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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Memory usage command with syntax similar to the time command

What command shows the memory usage of a program, i am looking for a command that is simple to use and has similar syntax to the time command. I am trying to find the memory usage of a md5 hashing ...
2
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2answers
445 views

swapoff fails when overcommit_memory==2

I've disabled memory overcommitting by setting overcommit_memory=2. Now when I tried to swapoff, I get this error: swapoff: /dev/sda5: swapoff failed: Cannot allocate memory But I in fact have 0 ...
2
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1answer
108 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 ...
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2answers
212 views

Viewing virtual memory usage

I started 700+ threads from a single program And my /proc/[PID]/status file shows the following output. VmPeak: 7228104 kB VmSize: 7228104 kB VmLck: 0 kB VmHWM: 3456 kB VmRSS: ...
2
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1answer
365 views

Which processes swaps memory

I can see swap's total, used, free etc. sizes from top command. But I can't figure out which process uses swap, is it possible to find out swap memory by process? I'm running CentOS 6.3.
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0answers
34 views

Determine which memory stick contains an address?

I just run memtester and found a single error: FAILURE: possible bad address line at offset 0x869a3bd8. I can re-run memtester with individual memory sticks to determine which one is bad, but I ...
13
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4answers
4k views

How to re-load all running applications from swap space into RAM?

If my desktop run out of memory and swaps a lot then I free or kill the application wasting my RAM. But, after that, all my desktop/applications have been swapped and are horribly slow, do you know a ...
0
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1answer
314 views

very high buffer memory usage [closed]

Is this normal - I've never seen buffers so high? $ cat /proc/meminfo MemTotal: 16332808 kB MemFree: 1112264 kB Buffers: 10630124 kB Cached: 699400 kB SwapCached: 0 kB Active: 3262924 kB Inactive: ...
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1answer
169 views

How do you track memory usage in a ksh93 script

We have a number of ksh scripts that run forever (inside a while loop), or at least until a shutdown event is delivered to them. We had a project where these scripts where converted to ksh93 (and ...
8
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2answers
715 views

How can I dump the full system memory?

After starting VirtualBox, the computer became sluggish and then hung completely due to OOM. Usually, OOM should be starting killing processes in order to free up some space, but this did not happen ...
2
votes
2answers
132 views

a handy tool to measure memory consumption of a program [duplicate]

I develop a C code on Debian. I am looking for a program to monitor memory consumption of my code in real-time. The only value I care is the maximum RAM consumption, it should hold the value even if ...
3
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1answer
224 views

Use all system memory in Solaris

I am doing server testing and intentionally trying to crash a virtual Solaris server by using all memory. Server has a ulimit of 15 GB (several hundred GB of total system/swap memory). Is there a ...
3
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1answer
898 views

/proc/meminfo MemTotal =?

What elements of /proc/meminfo sum up to MemTotal? Example of tee /tmp/proc/meminfo < /proc/meminfo MemTotal: 1279296 kB MemFree: 164092 kB Buffers: 62392 kB Cached: ...
0
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2answers
131 views

what is an application pool?

I'm reading this article: http://www.modrails.com/documentation/Architectural%20overview.html#web_app_models It talks about how Phusion Passenger extends Apache2 to act as an application server. ...
2
votes
4answers
5k views

What is “System Memory ” displayed in nmon in AIX?

I have a host with AIX 6.1 (6100-04-02-1007) upgraded from AIX 5.1 with Veritas Storage Foundation 5.1. Since the upgrade from AIX 5.3 to 6.1, Run vx services means a lots of memory consumed that I ...
0
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1answer
89 views

What is meant by “a process has open handles to system objects”? [closed]

The following are qualities of a process: virtual address space executable code open handles to system objects a security context a unique process identifier environment variables a priority class ...
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0answers
23 views

Where is the Virtual kernel Memory Layout? [duplicate]

