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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11
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6k views

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?
0
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1answer
38 views

HDD indicator blinks when I run out of memory, but I have no swap configured [duplicate]

I'm running Arch Linux, with 8 GB memory and no swap defined. Sometimes it ran out of memory, then my system get a little bit stuck, and I can see the HDD indicator blinking. Then I restart X, which ...
2
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2answers
86 views

Linux-swap on reboot

I'm wondering what actually happens to a Linux-swap partition reboot. I've been taking a course in computer organization and while installing/partitioning a new drive I became rather curious about ...
0
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1answer
63 views

How to create memory-based disk in linux? [duplicate]

I need to have a very fast disk for keeping cache. How can I do that in Linux?
6
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3answers
8k views

Swap usage too high?

I have a debian sid box, freshly installed about a month ago, with no desktop apps running at the moment. Any command I try to run (via ssh) makes the hard disk work very hard. The system worked ...
54
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5answers
24k views

What are high memory and low memory on Linux?

I'm interested in the difference between Highmem and Lowmem: Why is there such a differentiation? What do we gain by doing so? What features does each have?
1
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0answers
302 views

CentOS memory allocation

I was running my VPS with CentOS on 1G memory, but I saw the memory was getting "full" so I had 1G extra installed. This VPS is one I rent at a hosting company. That company did most of the ...
2
votes
0answers
134 views

Writing to Arbitrary Memory Addresses [closed]

I'm reading "Art of Exploitation 2nd Ed." and I have a question regarding a section on format string attacks. Target program Below code (fmt_vuln.c) is a target program. #include <stdio.h> ...
1
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2answers
225 views

Swap bash script pins htop's memory usage

I deployed a hack to add swap space to a VPS that otherwise didn't allow me to use swapon to create a file. Prior to adding and executing the script, I followed the steps outlined here. and ...
4
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1answer
213 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 ...
15
votes
2answers
909 views

Linux: Total swap used = swap used by processes +?

So, I'm trying to do some investigation on where does swap use come from in a system with high swap usage: # free total used free shared buffers cached Mem: ...
2
votes
2answers
233 views

How to reuse Physical memory in the absence of swapping?

How can I reuse physical memory in the absence of swapping?
2
votes
2answers
1k views

gnome-keyring-daemon couldn't allocate secure memory

I run logcheck on my Debian Linux system to get alerted to unusual lines in my log files, and recently I saw the following in /var/log/messages: gnome-keyring-daemon: couldn't allocate secure memory ...
2
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2answers
236 views

lsof - debug the output information

I was going through the questions of this site. In this particular question, I see the command lsof being used to list the files that are open for a particular user. I ran the below command in my ...
2
votes
1answer
309 views

Know when a memory address is aligned or unaligned

Im getting kernel oops because ppp driver is trying to access to unaligned address (there is a pointer pointing to unaligned address). Im not sure about the meaning of unaligned address. It means not ...
6
votes
2answers
1k views

What is “kernel dynamic memory” as reported by smem?

While diagnosing low memory problems in my desktop machine (details at U&L) I've noticed that my noncache "kernel dynamic memory" is big: # smem -twk Area Used ...
2
votes
2answers
157 views

How does a process handle the situation when it finds no memory to use?

What happens when a particular process finds that there is no memory to use? Will that process kill/restart another process to proceed their task ? Or what the process (that requires more memory) ...
0
votes
1answer
90 views

Running git with higher memory allocation

I am facing memory/data segment issues while running git. However, if I set my ulimits to a bit higher like below. ulimit -m 262144 ulimit -d 262144 It runs fine. Don't we have anyway to allocate ...
3
votes
0answers
641 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 ...
4
votes
2answers
375 views

Copying large file causes excessive swap

On a mid-class CentOS 6.4/64 server with 32 GB RAM, 3 TB free disk space, operating as KVM hypervisor, I start copying a 200 GB file to a destination in the same local filesystem. In fact, this file ...
0
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0answers
27 views

Can Any one Suggest good Linux OS Tutorial? [duplicate]

Can Anyone suggest me good tutorial regarding Linux os . My intention is to learn , 1) How Linux OS schedules the processes. 2) different process types. 3) operations on the process. 4) Linux ...
0
votes
2answers
464 views

How to monitor average stats of CPU and memory usage of a Solaris server using scripts?

I need to monitor average CPU and memory usage for a Solaris server. How can I automate the process using scripts to monitor daily CPU and memory usage and give it as an average over a month?
0
votes
2answers
228 views

Linux kernel with absolutely no virtual memory [duplicate]

I am interested in obtaining (or building myself) a version of the Linux kernel that has absolutely no virtual memory and none of its attendant overhead. No swap file, no nothing. What are my ...
1
vote
1answer
181 views

32-bit on 64-bit: memory usage for multiple processes

I'm working on a Linux hosting solution for game server software, however the software in question is 32-bit and I'd be running 64-bit on the host. Now, I know I can run 32-bit apps on a 64-bit host ...
2
votes
3answers
98 views

when awake from hibernate, will the VIRT column of top command show the swap space used by process?

top - 10:43:31 up 8 days, 1:28, 4 users, load average: 0.72, 0.57, 0.44 Tasks: 180 total, 1 running, 177 sleeping, 0 stopped, 2 zombie %Cpu(s): 8.9 us, 2.1 sy, 0.0 ni, 88.9 id, 0.0 wa, ...
1
vote
3answers
684 views

How can memtest check all memory while it is still loaded?

