From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935697Ab0COHsZ (ORCPT ); Mon, 15 Mar 2010 03:48:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34532 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933904Ab0COHsY (ORCPT ); Mon, 15 Mar 2010 03:48:24 -0400 Message-ID: <4B9DE635.8030208@redhat.com> Date: Mon, 15 Mar 2010 09:48:05 +0200 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.8) Gecko/20100301 Fedora/3.0.3-1.fc12 Thunderbird/3.0.3 MIME-Version: 1.0 To: balbir@linux.vnet.ibm.com CC: KVM development list , Rik van Riel , KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" 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: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH][RF C/T/D] Unmapped page cache control - via boot parameter Date: Mon, 15 Mar 2010 09:48:05 +0200 Message-ID: <4B9DE635.8030208@redhat.com> References: <20100315072214.GA18054@balbir.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: KVM development list , Rik van Riel , KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" To: balbir@linux.vnet.ibm.com Return-path: In-Reply-To: <20100315072214.GA18054@balbir.in.ibm.com> Sender: owner-linux-mm@kvack.org List-Id: kvm.vger.kernel.org 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