystem usage of redis is peaking every 20 minutes at the moment on my server. Sometimes from 63.1% to over 90.9%! This causes my monitoring to send me alerts if its over a longer time-frame. ...
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53 views

Linux always hangs when out of physical memory

I'm using ArchLinux, with 3.18.6-1 kernel, when a software uses more than physical memory (when total memory used is >5.8 GB), it always lags, unresponsive, and all that I can do is reset the ...
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131 views

The structure of /proc/kcore on 64-bit machine and relation to physical memory

Let me preface this question by saying that I've found a lot of answers for questions similar to my question but for 32-bit machines. However, I can't find anything for 64-bit machines. Please no ...
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66 views

Linux Debian memory leak? [duplicate]

I am running an application which needs to be restarted everyday. I am noticing that when I close this application and I run "free -m" It says: total used free shared ...
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1k views

Excessively high memory usage reported (3 GB) after reboot

Brief problem description: A 64-bit Gentoo on Intel Core-2 Q6600 reports about 3GB used out of 8GB total memory after reboot. This memory is neither claimed by any process, nor is it used by ...
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What does -/+ buffers/cache means in the output of free? [closed]

I know this is a lame question, but I want to understand why CentOS consumes my Physical memory when certain process stopped. Suppose I have opened a file of 10GB then it consumes 10GB in ram and ...
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CentOS Black Screen after 4+ hours of indexing

I am running a CentOS virtual image on virtual box. It has liferay and solr installed on it and I am trying to index a Lar file that is 50+ MB of metadata. This is estimated to take more than 12 hours ...
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How can I dump the full system memory?

After starting VirtualBox, the computer became sluggish and then hung completely due to OOM. Usually, OOM should be starting killing processes in order to free up some space, but this did not happen ...
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Loading and execution of programs in memory [closed]

While comparing between linking loader and linkage editor I came across a point that in case of linking loader linking and relocation takes place for each execution of the program( and happens at time ...
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1answer
565 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 ...
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1answer
151 views

RES memory more than initial and maximum memory for java

We have a java application running on Centos 6.4 what we notice is that the RES is around 370m which is more then the allocated max that is 256m. Does this signify that we the application is leaking? ...
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41 views

«nm» shows zero VMA: where is the symbol will be mapped?

I am look at the functions of my compiled application via «nm» — I need to find an address to set a breakpoint to the «send()» function. The problem is that this function accordingly to «nm»'s output ...
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doubts regarding memory control group and memory zones lru list?

I have doubts regarding memory control group and memory zones lru list ? I just want know whether memory control groups lru list is subset of memory zone lru list or they have different pages on them ...
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406 views

How do I find the resident memory size of a process on busybox?

I run top on busybox and it shows all processes and their virtual memory size. How do I determine how much RAM is being used by each process?
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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 ...
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200 views

Why message queues are not being used for any system level applications in Ubuntu OS?

In my Linux machine, when i run 'ipcs' command, I have the below information listed srinivas@srinivas-G41MT-S2:~$ ipcs -a ------ Shared Memory Segments -------- key shmid owner ...
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1answer
531 views

How can I monitor per process/per thread memory consumption (divided into heap, stack, data, code)?

Before jumping in and writing my own code, I want to find out if there is GNU/Linux software that is able to output something similar to QNX's showmem. For each thread of each process that is ...
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2answers
30 views

find the application that consuming large memory

How to find which application is consuming large memory? Is there any other way than using top?
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0answers
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How can the RES memory reported for a Java process be higher than the VIRT memory?

I've been monitoring a Java process (Oracle Weblogic) using TOP and have observed that sometimes the following will happen: RES will increase from it's usual stable level of 2,097,152 KB up to ...
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What does “task mysqld:xxx blocked for more than 120 seconds” mean?

We are troubleshooting a MySQL issue where some queries are taking a very long time complete and I see many of these entry in /var/log/messages: Jan 28 05:52:15 64455-alpha01 kernel: [2529273.616327] ...
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Why is the theoretical RAM limit for RHEL 6 128 TB and how is this determined?

I'm studying for RHCSA and am confused by a statement I came across in some training material: There is no practical maximum RAM, as theoretically, you could run 128 TB of RAM on RHEL 6. But ...
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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 ...