From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 30 Nov 2006 10:39:33 -0800 (PST) From: Christoph Lameter Subject: Re: [RFC][PATCH 0/1] Node-based reclaim/migration In-Reply-To: <6599ad830611301035u36a111dfye8c9414d257ebe07@mail.gmail.com> Message-ID: 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> <6599ad830611300325h3269a185x5794b0c585d985c0@mail.gmail.com> <6599ad830611301035u36a111dfye8c9414d257ebe07@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Menage Cc: KAMEZAWA Hiroyuki , linux-mm@kvack.org, akpm@osdl.org List-ID: On Thu, 30 Nov 2006, Paul Menage wrote: > It sounds as though if we come across a page with page_mapcount() = 0 > while gathering pages for migration, it's probably in the process of > being swapped out and so is best not to muck around with anyway? F.e. A page cache page may have mapcount == 0. Mapcount 0 only means that the page is not mapped into any processes memory via a page table. It may be used for purposes that do not require mapping into a processes memory. If the reference count is zero (page freed) then page migration will discard the page and consider the migration a success. -- 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