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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6answers
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How to find which processes are taking all the memory?

I'm looking for somthing like top is to CPU usage. Is there a command line argument for top that does this? Currently, my memory is so full that even 'man top' fails with out of memory :)
1
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2answers
117 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
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3answers
2k 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
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1answer
343 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 ...
2
votes
1answer
426 views

How do you track memory usage in a ksh93 script

We have a number of ksh scripts that run forever (inside a while loop), or at least until a shutdown event is delivered to them. We had a project where these scripts where converted to ksh93 (and ...
15
votes
3answers
508 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
100 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
60 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 ...
0
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2answers
718 views

Is Inactive memory related to the Commited but unused?

From the Linux procfs documentation: Active: Memory that has been used more recently and usually not reclaimed unless absolutely necessary. Inactive: Memory which has been ...
1
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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 ...
4
votes
1answer
2k views

How to monitor RAM ECC errors on Ivy Bridge Xeon E3 processor in Linux?

How can I monitor if there are any errors in RAM that get corrected by ECC? The processor is an Intel Xeon (Ivy Bridge) processor, the operating system is Scientific Linux 6.3. On a previous system I ...
1
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2answers
144 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 ...
10
votes
2answers
850 views

Reserve fixed RAM memory region as a block device ( with a given start physical address)

There have been a lot of questions about RAM Disks and I am aware of ramfs and tmpfs which allow the use of ram as a block device. However my interest is in using a fixed memory address range as a ...
1
vote
1answer
87 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 ...
4
votes
2answers
539 views

Centos 6.5 only using 24GB/48GB of memory

I recently installed an additional 32GB of memory in my Dell PowerEdge R900 home virtual machine server. Memory check passed and I booted into CentOS. When I opened the Virtual machine manager and ...
1
vote
3answers
960 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
615 views

How to get the Physical memory usage in Solaris using commandline

I need to show physical memory statistics in Solaris, like total memory, used and free memory. Don't want to create a script, so is it possible to get all these details using commandline only?
0
votes
1answer
198 views

Fedora 20 memory.limit_in_bytes not working

Fedora 29 (kernel 3.15.10-201.fc20.x86_64) This worked in F19. I'm trying to use cgroups to limit memory usage for some apps that are prone to misbehaviour, and I'm encountering problems. I'm ...
2
votes
1answer
176 views

Find something that is occupying lots of memory and not visible in `ps` or similar

I have a VM that's having memory issues. One of the tasks I'd like to run in it is crashing with out-of-memory errors. However, when it crashes, the system still stays memory starved. I'm not sure if ...
2
votes
1answer
351 views

Dirty in /proc/meminfo for dd

I read from here that the below command gives me the amount of data that needs to be written to the disk. grep ^Dirty /proc/meminfo It particularly says Ever ask yourself "How much data would be ...
10
votes
1answer
7k views

How OOM killer decides which process to kill first?

This answer explains the actions taken by the kernel when an OOM situation is encountered based on the value of sysctl vm.overcommit_memory. When overcommit_memory is set to 0 or 1, overcommit is ...
1
vote
1answer
43 views

RHEL 5 Server running with 8 core. Load is always 0 or 1. but RAM (8GB) always occupied

I am seeing load is 0 or 1 since a few weeks on my RHEL5 server with 8 cores. But RAM always fully occupied. I am trying to debug the issue. How can we diagnose where memory is going?
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vote
2answers
277 views

How to increase the memory used by Java in linux?

I have a program Vuze that is written in Java, which I use to download very large files, and I'm having a problem with it. I need to increase the amount of memory it uses. I've followed the directions ...
1
vote
1answer
96 views

Memory usage stays high after compilation jobs

I am operating a small Linux VM with 1Gb of RAM. It is a fairly typical LAMP setup which takes about 16% of memory on normal usage I used the box to compile stuff yesterday, the memory went up to 60% ...
0
votes
0answers
61 views

how to limit dma address to specific range in linux kernel?

I want to limit the dma address the device can access to 0x0100_0000~0x03ff_ffff. But I don't know how to set the dma_mask and coherent_dma_mask. It's easy to set the "dma mask" for a range start ...
2
votes
2answers
307 views

How to compare usage of memory by Window Managers?

I'd like to test a few window managers to see which of them takes less memory and CPU in certain time period (so is better choice for older computers). I'd like to make the tests myself (not to read a ...
2
votes
2answers
3k views

find out the memory allocated for a particular process in ubuntu

Could anyone please tell me how to find out the memory allocated for a particular process in ubuntu?
1
vote
0answers
197 views

Swap appears to not be in use

(I am currently using Ubuntu 14.04 LTS, GNOME environment) tl;dr How can I force more memory swapping (swappiness already at 100)? I have recently been experiencing a lot of system freezes/crashes. ...
0
votes
3answers
258 views

Lots of free memory, but Java won't start (SunOS 5.10)

vmstat gives: swap free 37489684 110178592 Still I have issues, while trying to run Java process with 10g heap: > java -Xmx10g -Xms10g -d64 HelloWorldApp Error occurred during ...
1
vote
1answer
63 views

Reserve memory for a program

Is it at all possible to set aside say 50MB of memory so that in an emergency where something uses all my memory or loads the CPU I could open a terminal, find the offending process, and kill it?
2
votes
3answers
10k views

How to get free memory on AIX?

