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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Ubuntu 14.04 using 100% swap space, with more than 40GB free memory, why?

I'm a bit at a loss trying to figure out why this would be the case. Can anyone provide some helpful ideas on troubleshooting this? $ free -m total used free shared ...
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Does /proc/[pid]/status always use kB?

Particularly, does proc always list the VmRSS value in kB? I can't find a solid answer on the documentation, although it appears that it sticks to one unit.
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31 views

How to check if allocated memory was freed?

Does anyone know which command I need to enter on the terminal, so I can check whether all allocated memory was successfully freed?
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28 views

What memory is not used by processes and freed by `echo 3 > /proc/sys/vm/drop_caches`?

Without programs open, my computer uses about 512M of memory. Yesterday, I had nothing open, yet 2 GB of mem use (used - cache = 2153): total used free shared buffers ...
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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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46 views

What proportion of memory does the Linux kernel use of the installed RAM?

I'm developing a compute cluster and I'm trying to determine the maximum amount of RAM I can give to a single process. On a machine with 16GB of ram, the answer is that I can allocate (and touch) ...
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25 views

malloc(): memory corruption on Oracle Virtual Box [on hold]

I have a code which run great on an OpenSuse laptop, but I get a malloc(): memory corruption error when running it on windows via OpesnSuse installed on Oracle Virtual Box. Is there a setting in ...
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41 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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39 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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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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745 views

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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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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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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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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47 views

Process Being Killed due to low swap

I'm running a python (2.7) script on mac osx yosemite. The script is fairly computationally intensive, certainly bumping up against my machine's RAM limitations. The computer crashes and restarts ...
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1answer
63 views

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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57 views

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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1answer
105 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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1answer
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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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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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2answers
59 views

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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Do I need swap space if I have more than enough amount of RAM?

From what I understand, the purpose of a swap partition in Linux is to free up some "not as frequently accessed" information from RAM and move it to a specific partition on your harddrive (at the cost ...
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2answers
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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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1answer
79 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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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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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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1answer
34 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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1answer
78 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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1answer
49 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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1answer
81 views

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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1answer
25 views

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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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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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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Java process gets killed frequently by OOM - Killer on upgraded hardware

I am running solr on an Ubuntu server along with 4 other java processes. Current index size is 30 GB. My solr process gets killed frequently in few hours. It clearly mentions that its an OOM killer. I ...
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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
63 views

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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2answers
528 views

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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240 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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493 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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What uses Linux “application memory”?

Just for fun, I wanted to watch what ls -lR / does to my "buffers" memory on a Linux system. As expected, the value increased. But I noticed that the "application memory" (i.e. "used" - (buffers + ...
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36 views

Accounting for “missing memory” from sysctl

I'm on OS X Yosemite, ran this code: unsigned long num_; sysctl((int[]){CTL_HW, HW_PHYSMEM}, 2, &num_, &len, NULL, 0); printf("AMT MEM: , %lu\n", num_); and getting back 140735340871680 ...
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1answer
89 views

Equivalent command for ``time`` for memory usage?

by using time we can easily get the information about how long a program run, I was wondering if there is any equivalent command I can use for memory usages? Like how many memory are allocated for ...
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58 views

Correctly determining the REAL linux memory usage

I have a curiosity about memory management in Linux: It is possible to determine the use of real memory? (That memory that is being used actually, without being allocated only). How can I do it? ...
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1answer
94 views

what's the difference between page cache and buffer cache?

In linux OS, you can type command "echo 3 > /proc/sys/vm/drop_cache" to release memory, and you can type command "sync" to release the memory. And in linux kernel there are two kind of cache, one is ...
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96 views

GNU Parallel Limit Memory Usage

Is it possible to limit the memory usage of all processes started by GNU parallel? I realize there are ways to limit the number of jobs, but in cases where it isn't easy to predict the memory usage ...
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take the DRAM performance of the processes into consideration when scheduling

The CFS scheduler in Linux schedules the processes based on the virtual runtime of CPU. But, the DRAM memory is the bottleneck in most of the emerging domains. Why not take the DRAM performance of ...
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55 views

Memory Required for SSH-only Linux Setup

I am attempting to set up a minimal Debian or CentOS installation for internal network access. The purpose of the setup will be to allow SSH access into the rest of the internal network—that's it. It ...
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Why does saving a KVM-QEMU VM requires additional memory?

I have three VMs running on Red Hat Enterprise Linux with 8 GB RAM, each of the VMs has 3 GB allocated, and I also run a 512 MB VM. If we also consider the guest OS's memory usage (usually 1.5 GB due ...