In computing, memory refers to the state information of a computing system, as it is kept active in some physical structure.

learn more… | top users | synonyms

0
votes
2answers
74 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 ...
56
votes
12answers
10k views

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 ...
1
vote
2answers
146 views

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?
4
votes
1answer
276 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 ...
-1
votes
2answers
165 views

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.
1
vote
1answer
328 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, ...
1
vote
1answer
29 views

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. ...
1
vote
1answer
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 ...
2
votes
1answer
133 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 ...
0
votes
1answer
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 ...
2
votes
1answer
118 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 ...
1
vote
1answer
34 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 ...
0
votes
2answers
319 views

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 ...
0
votes
0answers
11 views

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 ...
1
vote
0answers
153 views

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 ...
0
votes
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?
2
votes
0answers
89 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 ...
0
votes
2answers
1k 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] ...
7
votes
1answer
544 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 ...
1
vote
1answer
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 ...
2
votes
0answers
48 views

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 + ...
1
vote
1answer
50 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 ...
2
votes
1answer
142 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 ...
0
votes
0answers
70 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? ...
4
votes
1answer
141 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 ...
3
votes
1answer
135 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 ...
1
vote
1answer
35 views

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 ...
0
votes
1answer
69 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 ...
3
votes
0answers
136 views

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 ...
0
votes
0answers
522 views

Increasing ulimit stack size benefits?

Hello I'm new in Linux and at my work I have a server that runs a banking software. The company that made the software said that the stack size should be set to unlimited. Does this make the software ...
3
votes
4answers
577 views

Memory consumption Fail2Ban CentOS

Fail2Ban is using a huge amount of memory on my system (1.2 GB). There are several articles which describe how to reduce it. Below is an example for Debian. append the 1ulimit1 command to ...
3
votes
2answers
371 views

Less resource hungry alternative for piping `cat` into gzip for huge files

I have some files of which some are very large (like several GB), which I need to concatenate to one big file and then zip it, so something like this: cat file1 file2 file3 file4 | gzip > ...
1
vote
0answers
308 views

About mem and vmem

I am working with a cluster machine running under linux. I have a shell script that uses mpirun to submit my jobs to the cluster machine. In that same script, I can choose the number of nodes that ...
5
votes
1answer
284 views

List all files that are present in the cache

This question answers to the question on how to find the what is part of cache. However, in the fincore executable you have to pass the filename to check if it is part of cache. Is there a tools or a ...
1
vote
1answer
102 views

Linux server Cpu,memory,swap,run que value to display in percentage

how to write a script to get a linux server below details: CPU |Memory |Swap |Run Queue Peak(%) Relative Avg(%)|Peak(%) Relative Avg(%) ...
1
vote
2answers
811 views

How to monitor use of Huge Pages per process

I'm trying to determine which process is using a large number of Huge Pages, but I can't find a simple Linux command (like top) to view the Huge Page usage. The best I could find was $ cat ...
2
votes
1answer
5k views

How to check which process is using most memory

When I check free in one of Prod server it showing 70% of memory is being used: total used free shared buffers cached Mem: 164923172 141171860 23751312 ...
0
votes
1answer
25 views

attaching to Unix shared segment

Can a UNIX program running as root attach to a shared memory segment created by another user with permissions allowing access only to creator?
1
vote
2answers
108 views

Find average CPU, vMem, sMem usage on 1, 5, and 15min

I am trying to find at time T the average CPU usage on 1, 5, and 15min, just like what you get from /proc/loadavg Same thing for virtual memory, and swap memory. I would be fine with a python ...
1
vote
3answers
847 views

Actual memory usage of a process

The following are the memory usage of mysql and apache respectively on my server. As per the output of pmap say, mysql is using about 379M and apache is using 277M. [root@server ~]# pmap 10436 | ...
0
votes
1answer
275 views

Opening files of size larger than RAM, no swap used.

I found myself asking this question while doing small experiments and reading upon how memory is managed in Linux. I have a 64-bit Centos 6.5 machine with 512M RAM and 1G SWAP. I created a 1GB file ...
1
vote
1answer
122 views

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 ...
3
votes
2answers
414 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?
15
votes
3answers
457 views

How to force Linux kernel to “freeze” (or nearly freeze) for a few hundred milliseconds

We are running a real-time process on a non real-time kernel (CentOS 6), and this is probably not going to change. We have a streaming video application that requires about 500 MB/s of PCIe traffic ...
1
vote
1answer
94 views

Why can't I see my file in RAM?

In nano, I created a simple text file named 'blue_pink_red_orange_green' with the following contents: red blue orange green pink I then opened the file again and did: sudo strings /dev/mem | ...
0
votes
0answers
48 views

Zone Normal range in system with 4G RAM

I have a 4GB RAM in my system. Following is my BIOS provided RAM map. [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009d7ff] usable [ 0.000000] BIOS-e820: [mem ...
1
vote
2answers
2k views

Using only 3.3GB but I have 8GB RAM even on Ubuntu 14.04 64bit

I have 2x 4GB(8GB) RAM installed on my motherboard and BIOS/UEFI can confirm it, but on Ubuntu 14.04 64bit only has 3424776kB or 3.266120911GB. uname -a returns: 3.13.0-36-generic #63-Ubuntu SMP Wed ...
1
vote
2answers
118 views

How to get a procesess's actual memory usage (including data in swap)

I'm trying to check how much memory strain a process is actually putting on the system, but ps, top and friends are almost useless for that purpose as they only report 3 statistics: RES - the ...
0
votes
1answer
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 ...
1
vote
1answer
77 views

benefits of huge pages on a laptop/desktop

I have read about huge pages and its the (potential) benefits. However, I am still confused whether this is mostly beneficial on a server with lots of RAM, or if it can be advantageous on a ...