How can I see the free memory on an AIX? There is no free -m under it. AIX oslevel: 6100-03-03-0943
2
votes
2answers
153 views

Memory allocation for sparse array in awk

I have searched but didnt reach to any conclusion that when i defined an sparse array does it reserve all the contiguous memory upto maximum index or it allocate the memory at that particular index ...
10
votes
6answers
4k views

Is there a tool that allows logging of memory usage?

I want to monitor memory usage of a process, and I want this data to be logged. Does such a tool exist?
1
vote
0answers
230 views

Inexplicable high memory usage (apparently not caused by programs, buffers, cache, or slab cache)

I've got a server that claims 1.7 of its 2 GB of RAM are used, but the combined memory usage of the running processes doesn't come anywhere near that figure: $ free -m total used ...
4
votes
1answer
16k views

How to find Heap memory of a running process? [duplicate]

I would like to know how to find the heap memory of a process that is running in the background. Is there any command that allows such?
0
votes
2answers
120 views

Use/See whole the flash memory space

When we bought a N Giga Byte flash memory, the free space that the OS provide for us, is less than N GigaBytes. For example, for a 2 GB flash memory, total space that we can use, is 1.86 GB. As far ...
0
votes
0answers
48 views

Is there anything in RHEL 6.5 that would affect I/O speed for something <24K vs >24K?

Generally, transactions for my app of setting and getting data internally are measured in a couple of millis. However, over 24K in size, that time can jump to just over 100 millis. Is there anything ...
6
votes
2answers
2k views

Defragging RAM / OOM failure

This question is fairly lengthy, so I'll ask the questions at the top and then go through my method of coming to the questions: Did (Busybox based) rm not execute because there wasn't enough ...
1
vote
1answer
135 views

Fastest and Safest way to increase Swap Space on Scientific Linux

Memory Swap Ratio Company System Today, a monitoring system indicated that one of the systems in the company has run out of memory. Executing htop on this system indicated that the Memory was nearly ...
1
vote
2answers
180 views

Why does Linux only see 3832MB of my 4096MB of RAM?

I am setting up a lot of 64-bit RedHat VMs (VMware vSphere) for our development department in my company. Most of them start with 4096MB of RAM, but Linux only seems to recognize 3832MB. Can anyone ...
-1
votes
1answer
152 views

How to prevent certain memory location to be accessed [duplicate]

I have 2 corrupted RAM module, on offset: 46xx MB and 13xxx MB (from memtest on boot) How to prevent Linux to access/alloc/read/write into those offset? Here's the result of memtester on ~1000 MB to ...
0
votes
1answer
76 views

How can I tell if lack of memory is causing these crashes?

I have a tornado web server running a flask application that connects to a postgres 9.3 database on an ubuntu 12.04 box. The application has been crashing intermittently and I am trying to understand ...
1
vote
1answer
819 views

Real vs Actual memory in Xymon/Hobbit

What is the difference between real and actual memory usage in xymon ?
0
votes
2answers
248 views

What are the positions in `free` called?

I am trying to compare the output of free with the output of sar -r: # sar -r 12:00:01 AM kbmemfree kbmemused %memused kbbuffers kbcached kbcommit %commit 12:10:01 AM 629756 65293976 ...
24
votes
3answers
5k views

What does the vm.swappiness parameter really control?

Per the kernel documentation: This control is used to define how aggressive the kernel will swap memory pages. Higher values will increase aggressiveness, lower values decrease the amount of swap. ...
3
votes
4answers
2k views

How much RAM needed for preventing use swap?

At my system always available some "Free" and "Inactive" memory, but sometimes system move couple megabytes to swap. Per night it maybe around 100MB, but for a few days in swap could be more than ...
0
votes
0answers
69 views

Why does Android crash when stressed on Memory where as GNU-Linux keeps running?

I have two devices, an Android phone with an eGlibC stack running side by side with Bionic, and an old HP tower with Debian. My HP tower has 512 MB of RAM. My phone has 2GB of RAM. I run top on ...
3
votes
4answers
219 views

What is using memory? [closed]

According to htop and free, the machine I'm looking at is currently at 6631 / 11907 MB of RAM. That's more or less half of the RAM available. However when I sort top or htop by MEM%, the most memory ...
7
votes
2answers
2k views

How does stack allocation work in Linux?

Does the OS reserve the fixed amount of valid virtual space for stack or something else? Am I able to produce a stack overflow just by using big local variables? I've wrote a small C program to test ...
5
votes
2answers
50 views

How to monitor Memory utilization of the single process?

How to monitor Memory and CPU usage of the single process by program/executable name(not PID);