restore(8) && used memory not freed-up

[Trond Endrestøl]

On Fri, 24 Jan 2014 11:32+0100, Matthias Apitz wrote:

> Hello,
> 
> I was restoring some files which I removed while updating from KDE3 to
> KDE4 and encountered the following interesting problem:
> 
> # mount -o ro /dev/da1s1a /mnt
> # cd /tmp
> # restore -x -f /mnt/Tiny/dumpsTiny-20131025/usrLocal.dmp ./guru/.kde/share/apps/knode
> 
> after the restore was finished(!) the memory in top was shown as:
> 
> Mem: 535M Active, 1136M Inact, 270M Wired, 28M Cache, 90M Buf, 14M Free
> 
> only the unmount of the device freed-up the memory:
> 
> # umount /mnt
> 
> Mem: 535M Active, 46M Inact, 192M Wired, 8104K Cache, 90M Buf, 1203M Free
> 
> Why is the memory reserved by the system (10-CURRENT, i386)?

I assume you're referring to the amount of inactive pages. These are 
freed pages ready for consumption by other processes, however their 
contents has not been overwritten and they can thus be reactivated 
without any disk activity. Once you unmounted the filesystem, the 
contents of these inactive pages became invalid and the pages were 
moved to the free list.

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