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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Linux memory usage?

We have 1TB of memory on a server which hosts an SAP application. When the app is running the memory usage shown in top is around 700GB. When the app is stopped the memory usage shown in top comes ...
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How much memory is lost on startup

I was wondering the following: As I start my computer and Xubuntu, it starts many programs before the login screen. Is it possible to measure by Valgrind the total number of lost bytes during startup? ...
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436 views

How to reduce chrome's virtual memory usage?

I am running a Debian Jessie and having memory issues when using Google Chrome I tried disabling extensions, disabling cache, flushing the cache, and disabling the web 3d rendering, but nothing ...
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0answers
48 views

Cgroups - memory subsystem

I want to set the memory.limit_in_bytes parameter for a control group and disable OOM, so processes freeze when the limit is reached. But i want to change that limit dynamically, if there is more ...
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1answer
677 views

What is equivalent to Mac's purge in Linux?

In Mac I use purge to free up some memory. What is equivalent to it in Linux(Ubuntu Server)? apt-get install purge gave me nothing. If you are no familiar with Mac's purge here is it's man page: ...
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9answers
10k views

Why can't Vim open a 100 MB text file when I have 16 GB RAM?

I have a 100MB MySQL database backup file and I have trouble to open it in Vim on my Linux box that has 16G of RAM. Vim just hangs (at least unusable). This is something I don't understand. I have 16 ...
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2answers
147 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 ...
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1answer
379 views

How to compute Linux slab memory leak in GNU/Linux ( proc/slabinfo ) of running process

How to compute Linux slab memory leak in GNU/Linux ( proc/slabinfo ) of running process ? I'm want to free usage is not working properly . I want to way how to check Memory Usage & Memory Leak ...
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1answer
330 views

How to figure out memory leaks? [closed]

I'm running Ubuntu 14.04 on Digitalocean to host my blog. I'm using HHVM + nginx + MySQL. Every few hours (~12h), there's no more RAM left and nginx throws an 502 error. I check the memory usage for ...
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1answer
76 views

Random application crashes in Linux

Sometimes after booting my computer, some applications fail to start: they crash. They're usually the largest ones, such as firefox, thunderbird or virtualbox. Rebooting or cleaning the cache usually ...
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2k views

Will Linux start killing my processes without asking me if memory gets short?

I was running a shell script with commands to run several memory-intensive programs (2-5 GB) back-to-back. When I went back to check on the progress of my script I was surprised to discover that some ...
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2answers
274 views

How to mount a dd-image which was created via fmem (memory dump tool)

I'm quite new to Linux. I've used the tool fmem for creating a memory dump dd-file. That works fine. But how can I access this image? I've tried it with mount but it says I have to specify a ...
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2answers
228 views

Out of Swap - What happens?

On my debian VM machine with 512MB RAM and 348MB Swap, what will happen if i open a 1GB file in an editor and get out of memory? Will it crash the system? Or if not, how will linux handle this? ...
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1answer
466 views

What do the different memory counters in FreeBSD mean?

top tells me: last pid: 64807; load averages: 0.99, 0.97, 0.92 up 189+04:47:22 09:16:17 45 processes: 1 running, 44 sleeping CPU: 0.4% user, 0.0% nice, ...
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2answers
78 views

Swap to RAM, or not

Having a 32-bit system with 4G RAM and 7G swap. Linux 3.5.0-49-generic i686. From time to time the memory bank is filled up and everything lags down. In 99% of the cases it is Chrome using vast ...
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293 views

How to limit the total resources (memory) of a process and its children

There are plenty of questions and answers about constraining the resources of a single process, e.g. RLIMIT_AS can be used to constrain the maximum memory allocated by a process that can be seen as ...
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2answers
378 views

Does BIOS read directly the bootloader or load it into RAM?

