Re: [RFC] recursive pagetables for x86 PAE

From: Dave Hansen (
Date: Sat Jun 14 2003 - 12:49:57 EST

On Sat, 2003-06-14 at 04:27, Oliver Neukum wrote:
> Am Freitag, 13. Juni 2003 23:47 schrieb Dave Hansen:
> > The following patches implement something which we like to call UKVA.
> > It's a Kernel Virtual Area which is private to a process, just like
> > Userspace. You can put any process-local data that you want in the
> > area. But, for now, I just put PTE pages in there.
> If you put only such pages there, do you really want that memory to
> be per task? IMHO it should be per memory context to aid threading
> performance.

I think you're confusing what I mean by tasks and processes. A task is
something with a task_struct and a kernel stack. A process is a single
task, or multiple tasks that share an mm. If things share an mm, they
share pagetables implicitly. Per-process _is_ per memory context.

> Secondly, doesn't this scream for using large pages?

Large pages aren't used for generic user memory at all. That would take
some serious surgery. (Don't get Bill started on it :)

Dave Hansen

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