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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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
62k views

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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84 views

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
53 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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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
84 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
46 views

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
879 views

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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102 views

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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5answers
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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
161 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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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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2answers
4k views

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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2answers
1k views

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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2answers
167 views

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 ...
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1answer
218 views

Is there a way to know how much memory Linux Os is using?

I am looking for a way to know the size of the memory that Linux os is using (I'm not worried about the other applications memory size). I am using Ubuntu distribution (Ubuntu 15.10). Thanks for your ...
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179 views

Why are slab objects not reclaimed automatically

Everyday after a full system backup, various programs are failing with read errors until I run echo 2 > /proc/sys/vm/drop_caches to free reclaimable slab objects. For example, here's the output of ...
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3answers
170 views

Is it possible to impose some kind of soft limit on the memory consumption of processes?

I reckon it's not such an uncommon problem: one process allocates massive amounts of memory (be it due to a memory-leak bug, because you try to process an infeasibly large input file, or whatever). ...
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24 views

What does “wrap around” mean in DMA?

Recently working on a PCI driver project and trying to understand the Scatter Gather DMA. In my project, the PCI device(in a PC's PCI slot) is the DMA master and I want to do a DMA write to the PC's ...
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1answer
101 views

Does my system use all available RAM?

I installed 16GB of RAM on a motherboard that shouldn't take it. Should I buy a better motherboard or change anything at all? It seems to be working fine. Memory: Crucial Ballistix Sport "(8GBx2) ...
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2answers
125 views

Is there a way to free memory? [duplicate]

I remember, back from my days with Windows Vista/7, that there was a tool called memclear or memclean that would free some memory by invoking the NT garbage collection API. Probably it cleared cache ...
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1answer
57 views

How to find hugepage size on system?

I am getting following two different result. which one i should consider for Hugepage? [root@server ~]# getconf PAGESIZE 4096 [root@server ~]# grep -i hugepagesize /proc/meminfo Hugepagesize: ...
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1answer
663 views

How to find out how much memory lxc container is allowed to consume?

I'm trying to make ansible set InnoDB buffer pool size to some percent of available memory. But ansible_memtotal_mb and free report how much memory the host has. How do I figure out how much memory is ...
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23 views

Best small distro for ROM burning of the system for an embedded system

I am building a specific device and I would like to know what Linux based small distribution would be good when I would choose the put-Linux-on-the-ROM route, so, that the system is not possible to ...
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How to check if an application uses my video card memory?

We can check the core, cpu utiliztion, memory etc of a particular process. Can we check if it uses video card too and if it is how much memory it is using?
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4answers
20k 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 ...
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47 views

How can I profile/benchmark RAM performance?

I would like to know if my memory hardware is a bottleneck of my system performance. I am dealing with really old hardware (late 2000). If there is room for improvement, I would like to upgrade. ...
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0answers
43 views

how to enable 1MB dma-kmalloc

I'm running a ubuntu 15.10 VM and testing code that will allocate 1MB dma buffers. However, from the /proc/slabinfo, the max that can be allocated is 8K dma-kmalloc-8192 0 0 8192 4 ...
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1answer
27 views

What is taking up my memory in my Linux virtual machine

I'm trying to debug an application (mongodb) memory usage on a a virtual machine. mongod, is taking 11% of memory. I know this by using top but when I want to see how much of my 7.5GB is free, I ...
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23 views

Working my way through dmesg output on a custom 3.5.4 kernel

Having read this thread here: What does the Virtual kernel Memory Layout in dmesg imply? It sounds like 'lowmem' is exclusively meant for kernel-space. [ 0.000000] virtual kernel memory layout: ...
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2answers
30 views

What tools can I use to diagnose the exact reason for laptop slowness? And how do I use those tools?