I'm trying to understand the very first steps of the boot process. The CPU read the BIOS It reads a fixed address instruction It will jump to the first BIOS instructions address It will execute ...
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1answer
103 views

Virtual Memory Usage Exceeding Physical Drive Space

I have a machine running Ubuntu on Amazon EC2. The machine has a 43 Gb root drive and 30 Gb of RAM. I am running a processor and memory intensive process and I've noticed that it sometimes stalls for ...
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1answer
139 views

xentop gives static info about memory usage

I am using CentOS 6.5 and Xen 4.2.4-30 xentop does not change MEM(%) at all. NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k) MAXMEM(%) VCPUS NETS NETTX(k) NETRX(k) VBDS VBD_OO ...
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1answer
46 views

Memory consumption of a script

Is there way to check the memory (physical & virtual) consumption of a script, of course in the moment of its execution. Calculating the used memory minus the used memory before and after the ...
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1answer
208 views

Does 'ulimit -m' not work on (modern) Linux?

This article claims that the -m flag to ulimit does nothing in modern Linux. I can find nothing else to corroborate this claim. Is it accurate? You may try to limit the memory usage of a process ...
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1answer
101 views

How to extract running Apache configuration from core dump?

Apache is loading the configuration from files into its memory. If the config files are changing the Apache process won't activate it until a reload/restart happens. Now I have to debug the current ...
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1answer
685 views

How to display `top` results sorted by memory usage in real time?

How can I display the top results in my terminal in real time so that the list is sorted by memory usage?
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1answer
262 views

Fastest `uniq` tool in linux

I have large text file (1.5 G), I want to know what the fastest and more reliable tool in linux is. I usualy use: awk '!x[$0]++' file.txt But when I use htop command I see my memory usage is ...
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2answers
1k views

Debug out-of-memory with /var/log/messages

The following report is thrown in my messages log: kernel: Out of memory: Kill process 9163 (mysqld) score 511 or sacrifice child kernel: Killed process 9163, UID 27, (mysqld) total-vm:2457368kB, ...
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2answers
108 views

cannot find what has used all the memory

The server has about 24GB memory. By running free -g I find the memory is used up total used free shared buffers cached Mem: 23 23 0 ...
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1answer
872 views

What would happen if the amount of free memory (vm.min_free_kbytes) was too low?

I came across the following parameter in kernel settings (in sysctl): vm.min_free_kbytes This is the amount of free memory (RAM) that's always free no matter what. In my case, I have only 1 GiB of ...
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3answers
477 views

how is page size determined in virtual address space?

Linux uses a virtual memory system where all of the addresses are virtual addresses and not physical addresses. These virtual addresses are converted into physical addresses by the processor. To ...
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1answer
98 views

buffer cache and free memory

Below is the output of free in Ubuntu: $ free total used free shared buffers cached Mem: 8173180 8013092 160088 0 1076276 3091136 -/+ ...
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1answer
85 views

32 bit OS memory limitation on NUMA systems

Running 32 bit Rhel 6.5 with kernel 2.6.32-431.el6.i686 on a server with 46 Gb RAM and NUMA support. CONFIG_X86_PAE=y Intel(R) Xeon(R) CPU E5-2660 0 @ 2.20GHz OS is not able to see more than 14GB ...
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0answers
279 views

About Linux Memory Compaction (CONFIG_COMPACTION)

I have a question regarding memory compaction on Linux. Generally compaction is triggered when system cannot satisfy a large contiguous memory allocation. This causes the compaction to run on all ...
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2answers
448 views

/proc/pid/maps addresses (and converting them)

When looking at the memory maps in /proc/pid/maps, we can see different length addresses 00400000-0042e000 r-xp 00000000 fb:01 268953 /bin/nano 0062e000-0062f000 r--p ...
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1answer
665 views

kernel: disabling /dev/kmem and /dev/mem

I understand that /dev/kmem and /dev/mem provide access to the memory (i.e. raw RAM) of the system. I am also aware, that /dev/kmem can be completely disabled in kernel and that access can be ...
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0answers
49 views

Getting non-stored password from Icedove

I've recently changed my mail password (because of Heartbleed), but I've forgotten the new one. When entering the new password in Icedove, I didn't think of clicking "remember password", but the ...
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1answer
46 views

Is memory in user space always low to high

I mean that if its true always that first lower addresses are used and then increment the address to access higher address. Can it be in reverse order?
5
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1answer
74 views

How the network packets are transferred to the memory on linux?

