`mmap' questions

Angelo Ferrigno (aferrign@micronet.it)
Wed, 26 Jul 1995 08:38:12 +0200

First of all, thanks to all those that have worked on `mmap'-ing for Linux:
with kernel 1.3.11 it works wery well. I have, howewer, a couple of questions:

1) I have a 24 Meg machine, on which mmap-ing an 8 Meg file doesn't yield any
disk/swapping activity; after exiting a program using `mmap', it seems that
only the portion of the file corresponding to the last mmap-ed page is updated
(actually, I `mmap' an integral number of pages, which amount to 16 Meg, plus
a small fraction of a page, that should be translated by the mmap-ing
algorithm to a whole VM page; this is the part which is actually updated in
the disk file). Any idea about this strange behaviour?

2) Is there any syscall which performs the `msync' action? I just need to know
how to code a routine that uses SYSCALLx to perform msync-ing.

Angelo Ferrigno                        E-Mail: aferrign@micronet.it
IT Consultant                          Milan, Italy