lkml.org 
[lkml]   [2004]   [Feb]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Active Memory Defragmentation: Our implementation & problems
From
Date
On Wed, 2004-02-04 at 10:54, Alok Mooley wrote:
> --- Dave Hansen <haveblue@us.ibm.com> wrote:
>
> > The "work until we get interrupted and restart if
> > something changes
> > state" approach is very, very common. Can you give
> > some more examples
> > of just how a page fault would ruin the defrag
> > process?
> >
>
> What I mean to say is that if we have identified some
> pages for movement, & we get preempted, the pages
> identified as movable may not remain movable any more
> when we are rescheduled. We are left with the task of
> identifying new movable pages.

Depending on the quantity of work that you're trying to do at once, this
might be unavoidable.

I know it's a difficult thing to think about, but I still don't
understand the precise cases that you're concerned about. Page faults
to me seem like the least of your problems. A bigger issue would be if
the page is written to by userspace after you copy, but before you
install the new pte. Did I miss the code in your patch that invalidated
the old tlb entries?

--dave

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

\
 
 \ /
  Last update: 2005-03-22 14:00    [W:0.069 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site