Inspired by this question. If you're testing your memory, you have to test all memory - you shouldn't trust any of it to be good. How can memtest effectively do this when memtest itself will consume ...
3
votes
1answer
802 views

Does segfaults mean bad memory

This is a brand new server with a new install and fresh compile of Apache/PHP with nothing crazy. Just a WordPress site hosted and I get the following. Could this just mean bad RAM? If so how can I ...
0
votes
1answer
145 views

No virtual memory (-v) item in output of ulimit -a

When I run command ulimit -a, I see no virtual memory item in the list of output of the command. It is unlimited for some user IDs though. Does that mean I am assigned no virtual memory?
20
votes
3answers
3k views

grep: memory exhausted

I was doing a very simple search: grep -R Milledgeville ~/Documents And after some time this error appeared: grep: memory exhausted How can I avoid this? I have 10GB of RAM on my system and few ...
4
votes
2answers
335 views

Memory usage command with syntax similar to the time command

What command shows the memory usage of a program, i am looking for a command that is simple to use and has similar syntax to the time command. I am trying to find the memory usage of a md5 hashing ...
2
votes
2answers
772 views

swapoff fails when overcommit_memory==2

I've disabled memory overcommitting by setting overcommit_memory=2. Now when I tried to swapoff, I get this error: swapoff: /dev/sda5: swapoff failed: Cannot allocate memory But I in fact have 0 ...
2
votes
1answer
213 views

Static files give ever changing checksum value on Linux

When I cksum large files (150MB) they will often report different checksums on each call. $ cksum test3 1233504235 170213376 test3 $ cksum test3 825031809 170213376 test3 $ cksum test3 189847968 ...
1
vote
2answers
362 views

Viewing virtual memory usage

I started 700+ threads from a single program And my /proc/[PID]/status file shows the following output. VmPeak: 7228104 kB VmSize: 7228104 kB VmLck: 0 kB VmHWM: 3456 kB VmRSS: ...
2
votes
1answer
651 views

Which processes swaps memory

I can see swap's total, used, free etc. sizes from top command. But I can't figure out which process uses swap, is it possible to find out swap memory by process? I'm running CentOS 6.3.
13
votes
4answers
5k views

How to re-load all running applications from swap space into RAM?

If my desktop run out of memory and swaps a lot then I free or kill the application wasting my RAM. But, after that, all my desktop/applications have been swapped and are horribly slow, do you know a ...
0
votes
1answer
480 views

very high buffer memory usage [closed]

Is this normal - I've never seen buffers so high? $ cat /proc/meminfo MemTotal: 16332808 kB MemFree: 1112264 kB Buffers: 10630124 kB Cached: 699400 kB SwapCached: 0 kB Active: 3262924 kB Inactive: ...
9
votes
2answers
1k views

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 ...
2
votes
2answers
225 views

a handy tool to measure memory consumption of a program [duplicate]

I develop a C code on Debian. I am looking for a program to monitor memory consumption of my code in real-time. The only value I care is the maximum RAM consumption, it should hold the value even if ...
3
votes
1answer
262 views

Use all system memory in Solaris

I am doing server testing and intentionally trying to crash a virtual Solaris server by using all memory. Server has a ulimit of 15 GB (several hundred GB of total system/swap memory). Is there a ...
3
votes
1answer
2k views

/proc/meminfo MemTotal =?

What elements of /proc/meminfo sum up to MemTotal? Example of tee /tmp/proc/meminfo < /proc/meminfo MemTotal: 1279296 kB MemFree: 164092 kB Buffers: 62392 kB Cached: ...
0
votes
2answers
221 views

what is an application pool?

I'm reading this article: http://www.modrails.com/documentation/Architectural%20overview.html#web_app_models It talks about how Phusion Passenger extends Apache2 to act as an application server. ...
2
votes
4answers
6k views

What is “System Memory ” displayed in nmon in AIX?

I have a host with AIX 6.1 (6100-04-02-1007) upgraded from AIX 5.1 with Veritas Storage Foundation 5.1. Since the upgrade from AIX 5.3 to 6.1, Run vx services means a lots of memory consumed that I ...
0
votes
1answer
96 views

What is meant by “a process has open handles to system objects”? [closed]

The following are qualities of a process: virtual address space executable code open handles to system objects a security context a unique process identifier environment variables a priority class ...
1
vote
1answer
115 views

Eclipse makes laptop unusable

Currently I can't use my eclipse project. I'm using ArchLinux: -` .o+` rkmax@satellite `ooo/ OS: Arch Linux ...
3
votes
3answers
68 views

Contents of stack area of a process

I've been going through some Unix text books and I can't have a clear picture on the contents of the stack area of the process. Can anyone please explain or point out some references?
6
votes
0answers
258 views

Allocated Memory difference in xen guests after using Linux 3+ kernel [closed]

Can someone explain to me why there is a memory difference in Guests with the same configuration? Hypervisor: xen 4.2 64 bit VM1: Centos 5.7 with 2.6.18-274.el5xen Assigned memory from xen is ...
1
vote
1answer
398 views

private memory calculated by pmap, a combination of virtual memory size and resident memory size?

You can use the ps command to get the virtual memory size and the resident memory size of a process: $ ps aux | grep apache2 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME ...
2
votes
1answer
234 views

pmap and memory usage

On Ubuntu 12.04, I have several apache2 processes running (the 1130 parent and the children it spawned), and as you can see, they have around 300-400 mb of virtual memory and 10 mb of resident memory: ...
3
votes
0answers
110 views

What does hierarchy support do in cgroup?

cgroup has 2 options for memory control: memory.use_hierarchy = 1 : use hierarchy memory.use_hierarchy = 0 : use flat hierarchy, according to this answer What is the difference between the two? I ...
10
votes
3answers
538 views

After researching, still confused about monitoring RAM usage

I went through this article, which explains various methods for checking your RAM usage. However, I can't reconcile the different methods and don't know which one is correct. When I first login, I'm ...