From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx115.postini.com [74.125.245.115]) by kanga.kvack.org (Postfix) with SMTP id 902EE6B0002 for ; Wed, 27 Mar 2013 01:16:17 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 96C6A3EE0BB for ; Wed, 27 Mar 2013 14:16:15 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 7934745DDCF for ; Wed, 27 Mar 2013 14:16:15 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 57FE645DE56 for ; Wed, 27 Mar 2013 14:16:15 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 376FB1DB8040 for ; Wed, 27 Mar 2013 14:16:15 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id CD5051DB8044 for ; Wed, 27 Mar 2013 14:16:14 +0900 (JST) Message-ID: <5152807D.5010905@jp.fujitsu.com> Date: Wed, 27 Mar 2013 14:15:41 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [RFC] mm: remove swapcache page early References: <1364350932-12853-1-git-send-email-minchan@kernel.org> In-Reply-To: <1364350932-12853-1-git-send-email-minchan@kernel.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Dan Magenheimer , Seth Jennings , Nitin Gupta , Konrad Rzeszutek Wilk , Shaohua Li (2013/03/27 11:22), Minchan Kim wrote: > Swap subsystem does lazy swap slot free with expecting the page > would be swapped out again so we can't avoid unnecessary write. > > But the problem in in-memory swap is that it consumes memory space > until vm_swap_full(ie, used half of all of swap device) condition > meet. It could be bad if we use multiple swap device, small in-memory swap > and big storage swap or in-memory swap alone. > > This patch changes vm_swap_full logic slightly so it could free > swap slot early if the backed device is really fast. > For it, I used SWP_SOLIDSTATE but It might be controversial. > So let's add Ccing Shaohua and Hugh. > If it's a problem for SSD, I'd like to create new type SWP_INMEMORY > or something for z* family. > > Other problem is zram is block device so that it can set SWP_INMEMORY > or SWP_SOLIDSTATE easily(ie, actually, zram is already done) but > I have no idea to use it for frontswap. > > Any idea? > Another thinking....in what case, in what system configuration, vm_swap_full() should return false and delay swp_entry freeing ? 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