Questions tagged [memory]
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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Mystery Linux RAM usage (5.14)
My system is reporting >50% RAM usage with very few processes running, which causes my system to start swapping as soon as I open any substantial application. What's using my RAM?
System: Dell G5 ...
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25 views
Loading a file into memory at a particular address
I have a file called myfile.bin.
$ du -b myfile.bin
1866 myfile.bin
I want to load these 1866 bytes at a particular address in Linux memory (RAM) and be able to read back from it. Is there a way ...
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'apache2 -k start' keeps on appearing in htop and chokes memory
I had some "Out of memory" problems on my ec2 instance, so i enlarged it a bit so i can at least ssh into it and find out what's the problem.. the server itself runs apache2 and serves 2 ...
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1answer
26 views
X11 video memory requirements with multiple desktops and windows open
I am running i3 window manager on a single 4k display. However, I have 12 desktops and maybe 50 windows open. Recently I noticed that zoom video is very laggy at times, also it takes a second to ...
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Get Percentage of used memory in Solaris [duplicate]
I wish to get Percentage of used memory in Solaris as non-root user.
The solution proposed here does not work for me and I get error.
$ /usr/sbin/prtconf 2>/dev/null | /usr/bin/awk '/Memory/ {print ...
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1answer
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need RAM & SWAP Memory monitoring Threshold
I wish to setup monitoring alerts upon used memory percentage.
I had setup 0-80% used RAM as Green (good)
81-90% as yellow(acceptable)
91-95% as orange(warning)
96+ as Red(critical)
However, i see ...
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allocating contiguous memory in QEMU VM result in failure in alloc_pages_nodemask
I am trying to allocate around 33M of contiguous memory but most of the times it fails in __alloc_pages_nodemask call. This is a QEMU Guest OS, and the kernel version I am using is 5.9.1. This ...
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Which parts of a (docker) container are loaded into memory?
I was wondering how containers and RAM/swap are related.
Please correct me where I am wrong in my assumptions below.
All container-related functionality that the kernel offers is always loaded into ...
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2answers
62 views
When to upgrade RAM based on free output [closed]
I have a java application that runs on a Linux server with physical memory(RAM) allocated as 12GB where I would see the normal utilization over a period of time as below.
sys> free -h
...
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Shared memory as reported by free not equal df reported one. Cache takes huge amount of memory despite recent drop_caches
I'm running Linux Mint 20. I often encounter low memory situations. Today I do not understand why available is so low. As per What is the meaning of `shared` memory in the `free` command? shared is ...
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2answers
310 views
Creating swap when out of memory
Out of memory is a common issue and the official OOM is not efficient. Several other programs have been introduced to do the killing job faster.
I wonder why there is no approach to creating swap ...
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Fedora - How to free up space?
How to free up space at fedora by removing GUI and dialoge related pkgs?
for example:
I'm looking for something like this but with dnf:
sudo apt purge --auto-remove libx11-6 libwayland-client0
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1answer
32 views
Feasibility of storing keys unencrypted on RAM under certain assumptions
We have IoT gateways that run Linux 5.4.31 kernel. These gateways need to manage thousands of devices which are mobile and each has a unique encryption key. The idea is to fetch the key of a device ...
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1answer
29 views
Does a process' kernel virtual memory contain process specific data?
I don't quite understand this picture from the CS:APP book.
It shows how the kernel virtual memory of a process has a region different from other processes.
Does this mean, that the kernel in the ...
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37 views
Kernel LOADADDR for QEMU ‘virt’ generic virtual platform? Not enough space for DTB after kernel/initrd
I am trying to emulate an Arm Cortex A8 processor / Texas Instruments Sitara AM335x processor using QEMU to run the firmware of an embedded device. My first attempt was to cross-compile kernel and ...
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How to diagnose high `Shmem`? (was: Why `echo 3 > drop_caches` cannot zero the cache?)
I have a problem with my Linux machine where system now seems to run easily out of RAM (and trigger OOM Killer) when it normally can handle similar load just fine. Inspecting free -tm shows that buff/...
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1answer
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How does the page table of a process knows which page was swapped?
I'm refering to those links:
Page table content when the physical page we are looking for is in swap area
how does linux update page table after context switch
How does the kernel address swapped ...
