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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 ...
2
votes
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 ...
1
vote
1answer
62 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
158 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
44 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
152 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
755 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

How do I vmtouch a directory (not the files it contains)?

The vmtouch(8) tool allows locking a file or files in memory. It has recursive mode, but the directories are used just for discovering files and are not locked themselves. How do I lock a directory ...
2
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0answers
39 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
64 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
96 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
186 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
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0answers
36 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
294 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
347 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
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0answers
50 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? ...
1
vote
0answers
165 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
vote
0answers
595 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
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0answers
28 views

Why process is killed while a lot of memory is free?

I am running a python script in ipython. This script will take about 8GB RAM. The system has more than 80 GB free RAM but the swap is nearly 0. My script was killed after it runned for a while. I want ...
0
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0answers
31 views

Is High Virtual Memory usage a problem or may cause problems?

In our server, we have a python based code that listen ports. The amount of Virtual Memory it uses is increased greatly with time Like: USER PID %CPU %MEM VSZ RSS TTY STAT ...
0
votes
0answers
14 views

Page Fault Frequency Algorithm - Compute number of frames and mean resident set

I'm reading about Page Fault Frequency algorithm but I don't understand how can I compute the number of frames. For example I have my reference string: 112233444412412214432255543 and control ...
0
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0answers
29 views

fast way to find the address range from the given info

I have a question, If I am given some memory devices with size specifications, how do i map it to address range quickly. if the address space is of 32 GB. Ex: ROM - 1Mb 3 RAMs - 2 GB each 2 FLASH - ...
0
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0answers
349 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 ...