Is there some command or tool for monitoring network packets and how those packets are handled by the memory and than proceeded to the CPU on linux platform? Using tcpdump I can capture many apache ...
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1answer
40 views

Configure the OOM to avoid having the system grind to a halt

I have an SSD and therefore no swap. However, when I open a lot of tabs in the browser, the system tends to grind to a halt. If I'm lucky, I can close one or two tabs before the system is completely ...
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0answers
254 views

Debian 64-bit sees less than 4GB of RAM

I have a Debian wheezy (7.4) amd64 virtual machine running under VirtualBox 4.3.10 on a Win7 x64 host with AMD A10-5700 processor. The virtual machine is configured with 16GB of memory (the host has ...
2
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1answer
487 views

Why is swap used when a lot of memory is still free? [duplicate]

In the below 2.6.18 Linux Kernel (Red Hat) server, there is a lot of free memory, but I see some swap is used. I always thought of swap as an overflow when memory has been depleted. Why would it ...
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1answer
108 views

Can continually assigning a variable in a shell script cause a memory leak?

I've written a short script to copy Apache's server status to a log: #Save date and time to a variable dt=$(date) #Echo date and time to the log file as it's not included in server-status echo "Time ...
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1answer
48 views

Having an independent console to kill rogue process?

Sometimes a flash plugin starts using all the mem and CPU or an app is also behaving "naughtily" and my system starts to crawl until i finally get a terminal with htop up and kill the rogue process, ...
2
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0answers
169 views

What is the structure of Libvirt Qemu VM dump/save files?

I need to do some exploration of Qemu-KVM virtual machines physical memory (particularly I need to check the fact of the physical memory intersection). In order to do that I'm trying to save VM's ...
2
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0answers
73 views

Set up OS and Runnig app using x32-ABI

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 they ...
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1answer
84 views

What happens to the files when they are being decrypted?

I have the server's webroot directory mounted on a partition which is being protected with LUKS encryption. I want to know what happens to the files within when that partition is being decrypted. Does ...
2
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0answers
66 views

Automatically memtest and then boot

Is there some way to reboot server, so it runs memtest (say, 1 or 2 passes) and then reboots back to Linux and writes report to some log? This feature in Windows Server 2012 helped me to diagnose bad ...
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3answers
764 views

On system memory… specifically the difference between `tmpfs,` `shm,` and `hugepages…`

I've been curious lately about the various Linux kernel memory based filesystems. Note: As far as I'm concerned, the questions below should be considered more or less optional when compared with a ...
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About the usage of Memory in a linux server [duplicate]

I find my server's memory usage is so high, part of the output of command free is shown below: total used free shared buffers cached Mem: 82446460 81961412 ...
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1answer
2k views

How to dump memory image from linux system?

I know to dump memory images in Window. (eg-dumpit) But I don't know how to dump memory images in Linux. I wanna get memory images in Linux and from linux to linux with ssh connection or something. ...
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1answer
41 views

program executing for 2 days

I have a java program which implements the Hungarian algorithm. I made changes to the existing code in such a way that the input is read from file. I have a pretty huge input around 32,000 rows for ...
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7answers
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cron Vs. sleep - which is the better one in terms of efficient cpu/memory utilization?

The Case: I need to run some commands/script at certain intervals of time and for this I have two options - 1. set up a cron-job or, 2. implement a loop with sleep in the script itself. Question: ...