Re: [PATCH/RFC] Shared page tables

Brian Twichell
2006-01-14T20:45:41Z

Phillip Susi wrote:

> Shouldn't those kind of applications already be using threads to share
> page tables rather than forking hundreds of processes that all mmap()
> the same file?
>
We're talking about sharing anonymous memory here, not files.

The feedback we've gotten on converting from a process-based to a
thread-based model is that it's a major undertaking,
when development and test expense is considered. It's understandable if
one considers that they'd probably want to convert
across on several operating systems at once to minimize the number of
source trees they have to maintain.

Also, the case for conversion isn't helped by the fact that at least two
prominent commercial UNIX flavors either inherently
share page tables, or provide an explicit memory allocation mechanism
that achieves page table sharing (e.g. Intimate Shared
Memory).

Cheers,
Brian