From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755904AbbI1Gti (ORCPT ); Mon, 28 Sep 2015 02:49:38 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:51035 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755110AbbI1Gth (ORCPT ); Mon, 28 Sep 2015 02:49:37 -0400 Date: Sun, 27 Sep 2015 23:49:36 -0700 From: Christoph Hellwig To: Petros Koutoupis Cc: linux-kernel@vger.kernel.org, "devel@rapiddisk.org" Subject: Re: [PATCH] Patch to integrate RapidDisk and RapidCache RAM Drive / Caching modules into the kernel Message-ID: <20150928064936.GA22280@infradead.org> References: <1443374244.8013.7.camel@petros-ultrathin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1443374244.8013.7.camel@petros-ultrathin> User-Agent: Mutt/1.5.23 (2014-03-12) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 27, 2015 at 12:17:24PM -0500, Petros Koutoupis wrote: > Attached is a patch for two modules: RapidDisk & RapidCache. RapidDisk is a > Linux RAM drive module which allows the user to dynamically create, remove, > and resize RAM-based block devices. RapidDisk is designed to work with both > volatile and non-volatile memory. In the case of volatile memory, memory is > allocated only when needed. The RapidCache module in turn utilizes a RapidDisk > volume as a FIFO Write-Through caching node to a slower block device. Hi Petros, this is three things at the same time! We already have a ramdisk driver, a pmem drive, bcache and dm-cache, so for each of them please explain why we'd want to duplicate them instead of adding whatever features you need to them. First step is to identify those features.