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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Exceeding memory issues on server using PHP

PHP has memory limits set at a global level in the PHP.ini file. I also know that they can be configured at the local level. Our memory limit for a query is set to 132MB, but we keeping getting ...
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High memory usage but no process is using it

I run free -m on a debian VM running on Hyper-V: total used free shared buffers cached Mem: 10017 9475 541 147 34 909 ...
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6answers
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How to display meminfo in megabytes in top?

Sometimes it is not comfortable to see meminfo in kilobytes while you have several gigs of RAM. In Linux it looks like that: And here is how it looks in Mac OS X: Is there a way to display ...
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1answer
847 views

Java/malloc memory corruption error when running SDK Android Manager

I want to install Android SDK, so I manually installed Java JDK 7u51, downloaded SDK ADT bundle for Linux x64, and tried to run it. When I run android, the SDK manager windows hangs halfway through ...
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2answers
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How to reduce ClamAV memory usage?

I'm running a Ubuntu based web server (Apache, MySQL) on a 512MB VPS. This is more than sufficient for the website it is running (small forum). As I wanted to add some protection against viruses I ...
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1answer
17 views

Get current memory usage of a tmux session

As the title says. I need a way to the used memory of a current tmux session. I am not sure if that is even possible. I am using tmux to start multiple minecraft servers I'd like to know each servers ...
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3answers
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why we need ram if we having swap memory? [on hold]

In Linux we have a swap memory right. the system will use swap memory if ram memory is full.then what is require of RAM we can use directly swap memory.
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3answers
2k views

Discrepancy between reported used memory and sum of application memory usage

I'm running a desktop system that quite regularly suffers from lack of memory, this prompted me to investigate what causes the issue in the first place. Problem is, there's no single process that ...
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1answer
93 views

SOLVED Linux mint 17.1 keeps crashing

MODERATOR PLEASE CLOSE I have recently installed Linux Mint 17.1 Cinnamon on an Compaq presario c700 w/intel pentium dual core. It is dual booting with windows vista. The partition size is 19gb. I ...
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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 ...
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1answer
47 views

Why is the size of “/proc/kcore” file so bigger than the physical memory size?

From proc manual: /proc/kcore This file represents the physical memory of the system and is stored in the ELF core file format. With this pseudo-file, and an unstripped kernel ...
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1answer
26 views

Downsides of processes with high virtual size but low RAM and GPU memory use

I have noticed that some of my processes take a lot of virtual size in my computer. I understand that the virtual size of a process is the sum of memory it is actually using, memory it has mapped into ...
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1answer
19 views

FDT relocated by U-Boot cannot be accessed by Linux (in highmem)

We run a customized version of U-Boot on an ARM-based embedded system and would like to load Linux 4.3 with a device tree blob. The system features 1GB of RAM of which the top 128MB are reserved for ...
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1answer
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1answer
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Is forcing an application to release some the allocated memory possible?

Ever since I came back to Firefox a year or so ago I have been facing the same issue over and over again - the browser just keeps eating up my memory. The problem arises from (maybe the incorrect ...
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5answers
6k 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?
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2answers
19 views

Swap used even though most memory is “cached”? [duplicate]

I'm trying to make sense of this free -m output: total used free shared buffers cached Mem: 7971 7608 363 1 17 4703 ...
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0answers
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Question about DMA mapping API in Linux [migrated]

In Linux, some APIs are provided to do DMA mapping. My question is about "dma_alloc_coherent", it is defined in "linux/dma-mapping.h". And in the DMA-API.txt, it says: void * ...
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6answers
120k 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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2answers
36 views

How much RAM should an SSH connection typically use?

I'd like to ask about how much memory an SSH connection should take typically. Here is how I'm finding out how much of a RAM hit is incurred: Kindly don't get vehement that I'm using a GoDaddy shared ...
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1answer
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Redhat: Swap Memory Used is Much Higher Than Total

The top command showed the following information: Mem: 132110132k total, 10447536k used, 121662596k free, 76120k buffers Swap: 16777212k total, 18446744063504593392k used, 10221735436k free, ...
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12answers
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How to fill 90% of the free memory?

I want to do some low-resources testing and for that I need to have 90% of the free memory full. How can I do this on a *nix system?
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1answer
2k views

Is it possible to find the physical address range of a DIMM?

I note that SMBios Type 20 would help here, but it's optional as of version 2.5 (2006-09-05) pp. 25, L796, and pp. 131, whereas types 16, 17 and 19 are mandatory, but don't quite help. Physical ...
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0answers
31 views

Why does /proc/*/status not account for all swap used on a system?

I have a system that has been swapping recently and am unable to account for all swap that is shown as in use by tools like 'free' or 'top'. Specifically, I can account for 19GB of 28GB swap used ...
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1answer
30 views

determine the actual memory usage of several processes that share a large memory segment

I just took a look at the output of top and it showed me (amongst other processes) the following: As once can see I have ten processes consuming approx 10GB each so 100GB in total. The computer ...
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0answers
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PDOException: SQLSTATE[HY000]: General error: 23 Out of resources when opening file xxxx.MYD' (Errcode: 24) [duplicate]

I am getting this error message when trying to access a php page: PDOException: SQLSTATE[HY000]: General error: 23 Out of resources when opening file xxxx.MYD' (Errcode: 24) How can I solve this ...
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2answers
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how to deallocate /dev/ram0

I have allocated /dev/ram0: dd if=/dev/zero of=/dev/ram0 bs=1M count=1024 Now I have 1Gb sitting in memory. How do I free up the allocated space ?
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Does Linux keep programs in RAM after 1 execution?

