From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 17 Nov 2008 14:03:04 +1100 Message-ID: <87skpryryv.wl%peter@chubb.wattle.id.au> From: Peter Chubb In-Reply-To: <200811141835.17073.nickpiggin@yahoo.com.au> References: <491C61B1.10005@goop.org> <200811141417.35724.nickpiggin@yahoo.com.au> <491D0B2F.7050900@goop.org> <200811141835.17073.nickpiggin@yahoo.com.au> MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Subject: Re: [PATCH 1/2] mm: implement remap_pfn_range with apply_to_page_range Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Jeremy Fitzhardinge , Andrew Morton , Linux Memory Management List , Linux Kernel Mailing List , "Pallipadi, Venkatesh" List-ID: >>>>> "Nick" == Nick Piggin writes: Nick> It's not meant to be pluggable. Actually this came up last I Nick> think when the UNSW wanted to add page table accessors to Nick> abstract this. They came up with a good set of things, but in Nick> the end you can't justify slowing things down in these paths Nick> unless you actually have a replacement page table structure that Nick> gets you a *net win*. So far, I haven't heard from them again. We tried hard. The slowdown wasn't all that much on system benchmarks, but you could see it on the microbenchmarks. And it made stuff a LOT cleaner. We wanted it to put super-page friendly pagetables in for architectures not wedded to the 3/4 level x86 pagetable hardware format. The people I had working on this left (finished a masters, finished a PhD, contract ran out and no more money), and I haven't had the manpower to maintain the patchset, especially after the negative responses we got from linux-MM. -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au http://www.ertos.nicta.com.au ERTOS within National ICT Australia -- 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