In computing, memory refers to the state information of a computing system, as it is kept active in some physical structure.
38
votes
3answers
16k 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 ...
16
votes
4answers
2k views
Measuring RAM usage of a program
time is a brilliant command if you want to figure out how much CPU time a given command takes.
I am looking for something similar that can measure the max RAM usage of the program and any children. ...
16
votes
6answers
5k 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 ...
7
votes
6answers
1k 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?
8
votes
4answers
3k views
how to “unswap” my desktop
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 ...
2
votes
2answers
213 views
`free`: output format
I use free to get the amount of free space on some of my servers. Its output is something like:
$ free -m
total used free shared buffers cached
Mem: 374 ...
4
votes
1answer
442 views
Tracking huge buffer usage under Linux
I have a Linux server running under Debian Lenny with 4Go of RAM.
It doesn't run much, just:
Postfix/spamassassin (daemon mode)
Bind9
KVM (one guest - 1Go of RAM for it)
Every day at exactly 3:05 ...
8
votes
2answers
1k 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 ...
4
votes
2answers
856 views
Can I identify my RAM without shutting down linux?
I'd like to price some new RAM for our in-house VMware testing server. (It's a consumer box we use for testing our software on and running business VMs). I've forgotten what kind of RAM it has and I'd ...
1
vote
1answer
322 views
htop reporting much higher memory usage than free or top
The following three outputs were taken essentially simultaneously:
top:
top - 02:54:36 up 2 days, 13:50, 3 users, load average: 0.05, 0.05, 0.09
Tasks: 181 total, 1 running, 179 sleeping, 0 ...
8
votes
1answer
4k views
Getting information about a process' memory usage from /proc/pid/smaps
For a given process in /proc/<pid>/smaps, for a given mapping entry what are:
Shared_Clean
Shared_Dirty
Private_Clean
Private_Dirty
Is Shared_Clean + Shared_Dirty the amount of memory that ...
19
votes
3answers
976 views
How to limit resource usage to save CPU+RAM for a certain process?
I have a dev server on which sshd sometimes stops working because the machine runs out of RAM. Yes we are running low on memory and upgrading is not a feasible choice right now. What I want to do is ...
12
votes
5answers
3k views
Is there a way to limit the amount of memory a particular process can use in Unix?
I need to test a process for memory management.
I do not have the source, so I need to do all the testing from the OS side.
I want to be able to say something like limitmemory 400k -p <pid>
...
10
votes
2answers
2k views
Why does my system show only 3.2 GiB of RAM when I definitely have 4.0 GiB
I have 2x2 GiB sticks of RAM installed.
Running memtest86 from the grub boot menu confirms this.. memtest86 reports no errors.
However every which way I check my available memory in a running ...
24
votes
3answers
13k views
Limit memory usage for a single Linux process
I'm running pdftoppm to convert a user-provided PDF into a 300DPI image. This works great, except if the user provides an PDF with a very large page size. pdftoppm will allocate enough memory to ...
9
votes
2answers
4k views
How to create a user with limited RAM usage?
So I have 4 GB RAM + 4GB swap. I want to create a user with limited ram and swap: 3 GB RAM and 1 GB swap. Is such thing possible? Is it possible to start applications with limited RAM and swap ...
7
votes
1answer
928 views
What does the vm.swappiness parameter really contol?
Per the kernel documentation:
This control is used to define how aggressive the kernel will swap
memory pages. Higher values will increase agressiveness, lower values
decrease the amount of swap.
...
4
votes
5answers
313 views
Unpredictable memory explosions
The main server at my company has recently been having a lot of downtime. For reasons that neither I nor the other admins can determine, it has random (VERY sudden) explosions in memory. It becomes ...
1
vote
2answers
202 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 ...
7
votes
2answers
404 views
What governs the limits of shell brace expansion?
In this example I refer to the expansion of a sequence of integers, but perhaps(?) the limits would be relevant to all aspects of brace expansion.. This more general view is also of interest to me.
...
4
votes
3answers
1k views
Swap usage too high?
I have a debian sid box, freshly installed about a month ago, with no desktop apps running at the moment.
Any command I try to run (via ssh) makes the hard disk work very hard. The system worked ...
2
votes
3answers
158 views
Human readable system memory reading crom CLI?
On OS X, I get a nice human readable system memory reading like so:
printf -v system_memory \
"$(system_profiler SPHardwareDataType \
| awk -F ': ' '/^ +Memory: /{print $2}')"
...
2
votes
2answers
425 views
RAM usage doesn't add up? (Free+used < total)
Lately I've been noticing that my monitoring script which reads from /proc/meminfo and /proc/<pid> has been showing odd readings, where several hundred MB seem to be missing. htop is showing the ...
2
votes
1answer
362 views
What is the buffers column in the output from free?
These questions briefly list the format of the free command, noting that buffers is kernel memory that must be written out to disk and cache is file data that does not need to be written disk.
On my ...
2
votes
1answer
1k views
Mathematical connection between SZ RSS and VSZ in ps o/p?
I wanted to know what mathematical connection is there between the SZ, RSZ and VSZ output in ps output e.g.
ps -p 2363 -o sz,rss,vsz
1
vote
2answers
113 views
Monitor single process to logfile perodicly
Based on this question, I would like to log the performance of a specific process, with a frequency of say one second, to a csv (comma separated value) log file.
Something like:
...
