From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753294Ab0E3SPz (ORCPT ); Sun, 30 May 2010 14:15:55 -0400 Received: from mail-px0-f174.google.com ([209.85.212.174]:54571 "EHLO mail-px0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752736Ab0E3SPy (ORCPT ); Sun, 30 May 2010 14:15:54 -0400 Message-ID: <4C02AB5A.5000706@vflare.org> Date: Sun, 30 May 2010 23:45:54 +0530 From: Nitin Gupta Reply-To: ngupta@vflare.org User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-3.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Dan Magenheimer CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jeremy@goop.org, hugh.dickins@tiscali.co.uk, JBeulich@novell.com, chris.mason@oracle.com, kurt.hackel@oracle.com, dave.mccracken@oracle.com, npiggin@suse.de, akpm@linux-foundation.org, riel@redhat.com, avi@redhat.com, pavel@ucw.cz, konrad.wilk@oracle.com Subject: Re: [PATCH V2 0/4] Frontswap (was Transcendent Memory): overview References: <20100528174020.GA28150@ca-server1.us.oracle.com> In-Reply-To: <20100528174020.GA28150@ca-server1.us.oracle.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/28/2010 11:10 PM, Dan Magenheimer wrote: > [PATCH V2 0/4] Frontswap (was Transcendent Memory): overview > > Changes since V1: > - Rebased to 2.6.34 (no functional changes) > - Convert to sane types (per Al Viro comment in cleancache thread) > - Define some raw constants (Konrad Wilk) > - Performance analysis shows significant advantage for frontswap's > synchronous page-at-a-time design (vs batched asynchronous speculated > as an alternative design). See http://lkml.org/lkml/2010/5/20/314 > I think zram (http://lwn.net/Articles/388889/) is a more generic solution and can also achieve swap-to-hypervisor as a special case. zram is a generic in-memory compressed block device. To get frontswap functionality, such a device (/dev/zram0) can be exposed to a VM as a 'raw disk'. Such a disk can be used for _any_ purpose by the guest, including use as a swap disk. This method even works for Windows guests. Please see: http://www.vflare.org/2010/05/compressed-ram-disk-for-windows-virtual.html Here /dev/zram0 of size 2GB was created and exposed to Windows VM as a 'raw disk' (using VirtualBox). This disk was detected in the guest and NTFS filesystem was created on it (Windows cannot swap directly to a partition; it always uses swap file(s)). Then Windows was configured to swap over a file in this drive. Obviously, the same can be done with Linux guests. Thus, zram is useful in both native and virtualized environments with different use cases. Thanks, Nitin 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 C364C6B01BD for ; Sun, 30 May 2010 14:15:55 -0400 (EDT) Received: by pzk28 with SMTP id 28so3163718pzk.11 for ; Sun, 30 May 2010 11:15:53 -0700 (PDT) Message-ID: <4C02AB5A.5000706@vflare.org> Date: Sun, 30 May 2010 23:45:54 +0530 From: Nitin Gupta Reply-To: ngupta@vflare.org MIME-Version: 1.0 Subject: Re: [PATCH V2 0/4] Frontswap (was Transcendent Memory): overview References: <20100528174020.GA28150@ca-server1.us.oracle.com> In-Reply-To: <20100528174020.GA28150@ca-server1.us.oracle.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Dan Magenheimer Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jeremy@goop.org, hugh.dickins@tiscali.co.uk, JBeulich@novell.com, chris.mason@oracle.com, kurt.hackel@oracle.com, dave.mccracken@oracle.com, npiggin@suse.de, akpm@linux-foundation.org, riel@redhat.com, avi@redhat.com, pavel@ucw.cz, konrad.wilk@oracle.com List-ID: On 05/28/2010 11:10 PM, Dan Magenheimer wrote: > [PATCH V2 0/4] Frontswap (was Transcendent Memory): overview > > Changes since V1: > - Rebased to 2.6.34 (no functional changes) > - Convert to sane types (per Al Viro comment in cleancache thread) > - Define some raw constants (Konrad Wilk) > - Performance analysis shows significant advantage for frontswap's > synchronous page-at-a-time design (vs batched asynchronous speculated > as an alternative design). See http://lkml.org/lkml/2010/5/20/314 > I think zram (http://lwn.net/Articles/388889/) is a more generic solution and can also achieve swap-to-hypervisor as a special case. zram is a generic in-memory compressed block device. To get frontswap functionality, such a device (/dev/zram0) can be exposed to a VM as a 'raw disk'. Such a disk can be used for _any_ purpose by the guest, including use as a swap disk. This method even works for Windows guests. Please see: http://www.vflare.org/2010/05/compressed-ram-disk-for-windows-virtual.html Here /dev/zram0 of size 2GB was created and exposed to Windows VM as a 'raw disk' (using VirtualBox). This disk was detected in the guest and NTFS filesystem was created on it (Windows cannot swap directly to a partition; it always uses swap file(s)). Then Windows was configured to swap over a file in this drive. Obviously, the same can be done with Linux guests. Thus, zram is useful in both native and virtualized environments with different use cases. Thanks, Nitin -- 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