From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id B94C76B004D for ; Tue, 7 Jul 2009 21:35:03 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n681doqN008069 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Wed, 8 Jul 2009 10:39:50 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 78C2745DE54 for ; Wed, 8 Jul 2009 10:39:50 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 575B145DE4E for ; Wed, 8 Jul 2009 10:39:50 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 3D9261DB8043 for ; Wed, 8 Jul 2009 10:39:50 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.249.87.105]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id E676F1DB803A for ; Wed, 8 Jul 2009 10:39:49 +0900 (JST) Date: Wed, 8 Jul 2009 10:38:07 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC][PATCH 3/4] get_user_pages READ fault handling special cases Message-Id: <20090708103807.ae17396a.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090708090344.aa54a008.kamezawa.hiroyu@jp.fujitsu.com> References: <20090707165101.8c14b5ac.kamezawa.hiroyu@jp.fujitsu.com> <20090707165950.7a84145a.kamezawa.hiroyu@jp.fujitsu.com> <20090708090344.aa54a008.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Linus Torvalds , "linux-mm@kvack.org" , npiggin@suse.de, "hugh.dickins@tiscali.co.uk" , avi@redhat.com, "akpm@linux-foundation.org" List-ID: On Wed, 8 Jul 2009 09:03:44 +0900 KAMEZAWA Hiroyuki wrote: > On Tue, 7 Jul 2009 09:50:19 -0700 (PDT) > Linus Torvalds wrote: > > And I think that if we resurrect zero-page, then we should do it with the > > modern equivalent of PAGE_RESERVED, namely the "pte_special()" bit. > > Anybody who walks page tables had better already handle special PTE > > entries (or we could trivially extend them - in case they currently just > > look at the vm_flags and decide that the range can have no special pages). > > > Hm, ok. I'll remove pte_zero and use pte_special instead of it. > Can I make a question ? As far as I know, - ZERO PAGE was not accounted as RSS (in 2.6.9 age) - ZERO PAGE was accounted as file_rss (until 2.6.24) Maybe this one is the change. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a= commitdiff;h=4294621f41a85497019fae64341aa5351a1921b7 Is there a special reason to have to account zero page as file_rss ? If not, pte_special() solution works well. (I think not necessary..) This was one reason I added pte_zero(). Thanks, -Kame -- 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