Re: Concerning a post that you made about expandable anonymous shared mappings

[Stas Sergeev <stsp@aknet.ru>]

Hello.

William Tambe wrote:
> And it just doesn't make sens to have mmap() map ANONYMOUS shared memory 
> and mremap() not to expand it and make the expanded area available.
I agree with this, but the argument against
that approach was that then you can only
enlarge the backing-store, but never shrink.
I personally think it is a valid argument,
even though the problem is probably not very
important.
Also, you can't expand the SysV SHM with mremap
just as well - it will give you a SIGBUS too IIRC.
So for that discussion of 2004, I lost the
battle and was convinced that the proposed
approach is not very good...

> Would you happen to know how I can work around that issue for now, and 
> make writing in an expended area not to generate a Bus error?
Have you tried the Posix SHM instead? It works
very well for me. Back in 2004 the glibc had
bugs, so I couldn't easily use posix shm and
was thinking about the different approaches.
But now it should suffice.