From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4642C416.3000205@yahoo.com.au> Date: Thu, 10 May 2007 17:04:54 +1000 From: Nick Piggin MIME-Version: 1.0 Subject: Re: swap-prefetch: 2.6.22 -mm merge plans References: <20070430162007.ad46e153.akpm@linux-foundation.org> <200705100928.34056.kernel@kolivas.org> <464261B5.6030809@yahoo.com.au> <200705101134.34350.kernel@kolivas.org> <46427BDB.30004@yahoo.com.au> <2c0942db0705092048m38b36e7fo3a7c2c59fe1612b2@mail.gmail.com> <46429801.8030202@yahoo.com.au> <2c0942db0705092252n13a6a79aq39f13fcfae534de2@mail.gmail.com> In-Reply-To: <2c0942db0705092252n13a6a79aq39f13fcfae534de2@mail.gmail.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Ray Lee Cc: Con Kolivas , Ingo Molnar , ck list , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Ray Lee wrote: > On 5/9/07, Nick Piggin wrote: > >> Ray Lee wrote: >> > On 5/9/07, Nick Piggin wrote: >> > >> >> You said it helped with the updatedb problem. That says we should >> look at >> >> why it is going bad first, and for example improve use-once >> algorithms. >> >> After we do that, then swap prefetching might still help, which is >> fine. >> > >> > Nick, if you're volunteering to do that analysis, then great. If not, >> > then you're just providing a airy hope with nothing to back up when or >> > if that work would ever occur. >> >> I'd like to try helping. Tell me your problem. > > > Huh? You already stated one version of it above, namely updatedb. But So a swapping problem with updatedb should be unusual and we'd like to see if we can fix it without resorting to prefetching. I know the theory behind swap prefetching, and I'm not saying it doesn't work, so I'll snip the rest of that. >> What's wrong with the use-once we have? What improvements are you talking >> about? > > > You said, effectively: "Use-once could be improved to deal with > updatedb". I said I've been reading emails from Rik and others talking > about that for four years now, and we're still talking about it. Were > it merely updatedb, I'd say us userspace folk should step up and > rewrite the damn thing to amortize its work. However, I and others > feel it's only an example -- glaring, obviously -- of a more pervasive > issue. A small issue, to be sure!, but an issue nevertheless. It isn't going to get fixed unless people complain about it. If you cover the use-once problem with swap prefetching, then it will never get fixed. >> I don't think it is about energy or being mean, I'm just stating the >> issues I have with it. > > > Nick, I in no way think you're being mean, and I'm sorry if I've given > you that impression. However, if you're just stating the issues you > have with it, then can I assume that you won't lobby against having > this experiment merged? Anybody is free to merge anything into their kernel. And if somebody asks for my issues with the swap prefetching patch, then I'll give them :) -- SUSE Labs, Novell Inc. -- 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