Question [Q] internal memory size problem


I have rooted old phone with low internal storage and Link2SD installed.
The problem is, that even if I have almost all aplications linked (by Link2SD) to SD card, I've got low free space on internal storage.
I've executed "du -h -m -d 1" command to get sizes of all subfolders in "/data" folder (which I suppose is internal storage) and the results are in attached file.

Whole /data directory size is 297 MB.
/dalvik-cache + /sdext2 is 207 MB in total. Other folders' sizes are negligible.
My question is: Where is the difference of 297-207=90 MB?

Thanks for replies

Click image for larger version

Name:	Clipboard02.jpg
Views:	5
Size:	16.5 KB
ID:	2823428