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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11
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2answers
535 views

awk memory leak?

Base on this I'm running the command < /dev/urandom hexdump -v -e '/1 "%u\n"' | awk '{ split("0,2,4,5,7,9,11,12",a,","); for (i = 0; i < 1; i+= 0.0001) printf("%08X\n", 100*sin(...
1
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1answer
47 views

Eviction of Disk Cache in Memory

Say RAM is 100% used, some by disk-cache and some by applications. There is plenty of swap (on a hard disk available). If Linux decides to evict a page that contains application data, it would be ...
1
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1answer
56 views

How to log every memory access in linux of a single program? [closed]

I am trying to analyse the memory usage of a single program and need a list of every access the program made, so basically i need something like Valgrind but with a complete output.
0
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3answers
188 views

Understanding and configuring Cache Memory

I have few questions about Cache Memory In my system "free -h" command gave me below output, total used free shared buff/cache available Mem: 7.6G 2.1G 1....
10
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2answers
6k views

real memory usage

if I understand correctly, in the following output produced by free, 3535m is the actual free memory available to applications, only 413m is used, is this correct? need some clarification on the ...
1
vote
1answer
114 views

How to debug an Out of memory crash

Recently one of my CentOS6 server crashed because of an Out of memory Error: It seems to be related to the postgres database used by java web-applications (deployed on tomcat). But I cannot find ...
1
vote
1answer
34 views

vm.swappines parameter influence on system without swap partition

I run across following definition of vm.swappines: The swappiness parameter controls the tendency of the kernel to move processes out of physical memory and onto the swap disk. So, if I have ...
1
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1answer
21 views

Why do different instances of the same program use up different amounts of memory?

I simply started 5 instances of the default xterm, doing nothing in them at all. Looking at the output from htop, it appears that these instances use different amounts of RAM: VIRT RES ...
38
votes
8answers
69k views

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 ...
0
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0answers
25 views

Logging memory issues with Cron

I'm trying to log memory errors/issues using cron, however I'm still unsure how to do this. I'm new to cron, but I entered our system with it already using the tool. We've been having memory issues ...
1
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1answer
49 views

Why does OOM-killer sometimes fail to kill resource hogs?

If I type in my shell x=`yes`, eventually I will get cannot allocate 18446744071562067968 bytes (4295032832 bytes allocated) because yes tries to write into x forever until it runs out of memory. I ...
0
votes
1answer
96 views

Convert meminfo kB to bytes [duplicate]

To convert the readings in /proc/meminfo from "kB" to bytes, should I multiply by 1024, or 1000?
4
votes
1answer
199 views

Does /proc/[pid]/status always use kB?

Particularly, does proc always list the VmRSS value in kB? I can't find a solid answer on the documentation, although it appears that it sticks to one unit.
3
votes
2answers
109 views

C++ app. with mmap kills kernel? (kernel panic with mmap)

In my C++ program where intensive disk, network I/O and even CPU computation occur, I am using memory mapped region as an array. With very small data, it works fine. However when I ran the program ...
1
vote
1answer
99 views

What is difference between cached memory and used memory?

In my System Monitor panel applet in Linux Mint 17.3 Cinnamon, it shows me memory usage of used memory and cached memory combined, whereas in the system monitor application, it just shows used memory, ...
4
votes
2answers
2k views

What's the difference between ioremap and file operation mmap?

I'm currently working on a PCI device driver for Ubuntu. I have some example code about PCI driver, but I have difficult on understanding the ioremap and file_operation.mmap. The description of file ...
1
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2answers
66 views

What is the default memory allocation for shell process by linux

What is the default memory allocation for shell process by Linux , i mean is there any upper limit for shell process or any process.
0
votes
1answer
52 views

Memory leak on webserver

So I have lately been have some server performance issues. Currently we are running a Fedora server with 4GB and 160gb disk space. We are pretty much capping out the disk, with all of the files we ...
3
votes
1answer
160 views

How can I get the amount of available memory portably across distributions?

The standard files/tools that report memory seem to have different formats on different Linux distributions. For example, on Arch and Ubuntu. Arch $ free total used free ...
2
votes
2answers
1k views

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 -/+...
13
votes
9answers
4k views

Memory problems when compressing and transferring a large number of small files (1TB in total)

I have 5 million files which take up about 1TB of storage space. I need to transfer these files to a third party. What's the best way to do this? I have tried reducing the size using .tar.gz, but ...
0
votes
1answer
83 views

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 ...
67
votes
6answers
69k views

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 ...
2
votes
1answer
73 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 ...
-2
votes
3answers
68 views

why we need ram if we having swap memory? [closed]

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.
0
votes
1answer
172 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 ...
1
vote
1answer
139 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 (/usr/src/...
0
votes
1answer
80 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 ...
3
votes
1answer
174 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 ...
2
votes
1answer
41 views
5
votes
1answer
89 views

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 ...
10
votes
5answers
7k 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?
0
votes
2answers
43 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 -/+...
3
votes
2answers
202 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 ...
0
votes
1answer
86 views

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, ...
1
vote
1answer
72 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 ...
2
votes
0answers
16 views

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 ...
5
votes
2answers
283 views

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 ?
1
vote
2answers
85 views

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 ...
1
vote
2answers
2k 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, ...
1
vote
1answer
32 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 ...
2
votes
0answers
37 views

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?
-1
votes
1answer
55 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?
3
votes
2answers
536 views

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 ...
0
votes
0answers
18 views

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 ...
96
votes
4answers
65k 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 /proc/self/...
1
vote
1answer
72 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 ...
1
vote
0answers
38 views

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 ...
3
votes
1answer
113 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 ...
4
votes
1answer
56 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 ...