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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-/+ buffers/cache & Swap

When should the usage of swap get started? or How do I know that my swap is being used? At least some times if not always, considering the default swappiness of 60 Also, why does free offer to omit ...
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46 views

vmstat -s command fields meaning, specially “pages paged in” vs “pages swapped in”

Most of the fields are understandable but can someone please explain me the difference between "pages paged in" and "pages swapped in"?. I'm pretty sure that swapping is when the entire process is ...
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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(...
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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 ...
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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.
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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 ...
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1answer
113 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 ...
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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....
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3answers
142 views

Gentoo Hardened eats 3 GB of memory after running for ~12 hours with very few processes running

I'm running Gentoo Hardened AMD64 using kernel 4.3.3-hardened-r4. With my system only running some basic daemons like wpa_supplicant, cron or DHCP, and with an X session with only Windowmaker, GKrellM ...
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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 ...
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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 ...
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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 ...
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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?
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1answer
97 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, ...
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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 ...
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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.
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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
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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 ...
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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 ...
2
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1answer
72 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 ...
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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.
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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 -/+...
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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 ...
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1answer
41 views

How does OSX handle Out of Memory conditions?

Linux uses the OOM killer; what do Macs do?
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1answer
172 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 ...
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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 ...
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2answers
42 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 -/+...
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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 ...
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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, ...
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Why does /proc/*/status not account for all swap used on a system?

I have a system that has been swapping recently and am unable to account for all swap that is shown as in use by tools like free or top. Specifically, I can account for 19GB of 28GB swap used (...
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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
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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 ...
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2answers
84 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 ...
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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?
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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 ...
8
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1answer
295 views

What is using 4GB of memory? (Not cache, not a process, not slab, not shm)

We have some EC2 servers that experience a memory leak over days or weeks. Eventually there gets to be many GB of memory that is used (according to tools like free and htop) and, if we don't restart ...
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0answers
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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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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?
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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 ?
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0answers
109 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
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 ...
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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 ...
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 ...
3
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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 ...
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140 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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44 views

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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1answer
301 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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1answer
270 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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294 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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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). ...