From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zps75.corp.google.com (zps75.corp.google.com [172.25.146.75]) by smtp-out.google.com with ESMTP id kAUBPVXP001889 for ; Thu, 30 Nov 2006 03:25:33 -0800 Received: from nf-out-0910.google.com (nfbc31.prod.google.com [10.48.79.31]) by zps75.corp.google.com with ESMTP id kAUBOvuN027105 for ; Thu, 30 Nov 2006 03:25:21 -0800 Received: by nf-out-0910.google.com with SMTP id c31so4992930nfb for ; Thu, 30 Nov 2006 03:25:21 -0800 (PST) Message-ID: <6599ad830611300325h3269a185x5794b0c585d985c0@mail.gmail.com> Date: Thu, 30 Nov 2006 03:25:21 -0800 From: "Paul Menage" Subject: Re: [RFC][PATCH 0/1] Node-based reclaim/migration In-Reply-To: <20061130201232.7d5f5578.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20061129030655.941148000@menage.corp.google.com> <20061130093105.d872c49d.kamezawa.hiroyu@jp.fujitsu.com> <6599ad830611291631hd6d3e52y971c35708004db00@mail.gmail.com> <6599ad830611300245s5c0f40bdu4231832930e9c023@mail.gmail.com> <20061130201232.7d5f5578.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: clameter@sgi.com, linux-mm@kvack.org, akpm@osdl.org List-ID: On 11/30/06, KAMEZAWA Hiroyuki wrote: > > > How does kswapd do this safely? > > > kswapd doesn't touches page->mapping after page_mapcount() goes down to 0. OK, so we could do the same, and just assume that pages with a page_mapcount() of 0 are either about to be freed or can be picked up on a later migration sweep. Is it common for a page to have a 0 page_mapcount() for a long period of time without being freed or remapped? > > I think one of the biggest concern will be performance impact. And this will > touch objrmap core, it is good to start discussion with a patch. > I'll have a go. My initial thought is that the only performance impact on the rmap core would be that unlink_anon_vma() would need one extra check when determining whether to free an anon_vma Paul -- 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