In computing, memory refers to the state information of a computing system, as it is kept active in some physical structure.

learn more… | top users | synonyms

3
votes
1answer
21 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 ...
0
votes
1answer
24 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
votes
1answer
19 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
51 views

why we need ram if we having swap memory? [on hold]

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.
2
votes
2answers
177 views
+50

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 ...
0
votes
1answer
26 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 ...
2
votes
1answer
20 views

How does OSX handle Out of Memory conditions?

Linux uses the OOM killer; what do Macs do?
3
votes
1answer
21 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 ...
5
votes
1answer
50 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 ...
0
votes
2answers
19 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 ...
0
votes
0answers
7 views

Question about DMA mapping API in Linux [migrated]

In Linux, some APIs are provided to do DMA mapping. My question is about "dma_alloc_coherent", it is defined in "linux/dma-mapping.h". And in the DMA-API.txt, it says: void * ...
3
votes
2answers
37 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
8 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, ...
4
votes
0answers
31 views

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 ...
1
vote
1answer
31 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 ...
1
vote
2answers
41 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 ...
2
votes
0answers
25 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
vote
1answer
31 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 ...
5
votes
0answers
148 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 ...
0
votes
0answers
13 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 ...
0
votes
1answer
43 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?
5
votes
2answers
64 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
0answers
40 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 ...
1
vote
1answer
23 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
30 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
31 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
votes
1answer
52 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 ...
1
vote
0answers
42 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 ...
1
vote
0answers
23 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 ...
2
votes
1answer
53 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: ...
3
votes
1answer
142 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 ...
1
vote
2answers
83 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 ...
9
votes
3answers
146 views

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). ...
4
votes
0answers
120 views

Why are slab objects not reclaimed automatically

Everyday after a full system backup, various programs are failing with read errors until I run echo 2 > /proc/sys/vm/drop_caches to free reclaimable slab objects. For example, here's the output of ...
0
votes
0answers
16 views

What does “wrap around” mean in DMA?

Recently working on a PCI driver project and trying to understand the Scatter Gather DMA. In my project, the PCI device(in a PC's PCI slot) is the DMA master and I want to do a DMA write to the PC's ...
0
votes
2answers
84 views

Is there a way to free memory? [duplicate]

I remember, back from my days with Windows Vista/7, that there was a tool called memclear or memclean that would free some memory by invoking the NT garbage collection API. Probably it cleared cache ...
2
votes
1answer
65 views

Does my system use all available RAM?

I installed 16GB of RAM on a motherboard that shouldn't take it. Should I buy a better motherboard or change anything at all? It seems to be working fine. Memory: Crucial Ballistix Sport "(8GBx2) ...
0
votes
1answer
31 views

How to find hugepage size on system?

I am getting following two different result. which one i should consider for Hugepage? [root@server ~]# getconf PAGESIZE 4096 [root@server ~]# grep -i hugepagesize /proc/meminfo Hugepagesize: ...
2
votes
1answer
47 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 ...
2
votes
1answer
166 views

How to find out how much memory lxc container is allowed to consume?

I'm trying to make ansible set InnoDB buffer pool size to some percent of available memory. But ansible_memtotal_mb and free report how much memory the host has. How do I figure out how much memory is ...
0
votes
0answers
20 views

Best small distro for ROM burning of the system for an embedded system

I am building a specific device and I would like to know what Linux based small distribution would be good when I would choose the put-Linux-on-the-ROM route, so, that the system is not possible to ...
0
votes
2answers
99 views

It's safe to remove /var/log files

Today i was freeing my space in my Linux mint 17. In Disk analyzer i found that /var/log uses 54+ GB. So what does /var/log used for ? is it safe to delete /var/log ?
1
vote
0answers
18 views

How to check if an application uses my video card memory?

We can check the core, cpu utiliztion, memory etc of a particular process. Can we check if it uses video card too and if it is how much memory it is using?
1
vote
1answer
534 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 ...
0
votes
0answers
31 views

how to enable 1MB dma-kmalloc

I'm running a ubuntu 15.10 VM and testing code that will allocate 1MB dma buffers. However, from the /proc/slabinfo, the max that can be allocated is 8K dma-kmalloc-8192 0 0 8192 4 ...
0
votes
1answer
25 views

What is taking up my memory in my Linux virtual machine

I'm trying to debug an application (mongodb) memory usage on a a virtual machine. mongod, is taking 11% of memory. I know this by using top but when I want to see how much of my 7.5GB is free, I ...
1
vote
0answers
22 views

Working my way through dmesg output on a custom 3.5.4 kernel

Having read this thread here: What does the Virtual kernel Memory Layout in dmesg imply? It sounds like 'lowmem' is exclusively meant for kernel-space. [ 0.000000] virtual kernel memory layout: ...
2
votes
2answers
27 views

What tools can I use to diagnose the exact reason for laptop slowness? And how do I use those tools?

I am running Linux Mint 17 on my laptop. When using applications (mainly Web Browsers) the machine freezes for little time periods. The CPU indicates 100% usage at such times, but this only seems to ...
3
votes
0answers
85 views

Boot rescue kernel at high memory address using kexec on arm

Summary: Crashkernel boots at 512MB address in RAM with kexec -e/-l but not with kexec -p - why? Embedded platform with Marvell Armada XP (MV78460) (ARMv7 with 4 cores) and 1GB of RAM. production ...