Re: Adaptive thread creation by the kernel

[Alan Cox]

> > 	if (mincore(map, readlength, vec))
> > 		perror("mincore");
> > 
> > the vec[] contains a byte for each page you queried.  each byte has value 
> > "1" if the page is already in memory, otherwise "0".
> 
> You do a syscall every time you're going to read part of a file?
> How do you ensure it's still there by the time you actually read it?

It might not be,

> How do you force the page in when it's not in memory -- spawn
> another thread?

Bingo. Thats how the hacked thttpd uses mincore - a way to ask the kernel if
it should go making threads for this request