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1answer
43 views
Is the correct way to calculate the total memory currently being used to subtract 'MemAvailable' from 'MemTotal' in "/proc/meminfo"?
I am trying to as accurately as possible calculate the amount of ram being used by the system at any given time. I figured that if I subtracted MemAvailable from MemTotal and divided the difference by ...
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Explain Zram and Swap numbers
Ok, so there are really 2 questions here, why is my on disk swap being used? Is the compression of my swap really this good? It seems pretty unlikely, but it's also possible it is because it's memory ...
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1answer
36 views
How i get free disk space storage?
I am a new linux user and I have to install some packages that required me about 14GB storage.
How can I find out my storage? My device is a Nvidia Jetson TX2 that runs Ubuntu OS.
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1answer
38 views
Show absolute memory usage for each process with `top`
By default, top will show, for each process, the fraction of physical memory used by that process:
top - 12:39:34 up 87 days, 18:25, 3 users, load average: 4.73, 4.89, 4.23
Tasks: 255 total, 2 ...
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1answer
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Ubuntu: server is doing nothing, but memory is full
My server is actually on this state:
I am executing htop as root, so I'd see everything.
Sorting by MEM%, I see al processes under 1%. And this even in tree view).
But what does it mean when memory ...
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1answer
17 views
Ubuntu allow max ram usage for sbt java
sometimes during coding I realize that I have 100% ram used, and swap 100% ;)
Is it possible to dissalow for some processes like java, sbt etc. not to use more when for example 90% of ram is used ...
2
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1answer
71 views
Limiting a program's memory usage using `systemd-run`
I'm on Debian Bullseye (hence cgroups v2, afaik) and I'm trying to use systemd-run to limit the memory usage of a process. I need the process to be killed when it goes out of memory (I'm setting up ...
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1answer
98 views
Disable GTT on amdgpu?
How can I disable GTT on amdgpu?
According to https://www.kernel.org/doc/html/v4.20/gpu/amdgpu.html, adding amdgpu.gttsize=0 should work but that has no effect.
The reason why I am asking is, that my ...
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1answer
54 views
16GB installed but only 12GB available
I have a ThinkPad P14s Gen 2 AMD which has a AMD Ryzen 7 PRO 5850U with Vega 8 Graphics running Fedora 34. It has one 16GB DIMM installed, which the bios as well as dmideocde report correctly
Getting ...
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3answers
40 views
How to configure cache memory to automatically sync on program close?
Currently I have an issue with programs not de-allocating their stack upon close. It appears to be a natural behaviour of Linux page caching.
When I open my desktop, it runs at ~300-500MB. After ...
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1answer
26 views
What does Unison OS do with deferenced null pointers, index out of bounds access (not writing), and usage of unintialized variables?
I'm trying to determine if a particular given C language source code run on Unison OS that I have could conceivably lead to a crash, and through what vectors. There are sections of the code that will ...
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46 views
htop command displays 996GB instead of 1024GB for RAM
I have a little issue that I can't understand.
I have 8x128GB sticks of RAM, which makes 1024GB of RAM.
But the command htop displays 996G and not 1024G as expected.
You can see the following ...
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2answers
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How do I reduce memory latency?
My environment is OpenVZ, using the 3.10.0-1160.21.1.vz7.174.13 GNU/Linux kernel.
When executing vzstat, I am seeing the lat(ms) is very high (going to assume this means latency in miliseconds):
This ...
3
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1answer
263 views
Only half RAM memory available to linux in Legacy mode, UEFI shows full, why?
I have a problem with OS. All tools including kernel shows only half of my actual RAM memory. I have one 16G memory chip installed in my laptop and all is shown good in BIOS.
Some info about ...
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1answer
38 views
How to use SLAB memory allocation instead of SLUB allocation in Linux kernel?
As I understand it, both SLAB and SLUB are still integrated into the kernel in stable release 5.12. Is there a way to enable SLAB allocation to run on the system instead of SLUB allocation? Or is ...
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How do the Contiguous allocation, Segmentation, and Paging allocation schemes deal with the situation of expanding process memory?
How do the Contiguous allocation, Segmentation, and Paging allocation schemes deal with the situation of expanding process memory? For example there may be a growth in the data structures that a ...