Specifically, where is the lowmem address range for 64 bit Linux 3.2.0 ? Other posts get it from dmesg. It is not in: /var/log/boot /var/log/dmesg /var/log/kern.log /var/log/syslog
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1answer
97 views

Eclipse makes laptop unusable

Currently I can't use my eclipse project. I'm using ArchLinux: -` .o+` rkmax@satellite `ooo/ OS: Arch Linux ...
3
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3answers
59 views

Contents of stack area of a process

I've been going through some Unix text books and I can't have a clear picture on the contents of the stack area of the process. Can anyone please explain or point out some references?
6
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0answers
218 views

Allocated Memory difference in xen guests after using Linux 3+ kernel [closed]

Can someone explain to me why there is a memory difference in Guests with the same configuration? Hypervisor: xen 4.2 64 bit VM1: Centos 5.7 with 2.6.18-274.el5xen Assigned memory from xen is ...
5
votes
3answers
2k views

Why is the theoretical RAM limit for RHEL 6 128 TB and how is this determined?

I'm studying for RHCSA and am confused by a statement I came across in some training material: There is no practical maximum RAM, as theoretically, you could run 128 TB of RAM on RHEL 6. But ...
1
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1answer
230 views

private memory calculated by pmap, a combination of virtual memory size and resident memory size?

You can use the ps command to get the virtual memory size and the resident memory size of a process: $ ps aux | grep apache2 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME ...
2
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1answer
184 views

pmap and memory usage

On Ubuntu 12.04, I have several apache2 processes running (the 1130 parent and the children it spawned), and as you can see, they have around 300-400 mb of virtual memory and 10 mb of resident memory: ...
3
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0answers
75 views

What does hierarchy support do in cgroup?

cgroup has 2 options for memory control: memory.use_hierarchy = 1 : use hierarchy memory.use_hierarchy = 0 : use flat hierarchy, according to this answer What is the difference between the two? I ...
5
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1answer
753 views

Defragging RAM / OOM failure

This question is fairly lengthy, so I'll ask the questions at the top and then go through my method of coming to the questions: Did (Busybox based) rm not execute because there wasn't enough ...
10
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3answers
497 views

After researching, still confused about monitoring RAM usage

I went through this article, which explains various methods for checking your RAM usage. However, I can't reconcile the different methods and don't know which one is correct. When I first login, I'm ...
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0answers
115 views

Understanding the Buddy Allocator [closed]

I have a conceptual doubt in understanding the way Linux Kernel manages Free blocks. Here is what I interpreted through reading so far. The Buddy Allocator implementation is allocation scheme that ...
-1
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1answer
38 views

get Various types of address used [closed]

How to get various address ranges of a running machine or a crash dump? User virtual address Physical address Bus address Kernel logical address Kernel virtual address I don't need the bus ...
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2answers
439 views

Change the size of my memory pages?

I would like to change my kernel's page size from 4KB to 4MB as I have had a large addition of RAM to my computer and I am never running out of anymore. The idea is that programs requiring large ...
1
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1answer
328 views

Measurement of free ram through /proc/meminfo with ramdisk (initrd)

I am booting a disk image via PXE, it is a full system on an initrd ramdisk. I would like to measure the actual free memory of the system (not including buffers and file system caching). I was told ...
0
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0answers
70 views

Shared memory counted as cached

When i start my application that allocates about 5GB of shared memory, i instantly see that the the cache is up by 5GB. Why is the application shared memory is counted as also as cached memory? ...
52
votes
3answers
27k 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 ...
5
votes
2answers
240 views

What happened to my RAM?

