From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 31 Jan 2008 02:19:49 -0800 From: Andrew Morton Subject: Re: [PATCH] mm: MADV_WILLNEED implementation for anonymous memory Message-Id: <20080131021949.92715ba4.akpm@linux-foundation.org> In-Reply-To: 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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: Peter Zijlstra , hugh@veritas.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, npiggin@suse.de, riel@redhat.com, mztabzr@0pointer.de, mpm@selenic.com List-ID: On Thu, 31 Jan 2008 11:15:08 +0100 Andi Kleen wrote: > 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. > Yeah, the 2.5 switch to physical scanning killed us there. I still don't know why my allocate-swapspace-according-to-virtual-address change didn't help. Much. Marcelo played with that a bit too. -- 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