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23 views
Why can't I backup more than 15 minutes of a DVD to iso using a raspberry pi 3
I am using a raspberry pi 3. I am attempting to backup a DVD as an *.iso file (3 year old's movie). I have downloaded/installed the vlc's libdvdcss. I have tried a 1 and 2 USB portable DVD drive. I ...
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31 views
Enabling AMD Secure Memory Encryption (SME) cause not bootable system
Processor:
AMD Ryzen 5 3550H with Radeon Vega Mobile Gfx
The CPU supports SME
lscpu | grep sme
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat pse36 clflush mmx fxsr sse ...
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2answers
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Get full command name of high memory usage process in UNIX
I am trying to capture process name which are using high memory on my box. I ran below command to get that
while [ 1 ]
do
ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head
sleep 5
done
But the ...
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0answers
19 views
Linux kernel - Syscall Implentation - Page Table Walk
I am trying to learn a few things about the linux kernel and I have come across a kind of exercise which asks to implement two system calls on th 4.15.0+ linux kernel which aim at reading the pages ...
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1answer
32 views
Is there any way of checking the max memory consumption of a code that I run with the command line? [duplicate]
The time command is very useful for checking how much time it takes for a piece of code that I develop to run... However, I'd like to have a way to check the memory consumption of the codes that I ...
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1answer
34 views
How to jump X bytes down in hexedit?
I am looking through a memory dump
B79C6440 64 6F 6E 65 00 00 6C 5F 75 62 6C 65 20 73 68 6F done..l_uble sho
B79C6450 77 5F 00 00 5F 6F 6E 5F 72 75 70 00 00 61 63 6B w_.._on_rup..ack
...
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155 views
BUG:BUG: unable to handle kernel NULL pointer dereference at 0000000000000040, inside a kernel module
I am trying to reproduce a microarchitectural attack on SGX enclave described here. while doing so in one of the ioctl command (CACHEZOOM_IOCTL_TEST) I get the BUG: ble to handle kernel NULL pointer ...
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0answers
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How can I learn why kswapd has very low page reclaim efficiency?
Problem/context
I have a (managed) Postgres 10.16 instance running on Fedora 32 in a systemd-nspawn container. Periodically, I see a big spike in "system" CPU usage in our metrics, ...
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40 views
Cannot find the process which uses most memory
The result of free -g:
# free -g
total used free shared buff/cache available
Mem: 62 38 14 7 9 10
Swap: ...
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1answer
180 views
How to use swap less often?
I use an SSD swap just to avoid full memory related crashes. There are limited erasures that can occure on SSDs. The memory related crashes have stopped, but my system uses swap constantly and vmstat ...
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0answers
38 views
How can I use one input file into several separate operations
I would like to read one file, do an operation with several different parameters on it and finally save each output as a separate file.
Currently I do it as shown in the code snipped below.
This reads ...
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2answers
174 views
Errno28 "No space left on device" during pip install
I am trying to execute pip install tensorflow on my Raspberry but I'm getting an Errno 28 "No space left on device". I've read from multiple sources that it means that the folder used by pip ...
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1answer
53 views
What does order=0 mean in mem-info data (Orders are powers of two allocations, so does it mean no pages were being allocated?)
foobar.exe invoked oom-killer: gfp_mask=0x201da, order=0, oom_score_adj=0
What is an order=0 allocation? That's less than one page, so is it like a kmalloc32 or something smaller than page_size? ...
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1answer
40 views
USB memory stick unmounts and vanishes
I bought this device a few days ago, and checked it with utility f3. It is ostensibly a Philips 256 memory stick, internally seen as an
Bus 002 Device 034: ID 090c:2000 Silicon Motion, Inc. - Taiwan (...
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20 views
How to retrieve the I/O state of individual DDR4 memory chips
I've been wanting to put more use to the RGB of my machine for more than just simple aesthetics, but actual machine state monitoring for particular devices...
I have some corsair RAM with 10 RGB LEDs ...
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I can't see where is all of my disk memory
I have a disk partition where the Linux/Ubuntu system is installed. It was orginally made to posses 254 GB, but currently it's just 194 GB. I've got no idea what have happened recently that I can't ...
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92 views
How to get memory info without sudo command on bash
No idea how to create a bash script, without using sudo, that shows Memory Info like 8 x 16384 MB DIMM-1600 MT/s Samsung. number of memory + size of each + type + manufacturer
