From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030516AbWFIVXR (ORCPT ); Fri, 9 Jun 2006 17:23:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030513AbWFIVXR (ORCPT ); Fri, 9 Jun 2006 17:23:17 -0400 Received: from nz-out-0102.google.com ([64.233.162.194]:30603 "EHLO nz-out-0102.google.com") by vger.kernel.org with ESMTP id S1030517AbWFIVXQ (ORCPT ); Fri, 9 Jun 2006 17:23:16 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=MDXsx6S0RR5/Y7MfdqpSXCHDaWSI0b4KGK9qryXgH6kDOFrMXzC0/1ckiUmq6r+L3xssFAR46JOoGYpH2I6c+QTLLCGTNVwzgB1CqqxZwvtHcvP8FyP3hjGWcBWv+U3BQc+7JZ6X6kbAbASUH/L738VAfUvH1nnMQ/jOXKp2/yc= Message-ID: <305c16960606091423v58a9cf29xf61d37539e89915d@mail.gmail.com> Date: Fri, 9 Jun 2006 18:23:15 -0300 From: "Matheus Izvekov" To: "Lee Revell" Subject: Re: Idea about a disc backed ram filesystem Cc: "Horst von Brand" , "Sascha Nitsch" , "Linux Kernel Mailing List" In-Reply-To: <1149883402.3894.265.camel@mindpipe> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <305c16960606082159v2dc588abo6359d87173327c83@mail.gmail.com> <200606091343.k59DhC1f004434@laptop11.inf.utfsm.cl> <305c16960606090807g6372b69dy3167b0e191b2c113@mail.gmail.com> <1149878633.3894.224.camel@mindpipe> <305c16960606091227w7e62003bhef576fb07d0aa95@mail.gmail.com> <1149881504.3894.250.camel@mindpipe> <305c16960606091243h10638b2ayb7f1066bb839e496@mail.gmail.com> <1149883402.3894.265.camel@mindpipe> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 6/9/06, Lee Revell wrote: > Well, what you are trying to do seems hacky. What real world problem > are you trying to solve that setting swappiness to 0 is not sufficient > for? > > Lee For my usage, having processes swap is a complete loss. I have enough ram and if some process doesnt fits into ram i would rather have it killed than have it swap. Swap activity hogs my system and probably either the process would fill up the swap and die anyway or it would be too slow to be usable and i would kill it. But i have some processes which gain considerable performance benefit it they do their temporary work over tmpfs. The problem is that just sometimes, their temporary work just doesnt fit into ram. In that case swapping would be just fine. The simple dataformat on disk is a gain when the stuff you are working on doesnt need to survive unmounting/powerloss. Now ive considered two alternatives: 1) Creating a new filesystem, a very simple one which only stores the data in disk, and all the other stuff (superblock etc) is kept in kernel memory, and let pagecache do its work on keeping fresh stuff on ram. 2) Modifying tmpfs to accept a device, and when things dont fit in ram, they would be flushed to this device instead first, while there is space availiable, and then ultimately revert to swap when its present. It seems to me that both approaches would converge to the same thing, but 2 is better because there would be no functionality duplication, and it would get to keep the cool name