29 Sep
2021
29 Sep
'21
12:10 a.m.
On Tue, Sep 28, 2021 at 10:46:25AM -0700, Greg A. Woods wrote:
The "unix" nod to
single level storage by way of mmap() suffers from horribly bad design
and neglect.
I supported Xerox PARC when they were redoing their OS as a user space
application on SunOS 4.x. They used mmap() and protections to take
user level page faults. Yeah, there were bugs but that was ~30 years
ago.
In more recent times, BitKeeper used mmap() and protections to take the
same page faults (we implemented a compressed, XORed file storage that
filled in "pages" on demand, it was a crazy performance improvement)
and that worked on pretty much every Unix we tried it on. Certainly
worked on Linux first try.
So what is it about mmap you don't like?