Re: LANANA: To Pending Device Number Registrants

James Simmons
2001-05-15T18:37:28Z

> The only problem with mmap(): You cannot know, if the page
> changed under you a**.
>
> What would first mmap()ed page of the screen look like, if some
> accelerator wrote a line there? Invalidating all mmap()ed pages
> for each and every accelerator command would be evil. Forbidding
> reads of that page is evil, too.
>
> I have the same problem with DSPs, which like to mmap() some of
> their memory into the application, but can alter this memory
> every instruction the execute.

I know about this problem for some time :-( Unfortunely most cards don't
have OpenGL or some similar api on chip. Of course you don't have to
invalid all the mappings. Only the ones the accelerator affected. This
plus proper serialization could over come this.