Re: [RFC] kernel facilities for cache prefetching

[Andi Kleen]

Linus Torvalds <torvalds@xxxxxxxx> writes:
> 
> The downsides basically boil down to the fact that it's not as clearly 
> just one single point. You can't just look at the request queue and see 
> what physical requests go out.

The other problem is that readpages has no idea about the layout
of the disk so just doing it dumbly might end up with a lot of seeking.

I suppose you would at least need some tweaks to the scheduler to make
sure it doesn't give these reads any priority and keeps them in the
queue long enough to get real good sorting and large requests.

Problem is that this would likely need to be asynchronous to be any
useful unless you were willing to block a thread for a potentially
long time for each file to be prefetched.

-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/