I read somewhere that Android/Linux keeps programs in working memory after they close so that when they're opened later then they can be opened faster. Is this true? If it is not, is there a way to ...
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2answers
943 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, ...
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0answers
138 views

What is using 4GB of memory? (Not cache, not a process, not slab, not shm)

We have some EC2 servers that experience a memory leak over days or weeks. Eventually there gets to be many GB of memory that is used (according to tools like free and htop) and, if we don't restart ...
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1answer
31 views

Retrieve data from mem cache

Newbie to Linux. My application writes to a log file and for some reason it stopped writing to that file suddenly. We have restarted the application to fix this glitch. Is it possible to retrieve the ...
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0answers
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Any way to specify process to call on Linux when OOM activates?

On my embedded system I'd like to record when the system OOM killer actives, e.g. by setting an env. variable in u-boot. Is there any way to specify a hook function to call on the OOM event?
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1answer
42 views

What is page fault and when does it occur? [closed]

In an interview I was asked this question: what is a page fault and when does it happen?
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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 ...
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finding gyroscope memory location

How can I find the memory location of the gyroscope data for my machine? this tutorial provides a memory address for a specific device. How can I figure out what my memory location should be? I am ...
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4answers
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How do I read from /proc/$pid/mem under Linux?

The Linux proc(5) man page tells me that /proc/$pid/mem “can be used to access the pages of a process's memory”. But a straightforward attempt to use it only gives me $ cat /proc/$$/mem ...
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Memory Leak trackdown

I have a server running Red Hat Enterprise Linux Server release 6.7. The server runs a number of java processes including a tomcat server with nginx webserver. The server has 12 GB of ram allocated ...
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1answer
23 views

Monitoring GPU memory I/O

Is there any way to monitor GPU memory I/O from the shell, with Nvidia graphic cards used with CUDA? I use nvidia-smi to see the current memory utilization, but I would prefer to see the deltas ...
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0answers
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My SLES 11 uses 6 GB RAM while nothing is running. How can I find out what is needing it? [closed]

Can anybody tell me what is consuming that much memory on my SLES 11 SP3 server? I suspect a serious bug in the kernel that it does not release memory allocated by an application once it quits. This ...
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1answer
52 views

Creation of the heap region/segment in Linux

It's my understanding that on Linux the process loader doesn't automatically create a "heap" region for a process like it's the case for the stack, is that correct? I used /proc/$$/maps and before ...
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1answer
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Can I mark _current_ memory contents as non swappable?

Background: in my linux (ubuntu) workstation, I want to run some experiments that allocate more memory than the physical RAM while I do other 'normal' stuff in the GUI. Problem: I have plenty of ...
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0answers
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How to decide how much memory to allocate per core for MPI app GENE?

This is required information for some MPI using app that I am working with... From its Makefile template: #insert memory per core and uncomment the following line #PREPROC= -D'MB_PER_CORE=750' ...
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8answers
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Correctly determining memory usage in Linux

I'm a bit confused on some of the results I am seeing from ps and free. On my server, this is the result of free -m [root@server ~]# free -m total used free shared ...
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Creating a sparse (automatically expanding and contracting) swap file with hole-punching support

I have this crazy idea, and want to know the pitfalls of such an approach (or whether it can even work with no deadlocks.. etc). The goal is to create an automatically expanding and contracting ...
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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?
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1answer
52 views

How to interpreted top/htop memory usage

I have a htpc/server-ish ubuntu box running at home with kodi (xbmc) and some other webservices. I noticed kodi was laggish and ssh'ed into the box to see what was going on. I saw this htop output: ...
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0answers
23 views

getting kernel: pci 0001:02:00.0: BAR 0: can\'t allocate mem resource [0x60100000-0x600fffff] on reboot

On rebooting the board we are getting following errors: err: kernel: pci 0001:02:00.0: BAR 0: can\'t allocate mem resource [0x60100000-0x600fffff] Warning: kernel: aer: probe of 0001:02:00.0:pcie01 ...
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What is the appropriate value of vm.swappiness when using zram?

I'm using zram on my computer as a compressed RAM-backed swap. When the system needs to swap something out, swapping it to a zram-backed swap file is more or less equivalent to compressing that data ...
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Why does Linux purge the memory cache when it is nearly full?

Here's what the memory graph looks like on a VPS running CentOS with 512MB of RAM and nginx/php-fpm/mysqld serving (mostly static) content to a couple thousand visitors per day. (those are days on ...
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How to identify cause of large buffer memory usage?

I have a production machine running a 2.6 kernel (Centos 6.7) with 64 GB of RAM of which 18 GB is apparently used for buffer memory. I am interested in identifying specifically what that 18 GB is ...