From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 9E0206B00B2 for ; Wed, 4 Mar 2009 23:57:39 -0500 (EST) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN; charset=US-ASCII Received: from xanadu.home ([66.131.194.97]) by VL-MH-MR002.ip.videotron.ca (Sun Java(tm) System Messaging Server 6.3-4.01 (built Aug 3 2007; 32bit)) with ESMTP id <0KG000GSLOG1IE91@VL-MH-MR002.ip.videotron.ca> for linux-mm@kvack.org; Wed, 04 Mar 2009 23:57:38 -0500 (EST) Date: Wed, 04 Mar 2009 23:57:37 -0500 (EST) From: Nicolas Pitre Subject: Re: [RFC] atomic highmem kmap page pinning In-reply-to: <20090305132054.888396da.minchan.kim@barrios-desktop> Message-id: References: <20090304171429.c013013c.minchan.kim@barrios-desktop> <20090305080717.f7832c63.minchan.kim@barrios-desktop> <20090305132054.888396da.minchan.kim@barrios-desktop> Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: lkml , linux-mm@kvack.org, Russell King - ARM Linux List-ID: On Thu, 5 Mar 2009, Minchan Kim wrote: > On Wed, 04 Mar 2009 21:37:43 -0500 (EST) > Nicolas Pitre wrote: > > > My assertion is that the cost is negligible. This is why I'm asking you > > why you think this is a big cost. > > Of course, I am not sure whether it's big cost or not. > But I thought it already is used in many fs, driver. > so, whether it's big cost depends on workload type . > > However, This patch is needed for VIVT and no coherent cache. > Is right ? > > If it is right, it will add unnessary overhead in other architecture > which don't have this problem. > > I think it's not desirable although it is small cost. > If we have a other method which avoids unnessary overhead, It would be better. > Unfortunately, I don't have any way to solve this, now. OK. What about this patch then: