Re: [patch][rfc] 2.6.23-rc1 mm: NUMA replicated pagecache

[Lee Schermerhorn <Lee.Schermerhorn@hp.com>]

On Mon, 2007-07-30 at 05:16 +0200, Nick Piggin wrote:
> On Fri, Jul 27, 2007 at 10:30:47AM -0400, Lee Schermerhorn wrote:
> > On Fri, 2007-07-27 at 10:42 +0200, Nick Piggin wrote:
> > > Hi,
> > > 
> > > Just got a bit of time to take another look at the replicated pagecache
> > > patch. The nopage vs invalidate race and clear_page_dirty_for_io fixes
> > > gives me more confidence in the locking now; the new ->fault API makes
> > > MAP_SHARED write faults much more efficient; and a few bugs were found
> > > and fixed.
> > > 
> > > More stats were added: *repl* in /proc/vmstat. Survives some kbuilding
> > > tests...
> > > 
> > > --
> > > 
> > > Page-based NUMA pagecache replication.
> > <snip really big patch!>
> > 
> > Hi, Nick.
> > 
> > Glad to see you're back on this.  It's been on my list, but delayed by
> > other patch streams...
> 
> Yeah, thought I should keep it alive :) Patch is against 2.6.23-rc1.

D'Oh!  :-(  You could have just said "Read the subject line, Lee!"
> 
>  
> > As I mentioned to you in prior mail, I want to try to integrate this
> > atop my "auto/lazy migration" patches, such that when a task moves to a
> > new node, we remove just that task's pte ref's to page cache pages
> > [along with all refs to anon pages, as I do now] so that the task will
> > take a fault on next touch and either use an existing local copy or
> > replicate the page at that time.  Unfortunately, that's in the queue
> > behind the memoryless node patches and my stalled shared policy patches,
> > among other things :-(.
> 
> That's OK. It will likely be a long process to get any of this in...
> As you know, replicated currently needs some of your automigration
> infrastructure in order to get ptes pointing to the right places
> after a task migration. I'd like to try some experiments with them on
> a larger system, once you get time to update your patchset...

I'll try to make a pass this week, maybe next...

Lee