I am trying to understand the basics of the Linux OS. I'm running 64-bit Ubuntu 12.04 on a 64-bit CPU. The system has 2GB of RAM. cat /proc/meminfo MemTotal: 2012040 kB Question 1: Where is ...
3
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1answer
488 views

operation in /dev/shm causes overflow

I am repeating tens of thousands of similar operations in /dev/shm, each with a directory created, files written, and then removed. My assumption used to be that I was actually creating directories ...
4
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2answers
807 views

What is “automatic stack expansion”?

getrlimit(2) has the following definition in the man pages: RLIMIT_AS The maximum size of the process's virtual memory (address space) in bytes. This limit affects calls to brk(2), mmap(2) and ...
0
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1answer
549 views

Invoking memory compaction on linux 2.6.35 kernels and beyond

This LWN article about memory compaction indicates that memory compaction can be invoked in the linux kernel by Writing a node number to /proc/sys/vm/compact_node, causing compaction to happen on ...
3
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1answer
134 views

How to measure the clock pulse of my computer manually?

My PC has two processors, and I know that each one runs at 1.86 GHz. I have just read about clock cycles and I only have a (very) rough understanding, so I apologize beforehand if my question is so ...
0
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2answers
87 views

are daemon tmpfs executables copied unencrypted to memory upon execution? (prevent if so?)

When a daemon is executed, is the executable copied to memory? If so, can it be copied encrypted? If not, is there a way to prevent the executable from being copied to memory? The executable is ...
0
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1answer
89 views

Execute in Place an encrypted ram drive

I have found a few old posts claiming that tmpfs can execute in place. Is this true? If so, how? If not, is there a ram drive alternative? Can this be done with a ram drive that is encrypted? If ...
2
votes
1answer
39 views

Prevent or detect reading of daemon in memory

Is it possible to prevent the memory being used by a daemon to be read by anything else? If not, is it possible to detect an attempt to read? If so, is it possible to get in front of the actual read ...
2
votes
4answers
135 views

How to make sure, that certain functionality (like Alt+Ctrl+F1 switching into tty) is available in havily swapping system?

At the moment, when I accidentally launch application that eats a lot of memory (that causes system to heavily swap), the system become so unresponsive (waiting hours just to see the mouse move/or ...
1
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2answers
187 views

process memory usage

What is usually meant by the phrase process memory usage, what does this actually mean, i.e. what does this memory consist of? And what column does it correspond in ps aux output, RSS or VSZ?
1
vote
1answer
1k views

Redhat find process memory usage [duplicate]

When I cat /proc/meminfo I see: MemTotal: 1048576 kB MemFree: 11136 kB Buffers: 0 kB Cached: 0 kB SwapCached: 0 kB Active: 0 kB Inactive: ...
0
votes
1answer
109 views

“Acpi-State” in slabtop's output gets increased — what is it? Is it a bug?

Since boot it gets increased occupying even more RAM than anything else: Active / Total Objects (% used) : 680608 / 719176 (94.6%) Active / Total Slabs (% used) : 17390 / 17390 (100.0%) ...
7
votes
2answers
2k views

What is the appropriate value of vm.swappiness when using zram?

I'm using zram on my computer as a compressed RAM-backed swap. When the system needs to swap something out, swapping it to a zram-backed swap file is more or less equivalent to compressing that data ...
3
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3answers
156 views

Where is the environment string actual stored?

But when we first time we adding a new name,we have to call malloc to obtain >room for a new list of pointers. We copy the old environment list to this new area and store a pointer to the ...
23
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6answers
14k 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 ...
13
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2answers
702 views

Why does Linux purge the memory cache when it is nearly full?

Here's what the memory graph looks like on a VPS running CentOS with 512MB of RAM and nginx/php-fpm/mysqld serving (mostly static) content to a couple thousand visitors per day. (those are days on ...
2
votes
1answer
4k views

How to find Heap memory of a running process? [duplicate]

I would Like to know how to find the heap captured of a process which is running in the background? Is there any command by which you can find the process heap memory and here the process is still ...
1
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1answer
112 views

Looking for /procfs documentation, describing values and units of measurement

Surprisingly, comprehensive documentation for /procfs is hard to find. For my specific question, I am looking at: cat /proc/1/statm (let's use pid=1 because it seems to be always there). I just ran ...