I am running Linux Mint 17 on my laptop. When using applications (mainly Web Browsers) the machine freezes for little time periods. The CPU indicates 100% usage at such times, but this only seems to ...
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245 views

Boot rescue kernel at high memory address using kexec on arm

Summary: Crashkernel boots at 512MB address in RAM with kexec -e/-l but not with kexec -p - why? Embedded platform with Marvell Armada XP (MV78460) (ARMv7 with 4 cores) and 1GB of RAM. production ...
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239 views

Is unreclaimable memory allocated to slab considered used or available cache?

After evaluating /proc/meminfo, I see the following information: $cat /proc/meminfo MemTotal: 197852592 kB MemFree: 64755992 kB MemAvailable: 65655112 kB Buffers: 4388 kB ...
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74 views

Where is my memory being used?

Only 28G is being used by buff/cache. $free -h total used free shared buff/cache available Mem: 188G 87G 72G 17M 28G ...
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1answer
145 views

How do you prevent system from freezing when memory is used up?

I've been running a process (gdb) that can easily use up all my ram and swap space. Every time that happens the whole system becomes very non-responsive and Xorg will barely update, I can't swith to ...
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1answer
212 views

How to run free command by crontab

I want to run this command: free && sync && echo 3 > /proc/sys/vm/drop_caches && free -m by cron. That way I can free my RAM and cache in an Ubuntu system. I'm using ...
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1answer
46 views

How do I check how much total memory my VM has? [closed]

I've tried /proc/meminfo but my permission has been denied.
3
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1answer
200 views

What is the usual Allocation unit for a process on Linux?

I'm currently studying memory management in Operating Systems. Allocation Unit is the smallest unit of memory the OS will give to any process. I've read in this page, in the 'Memory allocation ...
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55 views

What does it mean when a private VM page is none of `rwx`?

UPDATE: It's a padding: every such non-rwx area is preceded with a readable and/or writable area and together they constitute a 64Mb segment (for 64bit architecture). A relevant question on SO: ...
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1answer
2k views

find: cannot fork: Cannot allocate memory

I want to delete 1 file at a time from my directory which contains so many files,So i want to remove 1 file at a time. Just to avoid too many reads and failed at too many arguments. find ...
3
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1answer
80 views

Shared memory v/s physical memory

I have a C++ process which is using shared memory to store and transfer data between its child processes. I want to check the shared memory usage while the parent process is executing just like top ...
2
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1answer
277 views

How can two identical virtual addresses point to different physical addresses?

Following a fork() call in Linux, two processes (one being a child of the other) will share allocated heap memory. These allocated pages are marked COW (copy-on-write) and will remain shared until ...
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1answer
57 views

difference between inactive and free memory in output of FreeBSD top utility?

top -d1 displays following SDRAM usage statistics on one of my older machines: 125M Active, 42M Inact, 51M Wired, 17M Cache, 34M Buf, 2720K Free In total, there is 256MiB of memory installed. ...
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1answer
73 views

Finding memory corruption bugs in Linux and FreeBSD

In windows, we can enable page heap verification using gflags to catch memory corruption bugs more easily. Is there a similar service/program for Linux and FreeBSD operating systems?
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4answers
32k 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 using bash. How do I gather this information?
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2answers
2k views

Restricting memory area for linux kernel

I am running ltib Linux on P1022RDK (P1022 Core) platform. I have 512 MB = 0x20000000 memory. I want my Linux kernel to use the second half of the board memory (i.e from 256 MB to 512 MB) and want the ...
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0answers
104 views

wProcess killed by OOM killer when plenty of memory apparently free

I'm working on an embedded ARM-based platform. 32-bit, 512MB of RAM, no swap. Linux 3.10.53 (some variety of Ubuntu, if that's relevant). Some code I'm working on is getting consistently oom-killed, ...
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1answer
48 views

Hardware specs for Linux machine for cluster administration [closed]

I have just started as cluster system administrator and was asked to choose some features to get bought a personal machine to work on, and most intensive calculations will be perform in the cluster. I ...
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2answers
774 views

Does sync command remove the dirty cache in the memory?

I am aware that sync command flushes the dirty cache into disk. I have run free command first, then sync, and then free again. The result of latter free command shows more free memory available than ...
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3answers
3k 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 ...