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2
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3answers
1k views

Linux / JVM - OutOfMemoryError: unable to create new native thread

I have a memory problem with a Linux server (CentOS). It is a VM. Below is the context. It has 70Gb of RAM. There are 2 tomcat running on it. One tomcat is given a heap of 13Gb and the other one a ...
1
vote
2answers
1k 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 ...
5
votes
1answer
209 views

GNU/Linux swapping blocks system

I have used GNU/Linux on systems from 4 MB RAM to 512 GB RAM. When they start swapping, most of the time you can still log in and kill off the offending process - you just have to be 100-1000 times ...
1
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1answer
30 views

Linux always hangs when out of physical memory

I'm using ArchLinux, with 3.18.6-1 kernel, when a software uses more than physical memory (when total memory used is >5.8 GB), it always lags, unresponsive, and all that I can do is reset the ...
1
vote
1answer
150 views

How does the kernel know how much user addressable memory to set aside?

I was reading up on a rather-dated article on the kernel managing memory and had this question on where the Page Table Entries (PTE) would go into. For this example, the author assumes we are on a ...
0
votes
1answer
37 views

«nm» shows zero VMA: where is the symbol will be mapped?

I am look at the functions of my compiled application via «nm» — I need to find an address to set a breakpoint to the «send()» function. The problem is that this function accordingly to «nm»'s output ...
3
votes
0answers
91 views

Why does saving a KVM-QEMU VM requires additional memory?

I have three VMs running on Red Hat Enterprise Linux with 8 GB RAM, each of the VMs has 3 GB allocated, and I also run a 512 MB VM. If we also consider the guest OS's memory usage (usually 1.5 GB due ...
3
votes
0answers
704 views

How extended (4MB) and regular (4KB) paging coexist?

On x86 architecture, "Extended paging" allows page frames (physical memory) to be 4 MB instead of 4 KB. The book "Understanding the Linux Kernel, 3rd" at chapter 2 "Memory Addressing", sub-chapter ...
2
votes
0answers
20 views

JVM low-memory tuning

What command-line options would provide the lowest memory-footprint JVM, in OpenJDK, or possibly other JVMs (Linux/Debian)? I'm willing to disable JIT, live with slow or choppy garbage collection, ...
2
votes
0answers
57 views

How can I let high priority processes continue when low priority processes are causing free memory to be low

Ok I'm not sure if this is the correct place to post this. It is more of a 'why not' question than a 'how to' one (assumption is that it isn't/can't be done). Why don't we allow RAM to be partitioned ...
2
votes
0answers
88 views

Disk page cache size in Linux for integrity purposes

I am trying to bound corruption in a block-based disk format in the presence of plausible machine failures in a Linux-specific application. That is, the file is read and written in application-defined ...
2
votes
0answers
162 views

Virtual kernel memory layout in dmesg linux kernel 2.6.31

I'm working on a embedded linux project for ARM architecture, kernel version is 2.6.31.12-rt21. In dmesg, I cannot see the virtual kernel memory layout like this: virtual kernel memory layout: ...
1
vote
0answers
31 views

In the Linux Kernel what file/process controls the assignment of permissions to memory pages?

A given memory page may be writable, readable or executable. What kernal source code file in the linux kernal describes the setting of these rights? What process or kernal data structure would set the ...
1
vote
0answers
218 views

Xorg consuming 1.1GB, is it a leak?

I am facing a problem wherein Xorg starts to consume more and more memory and finally eats up the whole swap space. As shown below, Xorg's virtual memory is about 1.1GB. My system runs only one GTK ...
1
vote
0answers
191 views

About mem and vmem

I am working with a cluster machine running under linux. I have a shell script that uses mpirun to submit my jobs to the cluster machine. In that same script, I can choose the number of nodes that ...
1
vote
0answers
140 views

Virtual address of Global variables in Kernel code

If my understanding is not wrong, every process has a Kernel Address space associated with it (which is typically 1GB). As far as local variables are concerned, they are assigned on the kernel stack ...
1
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0answers
534 views

Where does the Linux kernel reside in memory ?

From some book I have, I have in my notes that the Linux kernel resides at 0xc00000000 on 32-bit systems, and is mapped into user space for performance reasons. Is this accurate ? How can I verify ...
0
votes
0answers
41 views

How fast is a process reading/writting virtual memory?

So, we have top, htop, iotop, iostat, vmstat, etc, to measure many different things on Linux, but how can one measure how much MB/s a process is reading and writting to/from RAM, i.e., virtual memory? ...
0
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0answers
299 views

swap space allocation vs swaptotal

I created a Red Hat 9 virtual machine on VMware Workstion 9 by allocated the physical memory of 256MB. See pic. When installing Linux, I created the swap partition with a size of 256MB. See ...