From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 28CA26B01AF for ; Mon, 15 Mar 2010 03:48:13 -0400 (EDT) Message-ID: <4B9DE635.8030208@redhat.com> Date: Mon, 15 Mar 2010 09:48:05 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [PATCH][RF C/T/D] Unmapped page cache control - via boot parameter References: <20100315072214.GA18054@balbir.in.ibm.com> In-Reply-To: <20100315072214.GA18054@balbir.in.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: balbir@linux.vnet.ibm.com Cc: KVM development list , Rik van Riel , KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" List-ID: On 03/15/2010 09:22 AM, Balbir Singh wrote: > Selectively control Unmapped Page Cache (nospam version) > > From: Balbir Singh > > This patch implements unmapped page cache control via preferred > page cache reclaim. The current patch hooks into kswapd and reclaims > page cache if the user has requested for unmapped page control. > This is useful in the following scenario > > - In a virtualized environment with cache!=none, we see > double caching - (one in the host and one in the guest). As > we try to scale guests, cache usage across the system grows. > The goal of this patch is to reclaim page cache when Linux is running > as a guest and get the host to hold the page cache and manage it. > There might be temporary duplication, but in the long run, memory > in the guests would be used for mapped pages. > Well, for a guest, host page cache is a lot slower than guest page cache. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- 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