From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48D2A392.6010308@goop.org> Date: Thu, 18 Sep 2008 11:53:06 -0700 From: Jeremy Fitzhardinge MIME-Version: 1.0 Subject: Re: Populating multiple ptes at fault time References: <48D142B2.3040607@goop.org> <48D1625C.7000309@redhat.com> <48D17A93.4000803@goop.org> <48D29AFB.5070409@linux-foundation.org> In-Reply-To: <48D29AFB.5070409@linux-foundation.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Chris Snook , Nick Piggin , Hugh Dickens , Linux Memory Management List , Linux Kernel Mailing List , Avi Kivity , Andrew Morton , Rik van Riel , "Martin J. Bligh" List-ID: Christoph Lameter wrote: > I had a patch like that a couple of years back but it was not accepted. > > http://www.kernel.org/pub/linux/kernel/people/christoph/prefault/ > > http://readlist.com/lists/vger.kernel.org/linux-kernel/14/70942.html > > http://www.ussg.iu.edu/hypermail/linux/kernel/0503.1/1292.html > > Thanks, that was exactly what I was hoping to see. I didn't see any definitive statements against the patch set, other than a concern that it could make things worse. Was the upshot that no consensus was reached about how to detect when its beneficial to preallocate anonymous pages? Martin, in that thread you mentioned that you had tried pre-populating file-backed mappings as well, but "Mmmm ... we tried doing this before for filebacked pages by sniffing the pagecache, but it crippled forky workloads (like kernel compile) with the extra cost in zap_pte_range, etc. ". Could you describe, or have a pointer to, what you tried and how it turned out? Did you end up populating so many (unused) ptes that zap_pte_range needed to do lots more work? Christoph (and others): do you think vm changes in the last 4 years would have changed the outcome of these results? Thanks, J -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org