Re: Memory usage on debian

[Isaac To <kkto@csis.hku.hk>]

>>>>> "Colin" == Colin Watson <cjwatson@debian.org> writes:

>   quaternion:~$ free
>                total       used       free     shared    buffers     cached
>   Mem:        256104     251680       4424          0      67536      66640
>   -/+ buffers/cache:     117504     138600
>   Swap:            0          0          0
>   quaternion:~$ ./src/crap 
>   zsh: killed     ./src/crap
>   quaternion:~$ free
>                total       used       free     shared    buffers     cached
>   Mem:        256104      59900     196204          0       6828      13932
>   -/+ buffers/cache:      39140     216964
>   Swap:            0          0          0

    Colin> The usual cause of this one is as follows: to start with, you
    Colin> have a fairly quiet system with lots of data in the kernel's
    Colin> cache - see the 'buffers' and 'cached' entries - held there
    Colin> against the possibility that it will be needed in the
    Colin> future.

Hm... then why the numbers after "-/+ buffers/cache" can decrease (by nearly
80M) after running such crap?  There is no swap, so nothing can migrate
there.  Perhaps some clean mmapped pages are simply removed from memory?
(Does Linux do that?)  I simply can't tell for sure.

Regards,
Isaac.