From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765910AbYAaKP0 (ORCPT ); Thu, 31 Jan 2008 05:15:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754715AbYAaKPM (ORCPT ); Thu, 31 Jan 2008 05:15:12 -0500 Received: from mx1.suse.de ([195.135.220.2]:50898 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754196AbYAaKPL (ORCPT ); Thu, 31 Jan 2008 05:15:11 -0500 To: Peter Zijlstra Cc: Andrew Morton , hugh@veritas.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, npiggin@suse.de, riel@redhat.com, mztabzr@0pointer.de, mpm@selenic.com Subject: Re: [PATCH] mm: MADV_WILLNEED implementation for anonymous memory From: Andi Kleen References: <1201714139.28547.237.camel@lappy> <20080130144049.73596898.akpm@linux-foundation.org> <1201769040.28547.245.camel@lappy> <20080131011227.257b9437.akpm@linux-foundation.org> <1201772118.28547.254.camel@lappy> <20080131014702.705f1040.akpm@linux-foundation.org> <1201773206.28547.259.camel@lappy> Date: Thu, 31 Jan 2008 11:15:08 +0100 In-Reply-To: <1201773206.28547.259.camel@lappy> (Peter Zijlstra's message of "Thu\, 31 Jan 2008 10\:53\:26 +0100") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > > Ah, that is Lennarts Pulse Audio thing, he has samples in memory which > might not have been used for a while, and he wants to be able to > pre-fetch those when he suspects they might need to be played. So that > once the audio thread comes along and stuffs them down /dev/dsp its all > nice in memory. The real problem that seems to make swapping so slow is that the data tends to be badly fragmented on the swap partition. I suspect if that problem was attached the need for such prefetching would be far less because swap in would be much faster. -Andi