Hello,

This is not a bug, but a feature/enhancement request.

Many databases (e.g. BDB) use "mmap()" to create a
memory cache.
The problem: the modified cache is constantly written
to mmaped-file on the harddisk.

On *BSD you simply use the flag MAP_NOSYNC for "mmap()".
The *BSD manpage:
NOSYNC: Causes data dirtied via this VM map to be flushed to
physical media only when necessary (usually by the pager)
rather then gratuitously.  Typically this prevents the update
daemons from flushing pages dirtied through such maps and thus
allows efficient sharing of memory across unassociated processes
using a file-backed shared memory map.

Maybe this would be also a great idea for linux?

Thanks
Marcus