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 4040B6B01F1 for ; Thu, 26 Aug 2010 06:21:56 -0400 (EDT) Received: by iwn33 with SMTP id 33so1936534iwn.14 for ; Thu, 26 Aug 2010 03:21:55 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1282817160.1975.476.camel@laptop> References: <1282310110.2605.976.camel@laptop> <20100825155814.25c783c7.akpm@linux-foundation.org> <20100825173125.0855a6b0@bike.lwn.net> <1282810811.1975.246.camel@laptop> <1282817160.1975.476.camel@laptop> Date: Thu, 26 Aug 2010 19:21:55 +0900 Message-ID: Subject: Re: [PATCH/RFCv4 0/6] The Contiguous Memory Allocator framework From: Minchan Kim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: Jonathan Corbet , Andrew Morton , Michal Nazarewicz , linux-mm@kvack.org, Daniel Walker , FUJITA Tomonori , Hans Verkuil , Konrad Rzeszutek Wilk , Kyungmin Park , Marek Szyprowski , Mark Brown , Pawel Osciak , Russell King , Zach Pfeffer , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, Mel Gorman List-ID: On Thu, Aug 26, 2010 at 7:06 PM, Peter Zijlstra wrote: > On Thu, 2010-08-26 at 18:29 +0900, Minchan Kim wrote: >> As I said following mail, I said about free space problem. >> Of course, compaction could move anon pages into somewhere. >> What's is somewhere? At last, it's same zone. >> It can prevent fragment problem but not size of free space. >> So I mean it would be better to move it into another zone(ex, HIGHMEM) >> rather than OOM kill. > > Real machines don't have highmem, highmem sucks!! /me runs It's another topic. I agree highmem isn't a gorgeous. But my desktop isn't real machine? Important thing is that we already have a highmem and many guys include you(kmap stacking patch :))try to improve highmem problems. :) > > Does cross zone movement really matter, I though these crappy devices > were mostly used on crappy hardware with very limited memory, so pretty > much everything would be in zone_normal.. no? No. Until now, many embedded devices have used to small memory. In that case, only there is a DMA zone in system. But as I know, mobile phone starts to use big(?) memory like 1G or above sooner or later. So they starts to use HIGHMEM. Otherwise, 2G/2G space configuration. Some embedded device uses many thread model to port easily from RTOS. In that case, they don't have enough address space for application if it uses 2G/2G model. So we should care of HIGHMEM in embedded system from now on. > > But sure, if there's really a need we can look at maybe doing cross zone > movement. > -- Kind regards, Minchan Kim -- 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