Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758708AbXIRTbT (ORCPT ); Tue, 18 Sep 2007 15:31:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754662AbXIRTbG (ORCPT ); Tue, 18 Sep 2007 15:31:06 -0400 Received: from cantor.suse.de ([195.135.220.2]:42867 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754526AbXIRTbF (ORCPT ); Tue, 18 Sep 2007 15:31:05 -0400 Date: Tue, 18 Sep 2007 21:31:02 +0200 From: Andrea Arcangeli To: Goswin von Brederlow Cc: Mel Gorman , Andrew Morton , Joern Engel , Nick Piggin , Christoph Lameter , torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , William Lee Irwin III , David Chinner , Jens Axboe , Badari Pulavarty , Maxim Levitsky , Fengguang Wu , swin wang , totty.lu@gmail.com, hugh@veritas.com Subject: Re: [00/41] Large Blocksize Support V7 (adds memmap support) Message-ID: <20070918193102.GC7541@v2.random> References: <20070911060349.993975297@sgi.com> <200709110452.20363.nickpiggin@yahoo.com.au> <20070911121225.GE13132@lazybastard.org> <20070915014449.4f9cdb51.akpm@linux-foundation.org> <87ir6c3z2l.fsf@informatik.uni-tuebingen.de> <20070915155100.GA21861@v2.random> <20070916181504.GB16406@skynet.ie> <20070916185052.GG6708@v2.random> <87lkb643ug.fsf@informatik.uni-tuebingen.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lkb643ug.fsf@informatik.uni-tuebingen.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1386 Lines: 28 On Mon, Sep 17, 2007 at 12:56:07AM +0200, Goswin von Brederlow wrote: > When has free ever given any usefull "free" number? I can perfectly > fine allocate another gigabyte of memory despide free saing 25MB. But > that is because I know that the buffer/cached are not locked in. Well, as you said you know that buffer/cached are not locked in. If /proc/meminfo would be rubbish like you seem to imply in the first line, why would we ever bother to export that information and even waste time writing a binary that parse it for admins? > On the other hand 1GB can instantly vanish when I start a xen domain > and anything relying on the free value would loose. Actually you better check meminfo or free before starting a 1G of Xen!! > The only sensible thing for an application concerned with swapping is > to whatch the swapping and then reduce itself. Not the amount > free. Although I wish there were some kernel interface to get a > preasure value of how valuable free pages would be right now. I would > like that for fuse so a userspace filesystem can do caching without > cripling the kernel. Repeated drop caches + free can help. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/